کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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936948 | 1475199 | 2010 | 13 صفحه PDF | دانلود رایگان |
To investigate the effect of naloxone on a putative memory consolidation process underlying reacquisition of heroin and cocaine conditioned place preference, four studies were conducted in male Sprague–Dawley rats using a common procedure involving: place conditioning (0.3 or 1 mg/kg heroin or 20 mg/kg cocaine; ×4 sessions), extinction (vehicle × 4 sessions), and reconditioning (0 or 1 mg/kg heroin or 20 mg/kg cocaine; ×1 session). Systemic naloxone injections (0, 1 and 3 mg/kg) or bilateral intra-ventral tegmental area (VTA) naloxone methiodide infusions (2 nmol in 0.5 μl × side) were administered at different times following reconditioning. Post-reconditioning administration of naloxone dose-dependently blocked, attenuated and had no effect on reacquisition of heroin CPP when administered immediately, 1 h and 6 h after reconditioning, respectively. The highest dose of naloxone also blocked reacquisition of cocaine CPP, and did not produce a conditioned place aversion in heroin-naïve and heroin pre-treated animals. Post-reconditioning infusions in the VTA, but not in adjacent structures, blocked reacquisition of heroin CPP when administered immediately, but not 6 h, after reconditioning. These data suggest that reacquisition of drug-cues associations involves a memory consolidation process sensitive to manipulations of the endogenous opioid system, and indicate that opioid receptors in the VTA may be critically involved in the re-emergence of drug seeking behavior.
Journal: Neurobiology of Learning and Memory - Volume 93, Issue 2, February 2010, Pages 248–260