Drinking in the pigeon (Columba livia) in response to water deprivation and the influence of intracerebroventricular infusions of NaCl or sucrose solutions

Pigeons were deprived of fluid for 24 hours then allowed access to water and a 2.7% NaCl solution, the intakes of both solutions during the subsequent 60 min were observed. In a second experiment hypertonic or isotonic solutions of NaCl or sucrose were infused ICV, starting 5 min before access to the solutions and finishing 10 min after access, and the consummatory behaviour observed. Pigeons rehydrated themselves after the period of deprivation with a volume of water equal to the weight lost during the deprivation. Pigeons never drank the hypertonic NaCl solution. ICV infusions of hypertonic or isotonic sucrose attenuated drinking in response to 24 hours water deprivation. Isotonic or hypertonic NaCl infused ICV, on the other hand, had no significant effect. Thus, in the pigeon, drinking in response to 24 hours of water deprivation appears to be controlled by one mechanism, possibly osmoreceptor in nature (with the permissive control of CSF sodium concentration), since the birds drank a volume of water equal to their weight loss and changes in CSF sodium concentration influenced drinking in a manner similar to that described previously for osmotically induced drinking in pigeons.