Intraventricular neuropeptide Y decreases need-induced sodium appetite and increases pica in rats

Neuropeptide Y (NPY) is a potent endogenous stimulator of food intake. In addition to stimulating increased food intake, when paired with a novel-flavored solution, NPY produces an aversion to that flavor. Hence, exogenous NPY elicits 2 seemingly opposing behaviors, increased feeding and the formation of a conditioned taste aversion. One interpretation of these data is that NPY produces some form of malaise or visceral illness. NPY's orexigenic and malaise-inducing properties were tested in rats with 2 measures sensitive to malaise, increased kaolin consumption (pica behavior) and failure to express need-induced sodium intake. Administration of NPY resulted in increased food intake, increased kaolin consumption, and decreased need-induced sodium intake. These data support the hypothesis that exogenous NPY has both orexigenic and malaise-inducing properties.