gamma-Aminobutyric acid opens Cl-channels in cultured astrocytes

Brain Res. 1987 Feb 24;404(1-2):1-9. doi: 10.1016/0006-8993(87)91349-7.


Cultured astrocytes from cerebral hemispheres of early postnatal rats responded to gamma-aminobutyric acid (GABA) with membrane depolarization. This depolarization was affected by changes in extracellular [Cl-] and depended on the membrane potential. The reversal potential of the GABA-induced depolarization was determined by double electrode voltage clamp or depolarization by elevated [K+]o and ranged between -38 and -53 mV. Cell input resistance decreased after addition of GABA with the same time course as the membrane depolarization. GABA responses were temperature dependent yielding a peak at about 14 degrees C. At higher temperatures a decrease in the GABA-induced depolarization was seen indicating that the depolarization may not be mediated by an enzyme-coupled carrier system. Addition of ouabain at different temperatures did not change the size of the GABA depolarization. This excludes the possibility that an electrogenic component of the temperature-sensitive Na+,K+-ATPase activity causes the decrease in GABA-dependent depolarization at higher temperatures. Intracellular [Cl-] was measured with Cl- sensitive microelectrodes and found to be higher than the value calculated for a free distribution according to the Nernst equation (-40 mV). Addition of furosemide did not alter the reversal potential, but reduced the size of the GABA-induced membrane depolarization. From these observations and previous experiments on the pharmacological properties of the membrane response we conclude that the ionic mechanism underlying the GABA-dependent membrane depolarization of astrocytes results from a transient increase in Cl- -conductance similar to that of the neuronal GABAA-receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / metabolism*
  • Cells, Cultured
  • Chlorides / metabolism*
  • Electric Conductivity
  • Electrochemistry
  • Furosemide / pharmacology
  • Intracellular Membranes / metabolism
  • Ion Channels / drug effects*
  • Ouabain / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Temperature
  • gamma-Aminobutyric Acid / pharmacology*


  • Chlorides
  • Ion Channels
  • gamma-Aminobutyric Acid
  • Ouabain
  • Furosemide