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Effects of low concentration of dihydroouabain on intracellular calcium in guinea pig ventricular myocytes

Yin Jingxiang, Wang Yongli, Li Qing, Shang Zhonglin, Su Suwen

Department ofo Pharmacology,Institute of Basic Medicine,Hebei Medical University.Shijiazhuang 050017,Hebei

Abstract

The effects of low concentration of dihydroouabain (DHO) on intracellular calcium concentration ([Ca~(2+)]_(i)) were investigated in guinea pig ventricular myocytes. [Ca~(2+)]_(i) was detected by confocal microscopy and represented by fluorescent intensity. DHO (1 fmol/L-1mmol/L) increased [Ca~(2+)]_(i), especially at 10 pmol/L. Nisoldipine, egtazic acid, or tetrodotoxin partially inhibited the effect of 10 pmol/L DHO on [Ca~(2+]]_(i). The effects of DHO remained in the absence of extracellular K~(+) and Na~(+). These results suggest that low concentration of DHO might increase [Ca~(2+]_(i) via the receptor-operated Ca~(2+) channels, TTX-sensitive Na~(+) channels or/and triggering of intracellular calcium release; Na~(+)/K~(+) pump and Na~(+)/Ca~(2+) exchange seem not involved in the effect of DHO.

Key words: Dihydroouabain(DHO);Intracellular calcium;Ion pumps;Guinea pigs;Ventricular myocytes;Confocal microscopy;Fluorescent dyes

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Citing This Article：

Yin Jingxiang, Wang Yongli, Li Qing, Shang Zhonglin, Su Suwen. Effects of low concentration of dihydroouabain on intracellular calcium in guinea pig ventricular myocytes. Acta Physiol Sin 2002; 54 (5): (in Chinese with English abstract).