Pregnenolone sulfate antagonizes GABAA receptor-mediated currents via a reduction of channel opening frequency

Brain Res. 1989 Jun 5;489(1):190-4. doi: 10.1016/0006-8993(89)90024-3.

Abstract

Our previous study showed antagonism of GABAA receptor-mediated whole-cell currents by pregnenolone sulfate (PS). Here, the effects of PS, picrotoxin (PTX) and pentobarbital (PB) were tested on GABA-activated single Cl- channels recorded from membrane patches of rat cortical neurons in primary cultures. PS and PTX selectively decreased the opening frequency of the channels, while PB increased mean open time and burst duration without affecting opening frequency. It is suggested that PS and PTX may antagonize GABAA receptor function through the same mechanism and/or the same binding site.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Cerebral Cortex / cytology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / physiology*
  • Chloride Channels
  • Chlorides / physiology*
  • Ion Channels / physiology*
  • Membrane Potentials / drug effects
  • Membrane Proteins / physiology*
  • Pentobarbital / pharmacology
  • Picrotoxin / pharmacology
  • Pregnenolone / pharmacology*
  • Rats
  • Receptors, GABA-A / drug effects
  • Receptors, GABA-A / physiology*

Substances

  • Chloride Channels
  • Chlorides
  • Ion Channels
  • Membrane Proteins
  • Receptors, GABA-A
  • pregnenolone sulfate
  • Picrotoxin
  • Pregnenolone
  • Pentobarbital