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Reticular Formation (reticular + formation)
Selected AbstractsCellular mechanisms of the trigeminally evoked startle responseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2003Susanne Schmid Abstract The startle response is an important mammalian model for studying the cellular mechanisms of emotions and of learning. It consists of contractions of facial and skeletal muscles in response to sudden acoustic, tactile or vestibular stimuli. Whereas the acoustic startle pathway is well described, only a few recent studies have investigated the tactile startle pathway. It was proposed that there is a direct projection from the principal sensory nucleus to the central sensorimotor interface of the startle response, which is formed by the giant neurons in the caudal pontine reticular formation. We explored this projection in greater detail in vitro. Anterograde tracing in rat brain slices confirmed projections with large axon terminals from the ventral part of the principal sensory nucleus to the lateral caudal pontine reticular formation. Electrophysiological studies revealed a monosynaptic glutamatergic connection between principal sensory nucleus neurons and caudal pontine reticular formation giant neurons. The synapses displayed paired-pulse facilitation at high-frequency stimulation, and homosynaptic depression at 1 Hz stimulation. The latter form of plasticity is thought to underlie habituation of the startle response. Furthermore, postsynaptic currents in caudal pontine reticular formation giant neurons evoked by principal sensory nucleus neuron stimulation summed in a linear way with signals evoked by stimulation of auditory afferents. Synaptic plasticity and summation of synaptic currents correspond well with in vivo data previously published by other groups. We thus presume that these synapses mediate trigeminal input to the startle pathway. [source] Discharge patterns of neurons in the medial pontobulbar reticular formation during fictive mastication in the rabbitEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001K.-G. Westberg Abstract In this study, we describe functional characteristics of neurons forming networks generating oral ingestive motor behaviours. Neurons in medial reticular nuclei on the right side of the brainstem between the trigeminal and hypoglossal motor nuclei were recorded in anaesthetized and paralysed rabbits during two types of masticatory-like motor patterns induced by electrical stimulation of the left (contralateral) or right (ipsilateral) cortical masticatory areas. Sixty-seven neurons in nucleus reticularis pontis caudalis (nPontc), nucleus reticularis parvocellularis (nParv), and nucleus reticularis gigantocellularis (Rgc) were studied. These were classified as phasic or tonic depending on their firing pattern during the fictive jaw movement cycle. Phasic neurons located in the dorsal part of nPontc were active during the jaw opening phase, whilst those in dorsal nParv tended to fire during the closing phase. In most neurons, burst duration and firing frequency changed between the two motor patterns, but there was little change in phase of firing. Tonic units were mainly recorded in the ventral half of nPontc, and at the junction between Rgc and caudal nParv. Cortical inputs with short latency from the contralateral masticatory area were more frequent in phasic (82%) than tonic (44%) neurons, whilst inputs from the ipsilateral cortex were equal in the two subgroups (57% and 56%). Phasic neurons had significantly shorter mean contralateral than ipsilateral cortical latencies, whilst there was no difference among tonic neurons. Intra- and perioral primary afferent inputs activated both types of neurons at oligo-synaptic latencies. Our results show that subpopulations of neurons in medial reticular nuclei extending from the caudal part of the trigeminal motor nucleus to the rostral third of the hypoglossal motor nucleus are active during the fictive masticatory motor behaviour. Unlike masticatory neurons in the lateral tegmentum, the medial subpopulations are spatially organized according to discharge pattern. [source] From neuroanatomy to gene therapy: searching for new ways to manipulate the supraspinal endogenous pain modulatory systemJOURNAL OF ANATOMY, Issue 2 2007I. Tavares Abstract The endogenous pain modulatory system is a complex network of brain areas that control nociceptive transmission at the spinal cord by inhibitory and facilitatory actions. The balance between these actions ensures effective modulation of acute pain, while during chronic pain the pronociceptive effects appear to prevail. The mechanisms underlying this imbalance were studied as to the role of two medullary components of the pain modulatory system: the dorsal reticular nucleus and the caudal ventrolateral medulla, which function primarily as pronociceptive and antinociceptive centres, respectively. Both areas are connected with the spinal dorsal horn by closed reciprocal