Effects of cyclovirobuxine D on intracellular Ca2+ and L-type Ca2+ current in rat ventricular cardiomyocytes
Chen, Q-Wen.; Shan, H-Li.; Sun, H-Li.; Wang, H.; Yang, B-Feng.
Yao Xue Xue Bao 39(7): 500-503
2004
ISSN/ISBN: 0513-4870 PMID: 15493836 Document Number: 582276
Aim To determine the effects of cyclovirobuxine D ( CD) on intracellular Ca2+ mobilization and L-type Ca2+ current (ICa-L) in isolated rat cardiomyocytes. Methods The effects of CD on the amplitude of ICa-L and intracellular Ca2+ mobilization induced by KCl 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 ICa-L in a concentration-dependent manner. At 10 mV, 1 and 10 mumol. L-1 CD decreased ICa-L density from (-9.9 +/- 1.8) pA/pF to (-6.4 +/- 1.4) and (-4.2 +/- 0.6) pA/pF, respectively. Confocal experiments showed that intracellular fluorescent intensity (FI) value of (Ca2+)i in control resting level was not changed by 1 and 10 mumol. L-1 CD. (Ca2+)i increase in response to KCl could not be reduced by CD. The rise of (Ca2+)i in response to caffeine was further enhanced by pretreatment with CD. Conclusion CD decreased ICa,L in a concentration-dependent manner and increased (Ca2+)i; release induced by caffeine in rat ventricular cardiomyocytes.