%0 Journal Article %A NORMAN J. TJRETSKY %A LEWIS S. SEIDEN %T EFFECT OF α-METHYL DOPA ON THE RESERPINE-INDUCED SUPPRESSION OF MOTOR ACTIVITY AND THE CONDITIONED AVOIDANCE RESPONSE %D 1969 %J Journal of Pharmacology and Experimental Therapeutics %P 153-162 %V 168 %N 1 %X The reserpine-induced suppression of the conditioned avoidance response in rats was partially and temporarily reversed by the injection of α-methyl-dihydroxyphenylalanine (α-methyl dopa) (200 mg/kg). α-Methyl dopa also reversed the reserpine-induced suppression of motor activity in rats. Occurring concomitantly with the increase in motor activity was a rise in brain α-methylated amines. The brain α-methylated amine levels, however, declined more slowly than did the motor activity. Both the increase in motor activity and the amount of α-methylated amines formed were dependent on the dose of α-methyl dopa administered. To determine the role of the α-methylated amines and α-methyl dopa in the reversal of the reserpine-induced suppression of motor activity, RO-4-4602, an aromatic amino acid decarboxylase inhibitor, was administered. Reserpine-pretreated animals, receiving RO-4-4602 (400 mg/kg) before α-methyl dopa (400 mg/kg), showed a lower brain content of α-methylated amines and a lower level of motor activity than animals not treated with the decarboxylase inhibitor. The brain levels of α-methyl dopa, however, were not changed. This would support the hypothesis that the α-methylated amines could act as false transmitters in the brain. For all doses of α-methyl dopa, the motor activity of animals pretreated with reserpine was markedly greater than that of animals pretreated with vehicle. A hypothesis was proposed to explain the difference in motor activity between the latter two groups on the basis of the present data. Received for publication October 28, 1968. © 1969, by The Williams & Wilkins Company %U https://jpet.aspetjournals.org/content/jpet/168/1/153.full.pdf