Satiety induced by central stresscopin is mediated by corticotrophin-releasing factor receptors and hypothalamic changes in chicks

The central mechanism that mediates stresscopin (SCP)-induced satiety is poorly understood, and its effect on avian appetite is not documented. Thus, this study was conducted to elucidate some of the central and behavioral mechanisms that are associated with SCP-induced satiety using broiler- and layer-type chicks (Gallus gallus) as model organisms. In Experiment 1, broiler-type chicks responded with decreased food and water intake but had increased plasma corticosterone concentration after intracerebroventricular (ICV) SCP injection. However, the effect on water intake was secondary to food intake, since food-restricted SCP-treated broiler-type chicks did not reduce water intake in Experiment 2. In Experiment 3, layer-type chicks responded with decreased food intake at much lower doses than broiler-type chicks. In Experiment 4, astressin (a non-selective corticotrophin-releasing factor [CRF] receptor antagonist) prevented SCP-induced anorexia in broiler-type chicks. In Experiment 5, SCP-treated broiler-type chicks had an increased number of c-Fos immunoreactive cells in the ventromedial hypothalamus, parvicelluar and magnocellular divisions of the paraventricular nucleus and the periventricular nucleus. In Experiment 6, SCP-treated broiler-type chicks had decreased feeding pecks and increased jumping, distance moved and more escape attempts. Thus, we conclude that central SCP causes anorexigenic and other behavioral effects in chicks, and the hypothalamus and CRF receptors are involved.