Shlykov S H
Ukr Biokhim Zh (1999). 2010 Mar-Apr;82(2):5-14.
The work deals with the study of molecular and membrane mechanisms of uterotonic peptide hormone oxytocin action on Ca ions homeostasis in the uterus myocites and activity of passive and active transport systems of this cation, localized in the myometrium subcellular structures. Biochemical mechanisms of additional Ca2+ influx into the myometrium cells from extracellular environment activated by oxytocin and thapsigargin were determined. Such Ca2+ influx has got the name of capacitative cation entry (CCE), or which is activated by intracellular store depletion (store-operated calcium entry). It was shown that cells from the nonpregnant human myometrium and PHM1-41 cells (immortalized pregnant human myometrial cells) expressed endogenous hTrpC1, 3, 4, 6 and 7 mRNA. The membrane-permeable derivative of diacylglycerol (OAG) stimulated an increase in oscillations of intracellular free Ca2+ concentration in PHM1-41 and myometrium cells. OAG-induced Ca2+ -oscillations were not affected by inhibition of PKC. It was proved that hTrpC channels take part in the regulation of free Ca ions concentration in the myometrium cells. On the basis of results of experiments, conducted on myometrium plasma membrane fraction, the conclusion was made that oxytocin does not influence the passive Ca2+ efflux. It was shown that peptyde hormone partially inhibited Ca2+ accumulation in plasma membrane fraction. Oxytocin also partially inhibited endoplasmic reticulum calcium pump activity of the myometrium cells. The conceptual pattern of myometrial Ca2+ exchange regulation by oxytocin is offered.
该研究探讨了子宫收缩肽激素催产素对子宫肌细胞钙离子稳态以及该阳离子在子宫肌层亚细胞结构中被动和主动转运系统活性的分子和膜机制。确定了由催产素和毒胡萝卜素激活的从细胞外环境向子宫肌层细胞额外流入Ca2+的生化机制。这种Ca2+流入被称为容量性阳离子内流（CCE），或由细胞内钙库耗竭激活的钙内流（SOC）。结果表明，未孕人类子宫肌层细胞和PHM1-41细胞（永生化的孕人类子宫肌层细胞）表达内源性hTrpC1、3、4、6和7 mRNA。二酰基甘油的膜通透性衍生物（OAG）刺激了PHM1-细胞和子宫肌层细胞内游离Ca2+浓度振荡的增加。OAG诱导的Ca2+振荡不受PKC抑制的影响。已证明hTrpC通道参与子宫肌层细胞游离钙离子浓度的调节。基于对子宫肌层质膜部分进行的实验结果，得出催产素不影响Ca2+被动外流的结论。结果表明，肽激素部分抑制质膜部分中Ca2+的积累。催产素还部分抑制子宫肌层细胞内质网钙泵的活性。提出了催产素调节子宫肌层Ca2+交换的概念模型。
