Characterization of cholecystokinin receptors in canine intestinal circular muscle.
We localized and characterized the binding of [3H](+/-)-L364,718 in canine small intestine circular muscle. The highest densities of [3H]L364,718 binding were located in the fraction enriched in deep muscular plexus synaptosomal membranes. In this fraction [3H]L364,718 binding was of high density (Bmax 136.78 +/- 53.66 fmol/mg) and high affinity (Kd 1.67 +/- 0.74 nM). Kinetics studies revealed that binding was reversible and yielded a similar Kd value. L364,718, CCK-8-S, and L365,260 fully displaced [3H]L364,718 binding, but ligands at CCKB receptors, gastrin-17, and YM022 did not. Therefore, CCKA receptors in canine intestine circular muscle are located on nerve endings.
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Y K
YK
Mao
Y F
YF
Wang
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EE
Daniel
D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D020109:Devazepide; D004285:Dogs; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000294:innervation / Q000378:metabolism*; D007700:Kinetics; D009130:Muscle, Smooth / Q000294:innervation / Q000378:metabolism*; D009411:Nerve Endings / Q000378:metabolism; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin / Q000378:metabolism*; D012530:Saxitoxin / Q000378:metabolism; D012844:Sincalide / Q000037:antagonists & inhibitors / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
D001570:Benzodiazepinones; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin; D012530:Saxitoxin; C058121:L 365260; D020109:Devazepide; D012844:Sincalide