γ-Aminobutyric acid B receptor 1 mediates behavior-impairing actions of alcohol in Drosophila : Adult RNA interference and pharmacological evidence

doi:10.1073/pnas.0830111100

γ-Aminobutyric acid B receptor 1 mediates behavior-impairing actions of alcohol in Drosophila: Adult RNA interference and pharmacological evidence

Department of Psychiatry, Psychiatric Institute, University of Illinois, Chicago, IL 60612

Edited by Michael S. Levine, University of California, Berkeley, CA, and approved February 21, 2003 (received for review January 8, 2003)

Abstract

In addition to their physiological function, metabotropic receptors for neurotransmitter γ-aminobutyric acid (GABA), the GABA_B receptors, may play a role in the behavioral actions of addictive compounds. Recently, GABA_B receptors were cloned in fruit flies (Drosophila melanogaster), indicating that the advantages of this experimental model could be applied to GABA_B receptor research. RNA interference (RNAi) is an endogenous process triggered by double-stranded RNA and is being used as a tool for functional gene silencing and functional genomics. Here we show how cell-nonautonomous RNAi can be induced in adult fruit flies to silence a subtype of GABA_B receptors, GABA_BR1, and how RNAi combined with pharmacobehavioral techniques (including intraabdominal injections of active compounds and a computer-assisted quantification of behavior) can be used to functionally characterize these receptors. We observed that injection of double-stranded RNA complementary to GABA_BR1 into adult Drosophila selectively destroys GABA_BR1 mRNA and attenuates the behavioral actions of the GABA_B agonist, 3-aminopropyl-(methyl)phosphinic acid. Moreover, both GABA_BR1 RNAi and the GABA_B antagonist CGP 54626 reduced the behavior-impairing effects of ethanol, suggesting a putative role for the Drosophila GABA_B receptors in alcohol's mechanism of action. The Drosophila model we have developed can be used for further in vivo functional characterization of GABA_B receptor subunits and their involvement in the molecular and systemic actions of addictive substances.

fruit fly‖GABAB receptors‖ethanol‖CGP 54626‖3-APMPA

Footnotes

↵ * To whom correspondence should be addressed at: Department of Psychiatry, Psychiatric Institute, University of Illinois, 1601 West Taylor Street, MC912, Chicago, IL 60612. E-mail: hmanev{at}psych.uic.edu.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

GABA,

γ-aminobutyric acid;

3-APMPA,

3-aminopropyl-(methyl)phosphinic acid;

dsRNA,

double-stranded RNA;

GABABR,

GABAB receptor;

D-GABABR,

Drosophila GABABR;

RNAi,

RNA interference