loops. In the spino-dorsal reticular nucleus loop, the ascending branch is strongly inhibited by spinal GABAergic neurons, which may act as a buffering system of the dorsal reticular nucleus-centred amplifying effect. In the spino-caudal ventrolateral medulla loop, the ascending branch is under potent excitation of substance P (SP) released from primary afferents, which is likely to trigger the intense descending inhibition detected in acute pain. During chronic pain, the activity in the lateral reticular formation of the caudal ventrolateral medulla changes, so that the action of the caudal ventrolateral medulla upon SP-responsive spinal neurons shifts from inhibitory to excitatory. The mechanisms of this modulatory shift are unknown but probably relate to the decresed expression of µ-opioid, ,-opioid and GABAB receptors. Normalizing receptor expression in the caudal ventrolateral medulla or controlling noci-evoked activity at the dorsal reticular nucleus or caudal ventrolateral medulla by interfering with neurotransmitter release is now possible by the use of gene therapy, an approach that stands out as a unique tool to manipulate the supraspinal endogenous pain control system. [source] Differential localization of carbachol- and bicuculline-sensitive pontine sites for eliciting REM sleep-like effects in anesthetized ratsJOURNAL OF SLEEP RESEARCH, Issue 1 2009VICTOR B. FENIK Summary Carbachol, a cholinergic agonist, and GABAA receptor antagonists injected into the pontine dorsomedial reticular formation can trigger rapid eye movement (REM) sleep-like state. Data suggest that GABAergic and cholinergic effects interact to produce this effect but the sites where this occurs have not been delineated. In urethane-anesthetized rats, in which carbachol effectively elicits REM sleep-like episodes (REMSLE), we tested the ability of 10 nL microinjections of carbachol (10 mm) and bicuculline (0.5 or 2 mm) to elicit REMSLE at 47 sites located within the dorsal pontine reticular formation at the levels -8.00 to -10.80 from bregma (B) (Paxinos and Watson, The Rat Brain in Stereotaxic Coordinates, Academic Press, San Diego, 1997). At rostral levels, most carbachol and some bicuculline injections elicited REMSLE with latencies that gradually decreased from 242 to 12 s for carbachol and from 908 to 38 s for bicuculline for more caudal injection sites. As the latencies decreased, the durations of bicuculline-elicited REMSLE increased from 104 s to over 38 min, and the effect was dose dependent, whereas the duration of carbachol-elicited REMSLE changed little (104,354 s). Plots of REMSLE latency versus the antero-posterior coordinates revealed that both drugs were maximally effective near B-8.80. At levels caudal to B-8.80, carbachol was effective at few sites, whereas bicuculline-elicited REMSLE to at least B-9.30 level. Thus, the bicuculline-sensitive sites extended further caudally than those for carbachol and antagonism of GABAA receptors both triggered REMSLE and controlled their duration, whereas carbachol effects on REMSLE duration were small or limited by its concurrent REMSLE-opposing actions. [source] Immunohistochemical and hodological characterization of calbindin-D28k-containing neurons in the spinal cord of the turtle, Pseudemys scripta elegansMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2007Ruth Morona Abstract Neurons and fibers containing the calcium-binding protein calbindin-D28k (CB) were studied by immunohistochemical techniques in the spinal cord of adult and juvenile turtles, Pseudemys scripta elegans. Abundant cell bodies and fibers immunoreactive for CB were widely and distinctly distributed throughout the spinal cord. Most neurons and fibers were labeled in the superficial dorsal horn, but numerous cells were also located in the intermediate gray and ventral horn. In the dorsal horn, most CB-containing cells were located in close relation to the synaptic fields formed by primary afferents, which were not labeled for CB. Double immunohistofluorescence demonstrated distinct cell populations in the dorsal horn labeled only for CB or nitric oxide synthase, whereas in the dorsal part of the ventral horn colocalization of nitric oxide synthase was found in about 6% of the CB-immunoreactive cells in this region. Choline acetyltransferase immunohistochemistry revealed that only about 2% of the neurons in the dorsal part of the ventral horn colocalized CB, whereas motoneurons were not CB-immunoreactive. The involvement of CB-containing neurons in ascending spinal projections to the thalamus, tegmentum, and reticular formation was demonstrated combining the retrograde transport of dextran amines and immunohistochemistry. Similar experiments demonstrated supraspinal projections from CB-containing cells mainly located in the reticular formation but also in the thalamus and the vestibular nucleus. The revealed organization of the neurons and fibers containing CB in the spinal cord of the turtle shares distribution and developmental features, colocalization with other neuronal markers, and connectivity with other tetrapods and, in particular with mammals. