Fomin V P, Singh D M, Brown H L, Natarajan V, Hurd W W
Department of Obstetrics and Gynecology, Indiana University Medical Center, Indianapolis, USA.
J Soc Gynecol Investig. 1999 May-Jun;6(3):147-52. doi: 10.1016/s1071-5576(99)00008-8.
To evaluate the effect of cocaine on intracellular free calcium ([Ca2+]i) regulation in human myometrial cells by determining the sources of Ca2+ it might mobilize, as well as assess the role cocaine might play in the catecholamine's effect on the cell's [Ca2+]i.
Primary culture of myometrial cells from pregnant women was used as an experimental model. [Ca2+]i relative changes in response to cocaine and norepinephrine were measured with fura-2 fluorometry and analyzed by means of one-way analysis of variance.
Cocaine alone (10(-8) to 10(-3) mol/L) increased [Ca2+]i by up to 43 +/- 18% over basal level in a dose-dependent manner. Norepinephrine also elevated [Ca2+]i in a concentration-dependent manner (202 +/- 24% over basal level at 10(-4) mol/L). The norepinephrine-evoked increase was inhibited in Ca(2+)-free media by 48%, whereas the cocaine response was not affected. The Ca(2+)-channel antagonist nifedipine caused decrease in the [Ca2+]i response to 10(-5) mol/L of norepinephrine by 84%, whereas the [Ca2+]i rise to 10(-5) mol/L cocaine was not significantly changed. Inhibitor of the sarcoplasmic reticulum Ca2+ pump, thapsigargin, completely blocked cocaine-evoked increases in [Ca2+]i, whereas norepinephrine responses were greatly reduced. At the same time, cocaine (10(-8) to 10(-3) mol/L) did not potentiate norepinephrine-evoked Ca2+]i increases in the cells.
These results indicate that cocaine increases [Ca2+]i in pregnant human myometrial cells, primarily by stimulating release of Ca2+ from intracellular stores rather than by direct stimulation of Ca2+ influx.
通过确定可卡因可能动员的钙离子来源，评估可卡因对人子宫肌层细胞内游离钙（[Ca2+]i）调节的影响，并评估可卡因在儿茶酚胺对细胞[Ca2+]i作用中可能发挥的作用。
以孕妇子宫肌层细胞原代培养作为实验模型。采用fura-2荧光测定法测量可卡因和去甲肾上腺素作用下[Ca2+]i的相对变化，并通过单因素方差分析进行分析。
单独使用可卡因（10(-8)至10(-3)mol/L）可使[Ca2+]i比基础水平升高多达43±18%，呈剂量依赖性。去甲肾上腺素也以浓度依赖性方式升高[Ca2+]i（10(-4)mol/L时比基础水平高202±24%）。在无钙培养基中，去甲肾上腺素引起的升高被抑制48%，而可卡因反应不受影响。钙离子通道拮抗剂硝苯地平使对10(-5)mol/L去甲肾上腺素的[Ca2+]i反应降低84%，而对10(-5)mol/L可卡因的[Ca2+]i升高无明显变化。肌浆网钙离子泵抑制剂毒胡萝卜素完全阻断可卡因引起的[Ca2+]i升高，而去甲肾上腺素反应则大大降低。同时，可卡因（10(-8)至10(-3)mol/L）并未增强细胞中去甲肾上腺素引起的[Ca2+]i升高。
这些结果表明，可卡因使孕妇子宫肌层细胞内[Ca2+]i升高，主要是通过刺激细胞内储存的钙离子释放，而非直接刺激钙离子内流。
