Dauricine-induced changes in monophasic action potentials and effective refractory period of rabbit left ventricle in situ

Abstract

Aim: To study the effects of dauricine and sotalol on monophasic action potentials and effective refractory period of the rabbit heart in situ.

Methods: Monophasic action potentials recording and programmed electrical stimulation techniques.

Results: Iv injection of dauricine 0.5 mg . kg-1 . min-1 for 24 min produced a decrease of the amplitude of monophasic action potentials from (17+/-6) mV to (7.1 +/- 1.5) mV (P < 0.05) and increased the duration of 50 % and 90 % repolarization of monophasic action potentials and effective refractory period from (130 +/- 26), (167 +/- 25), (128 +/- 12) ms to (198 +/- 33), (235 +/- 34), (185 +/- 25) ms (P < 0.05), respectively. Sotalol had the similar effects on monophasic action potentials and effective refractory period to that of dauricine. Dauricine and sotalol did not change the ratio between effective refractory period and the duration of 90 % repolarization.

Conclusion: Dauricine and sotalol decreased the amplitude of monophasic action potentials and increased the duration of 50 % and 90 % repolarization and effective refractory period.