Acetylcholine and cholecystokinin receptors functionally couple by different G‐proteins to phospholipase C in pancreatic acinar cells

FEBS Letters

Schultz, G.¹  Eckhardt, L.³  Schnefel, S.³  Banfic, H.²  Schulz, I.³ 

[1] Institut für Pharmakologie der Freien Universität Berlin, Berlin, Germany;Department of Physiology, Faculty of Medicine, University of Zagreb, Yugoslavia;Max-Planck-Institut für Biophysik, Kennedyallee 70, 6000 Frankfurt (Main) 70, FRG

关键词: Cholera toxin;    Pertussis toxin;    Inositol trisphosphate;    ADP-ribosylation;    GTPγS;    CCK-OP;    cholecystokinin octapeptide;    ACh;    acetylcholine;    CCh;    carbamylcholine chloride (carbachol);    G-protein;    guanine nucleotide binding protein;    IP3;    inositol trisphosphate;    GTPγS;    guanosine 5′-O-(3-thiotriphosphate);    VIP;    vasoactive intestinal polypeptide;    CT;    cholera toxin;    PT;    pertussis toxin;    f-MLP;    formyl Met-Leu-Phe;   

DOI  :  10.1016/0014-5793(88)80655-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have studied the involvement of GTP-binding proteins in the stimulation of phospholipase C from rat pancreatic acinar cells. Pretreatment of permeabilized cells with activated cholera toxin inhibited both cholecystokinin-octapeptide (CCK-OP) and GTPγS but not carbachol (CCh)-induced production of inositol trisphosphate. Pertussis toxin had no effect. Neither vasoactive intestinal polypeptide, a stimulator of adenylyl cyclase, nor the cAMP-analogue, 8-bromo cAMP, mimicked the inhibitory effect of cholera toxin on agonist-induced phospholipase C activation. This indicates that inhibition by cholera toxin could not be attributed to a direct interaction of cholera toxin activated G_s with phospholipase C or to an elevation of cAMP. In isolated rat pancreatic plasma membranes cholera toxin ADP-ribosylated a 40 kDa protein, which was inhibited by CCK-OP but not by CCh. We conclude from these data that both CCK- and muscarinic acetylcholine receptors functionally couple to phospholipase C by two different GTP-binding proteins.

【 授权许可】

Unknown