ETHANOL AND CELLULAR CALCIUM METABOLISM

最近的研究表明，几种细胞类型， 细胞内钙响应激素或 神经递质也水解磷脂酰肌醇4，5- 二磷酸，以产生二酰基甘油和三磷酸肌醇 (IP3)，这可能介导细胞内的动员 钙 在本研究中，我们调查了 IP3在大鼠脑微粒体中的钙动员。 乙醇- 在未受刺激的突触体中诱导神经递质释放 被发现是独立的突触体外钙 浓度. 因此，酒精对微粒体的影响 还研究了钙摄取和释放。 IP3引起了快速的 从脑微粒体释放钙。 体外添加 100 mM乙醇对ATP依赖性钙离子无影响 在微粒体中积累，但相同浓度的 乙醇释放了25%的总积累的钙， 微粒体 乙醇诱导钙释放的浓度- 在30 mM至500 mM的范围内以依赖性方式进行。 钙释放量随着高级醇的增加而增加。 的 乙醇的影响是温度依赖性的，这表明 钙转运的扩散控制过程。 这些结果 表明乙醇对静息释放的刺激作用 大鼠脑内神经递质的变化可能是由于微粒体 释放钙。

Recent studies show that several cell types that mobilize intracellular calcium in response to hormones or neurotransmitters also hydrolyze phosphatidylinositol 4,5- bisphosphate to produce diacylglycerol and inositol trisphosphate (IP3), which may mediate the mobilization of intracellular calcium. In the present study, we investigated the involvement of IP3 in calcium mobilization in rat brain microsomes. Ethanol- induced neurotransmitter release in unstimulated synaptosomes was found to be independent of the extrasynaptosomal calcium concentration. Therefore, the effects of alcohol on microsomal calcium uptake and release were also studied. IP3 caused a rapid release of calcium from brain microsomes. In vitro addition of 100 mM ethanol had no effect on ATP-dependent calcium accumulation in the microsomes, but the same concentration of ethanol released 25% of the total accumulated calcium from the microsomes. Ethanol induced calcium release in a concentration- dependent manner over the range of 30 mM to 500 mM. The amount of calcium release increased with higher alcohols. The effect of ethanol was temperature-dependent, suggesting a diffusion-controlled process for calcium transport. These results indicate that the stimulatory effect of ethanol on resting release of neurotransmitters in rat brain may be due to the microsomal release of calcium.