A study on short-term assessment procedures for the reinforcing effect in self-administration of drugs in the rhesus monkey (2nd report) - assessment of relatively weak reinforcing effect

• Published in: Journal of Pharmacological Sciences 2004, Vol.94 (suppl.3), p.223-223
• Main Authors: Mikio Sasaki, Yoshio Wakasa, Atsushi Fujiwara, Masahiko lino, Mitsuru Hoshino, Takahiro Ootsuka, Tomoji Yanagita
• Format: Article
• Language: Japanese
• ISSN: 1347-8613

We previously reported inverted U-shaped dose-response curves for cocaine, morphine, pentobarbital and pentazocine in short-term assessment procedures for the reinforcing effect in self-administration (SA) of drugs in rhesus monkeys. In this study, a dose-response curve for nicotine (N), known to possess a relatively weak reinforcing effect, was investigated in 3 animals. They were observed for SA of cocaine (0.03 mg/kg/inf. ), saline and nicotine at 4 or 5 doses (0.001-0.256 mg/kg/inf. ) in this order for at least 3 days for each drug and dose under a fixed-ratio 5 schedule of reinforcement with 1-min timeout period after each SA during daily 2-h sessions. The reinforcing effect of nicotine was demonstrated only in 1 animal, probably due to weak reinforcing effect of nicotine compared to other drugs such as cocaine and morphine. The peak effect was noted at a lower unit dose than those in other studies. This may be due the fact that unit doses of nicotine were gradually decreased in this study.