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

In order to elucidate sub-cellular mechanism In regulation of L-type cardiac Ca D12+ D1 channel byβ-adrenergc刺激和PKA activation我们cloned PKA anchoring protein （AKAP）和expressed the protein in Xenopus oocyte表达式system. The Ca D12+ D1 channel activities were membrane membrane measured electrophysiologically as membraneBa - D12+ D1目前。The oocytes expressed with Ca - D12+ D1 channel α - D21c - D2, α - D22 - D2，β - D21a - D2，G - D2S - D2α和β - D22 - D2 adrenergic receptor did not show the augmentation of Ca - D12+ D1 channelISO stimulated the channel when clude bovine poly(A)+RNAwas introduced into the oocyte. Cloned AKAP-79，ap -15和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 theamount of AKAP-79 cRNA injection. The Ba - D12+ D1目前amplitude also reduced upon expression ofAKAP-79. These data suggest that Ca D12+ D1 channel stimulation through β-adrenergic stimulationrequires intra-cellular protein(s) other than PKA anchoring proteins or calmodulins. These resultswere presented in 71th scientific meeting of american heart association（1998年，达拉斯）.Meanwhile，using the same Xenopus oocyte表达式系统我们succeeded to assess the blocking potencies of several Ca D12+ D1 channel antagonists onmultiple subtypes of expressed Ca channel. The results were published in J Pharmacol Exp asachievement of this grant。

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.