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Nerve Fibres (nerve + fibre)
Kinds of Nerve Fibres Terms modified by Nerve Fibres Selected AbstractsDevelopment of Galanin-Containing Nerve Fibres in Rat TibiaANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009M. Gajda Summary Galanin exerts tonic inhibition of nociceptive input to the central nervous system. Recently, this peptide was demonstrated in several neuronal and non-neuronal structures in bones and joints. In this study, the time of appearance and topographic localization of galanin-containing nerve fibres in bone were studied in rats from gestational day 16 (GD16) to postnatal day 21 (PD21). The tibia was chosen as a model of developing long bone and indirect immunofluorescence combined with confocal laser scanning microscopy was used to identify galanin-immunoreactive (GAL-IR) nerve fibres. The earliest, sparse GAL-IR fibres were observed on GD21 in the perichondrium of both epiphyses and in the periosteum of the diaphysis. From PD1 onwards, GAL-IR fibres were also seen in the bone marrow cavity and in the region of the inter-condylar eminence of the knee joint. Intramedullary GAL-IR fibres in proximal and distal metaphyses appeared around PD1. Some of them accompanied blood vessels, although free fibres were also seen. GAL-IR fibres located in the cartilage canals of both epiphyses were observed from PD7, in the secondary ossification centres from PD10 and in the bone marrow of both epiphyses from PD14. The time course and localization of galanin-containing nerve fibres resemble the development of substance P- and CGRP-expressing nerve fibres, thus suggesting their sensory origin. [source] Postnatal downregulation of inhibitory neuromuscular transmission to the longitudinal muscle of the guinea pig ileumNEUROGASTROENTEROLOGY & MOTILITY, Issue 9 2009X. Bian Abstract, Neuromuscular transmission is crucial for normal gut motility but little is known about its postnatal maturation. This study investigated excitatory/inhibitory neuromuscular transmission in vitro using ileal nerve-muscle preparations made from neonatal (,48 h postnatal) and adult (,4 months postnatal) guinea pigs. In tissues from neonates and adults, nicotine (0.3,30 ,mol L,1) contracted longitudinal muscle preparations in a tetrodotoxin (TTX) (0.3 ,mol L,1)-sensitive manner. The muscarinic receptor antagonist, scopolamine (1 ,mol L,1), reduced substantially nicotine-induced contractions in neonatal tissues but not adult tissues. In the presence of N, -nitro- l -arginine (NLA, 100 ,mol L,1) to block nitric oxide (NO) mediated inhibitory neuromuscular transmission, scopolamine-resistant nicotine-induced contractions were revealed in neonatal tissues. NLA enhanced the nicotine-induced contractions in neonatal but not in adult tissues. Electrical field stimulation (20 V; 0.3 ms; 5,25 Hz, scopolamine 1 ,mol L,1 present) caused NLA and TTX-sensitive longitudinal muscle relaxations. Frequency,response curves in neonatal tissues were left-shifted compared with those obtained in adult tissues. Immunohistochemical studies revealed that NO synthase (NOS)-immunoreactivity (ir) was present in nerve fibres supplying the longitudinal muscle in neonatal and adult tissues. However, quantitative studies demonstrated that fluorescence intensity of NOS-ir nerve fibres was higher in neonatal than adult tissues. Nerve fibres containing substance P were abundant in longitudinal muscle in adult but not in neonatal tissues. Inhibitory neuromuscular transmission is relatively more effective in the neonatal guinea pig small intestine. Delayed maturation of excitatory motor pathways might contribute to paediatric motility disturbances. [source] In vitro model for penetration of sensory nerve fibres on a Matrigel basement membrane: implications for possible application to intractable pruritusBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2009M. Tominaga Summary Background, Epidermal hyperinnervation occurs in dermatoses with intractable pruritus, such as atopic dermatitis, suggesting that the hyperinnervation is partly responsible for abnormal itch perception. Objectives, To investigate the mechanisms of penetration of sensory nerve fibres into the basement membrane of the skin. Methods, A rat dorsal root ganglion neurone culture system consisting of Matrigel and a Boyden chamber containing a nerve growth factor (NGF) concentration gradient was used. In some experiments, matrix metalloproteinase (MMP) blockers and semaphorin 3A (Sema3A) were added to the culture system. Matrigel-coated membranes were stained with anti-Tau antibody, and the number of nerve fibres that crossed the membrane was counted. Expression of MMPs in the cultured neurones was examined at mRNA and protein levels by quantitative reverse transcription,polymerase chain reaction and immunocytochemistry, respectively. The activity was also examined by zymography. Results, Nerve fibres penetrated into Matrigel in the presence of an NGF concentration gradient, which was dose-dependently inhibited by GM6001, a broad-spectrum MMP inhibitor. Transcripts for MMP2, but not MMP9, were increased in the cultured neurones, and the penetration was dose-dependently inhibited by MMP-2 blockers. MMP-2 and its activity were partially localized on the NGF-responsive growth cones. NGF also upregulated pro-MMP-2 activation molecules in the cultured neurones. Sema3A stimulation showed the opposite effects on these NGF-dependent events. Interestingly, MMP2 expression was modulated by extracellular matrix (ECM) substrates for this enzyme. Conclusions, Membrane-associated MMP-2 contributes to penetration of nerve fibres into Matrigel through modulation by axonal guidance molecules and/or ECM. These findings provide insight for understanding the development of intractable pruritus involving epidermal nerve density. [source] Suppression of neural activity of bronchial irritant receptors by surface-active phospholipid in comparison with topical drugs commonly prescribed for asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2000Hills Background Much indirect evidence has been put forward previously in support of the concept that surface-active phospholipid (SAPL) normally masks irritant receptors in the lungs and upper respiratory tract; but this physical barrier is deficient in asthmatics, imparting hyperresponsiveness of the bronchoconstrictor reflex. Objective To determine whether exogenous SAPL applied