Abstract
Rationale
To date, the literature on the intravenous self-administration of cocaine by laboratory animals lacks a compelling demonstration of an ascending limb to the dose-response function. It has been argued that previous demonstrations of an ascending limb are confounded by the extinction process.
Objective
The objective was to examine the relationship between cocaine dose and intravenous self-injection frequency at the low end of the cocaine dose range (0.03–0.00075 mg/kg per injection).
Methods
Three adult rhesus monkeys were given the opportunity to self-inject cocaine on a fixed-ratio 1 schedule of reinforcement with no timeouts between injections. Single cocaine doses were presented for between 13 and 27 consecutive 2-h sessions in the order of 0.03, 0.01, 0.003, 0.0015a, 0.00075, and 0.0015b mg/kg per injection.
Results
An ascending limb of the cocaine dose-response curve was found to exist between the doses of 0.00075 and 0.003 mg/kg per injection.
Conclusions
The fact that response rate increased from 0.00075 to 0.0015b mg/kg per injection, and remained stable at this intermediate level, negates the possibility that responding at 0.0015b mg/kg per injection is an artifact of experimental extinction. The finding that significantly less cocaine was taken at 0.0015b mg/kg per injection than at higher doses demonstrates that satiety was not the mechanism by which cocaine intake was regulated on the ascending limb of the dose-response curve.
Similar content being viewed by others
References
Deneau G, Yanagita T, Seevers MH (1969) Self-administration of psychoactive substances by the monkey. Psychopharmacologia 16:30–48
Everitt BJ, Robbins TW (2000) Second-order schedules of drug reinforcement in rats and monkeys: measurement of reinforcing efficacy and drug-seeking behaviour. Psychopharmacology 153:17–30
Goldberg SR, Kelleher RT, Morse WH (1975) Second-order schedules of drug injection. Fed Proc 34:1771–1176
Griffiths RR, Brady JV, Snell JD (1978) Progressive-ratio performance maintained by drug infusions: comparison of cocaine, diethylpropion, chlorphentermine, and fenfluramine. Psychopharmacology 56:5–13
Norman AB, Tsibulsky VL (2001) Satiety threshold regulates maintained self-administration: comment on Lynch and Carroll (2001). Exp Clin Psychopharmacol 9:151–154; discussion 160–162
Pickens R, Thompson T (1968) Cocaine-reinforced behavior in rats: effects of reinforcement magnitude and fixed-ratio size. J Pharmacol Exp Ther 161:122–129
Sizemore GM, Martin TJ (2000) Toward a mathematical description of dose-effect functions for self-administered drugs in laboratory animal models. Psychopharmacology 153:57–66
Tsibulsky VL, Norman AB (1999) Satiety threshold: a quantitative model of maintained cocaine self-administration. Brain Res 839:85–93
Wilson MC, Hitomi M, Schuster CR (1971) Psychomotor stimulant self administration as a function of dosage per injection in the rhesus monkey. Psychopharmacologia 22:271–281
Acknowledgements
This work was supported by USPHS grants DA-09161 and 1 F31 AA13224-01.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Flory, G.S., Woods, J.H. The ascending limb of the cocaine dose-response curve for reinforcing effect in rhesus monkeys. Psychopharmacology 166, 91–94 (2003). https://doi.org/10.1007/s00213-002-1336-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00213-002-1336-3