Different effects of behaviorally equipotent doses of amphetamine and methamphetamine on brain biogenic amines: specific increase of phenylethylamine by amphetamine.

The effects of acute semichronic (twice daily for three days) treatments with the same doses of amphetamine (AMPH) and methamphetamine (M-AMPH) on rat brain phenylethylamine (PEA) and catecholamines were evaluated. These treatments produced similar behavioral responses and hence are assumed to be generally equipotent. Both drugs entered the brain rapidly but at different rates. While AMPH and M-AMPH produced comparable changes in the contents of catecholamines and their metabolites in the hypothalamus and caudate nucleus, only AMPH significantly elevated PEA. The elevated brain PEA produced by AMPH was not due to alpha-demethylation of AMPH. It is concluded that brain PEA may mediate some of AMPH behavioral effects but not those of M-AMPH. The catecholamines appear to be involved in the effects of both drugs.