KINASE REGULATION OF L TYPE CALCIUM CHANNELS

离子通道作为血管平滑肌收缩活动的调节剂发挥核心作用。 在这方面特别相关的是控制钙进入细胞的电压门控L型Ca通道（Ca（L））。 Ca（L）通道的活性可以通过各种激酶级联来调节，这些激酶级联导致通道的直接磷酸化或一些上游中间体的磷酸化。 特别是，有令人信服的证据表明，cAMP/PKA途径，cGMP/PKG途径和PL/PKC途径作为Ca（L）通道的调节剂发挥重要作用。 然而，这些途径如何调节通道活动的细节仍不清楚。 本研究探讨了兔门静脉平滑肌细胞Ca（L）通道的激酶调节。 实验被描述为研究G蛋白亚基，锚定蛋白，磷酸二酯酶活性和磷酸酶活性作为PKA，PKG和PKC途径的介质/调节剂的作用。 将在天然血管肌细胞和哺乳动物HEK 293细胞中表达的Ca（L）通道上进行全细胞和分离的膜片记录。 这些研究的总体假设是，Ca（L）通道的激酶调节代表当激动剂与受体结合时启动的多种不同作用的总和。 通过更详细地了解控制钙进入血管平滑肌细胞的机制，我们可以帮助开发更有选择性地调节血管Ca（L）通道活性并因此调节血管张力的药物。 控制血管张力在血管疾病如高血压和血管痉挛的管理中至关重要，高血压和血管痉挛可导致缺血、中风、梗塞并最终死亡。

Ion channels play a central role as modulators of vascular smooth muscle contractile activity. Of particular relevance in this regard are voltage gated L-type Ca channels (Ca(L)) which control calcium entry into the cell. The activity of Ca(L) channels can be modulated by various kinase cascades that lead either to direct phosphorylation of the channel or phospharylation of some upstream intermediary. In particular, there is convincing evidence that the cAMP/PKA pathway, the cGMP/PKG pathway and the PL/PKC pathway play important roles as modulators of Ca(L) channels. However, the details of how these pathways modulate channel activity are still not clear. The present study investigates kinase regulation of Ca(L) channels in smooth muscle cells of the rabbit portal vein. Experiments are described to investigate the role of G-protein subunits, anchoring proteins, phosphodiesterase activity and phosphatase activity as mediators/modulators of the PKA, PKG and PKC pathways. Whole cell and isolated patch recordings will be undertaken on native vascular myocytes and on Ca(L) channels expressed in mammalian HEK293 cells. The overall hypothesis for these studies is that kinase regulation of Ca(L) channels represents a summation of multiple divergent actions which are set in motion when agonist binds to a receptor. By understanding in greater detail the mechanisms which control calcium entry into vascular smooth muscle cells we may aid in the development of drugs which more selectively modulate vascular Ca(L) channels activity and hence vascular tone. Controlling vascular tone is of central importance in the management of vascular diseases such as high blood pressure and vasospasm which can lead to ischemia, stroke, infarction and ultimately death.