Effect of magnesium on calcium-dependent brain function that prolongs ethanol-induced sleeping time in mice

The effect of intracerebroventricular (i.c.v.) administration of magnesium on calcium- and dopamine-dependent brain function was investigated behavior ally and biochemically. The duration of ethanol-induced sleeping time in mi ce was prolonged following i.c.v, administration of calcium chloride (10 mu mol/kg) or dopamine (30 nmol/mouse); however, it was not affected by magne sium chloride (10 or 40 mu mol/kg). The ability of calcium to prolong ethan ol-induced sleeping time was inhibited by the administration of magnesium c hloride. The brain dopamine level in mice was significantly increased follo wing i.c.v. administration of calcium chloride. Taking into consideration t hese results and those from previous studies, it is suggested that calcium enhances dopamine synthesis in the brain through a calmodulin-dependent sys tem, and the increase in dopamine level prolongs ethanol-induced sleeping t ime. However, magnesium inhibits dopamine release. Therefore, magnesium may inhibit calcium-dependent brain function through dopaminergic neurons, and consequently reduce the effect of calcium on ethanol activity. (C) 2000 El sevier Science Ireland Ltd. All rights reserved.