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source] Immunohistochemical distribution of enkephalin, substance P, and somatostatin in the brainstem of the leopard frog, Rana pipiensMICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2001Sherry L. Stuesse Abstract The brainstems of frogs contain many of the neurochemicals that are found in mammals. However, the clustering of nuclei near the ventricles makes it difficult to distinguish individual cell groups. We addressed this problem by combining immunohistochemistry with tract tracing and an analysis of cell morphology to localize neuropeptides within the brainstem of Rana pipiens. We injected a retrograde tracer, Fluoro-Gold, into the spinal cord, and, in the same frog, processed adjacent sections for immunohistochemical location of antibodies to the neuropeptides enkephalin (ENK), substance P (SP), and somatostatin (SOM). SOM+ cells were more widespread than cells containing immunoreactivity (ir) to the other substances. Most reticular nuclei in frog brainstem contained ir to at least one of these chemicals. Cells with SOM ir were found in nucleus (n.) reticularis pontis oralis, n. reticularis magnocellularis, n. reticularis paragigantocellularis, n. reticularis dorsalis, the optic tectum, n. interpeduncularis, and n. solitarius. ENK-containing cell bodies were found in n. reticularis pontis oralis, n. reticularis dorsalis, the nucleus of the solitary tract, and the tectum. The midbrain contained most of the SP+ cells. Six nonreticular nuclei (griseum centrale rhombencephali, n. isthmi, n. profundus mesencephali, n. interpeduncularis, torus semicircularis laminaris, and the tectum) contained ir to one or more of the substances but did not project to the spinal cord. The descending tract of V, and the rubrospinal, reticulospinal, and solitary tracts contained all three peptides as did the n. profundus mesencephali, n. isthmi, and specific tectal layers. Because the distribution of neurochemicals within the frog brainstem is similar to that of amniotes, our results emphasize the large amount of conservation of structure, biochemistry, and possibly function that has occurred in the brainstem, and especially in the phylogenetically old reticular formation. Microsc. Res. Tech. 54:229,245, 2001. © 2001 Wiley-Liss, Inc. [source] Functional neuroanatomy of the human pre-Bötzinger complex with particular reference to sudden unexplained perinatal and infant deathNEUROPATHOLOGY, Issue 1 2008Anna M. Lavezzi The authors are the first to identify in man the pre-Bötzinger complex, a structure of the brainstem critical for respiratory rhythmogenesis, previously investigated only in rats. The evaluation of the neurokinin 1 receptors and somatostatin immunoreactivity in a total of 63 brains from 25 fetuses, nine newborns and 29 infants, allowed to delineate the anatomic structure and the boundaries of this human neural center in a restricted area of the ventrolateral medulla at the obex level, ventral to the semicompact ambiguus nucleus. The neurons of the pre-Bötzinger complex were roundish in fetuses before 30 gestational weeks and lengthened after birth, embedded in a dendritic system belonging to the reticular formation. Besides, structural and/or functional alterations of the pre-Bötzinger complex were present in a high percentage of sudden deaths (47%), prevalent in late fetal deaths. In particular, different developmental defects (hypoplasia with a decreased neuronal number and/or dendritic hypodevelopment of the reticular formation, abnormal neuronal morphology, immunonegativity of neurotransmitters, and agenesis) were found. The authors suggest that the pre-Bötzinger complex contains a variety of neurons not only involved in respiratory rhythm generation, but more extensively, essential to the control of all vital functions. Sudden death and in particular sudden unexpected fetal death could therefore be ascribed to a selective process when developmental alterations of the pre-Bötzinger complex arise. [source] Ascending and descending brainstem neuronal activity during cystometry in decerebrate catsNEUROUROLOGY AND URODYNAMICS, Issue 4 2003Kimio Sugaya Abstract Aims This study was undertaken to examine the distribution of pontomedullary neurons related to micturition or urine storage, as well as the connections between the pontine micturition center (PMC), medullary neurons, and the spinal cord. Methods In decerebrate cats, extracellular recording of the rostral pontine and rostral medullary neurons was performed. Firing of each neuron was quantitated during cystometry. Connections between the PMC, medullary neurons, and the spinal cord (L1) were also examined electrophysiologically. Results Ninety-four neurons showed an increase or decrease of the firing rate during micturition. Units with an antidromic response to L1 stimulation and an increased firing rate were located in the nucleus