Transition from moderate to excessive drug intake: change in hedonic set point.
Differential access to cocaine self-administration produced two patterns of drug intake in rats. With 1 hour of access per session, drug intake remained low and stable. In contrast, with 6 hours of access, drug intake gradually escalated over days. After escalation, drug consumption was characterized by an increased early drug loading and an upward shift in the cocaine dose-response function, suggesting an increase in hedonic set point. After 1 month of abstinence, escalation of cocaine intake was reinstated to a higher level than before. These findings may provide an animal model for studying the development of excessive drug intake and the basis of addiction.
Ahmed
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SH
Division of Psychopharmacology, Department of Neuropharmacology, CVN-7, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. aserge@sage.scripps.edu
Koob
G F
GF
D000818:Animals; D016739:Behavior, Addictive; D003042:Cocaine / Q000008:administration & dosage*; D019970:Cocaine-Related Disorders / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology; D013997:Time Factors
D003042:Cocaine