Cyclic GTP imitates the potentiating effect of the nootrope vinpocetine on the high-threshold A-current in mollusk neurons.
Isolated common snail neurons were studied using two-microelectrode potential clamping to record high-threshold (threshold = 10 mV) rapidly-inactivating potassium current (I(Aht)); the effects of the nootrope vinpocetine on this current were studied and were compared with the effects of cyclic nucleotides. Intracellular application of dibutyryl derivatives of cyclic adenosine monophosphate (dcAMP) and guanosine monophosphate (dcGMP) was used. The results showed that vinpocetine potentiates or fails to alter I(Aht) in different cells, while dcGMP imitates the effect of vinpocetine. Simultaneous application of vinpocetine and dcGMP did not result in additive effects. Unlike dcGMP, dcAMP did not imitate the effects of vinpocetine, and decreased I(Aht) in most cells. These data suggest that cGMP mediates the potentiating effect of vinpocetine on I(Aht).
Solntseva
E I
EI
Science Research Institute of the Brain, Russian Academy of Medical Sciences, Moscow.
Bukanova YuV
D000818:Animals; D006152:Cyclic GMP / Q000494:pharmacology*; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D066298:In Vitro Techniques; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018697:Nootropic Agents / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D012908:Snails / Q000502:physiology*; D014748:Vinca Alkaloids / Q000494:pharmacology*
D018697:Nootropic Agents; D015221:Potassium Channels; D014748:Vinca Alkaloids; D003995:Dibutyryl Cyclic GMP; C013983:vinpocetine; D006152:Cyclic GMP