| Autor: |
Smith, James E, Co, Conchita, Coller, Michael D, Hemby, Scott E, Martin, Thomas J |
| Předmět: |
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| Zdroj: |
Neuropsychopharmacology; Jan2006, Vol. 31 Issue 1, p139-150, 12p, 9 Graphs |
| Abstrakt: |
The concurrent use of cocaine and opiate combinations (speedball) has increased since the 1970s and now represents a growing subset of intravenous drug abusers. An isobolographic analysis was applied to the ascending limb of the dose–effect curves for rat self-administration of cocaine, heroin, and their combination to determine the nature of the interaction. The addition of heroin to cocaine shifted the dose–effect curve for self-administration to the left, and the modulation in reinforcing efficacy of the combination of cocaine and heroin was found to be additive. A second experiment used microdialysis to determine the effects of this drug combination on nucleus accumbens (NAc) extracellular levels of dopamine ([DA]e) in rats self-administering low doses of cocaine, heroin, or cocaine/heroin combinations. These doses of cocaine and cocaine/heroin combinations significantly increased NAc [DA]e, while heroin alone did not. The ratio of the % baseline of [DA]e (or the dialysate concentrations of DA) to cocaine in the dialysate was higher during self-administration of cocaine/heroin combinations than with cocaine alone. These data indicate that although the interaction between cocaine and heroin in maintaining self-administration is additive, a potentiation of NAc dopaminergic neurotransmission is present, suggesting that NAc [DA]e may not be a direct measure of reinforcing efficacy and/or it is not central to the mediation of the self-administration of this drug combination.Neuropsychopharmacology (2006) 31, 139–150. doi:10.1038/sj.npp.1300786; published online 1 June 2005 [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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