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Ketoconazole blocks the stress-induced reinstatement of cocaine-seeking behavior in rats: relationship to the discriminative stimulus effects of cocaine. Psychopharmacology (Berl) 1999 Mar;142(4):399-407

Date

05/06/1999

Pubmed ID

10229065

DOI

10.1007/s002130050905

Scopus ID

2-s2.0-0032893173   93 Citations

Abstract

RATIONALE: Ketoconazole (Keto) is an antifungal agent that also inhibits the synthesis of adrenocorticosteroids and has been reported to act as a glucocorticoid receptor antagonist.

OBJECTIVE: The present experiments investigated the effects of Keto on the stressor-induced reinstatement of extinguished cocaine-seeking behavior and on the generalization of a stressor-induced discriminative stimulus to cocaine in rats.

METHODS: In the first experiment, male Wistar rats were trained to self-administer cocaine (0.5 mg/kg per infusion, IV) under a fixed-ratio 4 schedule of reinforcement with a 90-s limited hold. Following ten consecutive extinction sessions, the effects of Keto (25 or 50 mg/kg, IP) or vehicle on the ability of EFS (electric footshock; 15 min) to reinstate extinguished cocaine-lever responding were investigated. In the second experiment, rats were trained to discriminate cocaine (10 mg/kg, IP) from saline using a two-lever, food-reinforced drug discrimination design. The effects of Keto (50 mg/kg, IP) or vehicle on the EFS-induced generalization to cocaine were determined.

RESULTS: EFS reinstated extinguished cocaine- but not food-reinforced responding. Keto (25 and 50 mg/kg, IP) blocked the EFS-induced reinstatement of cocaine-seeking behavior and significantly attenuated the plasma corticosterone response to EFS. These same doses of Keto failed to affect responding in rats trained to self-administer food pellets under an FR4 schedule of reinforcement. EFS also produced significant cocaine-appropriate responding in rats trained to discriminate the drug from saline. However, Keto (50 mg/kg) failed to block the EFS-induced generalization to cocaine.

CONCLUSIONS: Overall, these data suggest that corticosterone contributes to the stressor-induced reinstatement of extinguished cocaine-seeking behavior.

Author List

Mantsch JR, Goeders NE

Author

John Mantsch PhD Chair, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Antifungal Agents
Cocaine
Corticosterone
Discrimination Learning
Ketoconazole
Male
Rats
Rats, Wistar
Reinforcement Schedule
Self Administration
Stress, Psychological