[Effects of emodin on the intracellular calcium concentration ([Ca2+]i) and L-type calcium current of the single ventricular mytocytes from guinea pig].
OBJECTIVE
To study the effects of emodin on intracellular calcium concentration ([Ca2+]i) and L-type calcium current of the single ventricular myocytes from guinea pig.


METHODS
Enzymatic dissociation was used to isolate single ventricular myocytes from adult guinea pig. They were loaded with Ca2(+)-sensitive fluorecent indicator Fluo-3/AM. [Ca2+]i represented by fluorescent intensity (FI) was measured by laser scanning confocal microscope. Whole cell patch clamp technique was used to record ICa-L.


RESULTS
At resting status, [Ca2+]i was not affected by emodin (1-100 mumol.L-1). Emodin at the concentration of 1 mumol.L-1 was shown to increase the [Ca2+]i induced by 60 mmol.L-1 KCl. The peak value of fluorescent intensity was increased from 1,877 +/- 551 to 2,905 +/- 739 (n = 8, P < 0.05). Emodin at the concentration of 10 mumol.L-1 had no effect on the increase of [Ca2+]i induced by 60 mmol.L-1 KCl. However, the increase of [Ca2+]i induced by KCl was reduced to 1,214 +/- 335 (n = 8, P < 0.05) by 100 mumol.L-1 emodin. The density of ICa-L was increased from (-6.2 +/- 1.3) pA/pF to (-8.3 +/- 0.3) pA/pF (n = 6, P < 0.05) by 1 mumol.L-1 emodin at the test pulse of 0 mV. The current was not altered by 10 mumol.L-1 emodin. But it was inhibited from (-6.6 +/- 1.0) pA/pF to (-3.80 +/- 0.16) pA/pF (n = 6, P < 0.05) by 100 mumol.L-1 emodin at the test pulse of +10 mV.


CONCLUSIONS
Emodin has two-way regulation on [Ca2+]i and ICa-L of cardiomyocytes in guinea pig.
Liu
Ying
Y
Department of Pharmacology, Harbin Medical University, Harbin 150086, China.
Shan
Hong-li
HL
Sun
Hong-li
HL
He
Shu-zhuang
SZ
Yang
Bao-feng
BF
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D002469:Cell Separation; D004305:Dose-Response Relationship, Drug; D004642:Emodin / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*
D020746:Calcium Channels, L-Type; D004642:Emodin; D002118:Calcium