REGULATION OF CALCIUM CHANNELS IN VASCULAR SMOOTH MUSCLE

血管平滑肌钙通道的调节

• 批准号: 2219656
• 负责人: NICHOLAS SPERELAKIS
• 金额: $ 22.39万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2219656
• 关键词: G protein; adenosine triphosphate; calcium channel; calmodulin dependent protein kinase; electrophysiology; enzyme inhibitors; laboratory rat; muscle contraction; neural transmission; neurotransmitters; phosphorylation; protein kinase C; vascular smooth muscle; vasoactive agent; vasomotion; voltage /patch clamp; voltage gated channel

DESCRIPTION: Calcium ion channels in the membrane of vascular smooth muscle (VSM) cells play an important role in excitation-contraction coupling and in setting vasomotor tone. Ca2+ channels may be regulated either directly or indirectly by neurotransmitters, vasoactive hormones and therapeutic agents; regulatory processes may include the formation or release of intracellular messengers such as Ca2+, cAMP, cGMP, IP3/IP4, and diacylglycerol. The objective of the proposed studies is to investigate in detail the specific characteristics and regulatory mechanisms of calcium channels in freshly-isolated VSM cells from several different types of vessels in the rat (small mesenteric artery, aorta, portal vein). Since blood vessels from different vascular beds have different degrees of excitability, the proportion of various ion channels and/or their regulatory processes may differ. Macroscopic and microscopic (single-channel) Ca2+ current (ICa) will be recorded using whole-cell voltage clamp and patch clamp techniques. Intracellular agents will be delivered through the use of the intracellular perfusion technique. A possible role of phosphorylation, mediated by various protein kinases (PK), in regulating ICa will be explored. Specific aims include: (1) Assessing the role of cAMP- and cGMP-dependent PK systems (PK-A and PK- G) and the effect of phosphorylation and dephosphorylation on ICa. Techniques will include the application of cyclic nucleotide analogs, PK-A (cat subunit) and PK-G, and phosphatases (PPases), as well as the use of PK and PPase inhibitors. (2) The role of PK-C in the modulation of ICa, will be explored. Responses to exogenous PK-C activators (i.e. DAG, OAG), to purified PK-C, and to PK inhibitors will be determined. (3) The role of Ca2+-calmodulin-dependent PK (Ca/CaM- PKII), will be investigated using specific activators and inhibitors of this PK. The influence of intracellular levels of calcium on Ca2+ channel activity will also be studied. (4) The role of metabolism and intracellular levels of ATP on ICa will be further studied through the use of stable ATP analogs, phosphorylation blockers and metabolic poisons. (Preliminary data showed that lowering intracellular ATP levels inhibited Ca2+ channel activity and ICa.) (5) The modulation of ICa by G-proteins and G-protein gating will be examined. The results of these studies should provide comprehensive information on the complex mechanisms involved in calcium channel regulation in VSM cells, and should help to define how calcium influx, cellular excitability, and contraction are altered by important vasoactive substances.

描述：钙离子通道在血管膜光滑 肌肉（VSM）细胞在兴奋-收缩中起重要作用 耦合和设置血管紧张素。 Ca 2+通道可能是 由神经递质直接或间接调节， 血管活性激素和治疗剂;调节过程可 包括细胞内信使的形成或释放， Ca 2+、cAMP、cGMP、IP 3/IP 4和甘油二酯。 拟议研究的目的是详细调查 钙的特性和调节机制 来自几种不同类型的新鲜分离的VSM细胞中的通道 大鼠的血管（肠系膜小动脉、主动脉、门静脉） 静脉）。 由于来自不同血管床的血管 不同兴奋程度，各种离子的比例 渠道和/或它们的监管过程可能不同。宏观 和微观（单通道）Ca 2+电流（伊卡）将是 使用全细胞电压钳和膜片钳记录 技术.细胞内试剂将通过使用 细胞内灌注技术。可能发挥的作用 磷酸化，由各种蛋白激酶（PK）介导， 将探讨如何规范伊卡。 具体目标包括：（1） 评估cAMP和cGMP依赖性PK系统（PK-A和PK-B）的作用 G）以及磷酸化和去磷酸化对伊卡的影响。 技术将包括应用环核苷酸类似物， PK-A（cat亚基）和PK-G，和磷酸酶（PP酶），以及 使用PK和PPase抑制剂。(2)PK-C在细胞凋亡调控中的作用 将对伊卡进行研究。 对外源性PK-C激活剂的反应 (i.e. DAG、OAG）、纯化的PK-C和PK抑制剂将是有效的。 测定(3)Ca ~（2+）-钙调素依赖性PK（Ca/CaM-1）在细胞内的作用 PKII），将使用特定的激活剂进行研究， 这种PK的抑制剂。细胞内钙离子水平的影响 还将研究对Ca 2+通道活性的影响。(4)的作用 伊卡的ATP代谢和细胞内水平将进一步 通过使用稳定的ATP类似物、磷酸化阻断剂 和代谢毒物。 （初步数据显示， 细胞内ATP水平抑制Ca ~（2+）通道活性和伊卡。 (5)通过G蛋白和G蛋白门控对伊卡的调节将 接受检查。 这些研究的结果应该提供 涉及的复杂机制的全面信息， 钙离子通道调节的VSM细胞，并应有助于确定如何 钙内流、细胞兴奋性和收缩发生改变 重要的血管活性物质。