環維黃楊星D對分離大鼠心室肌細胞內Ca（上標 2+）和L型鈣電流的影響

Aim To determine the effects of cyclovirobuxine D (CD) on intracellular Ca(superscript 2+)mobilization, and L-type Ca(superscript 2+),current (I(subscript Ca-L)) in isolated rat cardiomyocytes. Methods The effects of CD on the amplitude of I(subscript Ca-L). and intracellular Ca mobilization induced by KC1 and caffeine were studied with the method of patch-clamp technique and laser scanning confocal microscopy in rat ventricular myocytes. Results CD decreased the amplitude of I(subscript Ca-L) in a concentration-dependent manner. At 10 mV, 1 and 10L^(-1) CD decreased (I(subscript Ca-L)) density from (-9.9±1.8) pA/pF to(-6.4±l.4)and(-4.2±0.6) pA/pF, respectively. Confocal experiments showed that intracellular fluorescent intensity (Fl) value of [Ca(superscript 2+)] in control resting level as not changed by 1 and 10μmol.L^(-1) CD. [Ca(superscript 2+)] increase in response to KC1 could not be reduced by CD. The rise of [Ca(superscript 2+)] in response to caffeine was further enhanced by pretreatment with CD. Conclusion CD decreased (I(subscript Ca-L)) in a concentration-dependent manner and increased [Ca(superscript 2+)] release induced by caffeine in rat ventricular cardiomyocytes.