AJP - Gastrointestinal and Liver Physiology, Vol 252, Issue 1 77-G83, Copyright © 1987 by American Physiological Society
Carbachol regulates cholecystokinin receptor on pancreatic acinar cells
T. Honda, H. Adachi, M. Noguchi, S. Sato, S. Onishi, E. Aoki and K. Torizuka
We have examined the effect of carbamylcholine on the binding of
cholecystokinin (CCK) to dispersed acini from rat pancreas. The CCK
receptor on pancreatic acini possesses two classes of binding sites.
Simultaneous addition of carbamylcholine inhibited binding of CCK to acini
due to an apparent loss of high affinity CCK binding sites. Atropine
prevented the inhibitory effect of carbamylcholine, whereas calcium
ionophore A23187 did not alter binding of CCK.
12-O-tetradecanoylphorbol-13-acetate (TPA) inhibited binding of CCK in the
same manner as carbamylcholine. Inhibition by carbamylcholine was
reversible and the recovery was time dependent. By contrast, inhibition of
binding of CCK by TPA did not reverse after a 60-min incubation without the
agent. These findings, at least in part, account for the inhibition of the
CCK-induced stimulation of amylase secretion by carbamylcholine. The action
of TPA on binding of CCK suggests the possible involvement of the
activation of protein kinase C in the inhibition of binding.
