Characterization of gamma-aminobutyric acid responses with sulfate loading in cat bladder neurons.
In some cells in cat bladder ganglia gamma-aminobutyric acid (GABA) applied iontophoretically produced a hyperpolarizing response accompanied by an increase in input conductance when recorded with potassium sulfate-filled microelectrodes. This GABA-induced hyperpolarization was blocked by bicuculline and was converted to a depolarizing GABA response when extracellular chloride concentration was low suggesting that the hyperpolarizing GABA response was mediated by the opening of chloride channels. In other cells, continuous passage of a small negative current converted a depolarizing GABA response to a hyperpolarizing response with time. This effect was accompanied by a negative shift of the reversal potential. These data indicated that injection of impermeable sulfate ions decreased the intracellular chloride concentration.
D000320:Adrenergic Fibers / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001640:Bicuculline / Q000378:metabolism / Q000494:pharmacology; D002415:Cats; D002712:Chlorides / Q000378:metabolism; D005726:Ganglia, Parasympathetic / Q000166:cytology / Q000502:physiology*; D007478:Iontophoresis; D008564:Membrane Potentials / Q000187:drug effects; D013431:Sulfates / Q000378:metabolism*; D001743:Urinary Bladder / Q000294:innervation*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology*
D002712:Chlorides; D013431:Sulfates; C031512:potassium sulfate; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline