Journal of Comparative Physiology A

, Volume 188, Issue 6, pp 479–484 | Cite as

Brain serotonin and the control of food intake in rainbow trout (Oncorhynchus mykiss): effects of changes in plasma glucose levels

  •  C. Ruibal
  •  J. Soengas
  •  M. Aldegunde
Original Paper

Abstract.

The levels of 5-hydroxytryptamine and its main metabolite 5-hydroxyindoleacetic acid were assessed in two brain regions, hypothalamus and telencephalon, of rainbow trout (Oncorhynchus mykiss) submitted to increases or decreases in plasma glucose levels through different experimental approaches. Thus, intraperitoneal glucose treatment (500 mg kg–1) increased 5-hydroxytryptamine telencephalic levels. Long-term food deprivation up to 3 weeks significantly increased hypothalamic (2 weeks and 3 weeks) and telencephalic (1 week, 2 weeks, and 3 weeks) levels of 5-hydroxyindoleacetic acid, whereas the ratio 5-hydroxyindoleacetic acid/5-hydroxytryptamine significantly increased throughout the food-deprivation period assessed. Intraperitoneal treatment with bovine insulin (4 mg kg–1) decreased the 5-hydroxyindoleacetic acid/5-hydroxytryptamine ratio in hypothalamus after 1 h. Intraperitoneal administration of fenfluramine (3 mg kg–1) caused a depression in food intake coincident with a significant decrease of the hypothalamic 5-hydroxyindoleacetic acid/5-hydroxytryptamine ratio. These data are discussed in the context of the involvement of serotonergic system in the control of food intake in rainbow trout.

Glucose Hypothalamus Telencephalon Serotonin Rainbow trout, Oncorhynchus mykiss 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  C. Ruibal
    • 1
  •  J. Soengas
    • 2
  •  M. Aldegunde
    • 1
  1. 1.Laboratorio de Fisioloxía Animal (Dpto. de Fisioloxía), Facultade de Bioloxía, Universidade de Santiago de Compostela, Spain
  2. 2.Laboratorio de Fisioloxía Animal, Facultade de Ciencias, Universidade de Vigo, Spain

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