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Effects of daurisoline on intracellular Ca2+ activity in myocardium
1Department of Clinical Pharmacology, Tongji Medical University, Wuhan, China.
Aim:
To explain the effect of daurisoline (DS) on delayed afterdepolarization (DAD).
Methods:
Ca(2+)-sensitive microelectrode technic was used to record intracellular Ca2+ activity (alpha Cai) and triggered activity (TA) arising from DAD in myocardium.
Results:
Strophantin G 3 mumol.L-1 yielded an increase in resting myocardial alpha Cai by 0.19 +/- 0.11 mumol.L-1 and transient elevations of alpha Cai by 1.48 +/- 0.55 and 4.96 +/- 1.81 mumol.L-1, respectively during the development of DAD and TA. By pretreatment with DS or verapamil, strophantin G-caused elevations of the alpha Cai in resting and provoked myocardia were eliminated and TA disappeared. DS 50 mumol.L-1 reduced Na(+)-free medium-induced elevation of dog Purkinje fibrous alpha Cai and abolished caffeine-induced increase of dog myocardial alpha Cai.
Conclusions:
DS inhibited DAD and TA by preventing an increase of alpha Cai via transmembrane Ca2+ entry and Ca2+ release from the reticulum.