Effects of anorectic drugs on food intake under progressive-ratio and free-access conditions in rats

The effects of two anorectic drugs, dexfenfluramine and phentermine, on food intake under different food-access conditions were examined. Experiment 1 compared the effects of these drugs on food intake under a progressive-ratio (PR) schedule and free-access conditions. Dexfenfluramine decreased food intake under both conditions, but the doses required to decrease intake under free-access conditions were higher than those required to reduce intake under the PR condition. Intermediate doses of phentermine sometimes increased breaking points, and higher doses decreased them. Phentermine decreased food intake at the same doses under both access conditions. Thus the potency of dexfenfluramine, but not phentermine, to decrease food-maintained behavior depended upon the food-access condition. Experiment 2 used a novel mixed progressive-ratio schedule of food delivery to study the duration of drug effects. Sessions consisted of five components separated by 3-hr timeouts. The ratio requirement reset at the beginning of each component and a new breaking point was obtained. Both dexfenfluramine and phentermine dose-dependently decreased breaking points early in the session. In some rats, compensatory increases in breaking point were observed. That is, breaking points later in the session increased over control levels, resulting in no change in the total number of food pellets earned for the session compared to control. The present findings suggest that the effects of some anorectic drugs depend upon the access conditions for food; increasing the effort to obtain food may enhance their ability to decrease food-maintained behavior.

Medienart:

Artikel

Erscheinungsjahr:

2004

Erschienen:

2004

Enthalten in:

Zur Gesamtaufnahme - volume:82

Enthalten in:

Journal of the experimental analysis of behavior - 82(2004), 3 vom: 03. Nov., Seite 275-92

Sprache:

Englisch

Beteiligte Personen:

LeSage, Mark G [VerfasserIn]
Stafford, David [VerfasserIn]
Glowa, John R [VerfasserIn]

Themen:

Appetite Depressants
C045TQL4WP
Dexfenfluramine
E35R3G56OV
Journal Article
Phentermine
Research Support, U.S. Gov't, P.H.S.

Anmerkungen:

Date Completed 10.05.2005

Date Revised 10.12.2019

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM153514515