Galanin and bethanechol appear to activate the same inwardly rectifying potassium current in mudpuppy parasympathetic neurons.
Galanin- and bethanechol-activated whole cell currents were studied in dissociated mudpuppy parasympathetic neurons kept in 12.5 mM KCl. The bethanechol-induced current was reduced when generated during a galanin-induced current. The galanin and bethanechol currents reversed at -45 mV and exhibited inward rectification at more negative potentials. Both the galanin- and bethanechol-induced current relaxations recorded during negative voltage steps were fitted best by two exponentials with the averaged time constant values not significantly different for the galanin and bethanechol currents. We conclude that galanin and bethanechol activate a similar membrane potassium conductance which is different from the background potassium conductance.
Parsons
R L
RL
Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, Burlington 05405.
Merriam
L A
LA
D000818:Animals; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology*; D019004:Galanin; D005726:Ganglia, Parasympathetic / Q000502:physiology*; D006321:Heart / Q000294:innervation; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009337:Necturus; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D001626:Bethanechol Compounds; D009479:Neuropeptides; D010455:Peptides; D015221:Potassium Channels; D018723:Bethanechol; D019004:Galanin