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Title: Neuropeptide tyrosine in submucosal ganglia : neuromodulation and regional differences in innervation of the guinea-pig large intestine
Author: Cunningham, S. M. C.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1995
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A comparative study to explore regional differences in the neurochemical, electrophysiological and pharmacological characteristics of submucosal neurones in the guinea-pig large intestine was undertaken using dual-labelling immunohistochemistry and conventional intracellular electrophysiological recording techniques. The density of ganglia and vasoactive intestinal polypeptide-immunoreactive (VIP-IR) neurone somata declined by approximately 40% from proximal-to-distal intestine whilst the density of neuropeptide tyrosine (NPY)-IR neurone somata declined progressively by 90%. In addition, varicose NPY-IR intraganglionic fibres, a conspicuous feature of submucosal ganglia in the duodenum, caecum and distal colon, increased progressively from proximal colon (19% of ganglia) to rectum (95% of ganglia). Conventional intracellular electrophysiological recording techniques demonstrated that there were regional differences in the proportions of three electrophysiological types of submucosal neurone (S-,S/AH- and AH-neurones) in the caecum, ascending colon and descending colon, particularly with regard to the high incidence of AH-neurones in the descending colon (17% compared to 5% in the caecum). Noradrenergic slow inhibitory postsynaptic potentials (slow IPSPs) were observed in 92% of S- and S/AH-neurones in the caecum and 71% of S and S/AH-neurones in the ascending colon, but in only 16% of S-neurones in the descending colon. Furthermore, in the caecum and ascending colon, only those cells that exhibited a slow IPSP were hyperpolarized by noradrenaline, whereas in the descending colon some cells were hyperpolarized by noradrenaline despite lacking a slow IPSP. Cocaine, which blocks neuronal uptake of catecholamines, increased the duration of the slow IPSP in the ascending colon by approximately 150%.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available