title: Distribution and density of substance P receptors in the feline gastrointestinal tract using autoradiography.
abstract: Autoradiography was used to localize and quantify substance P receptors in the feline gastrointestinal tract. The specific binding of 125I-Bolton Hunter substance P was determined in the esophagus, lower esophageal sphincter, antrum, pylorus, duodenum, jejunum, ileum, ileocecal sphincter, and colon. Competitive binding studies indicated that substance P binding sites or NK-1 receptor sites were demonstrated. The concentration of NK-1 receptors was greatest in the distal half of the gastrointestinal tract, with the highest concentrations in the proximal colon. The circular muscle layer contained the greatest amount of substance P binding. The location and density of binding sites for substance P may be important in understanding the relative importance of both the pharmacological responses to this neuropeptide and the immunohistochemical evidence of the peptide at different sites in the intestine.
authors.affiliation: Department of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: R D
authors.initials: RD
authors.lastname: Rothstein
authors.forename: E
authors.initials: E
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: Ouyang
mesh_terms: D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001667:Binding, Competitive; D002415:Cats; D004064:Digestive System / Q000737:chemistry*; D007457:Iodine Radioisotopes; D008297:Male; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000302:isolation & purification*; D013373:Substance P / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013373:Substance P