Acute effects of beclamide on brain regional monoamine concentrations, their metabolites and radioligand binding studies.

The effects of beclamide on regional brain monoamine levels and radioligand binding have been studied in rats. One hour oral pre-treatment with beclamide (400 mg kg-1) increased rat striatal dopamine turnover by increasing the levels of its major metabolites (DOPAC and HVA) three-fold. Simultaneously the drug reduced the concentration of striatal dopamine by a similar factor, and the concentrations of 5-hydroxytryptamine, (5-HT), 5-hydroxyindoleacetic acid, (5-HIAA) and 3-methoxytyramine in the striatum were reduced below the detection limits of the assay. In the frontal cortex, beclamide depleted the dopamine, 5-HT and 5-HIAA content whilst having no significant effect on the noradrenaline level. The concentrations of bioamines and their metabolites in the hypothalamus were unaffected by such acute beclamide treatment. In radioligand binding studies beclamide lacked affinity and failed to displace radioligands from alpha 2, beta, 5-HT, 5-HT2 and dopamine D2 sites in selective loci of the rat brain.