Effects of disopyramide on the maximum rate of rise of action potential (Vmax) in guinea-pig papillary muscles.

摘要: The correlation between the steady state and non-steady depression of Vmax by 50 μM disopyramide was investigated in 2.7, 5.4 8.1 mM [K+]o using isolated guinea-pig papillary muscles. An elevation [K+]0 from 2.7 to strengthened depressant action drug on (steady state) at 1 5 Hz, but attenuated this 0.05 0.1 Hz. Vmax-membrane potential (Vm) relationship examined stimulation rates Hz increasing 19 mM. shifted normalized Vmax- Vm curve a hyperpolarizing direction, upward -90 -65 mV without shift along axis. recovery process (non-steady introducing premature stimuli or interrupting basic stimulus for certain period. control processes three were approximated triple exponential function (the earliest, intermediate latest components). slowed component, accelerated one earliest component situated within refractory period) when elevated finding that long diastolic intervals more than 10 sec quite unique.