Characterisation of calcitonin gene-related peptide-immunoreactive neurons in the myenteric plexus of rat colon.
A mechanical or chemical stimulus applied to the intestinal mucosa induces motility reflexes in the rat colon. Enteric neurons containing calcitonin gene-related peptide (CGRP) have been suggested as intrinsic primary afferent neurons responsible for mediating such reflexes. In the present study, immunohistochemistry was performed on whole-mount stretch preparations to investigate chemical profiles, morphological characteristics and projections of CGRP-containing neurons in the myenteric plexus of the rat colon. CGRP-positive neuronal cell bodies were detected in preparations incubated with colchicine-containing medium, whereas CGRP-positive nerve fibres were found in colchicine-untreated preparations. These neurons had large oval or round cell bodies that were also immunoreactive for the calcium-binding protein calretinin and neurofilament 200. Myenteric neurons positive for both calretinin and neurofilament 200 had several long processes that emerged from the cell body, consistent with Dogiel type II morphology. Application of the neural tracer DiI to the intestinal mucosa revealed that DiI-labelled myenteric neurons each had an oval or round cell body immunoreactive for calretinin. Thus, CGRP-containing myenteric neurons are Dogiel type II neurons and are immunoreactive for calretinin and neurofilament 200 in the rat colon. These neurons probably project to the intestinal mucosa.
Mitsui
Retsu
R
Department of Health Science and Social Welfare, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama, 359-1192, Japan. rmitsui@aoni.waseda.jp
D000818:Animals; D064032:Calbindin 2; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis*; D003078:Colchicine / Q000494:pharmacology; D003106:Colon / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism; D051959:ELAV Proteins / Q000096:biosynthesis; D000067777:ELAV-Like Protein 2; D007150:Immunohistochemistry; D008297:Male; D008744:Methylamines; D009197:Myenteric Plexus / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016900:Neurofilament Proteins / Q000096:biosynthesis; D009475:Neurons, Afferent / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000096:biosynthesis; D013194:Staining and Labeling; D050257:Tubulin Modulators / Q000494:pharmacology
C576764:CALB2 protein, human; C576512:Calb2 protein, rat; D064032:Calbindin 2; D051959:ELAV Proteins; D000067777:ELAV-Like Protein 2; C490170:Elavl2 protein, rat; D008744:Methylamines; D016900:Neurofilament Proteins; D064030:S100 Calcium Binding Protein G; D050257:Tubulin Modulators; C051774:neurofilament protein H; D015740:Calcitonin Gene-Related Peptide; D003078:Colchicine