The effects of gabapentin on different ligand- and voltage-gated currents in isolated cortical neurons.

A clear picture of the mechanisms of action of the anti-epileptic agent gabapentin is far from being accomplished. We have analyzed the effects of gabapentin on ligand- and voltage-gated currents in isolated adult rat cortical neurons. Gabapentin failed to modify glutamate currents and produced a slight reduction of GABA responses. Negligible inhibition of sodium, but consistent inhibition of high-voltage-activated calcium conductance was promoted by gabapentin. In addition, gabapentin reduced calcium current sensitivity to dihydropyridine agonist and antagonists. Interestingly, gabapentin also decreased a not-inactivating, cadmium-sensitive, potassium current. These unconventional effects might underlie its efficacy in a variety of diseases which involve periodic discharge patterns as neuropathic pain or essential tremor.