title: Long-lasting changes in GABA responsiveness in cultured neurons.
abstract: In neuronal cells, GABA evokes an increase in chloride conductance by activating GABA(A) and GABA(C) receptors. In mature neurons, this increase in conductance generally has a hyperpolarizing and inhibitory action. Using gramicidin-based perforated patch recordings, we show that in cultured motor neurons GABA-induced currents are significantly altered following activation of GABA receptors coinciding with changes in membrane potential. Changes in intracellular chloride concentration constituted the mechanism for this modulation. Because of low resting chloride conductance and low activity of chloride transporters, changes in intracellular chloride concentration and hence GABA response were long-lasting (time constant of recovery was about 2.5 min). Cultured dorsal horn and hippocampal neurons exhibited a similar response pattern, suggesting a general property of cultured neuronal cells. These long-lasting changes in GABA responsiveness may have major implications on neuronal excitability.
authors.affiliation: Laboratory of Physiology, Geert Callewaert, KULeuven, Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.
authors.forename: Joelle N
authors.initials: JN
authors.lastname: Chabwine
authors.forename: Philip
authors.initials: P
authors.lastname: Van Damme
authors.forename: Jan
authors.initials: J
authors.lastname: Eggermont
authors.forename: Humbert
authors.initials: H
authors.lastname: De Smedt
authors.forename: Ludwig
authors.initials: L
authors.lastname: Missiaen
authors.forename: Ludo
authors.initials: L
authors.lastname: Van Den Bosch
authors.forename: Jan B
authors.initials: JB
authors.lastname: Parys
authors.forename: Wim
authors.initials: W
authors.lastname: Robberecht
authors.forename: Geert
authors.initials: G
authors.lastname: Callewaert
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D006624:Hippocampus / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D009046:Motor Neurons / Q000378:metabolism*; D009433:Neural Inhibition / Q000502:physiology; D018408:Patch-Clamp Techniques; D020671:Posterior Horn Cells / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D002712:Chlorides; D005680:gamma-Aminobutyric Acid