WISTAR-KYOTO RATS IN THE MORRIS WATER MAZE - IMPAIRED WORKING-MEMORY AND HYPERREACTIVITY TO STRESS

Wistar-Kyoto (WKY) rats were tested as a potential animal model for me mory dysfunction. These animals were reported to be highly reactive to stress and this was associated with findings of alterations in their hippocampal cholinergic activity. Since hippocampal cholinergic hypofu nction is often associated with deficits in memory processes, untreate d WKY rats were tested here in a working memory task in the Morris wat er maze. Animals were tested for five daily sessions, with two identic al trials per day, and their performance was compared to that of Sprag ue-Dawley (SD) rats. Results show that WKY rats failed to improve thei r performance both from day to day and within the two trials each day. This suggests impaired memory capabilities of WKY rats and may suppor t their use as an animal model of memory dysfunction. However, because of their increased tendency to float, speed of performance was also r educed in WKY compared to SD rats. This difference may be associated w ith their increased reactivity to stress. The combination of memory dy sfunction and stress hyper-reactivity seen in WKY rats may be used to study the association between these two functions, particularly the po ssible interaction between memory and depression.