Recent studies on apolipoprotein E (apoE) have stressed the importance
of this protein in neuronal viability, especially in the hippocampal
area. In the present study, we used the Morris water maze to assess sp
atial learning and memory in 6-month-old homozygous apoE-deficient and
heterozygous control mice. The apoE status was checked by genotyping
and immunocytochemistry. ApoE-knockout mice were not able to learn the
task at all, developed neither spatial nor other strategies to locate
the platform, but rather an unusual repetitive behavioral pattern of
'wall bumping'. Heterozygous control mice did not experience any diffi
culty with the task. Swimming ability and general locomotor activity o
f both groups were comparable. These results indicate that absence of
apoE in these animals might be critical for spatial learning and memor
y abilities. (C) 1977 Elsevier Science B.V.