GABA generates excitement.
In the CNS, gamma-aminobutyric acid (GABA) acts as an inhibitory transmitter via ligand-gated GABA(A) receptor channels and G protein-coupled GABA(B) receptors. Both of these receptor types mediate inhibitory postsynaptic transmission throughout the nervous system. For GABA(A) receptors, this inhibitory action is associated with a hyperpolarization due to an increase in conductance to chloride ions. Previous studies show that GABA(A) receptor activation in neonatal neurons and spinal cord neurons can be excitatory. Two papers recently appeared that clearly demonstrate that GABA can have a depolarizing and excitatory action in mature cortical neurons. Here we discuss the evolving story on chloride ion homeostasis in CNS neurons and its role in the bipolar life of the GABA(A) receptor.
Stein
Valentin
V
Departments of Cellular and Molecular Pharmacology and Physiology, University of California, San Francisco, San Francisco, CA 94143, USA.
Nicoll
Roger A
RA
D018846:Excitatory Amino Acids / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D011963:Receptors, GABA-A / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018846:Excitatory Amino Acids; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid