Lack of evidence for the involvement of catecholaminergic mechanisms in the behavioral anti-methamphetamine effect of L-histidine in the mouse

The effects of L-histidine (HIS) on the hypermotility and the changes in brain monoamine dynamics induced by methamphetamine (MAMP) were examined in mice. HIS (1000 mg/kg) completely inhibited the hypermotility induced by MAMP (1 mg/kg). MAMP (1 mg/kg) significantly increased the dopamine level and decreased the 3,4-dihydroxyphenylacetic acid level. MAMP (5 and 10 mg/kg) also produced changes in the levels of noradrenaline, serotonin and their metabolites. HIS administered alone caused no significant changes in the levels of these amines and metabolites, nor did it affect MAMP-induced alterations in monoamine dynamics. These results suggest that catecholaminergic mechanisms are not involved in the behavioral anti-MAMP action of HIS.