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.
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
S H
SH
Ahmed
G F
GF
Koob
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