Carroll ME, Mach JL, La Nasa RM, Newman JL. Impulsivity as a behavioral measure of withdrawal of orally delivered PCP and nondrug rewards in male and female monkeys.
Psychopharmacology (Berl) 2009;
207:85-98. [PMID:
19697013 DOI:
10.1007/s00213-009-1636-y]
[Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 07/23/2009] [Indexed: 12/01/2022]
Abstract
BACKGROUND
Withdrawal of phencyclidine (PCP), ethanol (ETOH), and other drugs reduces operant responding maintained by food.
OBJECTIVES
Experiment 1 examined the effects of withdrawing daily short access (2 h) to drug on impulsivity for saccharin (SACC) using a delay discounting task and comparing male and female rhesus monkeys. Experiment 2 examined the effects of withdrawing a nondrug substance (e.g., food or SACC) on impulsivity for PCP.
MATERIALS AND METHODS
In experiment 1, either PCP or ETOH was available daily with water for 2 h under a fixed ratio 16 (FR 16) or FR 8 schedule, respectively. In a second component, SACC was available for 45 min under a delay discounting schedule. Next, water was substituted, and drug access was then restored. In experiment 2, PCP was available under a delay discounting schedule during food satiation or restriction or during concurrent SACC vs water access.
RESULTS
In experiment 1, withdrawal of 0.5 mg/ml PCP increased impulsivity for SACC, but not SACC intake, in males and females. During 16% ETOH access, impulsivity for SACC was elevated compared to baseline water access, and it returned to baseline levels during ETOH withdrawal. In experiment 2, food restriction resulted in increased PCP intake in males and females and increases in impulsivity for PCP that were greater in males than in females. SACC withdrawal had no effect on impulsivity for PCP or PCP intake.
CONCLUSIONS
Withdrawal of PCP and reduced food access increased impulsivity for SACC or PCP, respectively. Impulsivity is a sensitive indicator of drug dependence.
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