A G-protein mediates secretagogue-induced gap junctional channel closure in pancreatic acinar cells.
Using the double whole-cell patch-clamp technique, we determined that dialysis of cell pairs by GTP[S] potentiated electrical uncoupling induced by extracellular addition of carbamylcholine (CCh). An inhibitor of diglyceride lipase, RHC 80267, further potentiated CCh/GTP[S]-induced junctional channel closure, probably by accumulation of diacylglycerol. Moreover, the protein kinase C inhibitor polymyxin B completely blocked uncoupling elicited by CCh/GTP[S]. These results provide the first evidence suggesting that gap junction channel closure by cholinergic stimulation is mediated by a G-protein, which acts by increasing phosphatidylinositol biphosphate breakdown and protein kinase C activity.
Somogyi
R
R
University of Konstanz, Faculty of Biology, Konstanz, FRG.
Kolb
H A
HA
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D003512:Cyclohexanones / Q000494:pharmacology; D004553:Electric Conductivity; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D007365:Intercellular Junctions / Q000187:drug effects / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008049:Lipase / Q000037:antagonists & inhibitors; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010179:Pancreas / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology
D003512:Cyclohexanones; D007473:Ion Channels; D013873:Thionucleotides; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C036535:1,6-bis(cyclohexyloximinocarbonyl)hexane; D006160:Guanosine Triphosphate; D002217:Carbachol; D008049:Lipase; D019204:GTP-Binding Proteins