Abstract
α-Methyltyrosine (α-MT) has been proposed to cause central nervous depression by blocking synthesis of brain catecholamines. However, interpretation of these reports is complicated by the toxicity of this drug. In the present study, the effects of α-MT on behavior and brain catecholamine content of rats were examined with doses and routes of administration that did not cause toxicity. Behavioral tests consisted of conditioned avoidance responding, rotarod performance and spontaneous locomotor activity. Single intraperitoneal injections of α-MT caused marked loss of avoidance responding only in doses that were toxic. Subcutaneous injections were only slightly effective in depressing behavior because of the poor absorption of α-MT. Oral (200 mg/kg) or multiple intraperitoneal injections (3 x 50 mg/kg) of α-MT impaired avoidance responding, rotarod performance and spontaneous locomotor activity without producing obvious toxic effects. The content of α-MT in the brain and depletion of brain norepinephrine and dopamine bothexhibited a time course similar to that of the behavioral depression.
Footnotes
- Received January 28, 1966.
- Accepted March 29, 1966.
- © 1966 by The Williams & Wilkins Co.
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