Inhibition of voltage-gated K+ channels and Ca2+ channels by diphenidol

Background: Although diphenidol has long been deployed as an anti-emetic and anti-vertigo drug, its mechanism of action remains unclear. In particular, little is known as to how diphenidol affects neuronal ion channels. Recently, we showed that diphenidol blocked neuronal voltage-gated Na(+) channels, causing spinal blockade of motor function, proprioception and nociception in rats. In this work, we investigated whether diphenidol could also affect voltage-gated K(+) and CA(2+) channels.

Methods: Electrophysiological experiments were performed to study ion channel activities in two neuronal cell lines, namely, neuroblastoma N2A cells and differentiated NG108-15 cells.

Results: Diphenidol inhibited voltage-gated K(+) channels and CA(2+) channels, but did not affect store-operated CA(2+) channels.

Conclusion: Diphenidol is a non-specific inhibitor of voltage-gated ion channels in neuronal cells.