to bronchial mucosa reduces the sensitivity of irritant receptors to a standard challenge used clinically to diagnose asthma and to compare the effects with those of corticosteroids and ,-stimulation. Methods Nerve fibres in the vagi were monitored to record action potentials from irritant receptors identified in the upper airways of rat lungs in response to a methacholine challenge. SAPL in the form of dipalmitoyl phosphatidylcholine (PC) and phosphatidylglycerol (PG) , 7 : 3 PC:PG , was applied as a fine dry powder to enhance surface activity and, hence, chemisorption to epithelium. Comparison was also made with clinical doses of i.v. hydrocortisone and instilled salbutamol together with liquid or solid controls, as appropriate. Results Neural activity of irritant receptors was found to be significantly (P = 0.0018) decreased by topical SAPL by 35.8% in response to a methacholine challenge in contrast to an increase of 11.2% in response to a solid (lactose) control. Instilled salbutamol and i.v. hydrocortisone also decreased responses to the same challenge by 43.4% and 14.7%, respectively, in contrast to a liquid (saline) control which increased by 24.5%. Conclusions Surface-active phospholipid has an appreciable effect upon irritant receptors in rat airways, reducing neural response to a methacholine challenge by an amount comparable to that of Salbutamol. These results support the concept of SAPL masking bronchial irritant receptors and warrant placebo-controlled clinical trials of this dry powder as a means of controlling asthma without the side-effects of current medication. Other possible roles discussed for the SAPL epithelial barrier include the exclusion of viruses and allergens. [source] Idiopathic polyneuropathy and impaired glucose metabolism in a Norwegian patient seriesEUROPEAN JOURNAL OF NEUROLOGY, Issue 8 2008M. Nebuchennykh Background and purpose:, North American studies have indicated a high prevalence of impaired glucose tolerance (IGT) in patients with sensory polyneuropathy. We searched for the occurrence of IGT in a Norwegian patient material with polyneuropathy. Methods:, Seventy patients with symptoms and signs of sensory polyneuropathy were included. Cases with known causes of neuropathy were excluded. All patients underwent a 2 h oral glucose tolerance test (OGTT). Nerve conduction studies (NCS), quantitative sensory testing (QST) and skin biopsy with assessment of intra-epidermal nerve fibre (IENF) density were performed. Results:, Sixteen patients (23%) had impaired glucose metabolism (IGM): 2 (3%) were found to have diabetes, 9 (13%) had IGT, 3 (4%) had impaired fasting glucose (IFG) and 2 (3%) both IFG and IGT. About 62% of the patients with IGM and polyneuropathy and 50% of those with chronic idiopathic axonal polyneuropathy (CIAP) had abnormalities on NCS. Reduction of IENF occurred in 37% of the patients with IGM and 43% of those with CIAP. Conclusions:, Patients with polyneuropathy and IGM had essentially the same degree of involvement of small and large nerve fibres as patients with CIAP. IGT seems less frequent in Norwegian patients with polyneuropathy than reported in North American populations. [source] Intraepidermal nerve fibre density, quantitative sensory testing and nerve conduction studies in a patient material with symptoms and signs of sensory polyneuropathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006S. Lųseth Small diameter nerve fibre (SDNF) neuropathy is an axonal sensory neuropathy affecting unmyelinated (C) and thin myelinated (A-delta) fibres. We have evaluated 75 patients with symptoms and signs suggesting SDNF dysfunction with or without symptoms and signs of co-existing large diameter nerve fibre involvement. The patients were examined clinically and underwent skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS). The purpose of this study was to compare the relationship between the different methods and in particular measurements of thermal thresholds and intraepidermal nerve fibre (IENF) density in the same site of the distal leg. The main subdivision of the patient material was made according to the overall NCS pattern. Patients with normal NCS (38) had 6.4 ± 3.8 and patients with abnormal NCS (37) had 4.4 ± 3.4 IENF per mm (P = 0.02). Limen (difference between warm and cold perception thresholds) was significantly higher (more abnormal) in those with abnormal than in those with normal NCS (22.1 ± 9.1 vs. 13.4 ± 5.6, P < 0.0001). Cold perception threshold was more abnormal (P < 0.0001) than warm perception threshold (P = 0.002). Correlation between IENF and QST was statistically significant only when NCS was abnormal, and thus dependent of a more severe neuropathic process in SDNFs. [source] Platelet-derived growth factor receptors expressed in response to injury of differentiated vascular smooth muscle in vitro: effects on Ca2+ and growth signalsACTA PHYSIOLOGICA, Issue 2 2001A. Lindqvist Vascular smooth muscle cells (VSMCs) in the intact vascular wall are differentiated for contraction, whereas the response to vascular injury involves transition towards a synthetic phenotype, with increased tendency for proliferation. Platelet-derived growth factor (PDGF) is thought to be important for this process. We investigated expression and functional coupling of PDGF receptors (PDGFRs) , and , in rat tail arterial rings kept in organ culture, in order to capture early events in the phenotypic transition. In freshly dissected rings no PDGFR immunoreactivity was found in medial VSMCs, whereas PDGFR , was detected in nerve fibres. After organ culture for 1,4 days PDGFR , and , as well as phospholipase C,2 (PLC,2), known to couple to PDGFR, were expressed in VSMCs within 100 ,m of the cut ends. Calponin, a marker for the contractile phenotype, was decreased near the injured area, suggesting that cells were in transition towards synthetic phenotype. In these cells, which showed functional Ca2+ -release from the sarcoplasmic reticulum, PDGF-AB (100 ng mL,1) had no effect on [Ca2+]i, whereas cultured VSMCs obtained from explants of rat tail arterial rings responded to PDGF-AB with an increase in [Ca2+]i. However, PDGFR within the cultured rings coupled to growth signalling pathways, as PDGF-AB caused a tyrphostin AG1295-sensitive activation of extracellular signal-regulated kinases 1 and 2 and of [3H]-thymidine incorporation. Thus, early expression of PDGFR in VSMC adjacent to sites of vascular injury