Summary
It has previously been claimed that the anti-convulsant valproate acts by augmenting GABA-ergic transmission, however, the data supporting this claim is controversial. Here we demonstrate that valproate strongly and reversibly potentiates the depressant effects of the GABA-A receptor agonist muscimol on locus coeruleus neurones recorded extracellularly from a midpontine slice preparation of the rat. The depressant effect of muscimol (2 μM) is augmented by bath applied valproate at concentrations of 50 μM, 100 μM and 1 mM. The effect of GABA is also potentiated by valproate. The potentiating effect is selective since the cell inhibition elicited by the GABA-B receptor agonist baclofen is not affected. Valproate on its own had no effect on the firing frequency.
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Olpe, HR., Steinmann, M.W., Pozza, M.F. et al. Valproate enhances GABA-A mediated inhibition of locus coeruleus neurones in vitro. Naunyn-Schmiedeberg's Arch Pharmacol 338, 655–657 (1988). https://doi.org/10.1007/BF00165630
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DOI: https://doi.org/10.1007/BF00165630