Spatial learning and long-term potentiation of mutant mice lacking d-amino-acid oxidase

We evaluated the role of d-amino-acid oxidase on spatial learning and long-term potentiation (LTP) in the hippocampus, since this enzyme metabolizes d-amino-acids, some of which enhance the N-methyl-d-aspartate receptor functions. The Morris water maze learning and the LTP in the CA1 area of the hippocampal slice were observed in wild-type mice and mutant mice lacking d-amino-acid oxidase. The mutant mice showed significantly shorter platform search times in the water maze and significantly larger hippocampal LTPs than the wild-type mice. These results suggest that the abundant d-amino-acids in the mutant mouse brain facilitate hippocampal LTP and spatial learning.