coincides with signs of dedifferentiation. These receptors couple to growth signalling, but do not activate intracellular Ca2+ release. [source] Evidence for a widespread involvement of NO in control of photogenesis in bioluminescent fishACTA ZOOLOGICA, Issue 4 2010Jenny Krönström Abstract Krönström, J. and Mallefet, J. 2009. Evidence for a widespread involvement of NO in control of photogenesis in bioluminescent fish. ,Acta Zoologica (Stockholm) 91: 474,483. The presence of nitric oxide synthase (NOS) and nerve fibres in the photophores of seven bioluminescent fish species (Hygophum benoiti, Myctophum punctatum, Electrona risso, Cyclothone braueri, Vinciguerria attenuata, Maurolicus muelleri and Porichthys notatus) with endogenous photocytes, were investigated. Antibodies directed against neuronal and inducible NOS (n and iNOS respectively) and NADPH-diaphorase activity were used to reveal the locations of NOS, while antibodies directed against acetylated tubulin were used to visualize nerve fibres. The nNOS antibody labelled structures in all investigated photophores except in the organs from P. notatus. The photocytes of P. notatus showed NADPH-diaphorase activity. In the myctophid species, NOS-like immunoreactivity was found in small intracellular structures of the photocytes and in nerve fibres reaching the photocytes. nNOS-positive fibres were also found among lens/filter cells in V. attenuata, and in M. muelleri the cytoplasm of lens/filter cells contained NOS-like material. In C. braueri, a cell type located at a collecting chamber for luminous products in the photophore contained NOS-like material. All photophores received an innervation reaching the photocytes, as well as other components including lens/filter areas. The results of this study comply with an involvement of nitric oxide in the control of bioluminescence in several fish species. [source] Microscopic structure of the sperm storage tubules in the polygynandrous alpine accentor, Prunella collaris (Aves)ACTA ZOOLOGICA, Issue 4 2001Akira Chiba Abstract We describe the microscopic structure of the sperm storage tubules (SSTs) of the polygynandrous alpine accentor, Prunella collaris. The SSTs were found at the utero-vaginal junction of the oviduct and were composed of a single layer of columnar epithelium. The cells of the tubule proper were non-ciliated and had a round or oval nucleus in their basal portion. Their cytoplasm was finely or coarsely vacuolated due to lipid inclusions. Under the electron microscope, the epithelial cells exhibited a number of mitochondria, Golgi bodies, occasional lysosome-like dense bodies, granular endoplasmic reticula, junctional complex, and tonofilaments. The apical margin of the cells was fringed with numerous microvilli. The epithelial lining of the SSTs was devoid of mucous cells, but showed occasional infiltration of lymphoid cells. No contractile elements were found in association with the SSTs, but a close apposition of unmyelinated nerve fibres to the basal part of the SST cells was recognized. Intraluminal sperm were arranged in bundles, and their heads were orientated towards the distal portion of the SSTs. Evidence for engulfment of sperm by the SST cells was obtained for the first time. A sign of atrophy or regression of the SSTs was found in one specimen. [source] Idiopathic polyneuropathy and impaired glucose metabolism in a Norwegian patient seriesEUROPEAN JOURNAL OF NEUROLOGY, Issue 8 2008M. Nebuchennykh Background and purpose:, North American studies have indicated a high prevalence of impaired glucose tolerance (IGT) in patients with sensory polyneuropathy. We searched for the occurrence of IGT in a Norwegian patient material with polyneuropathy. Methods:, Seventy patients with symptoms and signs of sensory polyneuropathy were included. Cases with known causes of neuropathy were excluded. All patients underwent a 2 h oral glucose tolerance test (OGTT). Nerve conduction studies (NCS), quantitative sensory testing (QST) and skin biopsy with assessment of intra-epidermal nerve fibre (IENF) density were performed. Results:, Sixteen patients (23%) had impaired glucose metabolism (IGM): 2 (3%) were found to have diabetes, 9 (13%) had IGT, 3 (4%) had impaired fasting glucose (IFG) and 2 (3%) both IFG and IGT. About 62% of the patients with IGM and polyneuropathy and 50% of those with chronic idiopathic axonal polyneuropathy (CIAP) had abnormalities on NCS. Reduction of IENF occurred in 37% of the patients with IGM and 43% of those with CIAP. Conclusions:, Patients with polyneuropathy and IGM had essentially the same degree of involvement of small and large nerve fibres as patients with CIAP. IGT seems less frequent in Norwegian patients with polyneuropathy than reported in North American populations. [source] Noxious heat-induced CGRP release from rat sciatic nerve axons in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2001S. K. Sauer Abstract Noxious heat may act as an endogenous activator of the ionotropic capsaicin receptor (VR1) and of its recently found homologue VRL1, expressed in rat dorsal root ganglion cells and present along their nerve fibres. We have previously reported that capsaicin induces receptor-mediated and Ca++ -dependent calcitonin gene-related peptide (CGRP) release from axons of the isolated rat sciatic nerve. Here we extended the investigation to noxious heat stimulation and the transduction mechanisms involved. Heat stimulation augmented the CGRP release from desheathed sciatic nerves in a log,linear manner with a Q10 of ,,15 and a threshold between 40 and 42 °C. The increases were 1.75-fold at 42 °C, 3.8-fold at 45 °C and 29.1-fold at 52 °C; in Ca++ -free solution these heat responses were abolished or reduced by 71 and 92%, respectively. Capsazepine (10 µm) and Ruthenium Red (1 µm) used as capsaicin receptor/channel antagonists did not significantly inhibit the heat-induced release. Pretreatment of the nerves with capsaicin (100 µm for 30 min) caused complete desensitization to 1 µm capsaicin, but a significant heat response remained, indicating that heat sensitivity is not restricted to capsaicin-sensitive fibres. The sciatic nerve axons responded to heat, potassium and capsaicin stimulation with a Ca++ -dependent CGRP release. Blockade of the capsaicin receptor/channels had little effect on the heat-induced neuropeptide release. We conclude therefore that other heat-activated ion channels than VR1 and VRL1 in capsaicin-sensitive