Effects of levetiracetam on axon excitability and synaptic transmission at the crayfish neuromuscular junction.

Levetiracetam (LEV) is a widely prescribed antiepileptic drug, but its actions on neuronal function are not fully characterized. Since this drug is believed to enter neurons by binding to a vesicular protein during endocytosis, we used motor axons of the crayfish opener neuromuscular junction to examine potential impacts of LEV on axon excitability. Two electrode current clamp from the inhibitory axon of the opener showed that LEV reduced action potential (AP) amplitude (AP ) and suppressed synaptic transmission, although the latter occurred with a longer delay than the reduction in AP .