ANTAGONISM BY MONOAMINE OXIDASE INHIBITORS OF -METHYLTYROSINE-INDUCED CATECHOLAMINE DEPLETION AND BEHAVIORAL DEPRESSION

¹ Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire

Multiple intraperitoneal injections of -methyl-tyrosine (MT, 50 mg/kg/4 hr for three doses) cause a reduction of brain stores of norepinephrine and dopamine and a progressive impairment of conditioned avoidance and Rotarod performance in rats. Rats which have been pretreated with monoamine oxidase inhibitors (JB516 or tranylcypromine, 10 mg/kg) 16 hr prior to the start of the MT injections exhibit significantly less loss of avoidance behavior and less brain catecholamine depletion than rats pretreated with saline. Pretreatment with either monoamine oxidase inhibitor also prevents the impaired Rotarod performance induced by MT but not that induced by urethane or fluphenazine. Monoamine oxidase inhibitors have no effect upon the brain and plasma contents of MT. Thus the behavioral deficit induced by MT is more closely related to the reduction of brain catecholamines than to the actual concentration of MT in the brain.

This article has been cited by other articles:

				D. E. Redmond Jr., I. W. Maas, A. Kling, C. W. Graham, and H. Dekirmenjian Social Behavior of Monkeys Selectively Depleted of Monoamines Science, October 22, 1971; 174(4007): 428 - 431. [Abstract] [PDF]

				A. Horita and A. E. Hamilton Lysergic Acid Diethylamide: Dissociation of Its Behavioral and Hyperthermic Actions by DL-agr-Methyl-p-Tyrosine Science, April 4, 1969; 164(3875): 78 - 79. [Abstract] [PDF]