Alcohol self-administration in monkeys (Macaca radiata): the effects of prior alcohol exposure.

Responding by 4 monkeys was maintained under a fixed ratio 10 (FR 10) schedule for either food, intravenous sucrose or alcohol. The 20 hr sessions were divided so that food was available during hours 1, 6, 11, 16 and alcohol or sucrose during hours 2-5, 7-10, 12-15, and 17-20. All animals failed to maintain responding for isocaloric sucrose but continued to respond for food during those sessions. Responding under alcohol conditions was positively accelerated in 2 animals that were not previously exposed to alcohol, whereas prior exposure to alcohol produced maximal response rates during the first alcohol test session. The effects of alcohol in all monkeys were to suppress responding maintained by food and this suppression could not be produced with programmed infusions of isocaloric sucrose.