title: Forskolin interaction with voltage-dependent K channels in Helix is not mediated by cyclic nucleotides.
abstract: The effects of the adenylate cyclase activator forskolin upon voltage-activated K(V) currents were investigated in Helix nerve cells. Forskolin induced a fast concentration-dependent inactivation of K(V) currents without modifying the activation kinetics. The induced fast inactivation did not result from a speeding up of the voltage-controlled slow inactivation; it could not be mimicked by intracellular injection of cAMP and it was not potentiated by inhibition of the phosphodiesterase. The forskolin induced K current relaxation can be simulated by a model assuming that the drug binds reversibly to open K channels with a dissociation constant of 16.4 microM.
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology*; D005724:Ganglia / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D006372:Helix, Snails; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects* / Q000502:physiology; D009712:Nucleotides, Cyclic / Q000494:pharmacology* / Q000502:physiology; D011188:Potassium / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D009712:Nucleotides, Cyclic; D005576:Colforsin; D011188:Potassium; D002118:Calcium