Central ghrelin acts as an anti-dipsogenic peptide in chicks

The aim of this study was to look at whether ghrelin has an anti-dipsogenic effect, as seen in the eel, when administered centrally in neonatal chicks. Intracerebroventricular (ICV) injection of chicken ghrelin inhibited water intake (WI) in chicks under both ad libitum and 17-h water-deprived drinking conditions at doses ranging from 0.01 to 0.1 nmol/chick. This inhibitory effect was observed when 0.1 nmol of rat ghrelin was injected. On the other hand, 0.1 nmol des-acyl rat ghrelin did not reduce WI. To examine the mechanism underlying the effect of ghrelin on WI, chicken B-type (or brain) natriuretic peptide (BNP), an anti-dipsogenic peptide in mammals, was injected at doses ranging from 0.1 to 1 nmol/chick. BNP did not affect WI in chicks under both normal and water-deprived drinking conditions. These findings indicate that ghrelin acts as an anti-dipsogenic peptide through the GHS receptor in the chicken.