and -insensitive nerve fibres may cause excitation, axonal Ca++ influx and subsequent CGRP release. [source] Hypocretin (orexin) in the rat pineal gland: a central transmitter with effects on noradrenaline-induced release of melatoninEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2001Jens D. Mikkelsen Abstract Hypocretin-1 (HCRT-1) and hypocretin 2 (HCRT-2), also known as orexin-A and orexin-B, are two neuropeptides derived from the same precursor. Hypocretinergic neurons have been found exclusively in the hypothalamic dorsolateral area. These neurons are implicated in sleep and feeding through activation of specific G-protein-coupled orexin-1 and orexin-2 receptor (OR-R1 and OR-R2). The purpose of this study was to determine the existence of the HCRT peptides in the central input of the rat pineal gland. Further, OR-R1 and OR-R2 expression was determined in the pineal gland and the effect of HCRT-2 on melatonin synthesis and secretion was analysed in dissociated rat pinealocytes. A large contingent of HCRT-positive nerve fibres and terminals were observed in the epithalamus, many of which entered into the pineal parenchyma. A significant number of nerve fibres endowed with positive boutons were identified in the pineal stalk, though the number of positive fibres decreased along the extension of the stalk. So far, no positive fibres have been found in the superficial pineal gland. RT-PCR analysis revealed the expression of OR-R2 mRNA, whereas OR-R1-receptor mRNA was not detected. When tested alone, HCRT-2 had no effect on secretion of melatonin from cultured rat pinealocytes. However, HCRT-2 partially inhibited (by a maximum of 30%) the ,-adrenergic-induced melatonin secretion. The same effect was seen on activation of N-acetyltransferase activity. The distribution and the large number of HCRT-positive fibres together with the effect on noradrenaline-mediated melatonin release through specific receptors suggests that these peptides may be significant central transmitters in pineal function, probably mediating homeostatic signals to the pineal gland. [source] Neuronal and vascular localization of histamine N-methyltransferase in the bovine central nervous systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2000Masahiro Nishibori Abstract Histamine N-methyltransferase (HMT) (EC 2.1.1.8) plays a crucial role in the inactivation of the neurotransmitter histamine in the CNS. However, the localization of HMT remains to be determined. In the present study, we investigated immunohistochemical localization of HMT in the bovine CNS using a polyclonal antibody against bovine HMT. The HMT-like immunoreactivity was observed mainly in neurons. Strongly immunoreactive neurons were present in the oculomotor nucleus and ruber nucleus in the midbrain, the facial nucleus in the pons, the dorsal vagal nucleus and hypoglossal nucleus in the medulla oblongata and in the anterior horn as well as intermediolateral zone of the spinal cord. Intermediately immunoreactive neurons were present in the piriform cortex and the inferior olivary nucleus. The grey matter of the forebrain regions was diffusely and faintly stained. In the cerebellum and the striatum, the nerve fibres in the white matter were positive. The tuberomammillary nucleus, where histaminergic neurons are present, were weakly positive. The other immunoreactive structures in the CNS were blood vessels. Almost all of the blood vessel walls, irrespective of whether they were arterial or venous, were variably stained. The glial fibrillary acidic protein- (GFAP-) immunoreactive astrocytes were not stained. These findings indicated that histamine released from histaminergic nerve terminals or varicose fibres is methylated mainly in postsynaptic or extrasynaptic neurons rather than in astrocytes. The localization of HMT in the blood vessel wall may mean that blood-borne histamine and histamine released from mast cells associated with the blood vessels are catabolized in this structure. [source] Opioids and the skin , where do we stand?EXPERIMENTAL DERMATOLOGY, Issue 5 2009Paul L. Bigliardi Abstract:, The common ectodermal origin of the skin and nervous systems can be expected to predict likely interactions in the adult. Over the last couple of decades much progress has been made to elucidate the nature of these interactions, which provide multidirectional controls between the centrally located brain and the peripherally located skin and immune system. The opioid system is an excellent example of such an interaction and there is growing evidence that opioid receptors (OR) and their endogenous opioid agonists are functional in different skin structures, including peripheral nerve fibres, keratinocytes, melanocytes, hair follicles and immune cells. Greater knowledge of these skin-associated opioid interactions will be important for the treatment of chronic and acute pain and pruritus. Topical treatment of the skin with opioid ligands is particularly attractive as they are active with few side effects, especially if they cannot cross the blood,brain barrier. Moreover, cutaneous activation of the opioid system (e.g. by peripheral nerves, cutaneous and immune cells, especially in inflamed and damaged skin) can influence cell differentiation and apoptosis, and thus may be important for the repair of damaged skin. While many of the pieces of this intriguing puzzle remain to be found, we attempt in this review to weave a thread around available data to discuss how the peripheral opioid system may impact on different key players in skin physiology and pathology. [source] Neurophysiological and neurochemical basis of modern pruritus treatmentEXPERIMENTAL DERMATOLOGY, Issue 3 2008Sonja Ständer Abstract:, Chronic pruritus of any origin is a frequent discomfort in daily medical practice, and its therapy is challenging. Frequently, the underlying origin may not be identified and symptomatic therapy is necessary. Conventional treatment modalities such as antihistamines often lack efficacy, and hence new therapeutic strategies are necessary. The neuronal mechanisms underlying chronic pruritus have been partly identified during the past years and offer new therapeutic strategies. For example, mast cell degranulation, activation of neuroreceptors on sensory nerve fibres and neurogenic inflammation have been identified to be involved in induction and chronification of the symptom. Accordingly, controlling neuroreceptors such as cannabinoid