On some relationships between dopaminergic and serotoninergic mechanisms in pentylenetetrazol convulsions in albino mice.

Experiments with pentylenetetrazol convulsion model in albino mice--80 mg/kg subcutaneously--have revealed the following. The inhibitory effect of 5-HT, introduced intracerebroventricularly in a dose of 100 micrograms per mouse is eliminated by 500 mg/kg L-DOPA, 100 mg/kg amantadine, 5 mg/kg amphetamine and apomorphine, while for lower doses of the dopaminergic agent only a tendency towards antagonism is observed. The inhibitory effect of 50HTP in a dose of 200 mg/kg i. p. is eliminated by 500 mg/kg L-DOPA, 50 mg/kg amantadine and 5 mg/kg amphetamine, but it is not influenced by these drugs in doses of 250 mg/kg L-DOPA, 25 mg/kg amantadine and 5 mg/kg apomorphine, although when applied independently L-DOPA and amantadine in these lower doses potentiate convulsive reactions. The results obtained show that the dopaminergic and 5-HT-ergic systems have an antagonist effect on the convulsive reactivity in the case of pentylenetetrazol convulsion model. These results are in agreement with our views about the determining role of the balance between the various neurotransmitter systems in convulsive-seizure reactions.