title: Reinforcing properties of intravenous procaine in rhesus monkeys.
abstract: The lever pressing behavior of rhesus monkeys was maintained by a fixed ratio 10 schedule of intravenous cocaine (3 monkeys) or codeine (2 monkeys) injections during 2 hour sessions. Saline or various doses of procaine hydrochloride were substituted for the baseline reinforcer for 6 consecutive sessions. Each substitution was separated by 3 or more days of cocaine or codeine reinforced responding. At one or more doses, procaine substitution resulted in response rates higher than saline control in all 5 animals. High response rates (greater than 30 injections per session) were obtained in 4 of the 5 monkeys. In addition, procaine self-administration was studied in two naive monkeys given 23 hour per day access to procaine following an initial 10 days of saline contingent operant level responding. At a dose of 0.3 mg/kg/injection, both animals initiated responding for procaine reinforcement. Drug intake varied widely from day to day, however each animal took over 1200 injections per day (over 360 mg/kg) at least once during the 30 days of access. With the exception of decreased food intake, there was little evidence for behavioral toxicity from these doses. Following a second 10 days of saline self-administration, both animals were given access to 3.0 mg/kg/injection procaine. A substantially greater intake of procaine was observed which was associated with marked toxicity.
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D003061:Codeine / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D000882:Haplorhini; D006801:Humans; D007275:Injections, Intravenous; D008253:Macaca mulatta; D008297:Male; D011343:Procaine / Q000008:administration & dosage / Q000494:pharmacology*; D012054:Reinforcement, Psychology; D019966:Substance-Related Disorders
chemical_list: D011343:Procaine; D003042:Cocaine; D003061:Codeine