| The pre-excitement of uterine smooth muscle leads to preterm labor. Intracellular free calcium ions is the key point in smooth muscle's excitation-contraction coupling. CRH is said to be "placenta bioclock" during pregnancy. BKCa channel plays an important role in regulating smooth muscle contractility and maintaining membrane potential. In order to obtain the possible mechanisms of CRH on uterine contractility, and the change of BKCa channel when pregnancy occurs, we studied the changes of intracellular free calcium ions by CRH in cultured myometrial cells and functional α -subunit of BKCa channel and their electrophysiological properties during pregnancy. Our results showed that exogenous CRH increased intracellular free calcium levels mainly through CRH-R1, but did not change their levels in term non-labor group. Expression of BKCa channel's α -subunit and the open rate of BKCa channels decreased significantly when labor occurred. |
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