Amino acid distribution in brain after use of amphetamines and beta-phenylethylamine

Amino acids in rat brain were assayed after IP injection d-amphetamine or beta-phenylethylamine (PEA). Results revealed elevated values when one utilized 2.0-12 mg/kg of d-amphetamine. At 15 mg/kg, however, all amino acids fell into the control range except tryptophan which was elevated nearly threefold, and methionine which showed a tenfold decrease. When utilizing PEA to induce the behavioral changes only methionine is decreased at all concentrations of PEA. Chlorpromazine did not disturb the amino acid distribution induced by amphetamine or PEA. When haloperidol was utilized as the neuroleptic to prevent behavioral change there was a significant increase above control of all the amino acids including homocysteine. The implications of this are discussed in the text.