| Abstract: | Experiments on male Wistar rats showed that injection of L-dopa in doses of 100–200 mg/kg causes a parallel increase in the dopamine and homovanillic acid concentrations in the brain, elevation of the 5-hydroxyindoleacetic acid level, and a decrease in the serotonin concentration. Increased emotional reactivity and aggressiveness of the animals was observed at the same time. L-dopa (100 mg/kg) reduced the binding of serotonin formed from tryptophan (100 mg/kg) and accelerated its catabolism in the brain. At the same time, L-dopa abolished the depressant effect of tryptophan on emotional reactivity and aggressiveness. It is suggested that inhibition of the serotoninergic system in the brain is an essential component of the mechanism of strengthening of emotional responses under the influence of L-dopa.Department of Pharmacology, Tartu University. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Anichkov). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 134–137, February, 1976. |
