Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug abuse. However, there are still many unanswered questions about the basic mechanisms of acupuncture. Studies have shown that the GABA (B) receptor system may play a significant modulatory role in the mesolimbic system in drug abuse, including ethanol. The in vivo microdialysis study was designed to investigate the effect of acupuncture on acute ethanol-induced dopamine release in the nucleus accumbens and the potential role of the GABA (B) receptor system in acupuncture. Male Sprague-Dawley rats were administered with the highly selective GABA (B) antagonist SCH 50911 (3 mg/kg, i.p.) 1h prior to an intraperitoneal injection of ethanol (1 g/kg). Immediately after ethanol treatment, acupuncture was given at bilateral Shenmen (HT7) points for 1min. Acupuncture at the specific acupoint HT7, but not at control points (PC6 or tail) significantly decreased dopamine release in the nucleus accumbens. Inhibition of dopamine release by acupuncture was completely prevented by SCH 50911. These results suggest that stimulation of specific acupoints inhibits ethanol-induced dopamine release by modulating GABA (B) activity and imply that acupuncture may be effective in blocking the reinforcing effects of ethanol.
A role for GABA mechanisms in the motivational effects of alcohol.Biochem Pharmacol. 2004 Oct 15;68(8):1515-25.
Low doses of ethanol have been hypothesized to act directly via proteins that form ligand-gated receptor channels, such as the gamma-aminobutyric acid (GABA) receptor complex, to allosterically alter function, particularly in specific brain areas such as those hypothesized to be involved in ethanol reinforcement. At the pharmacological level, one can antagonize the effects of ethanol with GABA antagonists, particularly its sedative, anxiolytic-like and acute reinforcing actions. Brain sites involved in the GABA ergic component of ethanol reinforcement include the ventral tegmental area, elements of the extended amygdala (including the central nucleus of the amygdala), and the globus pallidus. Chronic administration of ethanol sufficient to produce dependence and increased ethanol intake are associated with increased GABA release in the amygdala and increased sensitivity to GABA agonists. A hypothesis is proposed that GABA ergic interactions with the brain stress neurotransmitter corticotropin-releasing factor in specific elements of the extended amygdala may be an important component for the motivation for excessive drinking associated with the transition from social drinking to addiction.
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