Effects of anorectic drugs on the topography of feeding behavior in baboons.

Food intake of six adult male baboons (Papio c. anubis) was monitored during daily experimental sessions lasting 22 hr. Food was available under a chain schedule with two-components. After completion of the first "procurement component" response requirement, access to food, i.e., a meal, became available under the second "consumption component" during which each response produced a 1-g food pellet. After 10 min in which no response occurred, the consumption component was terminated. When given p.o. 45 to 60 min before the start of the daily session, anorectic drugs, with the exception of (+/-)-phenylpropanolamine, produced dose-dependent decreases in food intake, with the following order of potency: phentermine greater than mazindol greater than diethylpropion greater than phendimetrazine = chlortermine = phenmetrazine = chlorphentermine. Feeding topography was differentially affected by drug administration. The latency to the first meal was increased by all of the drugs except chlorphentermine. Only diethylpropion, phendimetrazine and mazindol decreased the number of daily meals, whereas only diethylpropion, phendimetrazine, phenmetrazine and clortermine decreased the size of the first meal. Mazindol was the only anorectic drug tested that did not decrease intake during the first 8 hr of the session. (+/-)-phenylpropanolamine did not decrease food intake in the tested dose range. Phencyclidine, by decreasing intake during the first 8 hr, but not the entire 22-hr session, affected feeding topography differently than the anorectic drugs. In contrast to anorectic drug administration, decreases in food intake after phencyclidine administration were followed by caloric compensation for this initial decrease.(ABSTRACT TRUNCATED AT 250 WORDS)