locus coeruleus alpha (LCa; n,=,8) corresponding to the PMC, and in the medial reticular formation (MRF) of the medulla (n,=,14). Units showing a decreased firing rate were located in the nucleus reticularis pontis oralis (PoO; n,=,26) and in the MRF (n,=,11). The latencies of antidromic and orthodromic responses of the LCa units were longer than those of the PoO units. MRF neurons responded antidromically and/or orthodromically to stimulation of the PMC or L1. Conclusions These results suggest that the pathway concerned with urine storage has a faster spinobulbospinal loop than the micturition reflex pathway and that rostral medullary neurons also play an important role in micturition and urine storage. There may be two descending pathways between the PMC and the spinal cord: both a direct pathway and one by means of medullary neurons. Neurourol. Urodynam. 22:343,350, 2003. © 2003 Wiley-Liss, Inc. [source] Connections of eye-saccade-related areas within mesencephalic reticular formation with the optic tectum in goldfishTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2007Maria A. Luque Abstract Physiological studies demonstrate that separate sites within the mesencephalic reticular formation (MRF) can evoke eye saccades with different preferred directions. Furthermore, anatomical research suggests that a tectoreticulotectal circuit organized in accordance with the tectal eye movement map is present. However, whether the reticulotectal projection shifts with the gaze map present in the MRF is unknown. We explored this question in goldfish, by injecting biotin dextran amine within MRF sites that evoked upward, downward, oblique, and horizontal eye saccades. Then, we analyzed the labeling in the optic tectum. The main findings can be summarized as follows. 1) The MRF and the optic tectum were connected by separate axons of the tectobulbar tract. 2) The MRF was reciprocally connected mainly with the ipsilateral tectal lobe, but also with the contralateral one. 3) The MRF received projections chiefly from neurons located within intermediate and deep tectal layers. In addition, the MRF projections terminated primarily within the intermediate tectal layer. 4) The distribution of labeled neurons in the tectum shifted with the different MRF sites in a manner consistent with the tectal motor map. The area containing these cells was targeted by a high-density reticulotectal projection. In addition to this high-density topographic projection, there was a low-density one spread throughout the tectum. 5) Occasionally, boutons were observed adjacent to tectal labeled neurons. We conclude that the organization of the reticulotectal circuit is consistent with the functional topography of the MRF and that the MRF participates in a tectoreticulotectal feedback circuit. J. Comp. Neurol. 500:6,19, 2007. © 2006 Wiley-Liss, Inc. [source] Generalized arousal of mammalian central nervous systemTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2005Donald Pfaff Abstract A fundamental capacity of the mammalian CNS is becoming amenable to study with the techniques of functional genomics. Emphasized in this review are ascending connections from the medullary reticular formation and descending connections from the paraventricular nucleus of the hypothalamus. In particular, sex hormone effects on neurons allow us to relate generalized arousal to a specific form of arousal which is required for reproductive behaviors. J. Comp. Neurol. 493:86,91, 2005. © 2005 Wiley-Liss, Inc. [source] Input,output organization of jaw movement-related areas in monkey frontal cortexTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2005Nobuhiko Hatanaka Abstract The brain mechanisms underlying mastication are not fully understood. To address this issue, we analyzed the distribution patterns of cortico,striatal and cortico,brainstem axon terminals and the origin of thalamocortical and intracortical fibers by injecting anterograde/retrograde tracers into physiologically and morphologically defined jaw movement-related cortical areas. Four areas were identified in the macaque monkey: the primary and supplementary orofacial motor areas (MIoro and SMAoro) and the principal and deep parts of the cortical masticatory area (CMaAp and CMaAd), where intracortical microstimulation produced single twitch-like or rhythmic jaw movements, respectively. Tracer injections into these areas labeled terminals in the ipsilateral putamen in a topographic fashion (MIoro vs. SMAoro and CMaAp vs. CMaAd), in the lateral reticular formation and trigeminal sensory nuclei contralaterally (MIoro and CMaAp) or bilaterally (SMAoro) in a complex manner of segregation vs. overlap, and in the medial parabranchial and Kölliker-Fuse nuclei contralaterally (CMaAd). The MIoro and CMaAp received thalamic projections from the ventrolateral and ventroposterolateral nuclei, the SMAoro from the ventroanterior and ventrolateral nuclei, and the CMaAd from the ventroposteromedial nucleus. The MIoro, SMAoro, CMaAp, and CMaAd received intracortical projections from the ventral premotor cortex and primary somatosensory cortex, the ventral premotor cortex and rostral cingulate motor area, the ventral premotor cortex and area 7b, and various sensory areas. In addition, the MIoro and CMaAp received projections from the three other jaw movement-related areas. Our results suggest that the four jaw movement-related cortical areas may play important roles in the formation of distinctive masticatory patterns. J. Comp. Neurol. 