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The role of G protein in Leu-enkephalin induced Ca~(2+)release from intracellular pool in myocytes

Wei Zhenyu, Tan Shijin, Tang Erhu, Pan Jingyun, Zhan Chengyang

Department of Physiology, Zunyi Medical College. Zunyi 563003, Guizhou；China

Abstract

The mechanism underlying Leu--enkephalin (LEK) induced increase of the intracellular concentration of free calcium ([ca~(2+)]i) in rat ventricular myocytes was investigated by using fura--2 AM as a calcium indicator. The results were as follows: KEK (60 #mu#mol/L) elevated [Ca~(2+)]i in ventricular myocytes to matter whether extracellular calcium was removed or not. However, the effect was no longer observed when the calcium in the intracellular pool was depleted by caffeine (5 mmol/L). The LEK effect could also be blocked by naloxone (100 #mu#mol/L), pretreatment of the cells with PTX (200 ng/L) 8--10 h or procain (2 mmol/L). The results suggest that the LEK effect is mediated by coupling of G--protein with #delta#--receptor that induced Ca~(2+)release from the intracellular pool in myocytes.

Key words: Myocyte;Leu-enkephalin;#delta#-receptor;G-protein;Free calcium

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Citing This Article：

Wei Zhenyu, Tan Shijin, Tang Erhu, Pan Jingyun, Zhan Chengyang. The role of G protein in Leu-enkephalin induced Ca~(2+)release from intracellular pool in myocytes. Acta Physiol Sin 1995; 47 (2): (in Chinese with English abstract).