Abstract
The effect of feeding conditions on the reinforcing efficacy of orally-delivered drugs was evaluated using a progressive-ratio (PR) paradigm and a behavioral economic analysis of demand. Seven monkeys self-administered phencyclidine (PCP) (0.06, 0.12, 0.25, 0.5, and 1.0 mg/ml) or ethanol (2, 4, 8, 16, and 32% wt/vol) and concurrent water from two drinking spouts under concurrent PR schedules. The ratios increased from 8 to 4096, and 40 liquid deliveries were available after completion of each ratio schedule. The entire range of drug concentrations was presented in nonsystematic order under two feeding conditions, food restriction and food satiation. Drug maintained responses, deliveries and break points were significantly greater than those maintained by water. Food restriction significantly increased the rate of PCP-maintained responses, deliveries and PR break points over the food satiation baseline. There was also a significant interaction between feeding condition and drug concentration. Although ethanol-maintained responses, liquid deliveries and break points consistently increased in five of seven monkeys during food restriction, only drug concentration produced significant differences in these measures. Using break point as a measure of reinforcing efficacy, food restriction increased the reinforcing efficacy of PCP and had a more pronounced effect at higher drug unit prices.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Author information
Authors and Affiliations
Additional information
Received: 8 February 1996 / Final version: 22 June 1996
Rights and permissions
About this article
Cite this article
Rodefer, J., Carroll, M. Progressive ratio and behavioral economic evaluation of the reinforcing efficacy of orally delivered phencyclidine and ethanol in monkeys: effects of feeding conditions. Psychopharmacology 128, 265–273 (1996). https://doi.org/10.1007/s002130050134
Issue Date:
DOI: https://doi.org/10.1007/s002130050134