The effects of quinidine, procaine amide and pyrilamine on the membrane resting and action potential of guinea pig ventricular muscle fibers
Johnson, E.A.
Journal of Pharmacology and Experimental Therapeutics 117(2): 237-244
1956
ISSN/ISBN: 0022-3565 PMID: 13332568 Accession: 025760791
The mean resting potential was 52.8 mV, and the action potential 67.2 mV. The mean maximum rate of rise of the leading phase of the action potential was 121 volts/sec. The action potential duration at a stimulation rate of 240/minute was 70-100 msec. No constant qualitative difference in action was seen between the three drugs. Their consistent effect was to reduce the maximum rate of rise of the action potential. An accompanying reduction in membrane resting potential (MRP) and overshoot sometimes occurred. The evidence suggests that the maximum rate of rise of the membrane action potential may change independent of the MRP.