Enforced water drinking induces changes in burying behavior and social interaction test in rats

The effect of water deprivation and water intake on experimental anxiety in rats was tested using burying behavior (BB) and social interaction (SI) anxiety paradigms. Two groups of animals were studied: a control group with free access to water, and a 72-h water-deprived experimental group. Anxiety was studied in a water-deprived group or following a 10-min period of ad lib water drinking. An increase in the mean time of defensive burying in animals deprived for 72 h was observed, whereas an important reduction occurred in the levels of burying behavior immediately after the animals were allowed to drink ad lib for 10 min. These results suggest that the observed increase in defensive burying in the water-deprived animals represents an anxiogenic effect, whereas the decrease in this behavior in water-satiated animals is considered an anxiolytic action. The temporal course of reduction in burying behavior, observed after water drinking, revealed that the anxiolytic action lasts 5 min, whereas 15-30 min after drinking, burying behavior levels were similar to those in the control group. In the social interaction experiment a partial anxiogenic/anxiolytic effect of water deprivation and water intake was observed. The adaptive meaning of anxiogenic and anxiolytic changes linked to consummatory behaviors in rats is discussed on the basis of behavioral and biochemical data.