MODULATION OF CALCIUM CHANNELS BY ETHANOL

最近的证据表明，调节膜离子通道， 重要的一价和二价离子穿过细胞膜的通量 可能对乙醇的作用特别敏感， 开发功能耐受性和有效的药理作用 乙醇可以介导功能耐受性和生理耐受性的发展。 慢性暴露后的依赖。 最近的研究表明， 是大脑中多种类型（L，N，T）的钙通道， 对有机钙通道阻滞剂阻滞的敏感性不同。 多种钙通道亚型的不均匀分布 脑可以解释钙通道脑区域差异 用乙醇观察到阻断。 特异性钙通道亚型 乙醇所阻断的那些是未知的，并试图表征这些 脑组织的异质性使影响复杂化。 的 本研究中描述的实验旨在研究 乙醇对不同类型的电压敏感性钙通道， 可在培养的大鼠肾上腺髓质嗜铬细胞和PC- 12间牢房 这些细胞是研究钙介导的细胞凋亡的良好模型。 发射器释放过程，似乎只有L型的 钙通道 然而，用神经刺激剂处理培养中的这些细胞， 生长因子（NGF）导致第二类型通道的表达 其类似于在神经中观察到的N型。 将进行研究 为了表征这些不同通道类型对 乙醇的抑制作用，并将与变化， NGF处理后的钙通道密度。 快速测量- 时相钙内流（45 Ca 2+）、细胞内游离钙（Fura-2 光谱）和内源性儿茶酚胺释放（高性能 液相色谱法）将由NGF处理的和未处理的细胞制备。 将测量NGF治疗后钙通道密度的变化 使用放射性配体结合技术。 急性和慢性的影响 乙醇暴露对这些细胞类型的结合参数的影响 为了将钙通道密度的变化与 离子流的功能变化，细胞内游离钙的调节 和神经生长因子处理后的儿茶酚胺释放。 这些实验 旨在研究乙醇对多种电压的作用- 敏感的钙通道，其可以在细胞培养物中表达， 应该会产生关于分子机制的有价值的见解 乙醇对神经元功能的复杂作用的基础。

Recent evidence has suggested that membrane ion channels which regulate the flux of important monovalent and divalent ions across the cell membrane may be particularly sensitive to the actions of ethanol and mediate the development of functional tolerance and potent pharmacological actions of ethanol an mediate the development of functional tolerance and physical dependence following chronic exposure. Recent studies have show that there are multiple types (L,N,T) of calcium channels in brain which exhibit different sensitivities to blockade by organic calcium channel blockers. An unequal distribution of multiple calcium channel subtypes throughout the brain may account for brain regional differences in calcium channel blockade observed with ethanol. the specific calcium channel subtype(s) which are blocked by ethanol is not know and attempts to characterize these effects are complicated by the heterogeneous nature of brain tissue. The experiments described in this study are designed to investigate the effects of ethanol on different types of voltage-sensitive calcium channels which can be expressed in cultured rat adrenal medullary chromaffin cells and PC- 12 cells. These cells are good models for the study of calcium-mediated transmitter release processes and appear to possess only the L-type of calcium channel. However, treatment of these cells in culture with nerve growth factor (NGF) results in the expression of a second type of channel which resembles the N-type observed in nerves. Studies will be conducted to characterize the sensitivity of these different channel types to the inhibitory actions of ethanol and will be correlated with changes in the density of calcium channels following NGF treatment. Measurement of fast- phase calcium entry(45Ca 2+), intracellular free calcium (Fura-2 spectroscopy) and endogenous catecholamine release (high performance liquid chromatography) will be made from NGF treated and untreated cells. Changes in calcium channel density following NGF treatment will be measured using radioligand binding techniques. The effects of acute and chronic ethanol exposure on the binding parameters of these cell types will be investigated in order to correlate changes in calcium channel density with functional changes in ion flux, regulation of intracellular free calcium and catecholamine release following NGF treatment. These experiments are designed to study the action of ethanol on multiple types of voltage- sensitive calcium channels which can be expressed in cell culture and should yield valuable insights regarding the molecular mechanisms underlying the complex actions of ethanol on neuronal function.