receptors by agonists or antagonists showed high antipruritic efficacy. Pruritus is transmitted to the central nervous system by specialized nerve fibres and sensory receptors. It has been demonstrated that pruritus and pain have their own neuronal pathways with broad interactions. Accordingly, classical analgesics for neuropathic pain (gabapentin, antidepressants) also exhibit antipruritic efficacy upon clinical use. In summary, these recent developments show that highlighting the basis of pruritus offers modern neurophysiological and neurochemical therapeutic models and the possibility to treat patients with refractory itching of different origin. [source] Induction of neuropeptides in skin innervating sensory neurons by stress and nerve growth factor as a possible reason for hair growth alterationEXPERIMENTAL DERMATOLOGY, Issue 9 2004A. Kuhlmei Recently, we introduced a mouse model launching experimental evidence for stress-induced hair growth inhibition (HGI), pointing to the existence of a brain-hair follicle axis (BFA). We suggested that nerve growth factor (NGF), besides neuropeptide substance P (SP), is a candidate mediator along the BFA. Published data further indicate that stress-related neuropeptides, e.g. calcitonin gene-related peptide (CGRP) and SP may be involved in HGI. SP and CGRP are synthesized in dorsal root ganglia (DRG) and released after axonal transport in the skin. Thus, aim of the present study was to investigate the effect of stress or subcutaneous injection of NGF, which mimics stress and regulates neuropeptide genes in sensory neurons, on the expression of SP and CGRP in DRG. Anagen was induced in C57BL/6 mice by depilation and retrograde tracing was employed on day 9 post-depilation (PD). On day 14 PD, mice were either exposed to sound stress (n = 4) injected subcutaneously with NGF (n = 4) or served as control (n = 4). On day 16 PD, DRG (mean of 30/mouse) were harvested and SP and CGRP in skin-specific sensory neurons, as identified by the tracer dye, were labelled by immunohistochemistry and counted. Stress exposure as well as NGF injection leads to a significant induction of SP and CGRP in retrograde-labelled neurons. This allows us to conclude that sensitive dermal nerve fibres are likely to originate from the presently identified neuropeptide-positive neurons. Peripheral activation of SP-expressing afferent nerve fibres via NGF-dependent pathways may cause neurogenic inflammation, eventually resulting in HGI. [source] The otic ganglion in rats and its parotid connection: cholinergic pathways, reflex secretion and a secretory role for the facial nerveEXPERIMENTAL PHYSIOLOGY, Issue 1 2006Nina Khosravani Otic ganglionectomy in rats was found to have affected the parotid gland more profoundly than section of the auriculotemporal nerve as assesssed by reduction in gland weight (by 33 versus 20%) and total acetylcholine synthesizing capacity (by 88 versus 76%) 1 week postoperatively and, when assessed on the day of surgery under adrenoceptor blockade, by reflex secretion (by 99 versus 88%). The facial nerve contributed to the acetylcholine synthesizing capacity of the gland. Section of the nerve only, at the level of the stylomastoid foramen, reduced the acetylcholine synthesis by 15% and, combined with otic ganglionectomy, by 98% or, combined with section of the auriculotemporal nerve, by 82%. The facial nerve was secretory to the gland, and the response was of a cholinergic nature. The nerve conveyed reflex secretion of saliva and caused secretion of saliva upon stimulation. Most of the facial secretory nerve fibres originated from the otic ganglion, since after otic ganglionectomy (and allowing for nerve degeneration) the secretory response to facial nerve stimulation was markedly reduced (from 23 to 4 ,l (5 min),1). The persisting secetory response after otic ganglionectomy, exaggerated due to sensitization, and the residual acetylcholine synthesizing capacity (mainly depending on the facial nerve) showed that a minor proportion of pre- and postganglionic nerve fibres relay outside the otic ganglion. The great auricular nerve, which like the facial nerve penetrates the gland, caused no secretion of saliva upon stimulation. Avulsion of the auriculotemporal nerve was more effective than otic ganglionectomy in reducing the acetylcholine synthesizing capacity (by 94 versus 88%) and as effective as otic ganglionectomy in abolishing reflex secretion (by 99%). When aiming at parasympathetic denervation, avulsion may be the preferable choice, since it is technically easier to perform than otic ganglionectomy. [source] Epidermal transient receptor potential vanilloid 1 in idiopathic small nerve fibre disease, diabetic neuropathy and healthy human subjectsHISTOPATHOLOGY, Issue 5 2007E P Wilder-Smith Aims:, The transient receptor potential vanilloid 1 (TRPV1) plays an important role in mediating pain and heat. In painful neuropathies, intraepidermal TRPV1 nerve fibre expression is low or absent, suggesting that pain generated is not directly related to sensory nerve fibres. Recent evidence suggests that keratinocytes may act as thermal receptors via TRPV1. The aim was to investigate epidermal TRPV1 expression in patients with neuropathic conditions associated with pain. Methods and results:, In a prospective study of distal small nerve fibre neuropathy (DISN; n = 13) and diabetic neuropathy (DN; n = 12) intraepidermal nerve fibre density was assessed using the pan axonal marker PGP 9.5 and epidermal TPVR1 immunoreactivity compared with controls (n = 9). Intraepidermal nerve fibres failed to show TRPV1 immunoreactivity across all groups. There was moderate and strong TRPV1 reactivity of epidermal keratinocytes in 41.8% and 6% for DISN, 32.9% and 2.9% for DN and 25.4% and 5.1% for controls, respectively. Moderate keratinocyte TRPV1 expression was significantly increased in DISN compared with controls (P = 0.01). Conclusion:, Our study suggests that in human painful neuropathies, epidermal TRPV1 expression is mainly in keratinocytes. [source] Administration of noradrenaline in the autonomic ganglia modifies the testosterone release from the testis using an ex vivo systemINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2009Zulema Y. Sosa Summary The male gonad receives nerve fibres from the autonomic ganglionic system. These fibres converge on the testis along two pathways, the superior and the inferior spermatic nerves. The superior