REGULATION OF ION CHANNELS IN VASCULAR SMOOTH MUSCLE

血管平滑肌细胞膜上的离子通道起着重要的作用， 在兴奋-收缩偶联和血管收缩中的重要作用 语气 这些离子通道的活性由 神经递质如去甲肾上腺素、血管活性激素如 血管紧张素-II是一种临床上有用的药物，如Ca 2+拮抗剂。 的 离子通道可以直接或间接地由这些离子通道调节。 物质，监管过程可能包括形成或 细胞内信使的释放，如Ca 2+，ATP，G蛋白，环 AMP、环GMP、磷酸肌醇（IP 3/IP 4）和甘油二酯。 在 某些疾病状态、离子通道的性质和/或调节 可以改变。 由于不同区域的血管具有不同的 兴奋性程度，k各种离子通道的比例和/或 它们的监管程序也可能不同。 本研究的目的是 详细研究其具体特征和监管 离子通道的机制，包括各种类型的Ca 2+和K+ 通道，在新鲜分离和培养的血管平滑肌细胞。 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Ca ~（2+）、ATP和环核苷酸水平的影响 对Ca 2+和K+通道活性的影响将由细胞内 这些物质的渗透。 磷酸化介导的可能作用 通过各种蛋白激酶（即，环核苷酸依赖性， Ca 2 +/钙调素依赖性和Ca 2 +/磷脂依赖性）调节 将探索离子通道活性和细胞兴奋性。 的 将研究血管活性物质的作用机制。 的 磷酸肌醇代谢的可能作用（即，IP 3、IP 4和 双脂环甘油形成）在激动剂的电生理作用中的作用 如血管紧张素II。 可能的离子门控 还将研究G蛋白的通道。 的结果予以 研究应该提供关于离子通道如何在 血管平滑肌功能和调节，并应有助于 阐明重要的血管活性物质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.