Normal inhibitory avoidance learning and anxiety, but increased locomotor activity in mice devoid of PrPC

Prions are the causative agents of transmissible spongiform encephalopathies. The transmissible agent (PrPSC) is an abnormal form of PrPC, a normal neuronal protein. The physiological role of PrPC remains unclear. In the present report, we evaluated behavioral parameters in Prnp(0/0) mice devoid of PrPC. Prnp(0/0) mice showed normal short- and long-term retention of a step-down inhibitory avoidance task and normal behavior in an elevated plus maze test of anxiety. During a 5-min exploration of an open field, Prnp(0/0) mice showed normal number of rearings, defecation, and latency to initiate locomotion, but a significant increase in the number of crossings. The results suggest that Prnp(0/0) mice show normal fear-motivated memory, anxiety and exploratory behavior, and a slight increase in locomotor activity during exploration of a novel environment. (C) 1999 Elsevier Science B.V. All rights reserved.