Characterization of neuropeptide Y,Y2 receptor knockout mice in two animal models of learning and memory processing

Neuropeptide Y (NPY) and, in particular, the Y-2 receptor subtype, has been suggested to be involved in learning and memory processing. However, the precise role of Y-2 receptors in learning and memory remains unclear. In the present study, mice lacking NPY Y-2-type receptors were assessed in two animal models of learning and memory processing. We found that NPY Y-2(-/-) mice displayed a deficit on the probe trial in the Morris water maze task, whereas acquisition performance, swim speed, and visible platform performance did not differ significantly between groups. In addition, NPY Y-2(-/-) mice exhibited a marked deterioration in object memory 6 h, but not I h, following initial exposure in the object recognition test. Both groups of mice showed similar locomotor activity profiles in a low-stress, open field test. These data support the hypothesis that Y-2 receptors are involved in the regulation of learning and memory processing.