Ratio Size and Cocaine Concentration Effects on Oral Cocaine‐reinforced Behavior

Abstract

Monkeys were given a choice between cocaine solutions and water under concurrent fixed-ratio reinforcement schedules. The operant response was spout contact. Six rhesus monkeys served as subjects. The cocaine concentration was varied from 0.0125 to 0.8 mg/ml, and the fixed-ratio value was varied from 8 to 128. Cocaine maintained higher response rates than did water over a wide range of conditions. Response rate and number of cocaine deliveries per session were inverted U-shaped functions of concentration. These functions were shifted to the right as the fixed ratio was increased. The number of cocaine deliveries was more persistent as fixed-ratio value was increased when the unit dose was larger rather than smaller. Cocaine consumption was analyzed as a function of unit price (fixed-ratio value divided by cocaine concentration), and unit price accounted for between 77% and 92% of the variance in cocaine consumption for individual monkeys. The current data support the claim that a drug's reinforcing effects increase directly with dose and underscore the need to gather parametric data when examining the effects of experimental manipulations on a drug-reinforced baseline.

Novelty-induced locomotion is positively associated with cocaine ingestion in adolescent rats; anxiety is correlated in adults

“…It established conditioned place preference when administered by gavage or when self-administered in a schedule-induced polydipsia paradigm (Seidman et al, 1992). Rats (Jentsch et al, 1998) and primates (Macenski and Meisch, 1998) lever pressed to drink cocaine solutions and cocaine drinking was not devalued by pairing with LiCl (Miles et al, 2003). Cocaine ingestion in humans produced similar peak plasma concentrations and a subjective “high” rating greater than that resulting from intranasal administration of the same dose (Van Dyke et al, 1978).…”

Effects of altering reinforcer magnitude and reinforcement schedule on phencyclidine (PCP) self-administration in monkeys using an adjusting delay task

“…However, the introduction of various constraints produces shifts in preference. Delay to reinforcer delivery (Anderson and Woolverton, 2003), dose (Iglauer and Woods, 1974; Macenski and Meisch, 1998), and cost or unit price (Bickel et al, 1990; Nader et al, 1993) are well-established determinants of choice among available reinforcers. Using a choice procedure in rhesus monkeys, a higher dose of cocaine was consistently chosen over a smaller one when the delays to each were equal (Anderson and Woolverton, 2003).…”

The generalized matching law as a predictor of choice between cocaine and food in rhesus monkeys

“…Indeed, laboratory research with both humans and non-humans has demonstrated a number of factors that influence the frequency of drug choice (see Higgins 1997). Among those factors are magnitude of reinforcement (Carroll 1985;Iglauer and Woods 1974;Nader and Woolverton 1991), relative response requirement (Carroll 1993;Macenski and Meisch 1998;Nader and Woolverton 1992), and probability of reinforcement (Woolverton and Rowlett 1998). However, attempts to integrate drug choice with prominent theoretical views of choice have been limited.…”