EFFECT OF THE SKELETAL-MUSCLE RELAXANT DANTROLENE SODIUM ON THE ISOLATED, PERFUSED HEART

Dantrolene sodium produced negligible cardiovascular changes in intact dogs and in patients, but caused depression in the isolated perfused heart. In 9 consecutive experiments, rats hearts were perfused with a modified Langendorff preparation of 3.5% bovine albumin in buffered, mammalian Ringer''s solution. Perfusion pressure and temperature were kept constant. Flow was measured with an infrared drop counter. Continuous recordings were made of heart rate, coronary flow, resting length, intraventricular pressure, force displacement and their first derivatives. Statistical analysis of all parameters before and during the perfusion with dantrolene sodium solution showed no significant changes for the same period of time. Dantrolene sodium has no effect and does not confirm recent publications which reported that it causes a marked myocardial depression.