Etomidate potentiation of GABAA receptor gated current depends on the subunit composition

Neurosci Lett. 1995 Feb 13;185(3):203-6. doi: 10.1016/0304-3940(95)11263-v.

Abstract

The role of the gamma 2 subunit in etomidate potentiation of GABAA receptor-gated chloride current was studied by whole cell patch clamp experiments on H293 cells expressing GABAA receptors. The GABAA receptor subunits alpha 1 beta 1 with or without the gamma 2 subunit expressed well, with an overall peak current of 157 +/- 42 pA/pF. At a clinically relevant concentration, etomidate potentiates the peak current induced by GABA equally well in receptors with or without the gamma 2 subunit. In contrast, the time course of current decay was prolonged only in receptors with the gamma 2 subunit. This gamma 2 subunit-dependent prolongation of the current time course was not blocked by the benzodiazepine receptor antagonist flumazenil. These results show that etomidate, an imidazole general anesthetic, interacts with the GABAA receptor in a gamma 2 subunit-dependent manner.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials
  • Animals
  • Cells, Cultured
  • Diazepam / pharmacology
  • Etomidate / pharmacology*
  • Patch-Clamp Techniques
  • Receptors, GABA / classification*
  • Receptors, GABA-A / drug effects*
  • gamma-Aminobutyric Acid / pharmacology

Substances

  • Receptors, GABA
  • Receptors, GABA-A
  • gamma-Aminobutyric Acid
  • Diazepam
  • Etomidate