Inhibitory effect of serotonin on feeding behavior in goldfish: involvement of CRF.
The possible action of 5-HT on feeding behavior in goldfish has been studied. Food intake was significantly reduced by intracerebroventricular (ICV) injection of serotonin (5-HT, 10 microg) at 2 h postinjection. After peripheral (intraperitoneal) administration of 5-HT (1 and 10 microg/g bw), no significant modifications in food intake were detected. Thus, it can be concluded that there is a central anoretic action of 5-HT in teleost fish. Taking in mind the inhibitory effect of corticotropin releasing factor (CRF) on feeding in teleosts and the interactions between 5-HT and CRF described in mammals, we investigated the possible involvement of CRF as mediator of the 5-HT anoretic action in goldfish. The ICV pretreatment with alpha-Helical CRF[9-41](20 microg) partially blocked the inhibitory effect of 5-HT on food consumption in goldfish. These results show that CRF mediates, at least in part, the 5-HT-induced feeding inhibition in goldfish. On the other hand, the alterations in hypothalamic indoleamines content evoked by ICV treatments would suggest that the activation of CRF neurons by 5-HT appears to inhibit hypothalamic serotoninergic transmission, supporting the intermediate role of this neuropeptide in the central anoretic effect of 5-HT in goldfish.
De Pedro
N
N
Departamento de Biología Animal II (Fisiología Animal), Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain.
Pinillos
M L
ML
Valenciano
A I
AI
Alonso-Bedate
M
M
Delgado
M J
MJ
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D006054:Goldfish / Q000502:physiology*; D007031:Hypothalamus / Q000502:physiology; D007276:Injections, Intraventricular; D012701:Serotonin / Q000008:administration & dosage*
D012701:Serotonin; D003346:Corticotropin-Releasing Hormone