Oxytocin prevents ethanol actions at delta subunit-containing GABA(A) receptors and attenuates ethanol-induced motor impairment in rats

Bowen, Michael T. and Peters, Sebastian T. and Absalom, Nathan and Chebib, Mary and Neumann, Inga D. and McGregor, Iain S. (2015) Oxytocin prevents ethanol actions at delta subunit-containing GABA(A) receptors and attenuates ethanol-induced motor impairment in rats. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 112 (10). pp. 3104-3109. ISSN 0027-8424,

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Abstract

Even moderate doses of alcohol cause considerable impairment of motor coordination, an effect that substantially involves potentiation of GABAergic activity at delta subunit-containing GABA(A) receptors (delta-GABA(A)Rs). Here, we demonstrate that oxytocin selectively attenuates ethanol-induced motor impairment and ethanol-induced increases in GABAergic activity at delta-GABA(A)Rs and that this effect does not involve the oxytocin receptor. Specifically, oxytocin (1 mu g i.c.v.) given before ethanol (1.5 g/kg i.p.) attenuated the sedation and ataxia induced by ethanol in the open-field locomotor test, wire-hanging test, and righting-reflex test in male rats. Using two-electrode voltage-clamp electrophysiology in Xenopus oocytes, oxytocin was found to completely block ethanol-enhanced activity at alpha 4 beta 1 delta and alpha 4 beta 3 delta recombinant GABA(A)Rs. Conversely, ethanol had no effect when applied to alpha 4 beta 1 or alpha 4 beta 3 cells, demonstrating the critical presence of the delta subunit in this effect. Oxytocin had no effect on the motor impairment or in vitro effects induced by the delta-selective GABA(A)R agonist 4,5,6,7-tetrahydroisoxazolo(5,4-c) pyridin-3-ol, which binds at a different site on delta-GABA(A)Rs than ethanol. Vasopressin, which is a nonapeptide with substantial structural similarity to oxytocin, did not alter ethanol effects at delta-GABA(A)Rs. This pattern of results confirms the specificity of the interaction between oxytocin and ethanol at delta-GABA(A)Rs. Finally, our in vitro constructs did not express any oxytocin receptors, meaning that the observed interactions occur directly at delta-GABA(A)Rs. The profound and direct interaction observed between oxytocin and ethanol at the behavioral and cellular level may have relevance for the development of novel therapeutics for alcohol intoxication and dependence.

Item Type: Article
Uncontrolled Keywords: MESSENGER-RNAS; A RECEPTORS; VASOPRESSIN; BRAIN; ANTAGONIST; MICE; SENSITIVITY; ADDICTION; SUBTYPES; NUCLEUS; oxytocin; alcohol; GABA; motor impairment; electrophysiology
Subjects: 500 Science > 590 Zoological sciences
Divisions: Biology, Preclinical Medicine > Institut für Zoologie > Tierphysiologie/Neurobiologie (Prof. Dr. Inga Neumann)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 24 Jul 2019 07:09
Last Modified: 24 Jul 2019 07:09
URI: https://pred.uni-regensburg.de/id/eprint/5797

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