Serotonin and forskolin modulation of a chloride conductance in cultured identified Aplysia neurons.
1. The effect of serotonin (5-HT) and forskolin on a hyperpolarization activated Cl- conductance (gCl-) was studied using voltage-clamp techniques in identified Aplysia neurons maintained in primary cell culture. 2. The hyperpolarization-activated conductance induced by intracellular Cl- loading was carried by Cl- as determined by the following criteria: the extrapolated reversal potential of the current closely approximated the reversal potential of a cholinergic Cl- conductance, the current was not affected by extracellular ion substitutions other than Cl-, extracellular thiocyanate ions reversibly inhibited the current and the current exhibited slow voltage-dependent exponential kinetics similar to those described for the hyperpolarization-activated Cl- current in Aplysia neurons in situ. 3. In the identified neurons B1, B2, R15, and R2, 5-HT or forskolin reversibly inhibited gCl-, suggesting that 5-HT acted via an adenosine 3',5'-cyclic monophosphate-dependent mechanism. 4. Serotonergic inhibition resulted from a change in the voltage dependence of Cl- channel gating.
Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254.
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Lotshaw
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Levitan
D000818:Animals; D001048:Aplysia; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology*; D004553:Electric Conductivity; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology*; D013861:Thiocyanates / Q000494:pharmacology
D002712:Chlorides; D013861:Thiocyanates; D005576:Colforsin; D012701:Serotonin