[Effects of O-(4-ethoxyl-butyl)-berbamine on isolated frog hearts].
OBJECTIVE
To study the effects of O-(4-ethoxyl-butyl)-berbamine (EBB) on isolated frog heart.


METHODS
The isolated frog hearts were prepared with Straub's method; heart contractions were recorded using LMS-2A recorder by tonotransducer.


RESULTS
EBB 1-100 mumol.L-1 caused concentration-dependent increase in systolic and diastolic activities, but did not alter the heart rate. EBB 250-500 mumol.L-1 slowed the heart beats and caused ventricular asystole. Cimetidine 10 mumol.L-1 or prazosin 100 mumol.L-1 did not inhibit the positive inotropic action of EBB. Whereas verapamil 0.01 mumol.L-1 antagonized the positive inotropic action of EBB. EBB enhanced positive inotropic action of CaCl2. The action of EBB was slower but longer than caffeine or isoproterenol. At room temperature (21.0 +/- 0.5) degree C, however, the onset of oubain was slower, but the duration of its peak action was longer, than EBB.


CONCLUSIONS
The positive inotropic action of EBB was, at least partially, via promoting the inward current of [Ca2+]o, rather than increasing the intracellular Ca2+ release.
Zheng
G H
GH
Department of Physiology, Guang-dong College of Pharmacy, Guangzhou, China.
Chen
Z L
ZL
Jiang
J H
JH
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D002316:Cardiotonic Agents / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology; D011898:Ranidae; D013268:Stimulation, Chemical; D014700:Verapamil / Q000494:pharmacology
D000470:Alkaloids; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; D002316:Cardiotonic Agents; C050387:O-(4-ethoxybutyl)berbamine; D010042:Ouabain; D014700:Verapamil; D007545:Isoproterenol; D002122:Calcium Chloride