MEMBRANE ELECTRICAL PROPERTIES OF VASCULAR MUSCLE

该项目定量膜兴奋步骤和Ca++释放， 引发血管肌肉收缩。 细胞内Ca++将 通过双折射信号定量和定位， 细胞和细胞内Ca++指标，将被引入到 细胞通过脂质体或通过紧密密封的移液管。 细胞外Ca++ 将使用光学指示剂进行测量，以指示Ca++流入 使进入细胞的Ca++部分与 在活细胞内释放。 除了光学和 激活的电学研究，Ca++进入和电压在 收缩器的激活将通过操纵 细胞外Ca++和K+。 膜片钳单离子通道记录 技术和电压钳中的整个单细胞记录将允许 Ca++电流和K+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Ca++激活的通道。 的相互作用 哇巴因和其他Na+泵抑制剂之间的细胞内 将研究Ca++。 这些离子流的测量也将允许 要控制的血管肌细胞的细胞内离子组成 第一次 制备物包括新生大鼠奇静脉和 成年大鼠脑动脉和肠系膜动脉。 在每种情况下， 分离的单细胞将与加压的研究相关， 在体外灌注相同血管的节段， 与血管兴奋相关的水平机制， 收缩性能

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.