Author(s): JI Ensheng, WANG Chuan, HE Ruirong
Pages: 204-209
Year: 2004 Issue:  2
Journal: ACTA PHYSIOLOGICA SINICA
Keyword:  genistein; fluorescence intensity; myocytes; intracellular calcium; Ca2+ channel; intracellular Ca2+ release; confocalmicroscopy;
Abstract: The effects of genistein (GST) on intracellular calcium concentration ([Ca2+]i) were investigated in guinea pig ventricular myocytes. [Ca2+]i was detected by confocal microscopy and represented by relative fluorescent intensity (FI-F0)/FI0, %). The results showed that GST (10～40 μrnol/L) reduced [Ca2+]i in normal Tyrode's solution, Ca2+-free Tyrode's solution and normal Tyrode's solution containing 3 mmol/L EGTA in a concentration-dependent manner. The effects of GST on [Ca2+]i in normal Tyrode's solution were partially inhibited by pretreatment with sodium orthovanadate, a potent inhibitor of protein tyrosine phosphatase, or L-type Ca2*channel agonist Bay K8644. GST also markedly inhibited the ryanodine-induced [Ca2+]i responses in Ca2+-free Tyrode's solution. When Ca2+ waves were produced by increasing extracellular Ca2+ concentration from 1 to 10 mmol/L, GST (40 μmol/L) could block the propagating waves of elevated [Ca2+]i, and reduce the velocity and duration of propagating waves. These results suggest that GST may reduce the [Ca2+]i in isolated guinea pig ventricular myocytes. The inhibition of voltage-dependent Ca2+ channel, tyrosine kinase inhibition,and alleviation of Ca2* release from SR are possibly involved in the GST effect.