Effects of intra-VMN mianserin and IL-1ra on meal number in anorectic tumor-bearing rats
Laviano, A.; Gleason, J.R.; Meguid, M.M.; Yang, Z.J.; Cangiano, C.; Rossi Fanelli, F.
Journal of Investigative Medicine the Official Publication of the American Federation for Clinical Research 48(1): 40-48
2000
ISSN/ISBN: 1081-5589 PMID: 10695268 Document Number: 520482
Background: Tumor growth in animals and humans is associated with the onset of anorexia and reduced food intake. We previously demonstrated that the ventromedial nucleus of hypothalamus (VMN) plays a contributory role in mediating cancer anorexia. Because serotonin and interleukin-1 (IL-1) are putative mediators of cancer anorexia, we hypothesized that their influence on food intake during tumor growth might occur via their action within the VMN. Methods: To test this hypothesis, 12 Fischer rats injected subcutaneously with 106 viable MCA sarcoma cells (TB rats) and their nontumor-bearing controls (NTB, n=13) were studied. When anorexia developed, TB and NTB rats received bilateral intra-VMN microinjections of the serotonin antagonist mianserin (200 nmol) or the IL-1 receptor antagonist (IL-1ra, 25 ng). Food intake and its determinants of meal number and size were continously recorded via a computerized device. Results: In NTB rats, intra-VMN mianserin did not affect food intake, whereas after IL-1ra or vehicle a momentary decrease in food intake due to a predominant reduction of meal size occurred. In TB rats, intra-VMN mianserin or IL-1ra selectively increased meal number, leading to improved food intake. Conclusions: Data suggest that intra-VMN serotonin and IL-1 are involved in influencing cancer related anorexia.