Effect of Ethanol Self-Administration on mu- and delta-Opioid Receptor-Mediated G-Protein Activity

Autor: Leslie J. Vogt, Herman H. Samson, Laura J. Sim-Selley, Dana E. Selley, Amanda L. Sharpe, Leah K. Brunk
Rok vydání: 2002
Předmět:
Zdroj: Alcoholism: Clinical and Experimental Research. 26:688-694
ISSN: 1530-0277
0145-6008
DOI: 10.1111/j.1530-0277.2002.tb02592.x
Popis: BACKGROUND This study examined the effects of ethanol self-administration on mu- and delta-opioid receptor-mediated G-protein activity in specific brain regions of male Long Evans rats. METHODS Rats were trained to self-administer ethanol by using a home-cage modification of the sucrose substitution paradigm. After 30 to 40 days of sucrose or sucrose/15% ethanol self-administration (20 min sessions, Monday-Friday), rats were killed for autoradiographic assays. Coronal sections of brains from sucrose and ethanol self-administering rats were collected and processed for basal and mu- and delta-stimulated [35S]guanosine-5'-O-(gamma-thio)-triphosphate (GTPgammaS) binding. Sections were exposed to film and then analyzed by using computer-assisted densitometry to determine levels of basal and agonist-stimulated [35S]GTPgammaS binding. RESULTS Mu-opioid-stimulated [35S]GTPgammaS binding was decreased in the prefrontal cortex of brains from ethanol compared with sucrose self-administering rats. Mu-opioid-stimulated [35S]GTPgammaS binding was unchanged in the cingulate cortex, caudate-putamen, nucleus accumbens, amygdala, hypothalamus, thalamus, and locus ceruleus of ethanol compared with sucrose self-administering rats. Basal and delta-opioid-stimulated [35S]GTPgammaS binding did not differ between the two groups in the prefrontal cortex or any other region analyzed. CONCLUSIONS These data demonstrate decreased mu-opioid-mediated G-protein activity in the prefrontal cortex of ethanol self-administering rats and suggest an interaction between ethanol and mu-opioid receptors in this region.
Databáze: OpenAIRE
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