Effects of an atypical barbiturate (valofan) on spontaneous and stimulated locomotor activity and on brain serotonin metabolism in mice.

The effects of an atypical barbiturate, 2-allophanyl-2-allyl-4-valerolactone (valofan), have been studied on spontaneous locomotor activity and amphetamine-induced hypermotility in mice. Some serotonergic agents were employed in order to evaluate the possible involvement of serotonin on its mechanism of action. Valofan (250 and 500 mg/kg) always reduced spontaneous locomotion and amphetamine-induced hypermotility; after the administration of L-tryptophan (10 mg/kg) and tranylcypromine (1 mg/kg) both locomotions decreased; when administered in combination with valofan they resulted in an additive effect. Similar results have been obtained by administration of 5-methoxy-N,N-dimethyltryptamine (1 mg/kg) and pindolol (5 mg/kg) alone or combined with valofan. Valofan affected the serotonin metabolism increasing 5-HT and 5-HIAA concentrations in a dose dependent way in the cortex, in the brainstem or in total brain. No correlation seems to exist between the effects of valofan, on its own or combined with serotonergic agents, on motor activity and its effects on the accumulation of 5-HT and 5-HIAA. We can therefore suggest that valofan manifests its central effects by an unclear mechanism which cannot completely be accounted for its metabolic effects on cerebral serotonin and dopamine.