[Cyclic GMP mimicks potentiation effect of the nootropic agent vinpocetine on the high threshold A-current in the mollusk neurons].

High-threshold transient K+ current (IAht) was recorded using a two-microelectrode voltage clamp technique in isolated neurons of the land snail. Effect of the nootropic drug vinpocetine on this current was studied and compared with cyclic nucleotides. The drug either enhanced or left unaltered the IAht, and dibutyryl cyclic GMP (dcGMP) imitated the effect. These two effects were not additive. Dibutyryl cyclic AMP did not imitate, the vinpocetine effect and decreased the amplitude of the IAht. The findings suggest that the cGMP mediated the vinpocetine effect on the Iaht.