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

Prions are the causative agents of transmissible spongiform encephalopathie s. The transmissible agent (PrPSC) is an abnormal form of PrPC, a normal ne uronal protein. The physiological role of PrPC remains unclear. In the pres ent 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 maz e test of anxiety. During a 5-min exploration of an open field, Prnp(0/0) m ice showed normal number of rearings, defecation, and latency to initiate l ocomotion, but a significant increase in the number of crossings. The resul ts suggest that Prnp(0/0) mice show normal fear-motivated memory, anxiety a nd exploratory behavior, and a slight increase in locomotor activity during exploration of a novel environment. (C) 1999 Elsevier Science B.V. All rig hts reserved.