title: Calcium, nifedipine and arrhythmias in isolated rat atria.
abstract: Arrhythmias were induced in isolated rat atrial muscle preparations by increasing the calcium concentration of the Ringer solution, while the potassium concentration was kept low. A rise in the resting tension occurred simultaneously. The release of aspartate aminotransferase (ASAT) from the fibrillating atria was not higher than the release from non-fibrillating atria pretreated with a calcium-antagonistic drug, nifedipine 100 microgram/l. It is suggested that calcium-induced rat atrial arrhythmias in the present experiments are caused by a direct effect on calcium influx through the excitable membrane and not as a result of myocardial lesion caused by calcium overload.
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D001219:Aspartate Aminotransferases / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D005260:Female; D006325:Heart Atria / Q000187:drug effects* / Q000201:enzymology; D009543:Nifedipine / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats
chemical_list: D011725:Pyridines; D001219:Aspartate Aminotransferases; D009543:Nifedipine; D002118:Calcium