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Peripheral Activation (peripheral + activation)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Induction of neuropeptides in skin innervating sensory neurons by stress and nerve growth factor as a possible reason for hair growth alteration

EXPERIMENTAL DERMATOLOGY, Issue 9 2004
A. 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]

Alpha B-crystallin is not a dominant peripheral T-cell autoantigen in multiple sclerosis amongst Sardinians

EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2003
S. Sotgiu
The heat shock protein alpha B-crystallin appears to be the dominantly recognized autoantigen in the early demyelinative process of multiple sclerosis (MS) in brain of patients. In Sardinia, MS is linked to human leucocyte antigen (HLA)-DR alleles that might influence the production of cytokines from peripheral lymphocytes. We tested the nature of peripheral anti-alpha B-crystallin-specific T-cell response in the context of predisposing HLA haplotypes both in MS patients and healthy controls. The alpha B-crystallin specific T-cell lines were generated by using the ,split-well' technique. The results indicate that the presence of short-term T-cell lines towards alpha B-crystallin is numerically comparable between the two groups and not restricted to MS-predisposing HLA-DR alleles. As for the T-cell characterization, CD4+ anti-alpha B-crystallin T cells secreting high levels of interferon- , are similarly identified in MS and healthy donors. In conclusion, the peripheral response towards the myelin antigen alpha B-crystallin is neither quantitatively nor qualitatively peculiar to MS, in contrast to the theoretical paradigm suggesting peripheral activation of myelin-reactive T cells to be the prerequisite for MS induction. [source]

In vivo evidence for a role of protein kinase C in peripheral nociceptive processing

BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2002
Adriano L S Souza
The present study was designed to characterize the nociceptive response induced by protein kinase C (PKC) peripheral activation and to investigate if this biochemical event is important for the nociceptive response induced by formaldehyde, and bradykinin (BK). Intraplantar injection of phorbol-12,13-didecanoate (PDD; 0.01, 0.1 or 1 ,g), a PKC activator, but not of 4,-PDD (inactive analogue), dose-dependently induced thermal hyperalgesia in rats. This response was not observed at the contralateral hindpaw. Intraplantar injection of PDD (0.01, 0.1 or 1 ,g) also induced mechanical allodynia. In mice, injection of PDD (0.1 or 1 ,g) into the dorsum of the hindpaw induced a spontaneous licking behaviour. Intraplantar co-injection of chelerythrine (10 or 50 ,g), a PKC inhibitor, attenuated the thermal hyperalgesia induced by PDD (0.1 ,g) in rats. The second phase of the nociceptive response induced by the injection of formaldehyde (0.92%, 20 ,l) into the dorsum of mice hindpaws was inhibited by ipsi-, but not contralateral, pre-treatment with chelerythrine (1 ,g). Intraplantar injection of BK (10 ,g) induced mechanical allodynia in rats. Ipsi- but not contralateral injection of bisindolylmaleimide I (10 ,g), a PKC inhibitor, inhibited BK-induced mechanical allodynia. In conclusion, this study demonstrates that PKC activation at peripheral tissues leads to the development of spontaneous nociceptive response, thermal hyperalgesia and mechanical allodynia. Most importantly, it also gives in vivo evidence that peripheral PKC activation is essential for the full establishment of the nociceptive response induced by two different inflammatory stimuli. British Journal of Pharmacology (2002) 135, 239,247; doi:10.1038/sj.bjp.0704434 [source]

Nerve growth factor-induced substance P in capsaicin-insensitive vagal neurons innervating the lower mouse airway

CLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2004
Q. T. Dinh
Summary Background Nerve growth factor (NGF) is elevated in allergic diseases such as bronchial asthma and can lead to an induction of substance P (SP) and related neuropeptides in guinea-pigs large-diameter, neurofilament-positive airway neurons. Objective In the present study, the effect of NGF on tyrosine kinase receptor trkA and the capsaicin receptor TRPV1 expression in airway-specific vagal sensory neurons located in the jugular,nodose ganglia complex (JNC) of mice was investigated. Methods Using retrograde neuronal tracing in combination with double-labelling immunohistochemistry, SP, trkA- and TRPV1-receptor expression was examined in airway-specific sensory neurons of BALB/c mice before and after NGF treatment. Results NGF injected into the lower airway was able to induce SP (13.0±2.03% vs. 5.9±0.33%) and trkA expression (78±2.66% vs. 60±2.11%) in larger diameter (>25 ,m), capsaicin-insensitive and trkA-positive vagal sensory neurons that were retrograde-labelled with Fast Blue dye from the main stem bronchi. Conclusion Based on the extent of SP and trkA co-expression in airway-specific neurons by NGF treatment, the present study suggests that, following a peripheral activation of trkA receptor on SP afferent by NGF which is elevated in allergic inflammation, there may be trkA-mediated SP induction to mediate neurogenic airway inflammation. [source]