Alcohol and Alcoholism Advance Access originally published online on November 18, 2004
Alcohol and Alcoholism 2005 40(1):25-34; doi:10.1093/alcalc/agh112
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Alcohol & Alcoholism Vol. 40, No. 1 © Medical Council on Alcohol 2005; all rights reserved
SPECIAL ISSUE ARTICLE
INTERACTIONS BETWEEN CANNABINOID AND OPIOID RECEPTOR SYSTEMS IN THE MEDIATION OF ETHANOL EFFECTS
Servicio de Psiquiatría y Centro de Investigación, Hospital Universitario 12 de Octubre, Avda. Córdoba s/n, 28041 Madrid, Spain
* Author to whom correspondence should be addressed: Edificio Materno-Infantil, Planta 6, 613-A, Hospital Universitario 12 de Octubre, Avda. Cordoba s/n, 28041 Madrid, Spain. Tel.: 34 91 390 8252; Fax: 34 91 390 8538; E-mail: jmanzanares6{at}terra.es
(Received 16 September 2004; first review notified 2 September 2004; in revised form 14 September 2004; accepted 16 September 2004)
Over the past few years, advances in the investigation of the neurochemical circuits involved in the development and treatment of alcohol dependence have identified peptides and receptors as potential key targets in the treatment of problems related to alcohol consumption. The endogenous opioid system is modified by alcohol intake in areas of the brain related to reward systems, and differential basal levels of opioid gene expression are found in rodents with a high preference for ethanol. This suggests a greater vulnerability to alcohol consumption in relation to differences in genetic background. Further evidence of the involvement of opioid peptides in alcohol dependence is the ability of the opioid antagonist naltrexone to reduce alcohol intake in animal models of dependence and in alcohol-dependent patients. Abundant evidence indicates that the activation of cannabinoid receptors stimulates the release of opioid peptides, therefore the cannabinoid receptor antagonists may presumably alter opioid peptide release, thus facilitating the reduction of ethanol consumption. However, little is known about the effects of ethanol on the endogenous cannabinoid system, the vulnerability of cannabinoid receptors to alcohol intake or their neurochemical implications in reducing consumption of alcohol. In this paper, we review the role of opioid and cannabinoid receptor systems, their vulnerability to alcohol intake and the development of dependence, and the targeting of these systems in the treatment of alcoholism.