Vol. 277, Issue 3, R705-R715, September 1999
Differential effects of lipopolysaccharide and cholecystokinin
on sucrose intake and palatability
Shelley K.
Cross-Mellor,
William D. T.
Kent,
Klaus-Peter
Ossenkopp, and
Martin
Kavaliers
Neuroscience Program and Department of Psychology, University of
Western Ontario, London, Ontario N6A 5C2, Canada
The differential effects of CCK and
lipopolysaccharide (LPS) on sucrose intake and palatability were
examined. Rats were injected with LPS (200 µg/kg ip) or NaCl (0.9%,
vehicle) and 2 h later received a second injection of either CCK (8 µg/kg ip) or NaCl. In experiment
1, sucrose (0.3 M) intake was
monitored for 1 h on three different test days 72 h apart, while in
experiment
2, palatability was assessed by means
of the taste reactivity test (TRT) on two separate days (72 h apart).
In the TRT, orofacial and somatic responses to brief (30 s) intraoral
infusions of sucrose were recorded and analyzed for response frequency.
Singly, LPS and CCK reduced sucrose intake, with a more pronounced
effect from combined LPS and CCK. LPS by itself did not alter sucrose palatability, as evidenced by continuous high levels of ingestive responding. In contrast, CCK-treated rats displayed a pattern of
responding indicative of satiety, as did the combined LPS-CCK-treated rats. These results suggest that LPS does not induce hypophagia by
altering palatability.
taste reactivity test; endotoxin; acute phase response; anorexia; food intake
