LP-BM5 infection impairs spatial working memory in C57BL/6 mice in the Morris water maze

Previous studies show that the LP-BM5 murine leukemia virus causes an acqui red immunodeficiency syndrome in C57BL/6 mice (MAIDS) and impairs learning and memory without gross motor impairment. To assess spatial working memory impairment after LP-BM5 infection and the time course of this impairment, we tested mice in a modified working-memory version of the Morris water maz e. Twenty mice were inoculated with LP-BM5; controls received medium (Minim um Essential Medium). In the test procedure, animals had two 1-min training sessions to learn the position of a randomly placed hidden platform. Thirt y seconds after the second training session, animals were placed in the maz e without the platform, and time and pathlength spent in each quadrant of t he maze were measured. For 9 weeks after LP-BM5 infection, both groups show ed preference for the target quadrant compared to the opposite quadrant. At 10 and 11 weeks after infection, the LP-BM5 virus infected mice lost this target quadrant preference. We conclude that LP-BM5 infection impaired spat ial working memory in a modified working-memory version of the Morris water maze test in C57BL/6 mice at 10 and 11 weeks after virus infection. (C) 20 00 Elsevier Science B.V. All rights reserved.