Can Cl- ions be extruded from a gamma-aminobutyric (GABA)-acceptive nerve cell via GABAA receptors on the plasma membrane cytoplasmic side?
1. In this commentary we discuss results obtained by a micromethod for the study of Cl- permeability across single nerve membranes from rabbit Deiters' neurons. 2. These results showed the presence of GABAA receptors on the nerve cell membrane cytoplasmic side. 3. We could show that these receptor complexes have a higher affinity for GABA than their extracellularly facing counterparts. Moreover, they present a phenomenon of desensitization. Another distinct property is that upon activation by GABA, they expose positive charges at their cytoplasmic mouths. 4. We propose that these receptor complexes could function in situ as a device for extruding Cl- anions from the nerve cell interior. This phenomenon would create an electrochemical gradient for Cl- penetration into the cell upon the action of extracellular GABA, after its presynaptic release.
Cupello
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A
Centro di Studio per la Neurofisiologia Cerebrale, CNR, Genova, Italy.
Palm
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A
Rapallino
M V
MV
Hydén
H
H
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D002712:Chlorides / Q000378:metabolism*; D003593:Cytoplasm; D008564:Membrane Potentials; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism*; D010852:Picrotoxin / Q000494:pharmacology; D011817:Rabbits; D011963:Receptors, GABA-A / Q000378:metabolism*; D003689:Vestibular Nucleus, Lateral / Q000378:metabolism* / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
D001640:Bicuculline; D002712:Chlorides; D010852:Picrotoxin; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid