Reverse tolerance by chronic methamphetamine and stress induced response -Behavioral and biochemical changes in response to footshock

The effects of repeated methamphetamine (MAP) treatment (4mg/kg per day for 14 days) on behavioral and neurochemical changes induced by footshock stress in rats were examined. The challenge by footshock was conducted 7 days after cessation of the chronic treatment. The duration of fighting behavior resulting from the footshock (2.5mA, 5Hz, 10min) was significantly longer in the MAP-treated rats than in controls. After the footshock stress, the number (Bmax) of specific [(3)H] -spiperone binding sites in the striatum decreased significantly in the MAP-treated rats. No differences were found between the MAP-treated rats and controls in the concentrations of monoamines and their metabolites in the frontal cortex, striatum and mesolimbic areas