Effects of daurisoline on intracellular Ca2+ activity in myocardium.
OBJECTIVE
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.
Wang
Z X
ZX
Department of Clinical Pharmacology, Tongji Medical University, Wuhan, China.
Zhu
J Q
JQ
Zeng
F D
FD
Hu
C J
CJ
Ma
Y L
YL
Zhong
S M
SM
D000200:Action Potentials / Q000187:drug effects; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D044182:Benzylisoquinolines; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D008297:Male; D008839:Microelectrodes; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000378:metabolism; D011690:Purkinje Fibers / Q000378:metabolism
D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; C023968:daurisoline; D002118:Calcium