spermatic nerve runs from the superior mesenteric ganglion alongside the testicular artery, whereas the inferior spermatic nerve originates in inferior mesenteric ganglion, accompanies the vas deferens and penetrates the inferior pole of the testis. The aim of this work was to evaluate androgen release after the addition of noradrenaline or adrenoreceptor antagonists (propranolol or phentolamine) to the ganglionic compartment. An ex vivo system used in a previous work was incubated in two separate containers, one for the testis and the other for the ganglion. Both organs remain interconnected (as in vivo) by the respective spermatic nerve. When noradrenaline was added to the inferior mesenteric ganglion, testosterone release in the gonad container underwent a progressive and significant increment. Propranolol diminishes and phentolamine increases the androgen release. When using the superior mesenteric ganglion, no changes were observed. These results indicate that the ganglionic stimulation of the autonomic system clearly participates in testosterone release from the testis. This effect depends on the ganglion involved. These results make it evident that not only the classical and well-known hypothalamus,hypophysial axis, but also the peripheral nervous system, via the autonomic ganglia, are directly involved in the endocrine control of the testis. [source] Tachykinins and their possible modulatory role on testicular function: a reviewINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2003Luciano Debeljuk Summary Tachykinins are vasoactive and smooth muscle-contracting peptides with widespread localizations. Tachykinins have been localized in the nerve fibres that supply the testes, in the Leydig cells of different animal species, and also in Sertoli cells of the Siberian hamster testes. The presence of substance P (SP) has also been demonstrated in ejaculated human spermatozoa and in the seminal plasma. Tachykinins have been shown to inhibit the release of testosterone by testicular fragments or by isolated Leydig cells in vitro. Acting on Sertoli cells, tachykinins have been shown to stimulate the release of lactate and transferrin by these cells in vitro, and also to stimulate aromatase activity. Leydig and Sertoli cells express the Preprotachykinin A gene, and this fact strongly suggests that tachykinins can be synthesized in the testes. These findings suggest that tachykinins may have a physiological function in the testes as modulators of the functions of the different cell types contained in these organs. [source] Megaoesophagus in Rassf1a -null miceINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2009Louise Van Der Weyden Summary Megaoesophagus, or oesophageal achalasia, is a neuromuscular disorder characterized by an absence of peristalsis and flaccid dilatation of the oesophagus, resulting in the retention of ingesta in the dilated segment. The aetiology and pathogenesis of idiopathic (or primary) megaoesophagus are still poorly understood and very little is known about the genetic causes of megaoesophagus in humans. Attempts to develop animal models of this condition have been largely unsuccessful and although the ICRC/HiCri strain of mice spontaneously develop megaoesophagus, the underlying genetic cause remains unknown. In this report, we show that aged Rassf1a -null mice have an enhanced susceptibility to megaoesophagus compared with wild-type littermates (,20%vs. ,2% incidence respectively; P = 0.01). Histological examination of the dilated oesophaguses shows a reduction in the numbers of nerve cells (both ganglia and nerve fibres) in the myenteric plexus of the dilated mid and lower oesophagus that was confirmed by S100 immunohistochemistry. There was also a chronic inflammatory infiltrate and subsequent fibrosis of the myenteric plexus and the muscle layers. These appearances closely mimic the gross and histopathological findings in human cases of megaoesophagus/achalasia, thus demonstrating that this is a representative mouse model of the disease. Thus, we have identified a genetic cause of the development of megaoesophagus/achalasia that could be screened for in patients, and may eventually facilitate the development of therapies that could prevent further progression of the disease once it is diagnosed at an early stage. [source] Structural diversification of the gustatory organs during metamorphosis in the alpine newt Triturus alpestrisJOURNAL OF ANATOMY, Issue 3 2007Krystyna Abstract Gustatory organs of the taste bud type occur in the epithelial lining of the oropharyngeal cavity of alpine newt larvae. They resemble the taste buds of bony fish, both in appearance (as revealed by scanning electron microscopy) and in detailed internal structure (seen on transmission electron micropscopy). During metamorphosis, at stage 55 of development, the secondary tongue (i.e. the soft tongue) is well formed and the anlages of taste discs are clearly apparent. Somewhat later, taste discs also appear in the epithelial lining outside the tongue, paralleling the disappearance of the taste buds. Well-developed taste discs of the newt differ from taste buds mainly by their structurally diversified set of ,associate cells' (mucous, wing and glial cells), which have no synaptic contact with nerve fibres. These cells accompany the neurosensory cellular components of the taste disc, i.e. the taste receptor cells and basal cells. This indicates that gustatory organs in metamorphosed newts, regardless of their small dimensions, fulfil the criteria established for taste discs previously defined in other Caudata and Anura species. Therefore, in the development of the newt there are two subsequent types of gustatory organs and two generations of the tongue: primary, in the larvae, and secondary, in metamorphosed animals. [source] Review: Energy regulation and neuroendocrine,immune control in chronic inflammatory diseasesJOURNAL OF INTERNAL MEDICINE, Issue 6 2010R. H. Straub Abstract., Straub RH, Cutolo M, Buttgereit F, Pongratz G (University Hospital Regensburg, Regensburg, Germany; University of Genova, Genova, Italy; and Charité University Medicine Berlin, Berlin, Germany). Energy regulation and neuroendocrine,immune control in chronic inflammatory diseases (Review). J Intern Med 2010; 267:543,560. Energy regulation (EnR) is most important for homoeostatic regulation of physiological processes. Neuroendocrine pathways are involved in EnR. We can separate factors