title: Cellular distribution of vanilloid VR1 receptor immunoreactivity in the guinea-pig myenteric plexus.
abstract: Recent investigations suggest that vanilloid receptor-1 (VR1) immunoreactivity occurs in the intestine. We have determined and quantified this immunoreactivity in the myenteric plexus with respect to cholinergic and neurofilament protein-positive neurones. Guinea-pig and rat preparations were dual-labelled with specific antibodies raised in rabbit or goat against vanilloid receptor-1 and against other neurochemical markers. In the rat ileum, both vanilloid receptor antibodies were co-distributed, whereas in the guinea-pig ileum and colon, tertiary fibres were also detected with the goat antibody. In the guinea-pig, all vanilloid receptor-1-immunoreactive cell bodies were choline acetyltransferase-immunopositive (100%) and showed some immunoreactivity to neurofilament proteins (NFP-200 kDa (79%) or triplet (10.8%)) or calretinin. Immunoreactive fibres in the secondary plexus co-localised with calcitonin gene-related peptide (CGRP) and with substance P, calretinin and synapsin I in the tertiary plexus. Subpopulations of cholinergic neurones including sensory, interneuronal and secretory neurones express vanilloid receptor-1. Co-localisation with substance P and calretinin in fibres suggests that vanilloid receptor-1 may be expressed by excitatory motor neurones. The association of vanilloid receptors with calcitonin gene-related peptide and synaptic protein in fibres implies a role for vanilloid receptors in neurotransmitter/neuropeptide release. Although it is likely that at least some of the vanilloid receptor-bearing fibres originate in immunopositive myenteric soma, the origin of all these fibres cannot be identified in the present study.
authors.affiliation: Department of Biomedical Science, Institute of Medical Sciences, University of Aberdeen, Scotland AB25 2ZD, Aberdeen, UK.
authors.forename: Sharon
authors.initials: S
authors.lastname: Anavi-Goffer
authors.forename: Angela A
authors.initials: AA
authors.lastname: Coutts
mesh_terms: D000818:Animals; D064032:Calbindin 2; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D002795:Choline O-Acetyltransferase / Q000032:analysis; D003106:Colon / Q000737:chemistry; D006168:Guinea Pigs; D007082:Ileum / Q000737:chemistry; D007150:Immunohistochemistry / Q000379:methods; D066298:In Vitro Techniques; D008297:Male; D009197:Myenteric Plexus / Q000737:chemistry* / Q000166:cytology; D009412:Nerve Fibers / Q000737:chemistry; D016900:Neurofilament Proteins / Q000032:analysis; D011955:Receptors, Drug / Q000032:analysis*; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D013373:Substance P / Q000032:analysis
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D016900:Neurofilament Proteins; D011955:Receptors, Drug; D064030:S100 Calcium Binding Protein G; C051774:neurofilament protein H; D013373:Substance P; D002795:Choline O-Acetyltransferase; D015740:Calcitonin Gene-Related Peptide