Effect of the 5-HT(1A) receptor agonist 8-OH-DPAT on food and water intake in chickens.

The effects of the 5-HT(1A) receptor agonist 8-OH-DPAT on food and water intake in 16-week-old male chickens were investigated. Injection of 25 or 50 microg/kg of 8-OH-DPAT 15 min before refeeding starved animals (starved-refed) produced a decrease in food intake 1 h after the start of refeeding. No effect was observed in water intake. The injection of 25 or 50 microg/kg of the 8-OH-DPAT 60 min after the start of refeeding (fed) produced increased food intake, but no effect was observed on water intake. The agonist 8-OH-DPAT (50 microg/kg) injected in water-deprived chickens 15 min before water presentation produced a rapid increase in water intake and an increase in food intake 90 min after the presentation of water. The effect on food intake was mainly apparent 60-90 min after injection. However, when the chickens were water-deprived, the intravenous administration of 8-OH-DPAT 15 min before the presentation of water produced an increase in water intake only 15 min after the start of the experiment. The results show that the effect on food intake of the agonist 8-OH-DPAT in chickens was similar to that observed in mammals. Also, the results show that the agonist-induced increase in water intake may act via a different mechanism. The results show that the 8-OH-DPAT, as in mammals, has a complex effect on food and water intake in chickens and that further works need to be carried out to understand the mechanisms involved in the food and water intake using different animal models.