EFFECTS OF PROPRANOLOL ON BEHAVIOR MAINTAINED UNDER FIXED-RATIO SCHEDULES OF COCAINE INJECTION OR FOOD PRESENTATION IN SQUIRREL-MONKEYS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 198  (3) , 626-634
Abstract
Behavior of squirrel monkeys was maintained under comparable 30-response fixed-ratio schedules of cocaine injection or food presentation. Every 30th key press in the presence of a green light produced an i.v. injection of 25 .mu.g/kg of cocaine in 1 group of moneys or delivery of a food pellet in a 2nd group of monkeys. Each cocaine injection or food presentation was followed by a 1 min timeout period, during which the green light was absent and responses had no programmed consequences. Responding at a mean rate of more than 1/s was maintained in the presence of the green light during each daily session. Propranolol doses from 0.3-3.0 mg/kg i.m. had no effect on food-maintained responding but decreased cocaine-maintained responding by approximately 30%. The selective disruption of cocaine-maintained responding by propranolol appeared to depend on the cumulative cocaine dose. Decreases in cocaine-maintained responding after propranolol became increasingly pronounced as the session progressed. Similar progressive decreases in cocaine-maintained responding were produced by increasing the dose of cocaine per injection.

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