大黄素对豚鼠单个心室肌细胞胞浆游离钙浓度及L-型钙电流的影响

Effects of emodin on the intracellular calcium concentration ([Ca^(2+)]_i) and L-type calcium current of the single ventricular mytocytes from guinea pig

目的 研究大黄素 (emodin)对豚鼠心室肌细胞钙信号的影响。方法 酶解法分离豚鼠单个心室肌细胞 ,应用激光扫描共聚焦显微镜联合全细胞膜片钳技术测量豚鼠心室肌细胞钙信号的变化。结果 在静息状态下 ,1～10 0 μmol·L- 1 大黄素对 [Ca2 +]i 均无影响 ;对 6 0mmol·L- 1 KCl诱导的外钙内流引起的胞浆钙升高有不同的影响 ,1μmol·L- 1 表现为促进作用 ;10 μmol·L- 1 无作用 ;10 0 μmol·L- 1 则表现为抑制作用。膜片钳研究结果表明 ,1μmol·L- 1 大黄素可明显促进L 型钙电流 ,10 μmol·L- 1 对L 型钙电流无影响 ;10 0 μmol·L- 1 明显抑制L 型钙电流。结论 大黄素对心肌细胞内钙及L

Aim To study the effects of emodin on intracellular calcium concentration ([Ca 2+]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 Ca 2+ sensitive fluorecent indicator Fluo 3/AM. [Ca 2+] i represented by fluorescent intensity (FI) was measured by laser scanning confocal microscope. Whole cell patch clamp technique was used to record I Ca L . Results At resting status, [Ca 2+ ] i was not affected by emodin (1-100μmol·L -1 ). Emodin at the concentration of 1 μmol·L-1 was shown to increase the [Ca 2+ ] 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 μmol·L -1 had no effect on the increase of [Ca 2+ ] i induced by 60 mmol·L -1 KCl. However, the increase of [Ca 2+ ] i induced by KCl was reduced to 1 214 ±335 ( n =8, P <0 05) by 100μmol·L -1 emodin. The density of I Ca L was increased from (-6 2 ±1 3) pA/pF to (-8 3 ±0 3) pA/pF ( n =6, P <0 05) by 1 μmol·L -1 emodin at the test pulse of 0 mV. The current was not altered by 10μmol·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 μmol·L-1 emodin at the test pulse of +10 mV. Conclusion Emodin has two way regulation on [Ca 2+ ] i and I Ca L of cardiomyocytes in guinea pig.