| Autor: |
George V. Rebec, Jeffery D. Steketee, Wen Lin Sun, YueQiang Xue |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
European Journal of Neuroscience. 33:1291-1298 |
| ISSN: |
0953-816X |
| DOI: |
10.1111/j.1460-9568.2010.07591.x |
| Popis: |
Relapse is a hallmark of cocaine addiction. Cocaine-induced neuroplastic changes in the mesocorticolimbic circuits critically contribute to this phenomenon. Preclinical evidence indicates that relapse to cocaine-seeking behavior depends on activation of dopamine neurons in the ventral tegmental area. Thus, blocking such activation may inhibit relapse. Because activity of dopamine neurons are regulated by D2-like autoreceptors expressed on somatodendritic sites, this study, using the reinstatement model, aimed to determine whether activation of D2-like receptors in the ventral tegmental area can inhibit cocaine-induced reinstatement of extinguished cocaine-seeking behavior. Rats were trained to self-administer intravenous cocaine (0.25 mg/infusion) under a modified fixed-ratio 5 schedule. After such behavior was well learned, rats went through extinction training to extinguish cocaine-seeking behavior. Then the effect of quinpirole, a selective D2-like receptor agonist microinjected into the ventral tegmental area on cocaine-induced reinstatement was assessed. Quinpirole (0 – 3.2 μg/side) dose-dependently decreased cocaine-induced reinstatement and such effects were reversed by the selective D2-like receptor antagonist eticlopride when co-microinjected with quinpirole into the ventral tegmental area. The effect appeared to be specific to the ventral tegmental area because quinpirole microinjected into the substantia nigra had no effect. Because D2-like receptors are expressed on rat ventral tegmental area dopamine neurons projecting to the prefrontal cortex and nucleus accumbens, our data suggest that these dopamine circuits may play a critical role in cocaine-induced reinstatement. The role of potential changes in D2-like receptors and related signaling molecules of dopamine neurons in the vulnerability to relapse was discussed. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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