Uptake of Sodium Valproate and Effects on GABA Transport in Astroglial Primary Culture

Abstract

The sodium salt of valproic acid (VPA) is an antiepileptic drug, which is effective in the treatment of several types of epilepsy. The drug has been postulated to exert its anticonvulsant effects by interaction with GABA-ergic systems in the brain. Results show a high-affinity uptake for sodium valproate in primary astroglial cultures from newborn rat cerebral cortex, with the kinetic parameters K_m and V_max not significantly different from those observed for GABA. This uptake was shown to interact with astroglial GABA transport in culture, with an increased K_m value for GABA uptake. Since failure in GABA-ergic systems is postulated to be one of the major factors in the aetiology of epilepsy, it is interesting to note that the transport system for GABA in astrocytes is affected by sodium valproate.