Different modes of Ca channel gating behaviour favoured by dihydropyridine Ca agonists and antagonists.
Single cardiac transmembranous Ca channels have three modes of gating behaviour in the absence of drugs, expressed as current records with brief openings (mode 1), with no openings because of channel unavailability (mode 0 or null mode) and with long-lasting openings and very brief closings that appear only rarely (mode 2). The dihydropyridine Ca agonist Bay K 8644 enhances Ca channel current by promoting mode 2, while the Ca antagonists nitrendipine and nimodipine inhibit the current by favouring mode 0.
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004553:Electric Conductivity / Q000187:drug effects; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects*; D007700:Kinetics; D009539:Nicotinic Acids / Q000494:pharmacology; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D009553:Nimodipine; D009568:Nitrendipine; D011898:Ranidae; D012508:Sarcolemma / Q000502:physiology*; D013329:Structure-Activity Relationship
D002121:Calcium Channel Blockers; D007473:Ion Channels; D009539:Nicotinic Acids; D009553:Nimodipine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009568:Nitrendipine; D009543:Nifedipine; D002118:Calcium