Ketamine self-administration by the rhesus monkey.
Intravenously administered ketamine served as a reinforcer of self-administration behavior in rhesus monkeys during daily 2-hour sessions. When the dose of ketamine was varied over a wide range at fixed-ratio schedules of reinforcement of 1, 8 and 64, the response rate was an inverted U-shaped function of the dose. Maximal response rates occurred at progressively higher doses as the fixed-ratio size was increased; drug intake per session was positively related to the dose. When the ketamine dose was held constant and the fixed-ratio was increased in a geometric series, the response rate increased as the fixed-ratio was increased to FR 128 or FR 256; additional increases in fixed-ratio size produced abrupt decreases in response rates. Since the response rate increased linearly as the fixed-ratio was increased geometrically, drug intake was a decreasing function of the response requirement. With respect to magnitude of reinforcement and fixed-ratio response requirement, the data show that ketamine maintains self-administration behavior in a manner similar to that of a number of other drugs and conventional reinforcers.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D000882:Haplorhini; D007275:Injections, Intravenous; D007649:Ketamine / Q000008:administration & dosage* / Q000494:pharmacology; D008253:Macaca mulatta; D008297:Male; D012055:Reinforcement Schedule; D012646:Self Administration
D007649:Ketamine