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Decreased reinforcing effects of cocaine following 2 weeks of continuous D-amphetamine treatment in rats.
Psychopharmacology (Berl). 2009 Oct; 206(3):447-56.P

Abstract

RATIONALE

Recent studies have investigated D-amphetamine as a potential agonist medication for cocaine dependence. In rats, a 14-day continuous infusion of D: -amphetamine via osmotic mini-pump has been shown to decrease cocaine-reinforced responding under a progressive ratio (PR) schedule of reinforcement.

OBJECTIVES

This study was designed to assess the influences of the D-amphetamine treatment dose and self-administered cocaine dose on the magnitude of this effect.

MATERIALS AND METHODS

Experiment 1: rats were trained to self-administer 1.5 mg/kg/inj cocaine under a PR schedule, then implanted with D-amphetamine mini-pumps for 14 days (days 1-7, 5 mg/kg/day; days 8-14, 7.5 mg/kg/day). Breakpoints were evaluated throughout the treatment period and 14 days post-treatment. Experiment 2: rats were trained to self-administer cocaine under a PR schedule and initial dose-response curves were determined before implantation of D-amphetamine mini-pumps. During the 14-day D-amphetamine (5 mg/kg/day) treatment period, rats self-administered one of four cocaine doses (0.19, 0.38, 0.75, or 1.5 mg/kg/inj). A post-treatment PR dose-response curve and responding under a fixed ratio 1 (FR1) schedule were evaluated after mini-pump removal.

RESULTS

Experiment 1: breakpoints for 1.5 mg/kg/inj cocaine were unchanged by the increasing dose of D-amphetamine. Experiment 2: the PR dose-response curve was shifted downward after the treatment period in rats that had self-administered 0.19 and 0.38 mg/kg/inj cocaine. In contrast, rats in the 0.75 and 1.5 mg/kg/inj groups demonstrated increased rates of cocaine intake under an FR1 schedule after the treatment period.

CONCLUSIONS

These data suggest that continuous D-amphetamine treatment attenuates the reinforcing effects of cocaine.

Authors+Show Affiliations

Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.No affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

19652955

Citation

Chiodo, Keri A., and David C S. Roberts. "Decreased Reinforcing Effects of Cocaine Following 2 Weeks of Continuous D-amphetamine Treatment in Rats." Psychopharmacology, vol. 206, no. 3, 2009, pp. 447-56.
Chiodo KA, Roberts DC. Decreased reinforcing effects of cocaine following 2 weeks of continuous D-amphetamine treatment in rats. Psychopharmacology (Berl). 2009;206(3):447-56.
Chiodo, K. A., & Roberts, D. C. (2009). Decreased reinforcing effects of cocaine following 2 weeks of continuous D-amphetamine treatment in rats. Psychopharmacology, 206(3), 447-56. https://doi.org/10.1007/s00213-009-1622-4
Chiodo KA, Roberts DC. Decreased Reinforcing Effects of Cocaine Following 2 Weeks of Continuous D-amphetamine Treatment in Rats. Psychopharmacology (Berl). 2009;206(3):447-56. PubMed PMID: 19652955.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Decreased reinforcing effects of cocaine following 2 weeks of continuous D-amphetamine treatment in rats. AU - Chiodo,Keri A, AU - Roberts,David C S, Y1 - 2009/08/04/ PY - 2009/03/30/received PY - 2009/07/11/accepted PY - 2009/8/5/entrez PY - 2009/8/5/pubmed PY - 2010/1/15/medline SP - 447 EP - 56 JF - Psychopharmacology JO - Psychopharmacology (Berl) VL - 206 IS - 3 N2 - RATIONALE: Recent studies have investigated D-amphetamine as a potential agonist medication for cocaine dependence. In rats, a 14-day continuous infusion of D: -amphetamine via osmotic mini-pump has been shown to decrease cocaine-reinforced responding under a progressive ratio (PR) schedule of reinforcement. OBJECTIVES: This study was designed to assess the influences of the D-amphetamine treatment dose and self-administered cocaine dose on the magnitude of this effect. MATERIALS AND METHODS: Experiment 1: rats were trained to self-administer 1.5 mg/kg/inj cocaine under a PR schedule, then implanted with D-amphetamine mini-pumps for 14 days (days 1-7, 5 mg/kg/day; days 8-14, 7.5 mg/kg/day). Breakpoints were evaluated throughout the treatment period and 14 days post-treatment. Experiment 2: rats were trained to self-administer cocaine under a PR schedule and initial dose-response curves were determined before implantation of D-amphetamine mini-pumps. During the 14-day D-amphetamine (5 mg/kg/day) treatment period, rats self-administered one of four cocaine doses (0.19, 0.38, 0.75, or 1.5 mg/kg/inj). A post-treatment PR dose-response curve and responding under a fixed ratio 1 (FR1) schedule were evaluated after mini-pump removal. RESULTS: Experiment 1: breakpoints for 1.5 mg/kg/inj cocaine were unchanged by the increasing dose of D-amphetamine. Experiment 2: the PR dose-response curve was shifted downward after the treatment period in rats that had self-administered 0.19 and 0.38 mg/kg/inj cocaine. In contrast, rats in the 0.75 and 1.5 mg/kg/inj groups demonstrated increased rates of cocaine intake under an FR1 schedule after the treatment period. CONCLUSIONS: These data suggest that continuous D-amphetamine treatment attenuates the reinforcing effects of cocaine. SN - 1432-2072 UR - https://www.unboundmedicine.com/medline/citation/19652955/Decreased_reinforcing_effects_of_cocaine_following_2_weeks_of_continuous_D_amphetamine_treatment_in_rats_ L2 - https://dx.doi.org/10.1007/s00213-009-1622-4 DB - PRIME DP - Unbound Medicine ER -