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VARIABLE‐INTERVAL SCHEDULES OF TIMEOUT FROM AVOIDANCE: EFFECTS OF CHLORDIAZEPOXIDE, CGS 8216, MORPHINE, AND NALTREXONE
Author(s) -
Galizio Mark,
Perone Michael
Publication year - 1987
Publication title -
journal of the experimental analysis of behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.75
H-Index - 61
eISSN - 1938-3711
pISSN - 0022-5002
DOI - 10.1901/jeab.1987.47-115
Subject(s) - chlordiazepoxide , timeout , naltrexone , morphine , antagonist , anesthesia , benzodiazepine , opioid antagonist , pharmacology , psychology , agonist , opioid , chemistry , (+) naloxone , medicine , diazepam , computer science , computer network , receptor
Rats were trained on concurrent schedules in which pressing one lever postponed shock and pressing the other occasionally (variable‐interval schedule) produced a 2‐min timeout during which the shock‐postponement schedule was suspended and its correlated stimuli were removed. These procedures provided a baseline for studying the effects of drugs on behavior maintained by different sources of negative reinforcement (shock avoidance and timeout from avoidance). Experiment 1 studied a benzodiazepine agonist, chlordiazepoxide, and antagonist, CGS 8216. Chlordiazepoxide (2.5–30 mg/kg) had little effect on avoidance responding except at higher doses, when it reduced responding. By comparison, responding on the timeout lever was increased in 5 of 6 rats. These effects were reversed by CGS 8216 (2.5–5 mg/kg) in the 2 rats tested, but CGS 8216 had no effect by itself. Experiment 2 studied an opiate agonist, morphine, and antagonist, naltrexone, with 3 rats. Morphine's (2.5–20 mg/kg) effects were opposite those of chlordiazepoxide: At doses that either increased or had no effect on avoidance responding, morphine depressed timeout responding. Naltrexone (5 mg/kg) reversed these actions but had no effect by itself.