[Potentiation of Delta9-tetrahydrocannabinol (THC) effects by magnesium deficiency in the rat]

Aggressive behavior can be classified into three major categories: defense, social attack and predatory behavior. The predatory behavior of rats, which prompts them to prey on mice (muricidal behavior) may be induced by injection of high doses (11 mg/kg) of Delta9-tetrahydrocannabinol (THC) or by acute magnesium deficiency. We have studied the effect of a single injection of low doses of THC (2, 4 or 8 mg/kg) in rats with a severe (50 ppm magnesium diet) or moderate (150 ppm) magnesium deficiency. The combination of moderate magnesium deficiency with low doses of THC induced muricidal behavior in all the rats and an increase in aggressiveness at the doses of 4 or 8 mg/kg of THC. Hyperaggressiveness increased with magnesium deficiency severity. Serotonin is probably involved in aggressiveness induced by both moderate magnesium deficiency and low doses of THC, but implication of other neurotransmitters and magnesium deficiency-induced alterations of CB1-and/or CB2-receptor expression are not excluded.