title: In vitro autoradiographic localization of (125)i-secretin receptor binding sites in rat brain.
abstract: Although the existence of the receptor for secretin in the brain was suggested, the localization of secretin receptor and the neuronal function of secretin have not been clarified yet. In the present study, the localization of secretin receptor was investigated in the rat brain by using an in vitro autoradiography technique. Frozen section autoradiography with (125)I-secretin showed intense binding in the nucleus of solitary tract, laterodorsal thalamic nucleus, and accumbens nucleus; moderate binding in the hippocampus, caudate/putamen, cerebellum, cingulate and orbital cortices. Scatchard plot analysis gave the Kd value of 125 pM with Bmax of 134 fmol/mg tissue in the hippocampus. The binding specificity was confirmed with secretin and its analogs, VIP, PACAP, and glucagon. These results indicate the secretin receptor system might have some neural functions in the brain, which could give the basis for therapeutic use of secretin in autistic children.
authors.affiliation: Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nozaki
authors.forename: Rika
authors.initials: R
authors.lastname: Nakata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mizuma
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishimura
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Kohashi
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D007457:Iodine Radioisotopes; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone / Q000032:analysis* / Q000378:metabolism; D012633:Secretin / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone; C029937:secretin receptor; D012633:Secretin