vasoactive-intestinal-peptide and Neuroma

Injury to branches of the trigeminal nerve can sometimes result in persistent dysaesthesia. In an attempt to understand the aetiology of this condition we are currently investigating changes which occur at the injury site. In the present study we have examined the expression of seven neuropeptides, all of which have been implicated in nociceptive transmission, or have previously been shown to have altered expression following nerve injury. In 20 adult ferrets the inferior alveolar nerve was sectioned and ligated, and recovery permitted for 3 days, 8 days, 3 weeks, 6 weeks or 12 weeks. Longitudinal sections of the neuromas were processed using immunohistochemical techniques to quantify the expression of substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, galanin, somatostatin, enkephalin and neuropeptide Y. After 3 days, all of the neuropeptides were expressed at the injury site. In the neuromas examined after longer recovery periods these levels of expression had declined and were similar to those found in the contralateral controls. This initial high level, followed by a decline, parallels the incidence of ectopic neural activity recorded electrophysiologically in the same model. It is, therefore, possible that the accumulation of neuropeptides at the injury site may play a role in the initiation or modulation of ectopic neural activity.

Topics: Animals; Calcitonin Gene-Related Peptide; Constriction; Cranial Nerve Neoplasms; Enkephalins; Female; Ferrets; Galanin; Immunohistochemistry; Male; Mandibular Nerve; Neuroma; Neuropeptide Y; Neuropeptides; Somatostatin; Substance P; Vasoactive Intestinal Peptide

Neurogenic appendicopathy is a frequent (17.8%), non-purulent form of appendicitis. Light microscopy enabled differentiation between an intramucosal variant, a type with central neuroma and neuromuscular proliferations in the submucosa. All nerves within the gut wall were visualized independently of neurotransmitters by immunostaining for neuron-specific enolase. Proliferation of nerve fibres with substance P- and VIP-immunoreactivity was observed in the intramucosal variant and in central neuroma. Moreover, an increase was found in stromal endocrine cells with 5-hydroxy-tryptamine-, somatostatin- and substance P-immunoreactivity. These endocrine stroma cells are considered to be the site of origin of appendix carcinoids. We, therefore, suggest that appendix carcinoids originate in-frequently multicentric-foci of small endocrine cell groups localized within proliferating nerve fibres in the subepithelial stroma, independent of the epithelial layer.

Topics: Antibody Specificity; Appendix; Cecal Diseases; Glucagon; Histocytochemistry; Humans; Immune Sera; Immunochemistry; Motilin; Nerve Fibers; Neuroma; Neurotensin; Pancreatic Polypeptide; Phosphopyruvate Hydratase; Serotonin; Somatostatin; Substance P; Vasoactive Intestinal Peptide