Regulation mechanism of cardiac L-type CaィイD12+ィエD1 channel by nitric oxide

在通过β-肾上腺素刺激和PKA激活调节L型心脏Caïi D12+ ïi D1通道的诱导亚细胞机制中，我们克隆了PKA锚定蛋白（AKAP），并在Xenopus oocyte表达系统中表达了蛋白质。The CaイイD12+イエD1 channel activities were measured electrophysiologically as·brane BaイD12+イエD1 current。The oocytes expressed with CaイイD12+イイD1 channelイD21cイD2、イイD21aイD2、イイD2SイD2和イD22 adrenergic receptor did not show the augmentation of CaイD12+イエD1 channel by stimulation with isoproterenol （ISO）。ISO在包括bovine poly（A）+RNA被引入细胞时刺激通道。克隆AKAP-79、AKAP-15和调节器失败，无法重建ISO下的钙通道刺激。Furthermore， ISO减少了使用AKAP-79表达式的Ca通道活动。这一减少取决于AKAP-79 RNA注射的数量。The BaイイD12+イエD1 current amplitude also reduced upon expression of AKAP-79。这些数据建议通过β-肾上腺刺激需要内部-细胞蛋白（s）其他PKA锚定蛋白或钙调蛋白的数据。这些结果是在美国心脏协会第71次科学会议（1998年，达拉斯）上提出的。虽然如此，使用相同的Xenopus oocyte expression系统，但我们成功地评估了对多个表现Ca通道子类型的阻塞潜力的拮抗剂。结果发表在J Pharmacol Exp Ther作为本赠款的成就。

In order to elucidate sub-cellular mechanism in regulation of L-type cardiac CaィイD12+ィエD1 channel by β-adrenergc stimulation and PKA activation, we cloned PKA anchoring protein (AKAP) and expressed the protein in Xenopus oocyte expression system. The CaィイD12+ィエD1 channel activities were measured electrophysiologically as membrane BaィイD12+ィエD1 current. The oocytes expressed with CaィイD12+ィエD1 channel αィイD21cィエD2, αィイD22ィエD2, βィイD21aィエD2, GィイD2SィエD2α and βィイD22ィエD2 adrenergic receptor did not show the augmentation of CaィイD12+ィエD1 channel by stimulation with isoproterenol (ISO). ISO stimulated the channel when clude bovine poly(A)+RNA was introduced into the oocyte. Cloned AKAP-79, AKAP-15 and calmodulin failed to reconstruct the Ca channel stimulation by ISO. Furthermore, ISO reduced the Ca channel activity with AKAP-79 expression. The reduction was dependent on the amount of AKAP-79 cRNA injection. The BaィイD12+ィエD1 current amplitude also reduced upon expression of AKAP-79. These data suggest that CaィイD12+ィエD1 channel stimulation through β-adrenergic stimulation requires intra-cellular protein(s) other than PKA anchoring proteins or calmodulins. These results were presented in 71 th scientific meeting of american heart association (1998, Dallas).Meanwhile, using the same Xenopus oocyte expression system, we succeeded to assess the blocking potencies of several CaィイD12+ィエD1 channel antagonists on multiple subtypes of expressed Ca channel. The results were published in J Pharmacol Exp Ther as achievement of this grant.