EFFECT OF TETANUS TOXIN ON BASAL AND EVOKED RELEASE OF 5-HYDROXYTRYPTAMINE AND DOPAMINE IN RAT HIPPOCAMPUS IN-VIVO

Tetanus toxin is a potent neurotoxin which produces seizures and usual ly death in mammals. In the present study, we have investigated the ef fect of tetanus toxin on extracellular basal and evoked release of 5-h ydroxytryptamine (5-HT), dopamine (DA) and their metabolites in vivo, 7 days after toxin injection into the hippocampus of rats. Tetanus tox in decreased both basal and evoked release of 5-HT and DA. The 5-HT me tabolite 5-hydroxyindoleacetic acid (5-HIAA) was not significantly dec reased in the extracellular space. Of the DA metabolites 3,4-dihydroxy phenylacetic acid (DOPAC) concentration was decreased while that of ho movanillic acid (HVA) was unchanged. These findings are considered in light of the possible contributory role that a decrease in monoamine c oncentration in the hippocampus might have in the effects of tetanus t oxin.