that provide energy-rich fuels to stores [parasympathetic nervous system (PSNS), insulin, insulin-like growth factor-1, oestrogens, androgens and osteocalcin] and those that provide energy-rich substrates to consumers [sympathetic nervous system (SNS), hypothalamic,pituitary,adrenal axis, thyroid hormones, glucagon and growth hormone]. In chronic inflammatory diseases (CIDs), balanced energy-rich fuel allocation to stores and consumers, normally aligned with circadian rhythms, is largely disturbed due to the vast fuel consumption of an activated immune system (up to 2000 kJ day,1). Proinflammatory cytokines such as tumour necrosis factor or interleukins 1, and 6, circulating activated immune cells and sensory nerve fibres signal immune activation to the rest of the body. This signal is an appeal for energy-rich fuels as regulators are switched on to supply energy-rich fuels (,energy appeal reaction'). During evolution, adequate EnR evolved to cope with nonlife-threatening diseases, not with CIDs (huge negative selection pressure and reduced reproduction). Thus, EnR is inadequate in CIDs leading to many abnormalities, including sickness behaviour, anorexia, hypovitaminosis D, cachexia, cachectic obesity, insulin resistance, hyperinsulinaemia, dyslipidaemia, fat deposits near inflamed tissue, hypoandrogenaemia, mild hypercortisolaemia, activation of the SNS (hypertension), CID-related anaemia and osteopenia. Many of these conditions can contribute to the metabolic syndrome. These signs and symptoms become comprehensible in the context of an exaggerated call for energy-rich fuels by the immune system. We propose that the presented pathophysiological framework may lead to new therapeutical approaches and to a better understanding of CID sequence. [source] Dual Excitatory and Inhibitory Effects of Stimulation of Intrinsic Innervation of the Anterior Pituitary on Adrenocorticotropic Hormone Release in the RatJOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2004L.-Z. Gao Abstract The gland cells of the mammalian anterior pituitary are innervated by substantial amounts of nerve fibres, and there is evidence that the nerve fibres are functionally active. In the rat, the nerve fibres make typical excitatory synapses with corticotropes. The physiological significance of this synaptic relationship was investigated in the present study. The anterior pituitary of the rat was sliced and stimulated with electrical field in a chamber. The perfusate was continuously collected and immunoradioassayed for adrenocorticotropic hormone (ACTH). When the gland slices were stimulated at a high frequency of 10 Hz, there was a significant inhibition of ACTH secretion. Stimulation at a low frequency of 2 Hz resulted in a quick and transient excitation of ACTH release. The results indicate that stimulation of the nerve fibres in the anterior pituitary has dual excitatory and inhibitory effects on ACTH secretion. [source] White Adipose Tissue: Getting NervousJOURNAL OF NEUROENDOCRINOLOGY, Issue 11 2003E. Fliers Abstract Neuroendocrine research has altered the traditional perspective of white adipose tissue (WAT) as a passive store of triglycerides. In addition to fatty acids, WAT produces many hormones and can therefore be designated as a traditional endocrine gland actively participating in the integrative physiology of fuel and energy metabolism, eating behaviour and the regulation of hormone secretion and sensitivity. WAT is controlled by humoral factors, para- and intracrine factors and by neural regulation. Sympathetic nerve fibres innervate WAT and stimulate lipolysis, leading to the release of glycerol and free fatty acids. In addition, recent research in rats has clearly shown a functional parasympathetic innervation of WAT. There appears to be a distinct somatotopy within the parasympathetic nuclei: separate sets of autonomic neurones in the brain stem innervate either the visceral or the subcutaneous fat compartment. We therefore propose that the central nervous system (CNS) plays a major role in the hitherto unexplained regulation of body fat distribution. Parasympathectomy induces insulin resistance with respect to glucose and fatty acid uptake in the innervated fat depot and has selective effects on local hormone synthesis. Thus, the CNS is involved not only in the regulation of hormone production by WAT, but also in its hormone sensitivity. The developments in this research area are likely to increase our insights in the pathogenesis of metabolic disorders such as hypertriglyceridemia, diabetes mellitus type 2 and lipodystrophy syndromes. [source] Disorder-specific changes in innervation in oral lichen planus and lichenoid reactionsJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2000Sirkku Niissalo Abstract: The peripheral nervous system was analysed in the oral mucosa of eight patients with oral lichen planus (OLP), five with a lichenoid reaction (LR) and three with mild chronic inflammation (MCI), by morphometric analysis of nerve fibres containing immunoreactive PGP 9.5, substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), or C-flanking peptide of neuropeptide Y (CPON). Overall nerve fibre density was higher in OLP (P=0.039) and LR (P=0.026) compared with healthy oral mucosa and was compatible with sprouting and collateral formation. In contrast to the innervation visualized with structural nerve fibre-marker PGP 9.5, the densities of neuropeptide-immunoreactive nerves were low in inflamed tissue. This is consistent with depletion via local release. Retraction and local loss of innervation were found in areas coinciding with the most severe inflammation and basal membrane (BM) damage. Interestingly, LR showed a twenty-eight-fold loss of post-ganglionic CPON-ir sympathetic nerve fibres (P=0.044). In LR, CPON-ir innervation was markedly lower than in OLP. Finally, the pattern of innervation in relation to inflammatory cell infiltrates and tissue structures differed between OLP and LR. In conclusion, the peripheral nervous system is implicated in the immunopathogenesis of lichen planus and lichenoid reactions, with a disorder-specific difference in this involvement. [source] Sensory-motor function of human periodontal mechanoreceptors,JOURNAL OF ORAL REHABILITATION, Issue 4 2006M. TRULSSON summary, Natural teeth are equipped with periodontal mechanoreceptors that signal information about tooth loads. In the present review, the basic force-encoding properties