Effects of cocaine administration and withdrawal on the performance of pigeons under a fixed-consecutive-number schedule with and without an external discriminative stimulus.
The effects of administering and withdrawing cocaine (0.3, 1, 3, and 10 mg/kg) were evaluated in pigeons responding under a fixed-consecutive-number schedule of food presentation with (FCN-S(D)) and without (FCN) an external discriminative stimulus. Under both schedules, acute administrations of 10 mg/kg reduced accuracy (per cent reinforced runs) and lower doses had no systematic effect. Both 3 and 10 mg/kg doses reduced response rates under the FCN schedule, but only the 10 mg/kg dose did so under the FCN-S(D) schedule. With chronic exposure to increasing doses (0.3, 1, 3, and 10 mg/kg), tolerance developed to the rate- and accuracy-decreasing effects of 10 mg/kg under both schedules. Abrupt withdrawal from chronic cocaine (10.0 mg/kg) did not disrupt performance under either schedule. This indicates that behavioral dependence did not occur in the present study.
Clark
R.D.
RD
Department of Psychology, Western Michigan University, Kalamazoo, Michigan 49008, USA Correspondence to: A. Poling at above address.
Poling
A.
A