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

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.