Characterization of cloned human cholecystokinin-B receptor as a gastrin receptor.
The cholecystokinin (CCK)-B receptor cloned from human brain was characterized as a gastrin receptor by using heterologous expression systems of COS-7 cells and Xenopus oocytes. 125I-gastrin binding to human CCK-B receptor expressed in COS-7 was time-dependent, saturable and also specific, as well as 125-I-CCK-8. The binding of 125I-gastrin was inhibited by CCK-8 about 10-fold more potently than by gastrin. The rank order of potency of several antagonists to 125I-gastrin binding was YM022 > CI-988 > L-365,260 > L-364,718. Addition of GTP gamma S, a nonhydrolysable analog of GTP, dose-dependently inhibited 125I-gastrin binding, and lowered the gastrin binding affinity, Gastrin (10(-9)-10(-7) M) also evoked a Ca(2+)-dependent Cl- current in Xenopus oocytes expressing CCK-B receptors. These results suggest that the pharmacological profile of the cloned human CCK-B receptor using 125I-gastrin is closely parallel to that reported in gastric mucosa, and that the receptor transduces cellular signals of gastrin as well as those of CCK-8.
Miyake
A
A
Molecular Medicine Research Laboratories, Yamanouchi Institute for Drug Discovery Research, Ibaraki, Japan.
Mochizuki
S
S
Kawashima
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002460:Cell Line; D003001:Cloning, Molecular; D005755:Gastrins / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D000882:Haplorhini; D006801:Humans; D007457:Iodine Radioisotopes; D008969:Molecular Sequence Data; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D012844:Sincalide / Q000378:metabolism; D014162:Transfection; D014981:Xenopus
D005755:Gastrins; D007457:Iodine Radioisotopes; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D012844:Sincalide