Effects of octylguanidine on heart activity: 1. Electrical cardiac response of guinea-pig as compared to Xenopus.

The effects of octylguanidine on electrical activity of Guinea-pig heart were investigated. The substance (2.7 x 10(-4)M) initially reduced the rate of rise of the action potential without a concomitant modification of the other action potential without a concomitant modification of the other action potential parameters, reminding the tetrodotoxin in its action. Subsequently, it reduced the action potential (resting membrane potential, overshoot and depolarization rate) as far as the cardiac stop (about 60 min), acting as a metabolic poison. Membrane and metabolic effects were basically analogous to those observed in Xenopus.