Tretter L, Adam-Vizi V
The effect of the neuroprotective drug, vinpocetine on the veratridine-evoked [Na+]i and [Ca2+]i rise in isolated nerve terminals was studied. Vinpocetine, in a pharmacologically relevant concentration range (0.4-10 microM)i reduced the increase of [Na+]i induced by veratridine (100 microM). The effect of the drug was concentration-dependent with 10 microM vinpocetine completely preventing the increase of [Na+]i. The [Ca2+]i rise in response to veratridine was also prevented by vinpocetine. In addition, the [Ca2+]i signal induced by depolarization with 20 mM K+ was reduced by vinpocetine (1-20 microM). This effect was not influenced by preincubation with 1 microM TTX and was also observed when Na+ was replaced by N-methyl glucamine in the medium. It is concluded that vinpocetine is capable of inhibiting voltage-dependent Na+ and Ca2+ channels, respectively, and these effects might contribute to the neuroprotection exerted by the drug.