NMDA receptor dependent and independent components of veratridine toxicity in cultured cerebellar neurons are prevented by nanomolar concentrations of terfenadine

Exposure of cultured neurons to nanomolar concentrations of terfenadine prevented the NMDA receptor-mediated early appearance (30min.) of toxicity signs induced by the voltage sensitive sodium channel activator veratridine. Terfenadine also provided an histamine-insensitive protection against delayed neurotoxicity by veratridine (24h), occurring independently of NMDA receptor activation, while not protecting from excitotoxicity following direct exposure of neurons to glutamate. Terfenadine reduced tetrodotoxin-sensitive inward currents, and reduced intracellular cGMP formation following veratridine exposure. Our data suggest that nanomolar concentrations of TEF may reduce excitatory aminoacid release following neuronal depolarization via a presynaptic mechanism involving voltage sensitive sodium channels, and therefore may be considered as a prototype for therapeutic drugs in the treatment of diseases that involve excitatory aminoacid neurotransmission.