REGULATION OF CALCIUM CURRENT IN ATRIAL CELLS

心房细胞钙流的调节

• 批准号: 6527415
• 负责人: RONALD W JOYNER
• 金额: $ 28.73万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6527415
• 关键词: age difference; atrium; cGMP dependent protein kinase; calcium channel; cyclic AMP; cyclic GMP; isozymes; laboratory rabbit; molecular site; myocardium; newborn animals; phosphorylation; western blottings

DESCRIPTION (adapted from the applicant's description): The overall hypothesis of this proposal is that both basal and stimulated L-type Ca currents (ICaL) in adult atrial cells are regulated synergistically by both cGMP and cAMP. This hypothesis builds on the principal investigator's novel observation that adult atrial cells retain their neonatal responsiveness to cGMP in contrast to adult ventricular cells, which do not. The proposal tests five specific predictions of the overall hypothesis. (1) Basal atrial ICa,L is modulated synergistically by cGMP and cAMP. Single rabbit atrial cells will be exposed to cGMP and/or cAMP via a perfusible patch pipette. (2) Stimulated atrial ICa,L is modulated synergistically by cGMP and cAMP. (3) The mechanism of PKG stimulated atrial ICa,L involves increased L-type Ca channel availability. (4) Site-specific differences in PKG activity correlate with differences in isoform expression. Expression of PKG isoforms (type I alpha & beta & type II) will be determined by Western immunoblotting with specific antibodies and by mRNA expression. (5) The maintained responsiveness of adult atrial ICa,L to cGMP compared to ventricular cells is a consequence of 2 phosphorylation sites, which as phosphorylated independently by PKG and PKA.

描述（改编自申请人的描述）：总体假设 该提议的核心是基础和刺激的 L 型 Ca 电流 (ICaL) 成人心房细胞受到 cGMP 和 cAMP 的协同调节。这 假设建立在首席研究员的新颖观察之上，即成人 与成人相比，心房细胞保留了新生儿对 cGMP 的反应性 心室细胞，但没有。该提案测试了五个具体预测 的总体假设。 (1) 基底心房ICa,L协同调节 通过 cGMP 和 cAMP。单个兔心房细胞将暴露于 cGMP 和/或 cAMP 通过可灌注的贴片移液管。 (2) 刺激心房 ICa,L 被调制 cGMP 和 cAMP 具有协同作用。 (3) PKG刺激心房的机制 ICa,L 涉及增加 L 型 Ca 通道可用性。 (4) 特定地点 PKG 活性的差异与亚型表达的差异相关。 将确定 PKG 亚型（I 型 α、β 和 II 型）的表达 通过使用特异性抗体的蛋白质免疫印迹和 mRNA 表达。 (5) 与成人相比，成人心房 ICa,L 对 cGMP 的持续反应性 心室细胞是 2 个磷酸化位点的结果， 由 PKG 和 PKA 独立磷酸化。