[Effects of cyclovirobuxine D on intracellular Ca2+ and L-type Ca2+ current in rat ventricular cardiomyocytes].
OBJECTIVE
To determine the effects of cyclovirobuxine D (CD) on intracellular Ca2+ mobilization and L-type Ca2+ current (I(Ca-L)) in isolated rat cardiomyocytes.


METHODS
The effects of CD on the amplitude of I(Ca-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 I(Ca-L) in a concentration-dependent manner. At 10 mV, 1 and 10 micromol x L(-1) CD decreased I(Ca-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+] in control resting level was not changed by 1 and 10 micromol x L(-1) CD. [Ca2+] 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.


CONCLUSIONS
CD decreased I(Ca,L) in a concentration-dependent manner and increased [Ca2+]i release induced by caffeine in rat ventricular cardiomyocytes.
Chen
Qing-Wen
QW
Department of Pharmacology, Harbin Medical University, Harbin 150086, China.
Shan
Hong-Li
HL
Sun
Hong-Li
HL
Wang
He
H
Yang
Bao-Feng
BF
D000818:Animals; D031235:Buxus / Q000737:chemistry; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D002469:Cell Separation; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology*; D005260:Female; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism*; D010946:Plants, Medicinal / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar
D020746:Calcium Channels, L-Type; D004365:Drugs, Chinese Herbal; C032939:cyclovirobuxine D; D002118:Calcium