Larsson C, Simonsson P, Hoek J B, Alling C
Department of Psychiatry and Neurochemistry, Lund University, Sweden.
Biochem Pharmacol. 1995 Aug 25;50(5):647-54. doi: 10.1016/0006-2952(95)00179-4.
The effect of ethanol on muscarinic receptor-stimulated formation of inositol 1,4,5-trisphosphate was studied in human neuroblastoma SH-SY5Y cells. Stimulation with carbachol induced a biphasic increase of inositol 1,4,5-triphosphate with an initial peak after 10 sec declining to a plateau phase of elevation above basal levels, which was sustained for at least 5 min in the presence of agonist. The peak, but not the plateau phase, was concentration-dependently decreased by exposure to ethanol. Maximal inhibition was obtained within 30 sec of exposure to ethanol. Ethanol caused an increase in the EC50 value of carbachol for the initial rate of inositol 1,4,5-trisphosphate formation, measured after 10 sec of stimulation, from 98 microM in the absence to 196 microM in the presence of 100 mM ethanol. The potencies of pirenzepine and hexahydro-sila-difenidol hydrochloride for inhibiting [3H]quinuclidinyl benzilate binding and inositol 1,4,5-trisphosphate formation suggest that both phases are mediated via the muscarinic M1 receptor. Phorbol 12-myristate 13-acetate inhibited both phases of inositol 1,4,5-trisphosphate formation, whereas okadaic acid and modulators of cAMP-dependent protein kinase were without any effect. There was no inhibitory effect of ethanol when protein kinase C was inhibited by H7 and calphostin C, indicating that the ethanol effect is dependent on protein kinase C activity.
在人神经母细胞瘤SH-SY5Y细胞中研究了乙醇对毒蕈碱受体刺激的肌醇1,4,5-三磷酸形成的影响。用卡巴胆碱刺激可诱导肌醇1,4,5-三磷酸双相增加，最初在10秒后出现峰值，随后下降至高于基础水平的平台期，在激动剂存在下该平台期至少持续5分钟。暴露于乙醇会使峰值（而非平台期）浓度依赖性降低。暴露于乙醇30秒内可获得最大抑制作用。乙醇导致卡巴胆碱刺激10秒后测得的肌醇1,4,5-三磷酸初始形成速率的EC50值增加，从无乙醇时的98μM增加到存在100 mM乙醇时的196μM。哌仑西平和盐酸六氢硅二苯酯抑制[3H]喹核醇基苯甲酸酯结合和肌醇1,4,5-三磷酸形成的效力表明，两个阶段均通过毒蕈碱M1受体介导。佛波醇12-肉豆蔻酸酯13-乙酸酯抑制肌醇1,4,5-三磷酸形成的两个阶段，而冈田酸和环磷酸腺苷依赖性蛋白激酶的调节剂则无任何作用。当蛋白激酶C被H7和钙磷蛋白C抑制时，乙醇没有抑制作用，这表明乙醇的作用依赖于蛋白激酶C的活性。