of human periodontal receptors will be presented along with a discussion about their likely functional role in the control of human mastication. Microneurographic recordings from single nerve fibres reveal that human periodontal receptors adapt slowly to maintained tooth loads. Most receptors are broadly tuned to the direction of force application, and about half respond to forces applied to more than one tooth. Populations of periodontal receptors, nevertheless, reliably encode information about both the teeth stimulated, and the direction of forces applied to the individual teeth. Information about the magnitude of tooth loads is made available in the mean firing rate response of periodontal receptors. Most receptors exhibit a markedly curved relationship between discharge rate and force amplitude, featuring the highest sensitivity to changes in tooth load at very low force levels (below 1 N for anterior teeth and 4 N for posterior teeth). Thus, periodontal receptors efficiently encode tooth load when subjects contact and gently manipulate food using the teeth. It is demonstrated that signals from periodontal receptors are used in the fine motor control of the jaw and it is clear from studies of various patient groups (e.g. patients with dental implants) that important sensory-motor functions are lost or impaired when these receptors are removed during the extraction of teeth. [source] Leprous neuropathy: a clinical and neurophysiological studyJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2004E Ghiglione Leprosy is one of the most common treatable causes of neuropathy in the world. Peripheral nerves and skin are commonly affected. We reported the clinical features and electrophysiological findings in 46 patients with leprosy. The aim of our study was to evaluate the nature of damage in the nerve fibres, especially in the first phase of disease. Forty-six patients (mean age: 44.8 ± 17.8) with diagnosed leprosy were studied by neurological examination and nerve conduction studies (NCS). Twenty-eight patients were examined for a mean period of 34.8 months. The number of tests for patients varied from 1 to 13 controls. Amplitude of sensory and motor action potentials (SNAP and MAP), sensory-motor conduction velocity of median, ulnar, tibialis, peroneal and sural nerves were evaluated. Abnormalities were found in 282 of 647 nerves investigated (37.56%), sensory nerve abnormalities being more frequent than motor (50.16% 29.45). Of 282 nerves with neurophysiological abnormalities, 123 were clinically asymptomatic (43.62%). A statistically significant correlation between duration of disease and number of electrophysiological abnormalities was demonstrated. In 19 nerves partial "conduction-block"(reduction of cMAP > 50% in the proximal response) was individuated. The first electrophysiological alteration, suggesting segmental demyelination, was detected in 41 nerves of 21 patients (33.3 %). According to this view, our data support the hypothesis that leprosy induces a neuropathy of demyelinating nature in the first phase. [source] SUB-CLINICAL PERIPHERAL NERVE INVOLVEMENT IN PSORIATIC ARTHRITISJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000C. Di Girolamo Immunological studies document the role of HLA in psoriasis and the correlation between neuropeptides, psoriasis, and related arthritis. Some anecdotal case reports, moreover, describe a noncasual association between peripheral neuropathy and psoriatic manifestations. To verify a possible subclinical peripheral nerve involvement in this disimmune pathology, we started a pilot study in twenty patients with psoriatic arthritis and in whom other common causes of peripheral neuropathies had been ruled out. We performed a complete clinical neurological examination and a neurophysiological examination (orthodromic sensory and motor nerve conduction velocity in median and tibial nerves; antidromic sensory nerve conduction velocity in sural nerve). In 40% of the patients there was a mild but definite "glove-stocking" hypoesthesia, while hypopallesthesia was detected in only 20%. Electrophysiologic examinations were less informative borderline distal conduction velocities in 30% of patients. These preliminary data suggest a peripheral nerve involvement in this pathology, mainly affecting the small nerve fibres. [source] Synaptic structure, distribution, and circuitry in the central nervous system of the locust and related insectsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002Alan Hugh David Watson Abstract The Orthopteran central nervous system has proved a fertile substrate for combined morphological and physiological studies of identified neurons. Electron microscopy reveals two major types of synaptic contacts between nerve fibres: chemical synapses (which predominate) and electrotonic (gap) junctions. The chemical synapses are characterized by a structural asymmetry between the pre- and postsynaptic electron dense paramembranous structures. The postsynaptic paramembranous density defines the extent of a synaptic contact that varies according to synaptic type and location in single identified neurons. Synaptic bars are the most prominent presynaptic element at both monadic and dyadic (divergent) synapses. These are associated with small electron lucent synaptic vesicles in neurons that are cholinergic or glutamatergic (round vesicles) or GABAergic (pleomorphic vesicles). Dense core vesicles of different sizes are indicative of the presence of peptide or amine transmitters. Synapses are mostly found on small-diameter neuropilar branches and the number of synaptic contacts constituting a single physiological synapse ranges from a few tens to several thousand depending on the neurones involved. Some principles of synaptic circuitry can be deduced from the analysis of highly ordered brain neuropiles. With the light microscope, synaptic location can be inferred from the distribution of the presynaptic protein synapsin I. In the ventral nerve cord, identified neurons that are components of circuits subserving known behaviours, have been studied using electrophysiology in combination with light and electron microscopy and immunocytochemistry of neuroactive compounds. This has allowed the synaptic distribution of the major classes of neurone in the ventral nerve cord to be analysed within a functional context. Microsc. Res. Tech. 56:210,226, 2002. © 2002 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||