title: Projections and pathways of submucous neurons to the mucosa of the guinea-pig small intestine.
abstract: Double-labelling immunohistochemistry and retrograde transport of the carbocyanine dye, DiI, were used to establish the pathways of submucous neurons to the mucosa of the guinea-pig small intestine. Following the application of DiI to a villus, DiI-labelled nerve cell bodies were found in the submucous plexus up to 8.3 mm circumferentially and 3.8 mm longitudinally. The size of each of the four characterised classes of submucous neurons was determined and their distributions and projections mapped. Cells characterised by vasoactive intestinal polypeptide immunoreactivity accounted for 52% of DiI-labelled cells and had the longest projections. Cells characterised by neuropeptide Y (19%) or by calretinin immunoreactivity (13% of all DiI-labelled neurons) had relatively short projections and cells with substance P immunoreactivity (20%) had intermediate lengths of projection. When DiI was applied directly to the submucous plexus, filled neurons of all classes had significantly shorter projections, indicating that they must run for considerable distances in other pathways to the mucosa, probably via the non-ganglionated plexus. On average, each villus is innervated by at least 70 submucous neurons. From quantitative estimates there are 9 submucous neurons per villus. Thus, each submucous neuron is likely to supply about 8 villi. This demonstrates a high degree of convergence and divergence in the innervation of the mucosa.
authors.affiliation: Department of Physiology, Centre for Neuroscience, Flinders University of South Australia, Adelaide.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Song
authors.forename: S J
authors.initials: SJ
authors.lastname: Brookes
authors.forename: P A
authors.initials: PA
authors.lastname: Steele
authors.forename: M
authors.initials: M
authors.lastname: Costa
mesh_terms: D000818:Animals; D001370:Axonal Transport; D064032:Calbindin 2; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D007413:Intestinal Mucosa / Q000166:cytology / Q000294:innervation*; D007421:Intestine, Small / Q000166:cytology / Q000294:innervation*; D009434:Neural Pathways / Q000648:ultrastructure; D009474:Neurons / Q000737:chemistry / Q000648:ultrastructure*; D009478:Neuropeptide Y / Q000032:analysis; D009924:Organ Culture Techniques; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D013373:Substance P / Q000032:analysis; D013869:Thiolester Hydrolases / Q000032:analysis; D043222:Ubiquitin Thiolesterase; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D064032:Calbindin 2; D005456:Fluorescent Dyes; D009478:Neuropeptide Y; D064030:S100 Calcium Binding Protein G; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase