SUPPRESSION OF CHANNEL CONDUCTANCE BY DIACETYL MONOXIME IN GUINEA-PIGAND EMBRYONIC CHICK CARDIOMYOCYTES

AIM: To examine the effects of diacetyl monoxime (DAM), and putative d ephospohrylating agent, on conductances of the cardiac Ca, Na, and K c hannels. METHODS: The Ca (I-Ca), Na (I-Na), and K (I-K) currents were recorded in single ventricular myocytes from guinea pigs and chick emb ryos before and after addition of DAM using the whole-cell voltage-cla mp technique. RESULTS: DAM 10 mmol . L(-1) reduced rapidly the amplitu des of I-Ca (by about 30 %), I-Na (by about 25 %), and I-K (by 25 % - 50 %) without alterations of the voltage-dependence. CONCLUSION: DAM w as a channel inhibitor of the unique type having nonselective phosphat ase activities.