佛波脂及Microcystine-LR对SHRsp内脏阻力血管平滑肌钙通道的影响

目的 研究佛波脂及ｍｉｃｒｏｃｙｓｔｉｎｅ－ＬＲＭＣＹＳＴ－ＬＲ）对卒中易感型自发性高血压大鼠（ＳＨＲｓｐ）及常压对照Ｗｉｓｔａｒ大鼠肠纱膜动脉Ａ４－Ａ５段分支阻力血管平滑肌电压依赖性钙通道的影响。方法 采用膜片箍全细胞钡电流方式记录钙通道的活力。结果 佛波脂激活蛋白激酶Ｃ（ＰＫＣ）或ＭＣＹＳＴ－ＬＲ换制细胞蛋白磷酸酶（ＰＰＩＡ、ＰＰⅡＡ）而相对增加磷酸化过程,均可激活内脏阻力血管平滑肌电压依赖性

The effects of phorbol 12-myristate 13-acetate and microcystine-LR on calcium channel in resistance vascular smooth muscle cells in SHRsp

OBJECTIVE: To investigate the effects of phorbol 12-myristate 13-acetate (PMA) and microcystine-LR (MCYST-LR) on the whole-cell barium currenta of voltage-dependent calcium channels (VDCs) of the resistance vascular smooth muscle cells (VSMC) from the A4-A5 branches of mesenteric artery in stroke-prone spontaneously hypertensive rats (SHRsp) and its normotensive control Wistar rats. METHODS: Using the whole-cell Ba2+ current recording of the patch clamp technique. RESULTS: It was found that PMA, a protein kinase C (PKC) agonist or MCYST-LR, a protein phosphatase IA and IIA inhibitor by which the enhancement of phosphorylation induced could apparently activate the VDCs of the visceral resistance VSMC. CONCLUSIONS: This activation would be significantly potentiated during hypertension, in which the increase of L-type calcium channel openings induced by PMA was obviously manifest, as the T-type calcium channel activity weakly potentiated. In normotensive Wistar rats, the increase of T-type calcium channel openings was greater than that of SHRsp. However, the effect of MCYST-LR appeared that only the increase of L-type calcium channel current in SHRsp was significant. It is suggested that the action of PKC and/or phosphorylation on the different components of calcium currents should be emphasized in the investigation of the mechanism in the increase in peripheral resistance during hypertension.