REGULATION OF ION CHANNELS IN VASCULAR SMOOTH MUSCLE

血管平滑肌细胞膜上的离子通道发挥着重要作用 在兴奋-收缩偶联和血管舒缩中的重要作用 语气。这些离子通道的活性受以下因素控制 神经递质，如去甲肾上腺素，血管活性激素，如 血管紧张素-II，一种临床有用的药物，如钙拮抗剂。这个 离子通道可以直接或间接地由这些 物质，而监管过程可包括形成或 细胞内信使的释放，如Ca~(2+)，ATP，G蛋白，循环 AMP、环状GMP、肌醇磷酸盐(IP3/IP4)和二酰甘油。在……里面 某些疾病状态、离子通道的特性和/或调节 可能会被更改。由于来自不同地区的血管不同， 兴奋性程度，k各种离子通道和/或 它们的监管流程也可能不同。这项研究的目的是 详细调查具体特征和监管 离子通道的机制，包括各种类型的钙离子和钾离子 通道，在新鲜分离和培养的血管平滑肌细胞中。 将记录宏观和微观(单通道)电流 分别采用全细胞电压钳和膜片钳技术。 细胞内钙离子、三磷酸腺苷和环核苷酸水平的影响 钙、钾通道的活性将由细胞内决定 这些物质的灌流。磷酸化介导的一种可能作用 通过各种蛋白激酶(即，环核苷酸依赖， 钙/钙调蛋白依赖和钙/磷脂依赖)参与调控 本课程将探讨离子通道活性和细胞兴奋性。这个 血管活性物质的作用机制将被研究。这个 磷脂酰肌醇代谢的可能作用(即IP3、IP4和 双环甘油形成)在激动剂的电生理作用中 如血管紧张素-II将被评估。离子可能的门控 G蛋白的通道也将被研究。这些研究的结果 研究应提供有关离子通道如何在体内 血管平滑肌功能受到调节，应有助于 阐明重要的血管活性如何改变细胞的兴奋性 物质。

The ion channels in the membrane of vascular smooth muscle cells play an important role in excitation-contraction coupling and in setting vasomotor tone. The activity of these ion channels is controlled by neurotransmitters such as norepinephrine, vasoactive hormones such as angiotensin-II, an clinically useful drugs such as Ca2+ antagonists. The ion channels may be regulated either directly or indirectly by these substances, and the regulatory processes may include the formation or release of intracellular messengers, such as Ca2+, ATP, G-proteins, cyclic AMP, cyclic GMP, inositol phosphates (IP3/IP4), and diacylglycerol. In some disease states, the properties and/or regulation of the ion channels may be altered. Since blood vessels from different regions have different degrees of excitability,k the proportion of various ion channels and/or their regulatory processes may differ also. The objective of this study is to investigate in detail the specific characteristics and regulatory mechanisms for the ion channels, including the various types of Ca2+ and K+ channels, in freshly isolated and cultured vascular smooth muscle cells. Macroscopic and microscopic (single-channel) currents will be recorded using whole-cell voltage clamp and patch-clamp techniques, respectively. The influence of intracellular levels of Ca2+, ATP, and cyclic nucleoties on the activity of Ca2+ and K+ channels will be determined by intracellular perfusion of these substances. A possible role of phosphorylation mediated by various protein kinases (i.e., cyclic nucleotide-dependent, Ca2+/calmodulin-dependent, and Ca2+/phospholipid-dependent) in regulating ion channel activity and cellular excitability will be explored. The mechanism of action of vasoactive substances will be investigated. The possible role of phosphoinositide metabolism (i.e., IP3, IP4, and diacyclglycerol formation) in the electrophysiological actions of agonists such as angiotensin-II will be assessed. The possible gating of ion channels by G-proteins will also be investigated. The results of these studies should provide comprehensive information about how ion channels in vascular smooth muscle function and are regulated and should help to clarify how cellular excitability is altered by important vasoactive substances.