Gating and blocking of calcium channels by dihydropyridines in the pancreatic B-cell.
The organic calcium-antagonist nifedipine inhibits glucose-stimulated 45Ca net uptake and insulin release by rat pancreatic islets. However, the chemically related dihydropyridine derivative BAY K 8644 (methyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5- carboxylate) enhances 45Ca net uptake and insulin release and protects the B-cell against the inhibitory action of nifedipine. It is proposed that a regulatory site exists in or near the calcium channels, in the B-cell plasma membrane, and that occupation of this site by selected dihydropyridines may either facilitate or inhibit Ca2+ influx into the B-cell.
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats
D007328:Insulin; D007473:Ion Channels; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009543:Nifedipine; D005947:Glucose; D002118:Calcium