Lateral hypothalamic serotenergic responsiveness to food intake in rat obesity as measured by microdialysis

Lateral hypothalamic serotenergic responsiveness to food intake in rat obesity as measured by microdialysis

Autor Mori, RCT Autor UNIFESP Google Scholar
Guimaraes, R. B. Autor UNIFESP Google Scholar
Nascimento, CMO Autor UNIFESP Google Scholar
Ribeiro, E. B. Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo The hypothalamic serotonergic system is involved in the regulation of food ingestion and energy metabolism. Since disturbances of both energy intake and expenditure can contribute to obesity, the objective of the present study was to evaluate the serotonergic response stimulated by food ingestion in two different models of obesity: the hyperphagic Zucker and the hypophagic and hypometabolic, monosodium glutamate (MSG) obese Wistar rat. for this we used microdialysis to examine the release of 5-hydroxytryptamine (serotonin, 5HT) and 5-hydroxyindoleacetic acid (5HIAA) in the lateral hypothalamus. Daily intake of MSG-obese rats was 40% lower while that of Zucker obese rats was 60% higher than that of the respective lean controls. in overnight-fasted animals, 20-min microdialysate samples were collected before (basal release) and during a 2-h period of access to a balanced palatable food mash. the animals began to eat during the first 20 min of food access, and food consumption was similar among the four groups in all six individual 20-min periods recorded. Ingestion of food increased 5HT release in all groups. in MSG-obese and lean Wistar rats, 5HT levels were similarly elevated during the whole experimental period. in the Zucker strain, 5HT increments of basal release tended to be higher in obese than in lean rats at 20 and 40 min, and a significantly higher increment was observed at 60 min after food access (40 and 135% for lean and obese, respectively). the area under the curve relating serotonin levels to the 120 min of food availability was significantly higher in Zucker obese (246.7 +/- 23.3) than MSG-obese (152.7 +/- 13.4), lean Wistar (151.9 +/- 11.1), and lean Zucker (173.5 +/- 24.0) rats. the present observation, of a food-induced serotonin release in the lateral hypothalamus of lean Wistar and Zucker rats, evidences that 5HT in the lateral hypothalamus is important in the normal response to feeding. in obese animals, the serotonin response was similar to (in the hypophagic-hypometabolic MSG model) or even higher than (in the hyperphagic Zucker model) that seen in the respective lean controls. This result indicates that the energy homeostasis disturbances of both these obesity models may not be ascribed to an impairment of the acute lateral hypothalamic serotonin response to a dietary stimulus.
Assunto serotonin
food intake
brain microdialysis
lateral hypothalamus
monosodium glutamate obesity
Zucker obesity
Idioma Inglês
Data 1999-04-01
Publicado em Canadian Journal of Physiology and Pharmacology. Ottawa: Natl Research Council Canada, v. 77, n. 4, p. 286-292, 1999.
ISSN 0008-4212 (Sherpa/Romeo, fator de impacto)
Editor Natl Research Council Canada
Extensão 286-292
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000081297400007

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