Mechanism of action 1 Valproate is a simple branched-chain fatty acid. Its mechanism of action is complex and not fully understood. Valproate inhibits the catabolism of GABA, reduces the turnover of arachidonic acid, activates the extracellular signal-regulated kinase (ERK) pathway thus altering synaptic plasticity, interferes with intracellular signalling, promotes BDNF expression and reduces levels of protein kinase C. Recent research has focused on the ability of valproate to alter the expression of multiple genes that are involved in transcription regulation, cytoskeletal modifications and ion homeostasis. Other mechanisms that have been proposed include depletion of inositol and indirect effects on non-GABA pathways through inhibition of voltage-gated sodium channels.