492:401,425, 2005. © 2005 Wiley-Liss, Inc. [source] GABAergic and glycinergic presympathetic neurons of rat medulla oblongata identified by retrograde transport of pseudorabies virus and in situ hybridizationTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2004Ruth L. Stornetta Abstract Electron microscopy suggests that up to half the synaptic input to sympathetic preganglionic neurons (SPGNs) is GABAergic or glycinergic. A proportion of this input is suspected to originate from neurons located within the medulla oblongata. The present study provides definitive evidence for the existence of these supraspinal presympathetic (PS) neurons with inhibitory phenotypes. PS neurons were identified by retrograde trans-synaptic migration of pseudorabies virus (PRV) injected into the adrenal gland. GABAergic or glycinergic cell bodies were identified by the presence of glutamate decarboxylase (GAD)-67 mRNA or glycine transporter (GlyT)-2 mRNA detected with in situ hybridization (ISH). Neither GABAergic nor glycinergic PS neurons were tyrosine hydroxylase (TH)-immunoreactive (ir). GABAergic PS neurons were located within the ventral gigantocellular nucleus, gigantocellular nucleus alpha, and medial reticular formation, mostly medial to the TH-ir PS neurons. About 30% of GABAergic PS neurons were serotonergic cells located in the raphe pallidus (RPa) and parapyramidal region (PPyr). Glycinergic PS neurons had the same general distribution as the GABAergic cells, except that no glycinergic neurons were located in the RPa or PPyr and none were serotonergic. PRV immunohistochemistry combined with ISH for both GlyT2 and GAD-67 mRNAs showed that at least 63% of midline medulla GABAergic PS neurons were also glycinergic and 76% of glycinergic PS neurons were GABAergic. In conclusion, the rostral ventromedial medulla contains large numbers of GABAergic and glycinergic neurons that innervate adrenal gland SPGNs. Over half of these PS neurons may release both transmitters. The physiological role of this medullary inhibitory input remains to be explored. J. Comp. Neurol. 479:257,270, 2004. © 2004 Wiley-Liss, Inc. [source] Localization of the mRNA encoding prolyl endopeptidase in the rat brain and pituitaryTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2004Gaelle Bellemère Abstract Prolyl endopeptidase (EC 3.4.21.26, PEP), a serine protease that hydrolyzes peptides at the carboxyl side of proline residues, is involved in the breakdown of several proline-containing neuropeptides and, thus, may contribute to the regulation of behavioral activities. In this study, the distribution of PEP mRNA was investigated in the central nervous system and pituitary of rat by means of quantitative reverse transcriptase-polymerase chain reaction analysis and in situ hybridization histochemistry. High densities of PEP transcripts were found in cerebellar Purkinje and granule cells, within most hypothalamic nuclei, in pyramidal neurons of the Ammon's horn, in granule cells of the dentate gyrus, and within the basolateral complex of the amygdala. Moderate levels of PEP mRNA were observed in layers 3,5 of the cerebral cortex, the anterior thalamic group, the septal region, the substantia nigra, the magnocellular neurons of the red nucleus, and the motor nuclei of the cranial nerves. Low concentrations of PEP mRNA were detected in the deep mesencephalic nuclei, the reticular formation, the pretectum, and the tectum. A high density of PEP mRNA was found in the intermediate and the anterior lobes of the pituitary, while the neural lobe was devoid of labeling. In several brain regions, the distribution pattern of PEP mRNA overlapped that of various neuropeptide receptors, suggesting that PEP is actually involved in the inactivation of regulatory neuropeptides. J. Comp. Neurol. 