Cocaine abuse involves a variety of behaviors including the initiation of cocaine-seeking, the self-selected patterning of cocaine administrations, and the cessation of cocaine-taking. To date, most human laboratory models of cocaine self-administration have only assessed the amount of cocaine consumed under a fixed set of conditions. This double-blind, randomized, within-subject, inpatient study evaluated a novel model of human cocaine self-administration that aimed to quantify the reinforcing value of cocaine after cocaine-taking was initiated. Cocaine-dependent volunteers (n=8) sampled cocaine (12.5, 25 or 50 mg per 70 kg i.v.) or placebo and were subsequently allowed to choose between another injection of the same dose or money over six trials during 12 experimental sessions. The value of the monetary alternative increased with each trial from $1 to 16. Each cocaine dose was assessed under three inter-choice intervals: 15 min, 30 min, and an interval selected by the volunteer. Injection choices increased dose dependently; however, there was little relationship between the value of the alternative reinforcer and the choice to take cocaine. Most volunteers exclusively chose injections when active cocaine was available and money when placebo was available. Inter-choice interval did not affect cocaine choices. These results illustrate the persistence of cocaine self-administration once cocaine-taking has been initiated.
|Number of pages
|Drug and Alcohol Dependence
|Published - Apr 1 2003
Bibliographical noteFunding Information:
This research was supported by grants from the National Institute on Drug Abuse R01 DA10753, R01 DA05196, T32 DA07209, and K05 DA00050. The authors thank the staff at BPRU especially Melissa Blank, Heather Cronin, Roxanna Kelly, Tim Mudric, Paul Nuzzo and John Yingling.
ASJC Scopus subject areas
- Psychiatry and Mental health
- Pharmacology (medical)