Vinpocetine is a semisynthetic derivative of the alkaloid vincamine (sometimes described as "a synthetic ethyl ester of apovincamine"), an extract from the periwinkle plant. Vinpocetine has been shown to selectively inhibit voltage-sensitive Na+ channels, resulting in a dose-dependent decrease in evoked extracellular Ca+ ions in striatal nerve endings. The Na+ channel inhibiting properties of vinpocetine are thought to contribute to a general neuroprotective effect through blockade of excitotoxicity and attenuation of neuronal damage induced by cerebral ischemia/reperfusion. Vinpocetine is also a phosphodiesterase (PDE) type-1 inhibitor, (with an IC50 of approximately 10−5 M.) leading to increases in intracellular levels of cyclic guanosine 3'5'-monophosphate (cGMP), an action that causes the vasorelaxant effects of vinpocetine on cerebral smooth muscle tissue.
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