471:128,143, 2004. © 2004 Wiley-Liss, Inc. [source] Select spinal lesions reveal multiple ascending pathways in the rat conveying input from the male genitaliaTHE JOURNAL OF PHYSIOLOGY, Issue 7 2010C. H. Hubscher The specific white matter location of all the spinal pathways conveying penile input to the rostral medulla is not known. Our previous studies using rats demonstrated the loss of low but not high threshold penile inputs to medullary reticular formation (MRF) neurons after acute and chronic dorsal column (DC) lesions of the T8 spinal cord and loss of all penile inputs after lesioning the dorsal three-fifths of the cord. In the present study, select T8 lesions were made and terminal electrophysiological recordings were performed 45,60 days later in a limited portion of the nucleus reticularis gigantocellularis (Gi) and Gi pars alpha. Lesions included subtotal dorsal hemisections that spared only the lateral half of the dorsal portion of the lateral funiculus on one side, dorsal and over-dorsal hemisections, and subtotal transections that spared predominantly just the ventromedial white matter. Electrophysiological data for 448 single unit recordings obtained from 32 urethane-anaesthetized rats, when analysed in groups based upon histological lesion reconstructions, revealed (1) ascending bilateral projections in the dorsal, dorsolateral and ventrolateral white matter of the spinal cord conveying information from the male external genitalia to MRF, and (2) ascending bilateral projections in the ventrolateral white matter conveying information from the pelvic visceral organs (bladder, descending colon, urethra) to MRF. Multiple spinal pathways from the penis to the MRF may correspond to different functions, including those processing affective/pleasure/motivational, nociception, and mating-specific (such as for erection and ejaculation) inputs. [source] Brainstem pathology in spasmodic dysphonia,THE LARYNGOSCOPE, Issue 1 2010Kristina Simonyan MD Abstract Spasmodic dysphonia (SD) is a primary focal dystonia of unknown pathophysiology, characterized by involuntary spasms in the laryngeal muscles during speech production. We examined two rare cases of postmortem brainstem tissue from SD patients compared to four controls. In the SD patients, small clusters of inflammation were found in the reticular formation surrounding solitary tract, spinal trigeminal, and ambigual nuclei, inferior olive, and pyramids. Mild neuronal degeneration and depigmentation were observed in the substantia nigra and locus coeruleus. No abnormal protein accumulations and no demyelination or axonal degeneration were found. These neuropathological findings may provide insights into the pathophysiology of SD. Laryngoscope, 2010 [source] Brainstem pathology in DYT1 primary torsion dystoniaANNALS OF NEUROLOGY, Issue 4 2004Kevin St. P. McNaught PhD DYT1 dystonia is a severe form of young-onset dystonia caused by a mutation in the gene that encodes for the protein torsinA, which is thought to play a role in protein transport and degradation. We describe, for the first time to our knowledge, perinuclear inclusion bodies in the midbrain reticular formation and periaqueductal gray in four clinically documented and genetically confirmed DYT1 patients but not in controls. The inclusions were located within cholinergic and other neurons in the pedunculopontine nucleus, cuneiform nucleus, and griseum centrale mesencephali and stained positively for ubiquitin, torsinA, and the nuclear envelope protein lamin A/C. No evidence of inclusion body formation was detected in the substantia nigra pars compacta, striatum, hippocampus, or selected regions of the cerebral cortex. We also noted tau/ubiquitin-immunoreactive aggregates in pigmented neurons of the substantia nigra pars compacta and locus coeruleus in all four DYT1 dystonia cases, but not in controls. This study supports the notion that DYT1 dystonia is associated with impaired protein handling and the nuclear envelope. The role of the pedunculopontine and cuneiform nuclei, and related brainstem other involved brainstem structures in mediating motor activity and muscle tone also suggest that alterations in these structures, in mediating motor activity and controlling muscle tone suggests that alterations in these structures could underlie the pathophysiology of DYT1 dystonia. Ann Neurol 2004 [source] Excitatory Amino Acid Transporter EAAT-2 in Tangle-bearing Neurons in Alzheimer's DiseaseBRAIN PATHOLOGY, Issue 4 2002Dietmar Rudolf Thal The excitatory amino acid transporter EAAT-2 is physiologically expressed in astrocytes. This study demonstrates that distinct subclasses of neurons exhibited EAAT-2 immunoreactivity in cases with Alzheimer's disease (AD). EAAT-2 was identified in the following types of neurons: Cortical pyramidal cells, fascia dentata granule cells, neurons of the basal nucleus of Meynert, the substantia nigra, the paraventricular nucleus of the hypothalamus, oral and central raphe nuclei, locus coeruleus, parabrachial nucleus, and neurons of the reticular formation of the brain stem. All EAAT-2-positive neurons displayed cytoskeletal abnormalities with abnormal ,-protein and often showed condensed and shrunken nuclei. None of the control cases without AD-related pathology showed EAAT-2-immunoreactive neurons. These results indicate that AD-related neurodegeneration is associated with the expression of the glutamate transporter EAAT-2 in altered neurons. Since an aberrant expression of EAAT-1 in neurons has recently been described, the finding of a neuronal expression of EAAT-2 strongly supports the hypothesis that abnormalities in the glutamate transport play an important role in the pathogenesis of AD. [source] | |||||||||||||||||||||||||