Characterization of muscarinic acetylcholine receptors on the rat pancreatic gastrin-producing cell line B6 RIN.
The mechanisms of cholinergic stimulation of gastrin cells were studied in the rat pancreatic cell line B6 RIN. Carbachol induced an increase in intracellular Ca2+ and stimulated gastrin release in a dose-dependent manner over the range 10(-5)-10(-3) M. These effects were completely abolished by atropine, suggesting the implication of muscarinic cholinergic receptors. The binding properties of these receptors were investigated. [N-Methyl-3H]scopolamine [( 3H]NMS) binding on cell homogenates was time-dependent, saturable and consistent with a single high-affinity binding class (Kd = 39.5 pM, and Bmax = 7.9 fmol/mg DNA). Carbachol competitively inhibited [3H]NMS binding. The potency of inhibition of [3H]NMS binding by subtype selective antagonists was hexahydrodifenidol greater than pirenzepine greater than AF-DX 116. These results suggest the M3 muscarinic receptors may be involved in the carbachol-induced gastrin release from B6 RIN cells.
Abello
J
J
INSERM U45, Hôpital E. Herriot, Lyon France.
Roche
C
C
Cuber
J C
JC
Bernard
C
C
Philippe
J
J
Chayvialle
J A
JA
D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D005755:Gastrins / Q000378:metabolism*; D019832:N-Methylscopolamine; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012602:Scopolamine Derivatives / Q000378:metabolism
D005755:Gastrins; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D002217:Carbachol; D002118:Calcium; D019832:N-Methylscopolamine