Augmented enhancement of valproate efficacy by taurine and pyridoxal phosphate via gabaergic metabolic support in epilepsy

A major clinical dilemma in epilepsy treatment lies in the difficulty of balancing efficacy and safety. First-line antiepileptic drugs such as valproic acid (VPA) exhibit dose-dependent side effects. Enhancing γ-aminobutyric acid (GABA)ergic inhibition is a core therapeutic strategy, but directly increasing drug doses intensifies toxicity. This study aims to explore the feasibility of optimizing current treatments by synergistically boosting endogenous GABA synthesis. Network pharmacology was employed to screen candidate molecules targeting GAD1, the gene encoding the key GABA-synthesizing enzyme, followed by molecular docking to analyze binding modes. In vitro, a magnesium-free model was used to induce epileptiform activity in primary neurons; synaptic transmission and neuronal excitability were recorded via patch-clamp, while GABA levels and GAD67 protein expression were measured. In vivo, a chronic pentylenetetrazol (PTZ) kindling rat model was established to evaluate behavioral outcomes and hippocampal GAD67 protein levels. The combined antiepileptic effects of the candidate combination with VPA were systematically assessed both in vitro and in vivo. Network pharmacology identified pyridoxal phosphate (PLP) and taurine as candidate molecules. Molecular docking suggested their complementary action on GAD67. At safe concentrations, the two drugs synergistically increased intracellular GABA levels in neurons. In the in vitro model, the combination restored the frequency of inhibitory synaptic transmission to control levels, partially suppressed neuronal hyperexcitability, and completely reversed the downregulation of GAD67 protein. In the in vivo model, the combination significantly prolonged seizure latency and restored hippocampal GAD67 expression. A key finding was that the combination markedly enhanced the efficacy of VPA: in vitro, 0.1 mM VPA combined with PLP and taurine achieved an effect comparable to 0.5 mM VPA monotherapy; in vivo, subtherapeutic-dose VPA combined with PLP and taurine reached the effect of therapeutic-dose VPA monotherapy in prolonging seizure latency. Taurine and pyridoxal phosphate can effectively enhance endogenous GABA synthesis by synergistically boosting GAD67 function. Not only do they exert independent antiepileptic effects, but they also serve as potent adjuncts that enhance the efficacy of VPA, achieving comparable therapeutic outcomes at lower doses. Not applicable