MOLECULAR BASIS OF ETHANOL ACTION ON CALCIUM CHANNELS

慢性心肌病的分子病因学研究 酒精消费还没有确定下来。在它的许多紧急行动中， 乙醇对心肌L型钙通道有抑制作用。因为L- 钙离子通道在兴奋-收缩偶联中起关键作用 在内心，已经提出了对这些的直接抑制 乙醇通道参与慢性酒精性心肌病。 乙醇也可能通过以下途径间接影响钙通道活性 调节β-肾上腺素能刺激或二氢吡啶的能力 对这些通道的抑制。因此，拟议的研究将审查这两个问题 乙醇作用的直接和间接机制。的长期目标 这一建议是：1)在分子水平上理解乙醇是如何 抑制心肌L型钙通道，以及2)确定激素如何 刺激(肾上腺素)和抗心律失常药物(如二氢吡啶) 可以调节这种抑制作用。这个项目将应用互补DNA， 分子生物学、生化和细胞电生理 检查以下具体目标的方法：1)确定 参与乙醇抑制作用的分子决定因素 重组L型钙离子通道；2)生物物理特性 乙醇对重组L钙通道的影响 探讨内在因素对抑制作用的调节作用 乙醇法制备重组L钙通道。尽管这些目标是 主要集中在心脏L型钙通道，也存在类似的通道 在其他可兴奋的组织中，如神经系统。在一些 建议的实验，脑内L型钙通道的亚型 作为额外的神经元电压门控钙通道，将被研究。因此， 从酒精研究中心的这一部分获得的结果 也应该与我们对乙醇作用的理解有关 心脏和神经系统。

The molecular etiology of the cardiomyopathy associated with chronic alcohol consumption is not established. Among its many acute actions, ethanol has been shown to inhibit cardiac L-type ca2+ channels. Because L- type ca2+ channels play a crucial role in excitation-contraction coupling in the heart, it has been proposed that the direct inhibition of these channels by ethanol contributes to chronic alcoholic cardiomyopathy. Ethanol may also have indirect effects on ca2+ channel activity through the ability to modulate the beta-adrenergic stimulation or dihydropyridine inhibition of these channels. Thus, the proposed studies will examine both direct and indirect mechanisms for ethanol action. The long-term goals of this proposal are; 1) to understand, at the molecular level, how ethanol inhibits cardiac L-type Ca2+ channels, and 2) to establish how hormonal stimulation (epinephrine) and antiarrhythmic drugs (e.g. dyhydropyridines) may modulate such inhibition. This project will apply complementary DNA, molecular biological, biochemical and cellular electrophysiological methodologies to examine the following specific aims: 1) to characterize the molecular determinants that contribute to the ethanol inhibition of recombinant L-type Ca2+ channels; 2) to characterize the biophysical effects of ethanol on recombinant L-type Ca2+ channels; and 3) to investigate the modulatory effects of intrinsic factors on the inhibition of recombinant L-type Ca2+ channels by ethanoL. Although these aims are focused on cardiac L-type ca2+ channels, similar channels are also present in other excitable tissues, such as the nervous system. In some of the proposed experiments, brain isoforms of the L-type ca2+ channel, as well as additional neuronal voltage-gated ca2+ channels, will be studied. Thus, the results obtained from this component of the Alcohol Research Center should also be relevant to our understanding of ethanol action in both the heart and the nervous system.