title: Ethanol activation of protein kinase A regulates GABAA α1 receptor function and trafficking in cultured cerebral cortical neurons.
abstract: Ethanol exposure produces alterations in GABAergic signaling that are associated with dependence and withdrawal. Previously, we demonstrated that ethanol-induced protein kinase C (PKC) γ signaling selectively contributes to changes in GABAA α1 synaptic receptor activity and surface expression. Here, we demonstrate that protein kinase A (PKA) exerts opposing effects on GABAA receptor adaptations during brief ethanol exposure. Cerebral cortical neurons from day 0-1 rat pups were tested after 18 days in culture. Receptor trafficking was assessed by Western blot analysis, and functional changes were measured using whole-cell patch-clamp recordings of evoked and miniature inhibitory postsynaptic current (mIPSC) responses. One-hour ethanol exposure increased membrane-associated PKC and PKA, but steady-state GABAA α1 subunit levels were maintained. Activation of PKA by Sp-adenosine 3',5'-cyclic monophosphothioate triethylamine alone increased GABAA α1 subunit surface expression and zolpidem potentiation of GABA responses, whereas coexposure of ethanol with the PKA inhibitor Rp-adenosine 3',5'-cyclic monophosphothioate triethylamine decreased α1 subunit expression and zolpidem responses. Exposure to the PKC inhibitor calphostin-C with ethanol mimicked the effect of direct PKA activation. The effects of PKA modulation on mIPSC decay τ were consistent with its effects on GABA currents evoked in the presence of zolpidem. Overall, the results suggest that PKA acts in opposition to PKC on α1-containing GABAA receptors, mediating the GABAergic effects of ethanol exposure, and may provide an important target for the treatment of alcohol dependence/withdrawal.
authors: Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
authors: Stephen L
authors: SL
authors: Carlson
authors: Sandeep
authors: S
authors: Kumar
authors: David F
authors: DF
authors: Werner
authors: Christopher E
authors: CE
authors: Comerford
authors: A Leslie
authors: AL
authors: Morrow
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D019921:Biotinylation; D015153:Blotting, Western; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects*; D000077334:Zolpidem
chemical_list: D000199:Actins; D002492:Central Nervous System Depressants; D004791:Enzyme Inhibitors; D018755:GABA Agonists; C546242:Gabra1 protein, rat; D011725:Pyridines; D011963:Receptors, GABA-A; D000431:Ethanol; D000077334:Zolpidem; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C