The increase in Cl- permeation across the Deiters' neuron membrane by GABA on its cytoplasmic side is abolished by protein kinase C (PKC) activators.
1. Cl- ion outward permeation across microdissected Deiters' neuron plasma membranes is augmented by GABA on the membrane cytoplasmic side. When these neurons are preincubated with a PKC activator, phorbol-12,13-dibutyrate (PdBu), there is a complex pattern of effects on basal and GABA-activated 36Cl- in-->out permeation. A distinct fact is an increase in basal Cl- passage and a disappearance of the 10(-6) M GABA effect at [PdBu] = 0.1 microM. 2. Likewise, 0.1 microM oleylacetylglycerol (OAG) treatment erases the effect completely, further supporting a role for PKC in modulating GABA-stimulated Cl- in-->out permeation. 3. The inactive ester, phorbol-12,13-didecanoate (Pdd), at 0.1 microM, does not affect GABA stimulation of Cl- passage. 4. High concentration (15-20 microM) of OAG and PdBu block the "intracellular" GABA efefct. However, the 20 microM PdBu effect is reversed by 30 microM H7. 5. These results indicate a role of endogenous PKC in Cl- extrusion by GABAA receptors on the cytoplasmic side of the Deiters' neuron membrane.
Rapallino
M V
MV
Centro di Neurofisiologia Cerebrale, CNR, Genova, Italy.
Cupello
A
A
Hydén
H
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D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002712:Chlorides / Q000378:metabolism*; D004075:Diglycerides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors; D011817:Rabbits; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D003689:Vestibular Nucleus, Lateral / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D002712:Chlorides; D004075:Diglycerides; D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011963:Receptors, GABA-A; D015240:Phorbol 12,13-Dibutyrate; D005680:gamma-Aminobutyric Acid; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C038237:1-oleoyl-2-acetylglycerol; D011493:Protein Kinase C