MEMBRANE ELECTRICAL PROPERTIES OF VASCULAR MUSCLE

该项目对膜刺激步骤和钙离子释放进行了量化， 随后引发血管肌肉收缩。细胞内的钙离子将会 通过固有的双折射信号进行定量和定位 细胞和细胞内的钙离子指示剂将被引入到 通过脂质体或紧密密封的移液管进入细胞。细胞外钙离子 将使用光学指示器进行测量，以指示Ca++内流 使进入细胞的部分Ca++与 活细胞的细胞内释放。除了光学和 心肌细胞激活、钙离子内流和电压作用的电学研究 将通过操作来研究收缩装置的激活 胞外Ca++和K+。膜片钳记录单离子通道 电压钳中的技术和整个单电池记录将允许 钙电流和钾电流的研究，并提供有关 控制决定膜兴奋性的离子通道。那些离子 将探索由细胞内钙离子激活的通道。互动 哇巴因与其他钠泵抑制剂在细胞内的相互作用 将对Ca++进行研究。这些对离子电流的测量也将允许 需要控制的血管肌细胞内离子组成 这是第一次。制剂包括新生大鼠奇静脉和 成年大鼠脑动脉和肠系膜动脉。在每一种情况下，对 分离的单个细胞将与加压的研究相关 体外灌流相同血管的节段以允许细胞 与血管兴奋相关的水平机制 收缩特性。

This project quantitates membrane excitation steps and Ca++ release which follows to trigger vascular muscle contraction. Intracellular Ca++ will be quantitated and localized by the birefringence signal intrinsic to the cells and by intracellular Ca++ indicators that will be introduced into the cells via liposomes or by tight seal pipettes. Extracellular Ca++ measurements will be made with optical indicators to indicate Ca++ influx to allow the fraction of Ca++ entering the cell to be separated from intracellular release in living cells. In addition to optical and electrical studies of activation, the role of Ca++ entry and voltage in activation of the contractile apparatus will be studied by manipulation of extracellular Ca++ and K+. Single ion channel recording by patch clamp techniques and whole single cell recording in voltage clamp will allow studies of Ca++ currents and K+ currents and provide information about the control of ion channels that determine membrane excitability. Those ion channels activated by intracellular Ca++ will be explored. The interaction between ouabain and other inhibitors of the Na+ pump with intracellular Ca++ will be studied. These measurements of ion currents will also allow the intracellular ion composition of vascular muscle cells to be controlled for the first time. Preparations include the neonatal rat azygous vein and adult rat cerebral and mesenteric arteries. In each case, studies of isolated single cells will be correlated with studies on pressurized perfused segments of the same blood vessels in vitro to allow cellular level mechanisms to be correlated with blood vessel excitation and contraction properties.