Matrix Metalloproteinases Contribute to Neuronal Dysfunction in Animal Models of Drug Dependence, Alzheimer's Disease, and Epilepsy

Table 2

Summary of impaired learning and memory parameters induced by MMP inhibition.

Test (type of memory)	MMP inhibitor	MMP-9^(−/−)	MMP-2^(−/−)
Y-maze test (short-term memory)	N.D.	±	⇓
Novel-object recognition test (short-term object memory)	N.D.	±	±
Novel-object recognition test (long-term object memory)	N.D.	⇓	±
Conditioned fear memory test (long-term fear memory)	⇓	⇓	±
Morris’s water maze test (hippocampus-dependent spatial memory)	⇓	N.D.	N.D.

Performance of MMP-9^(−/−) mice in various memory test indicates impairments of long-term memory in the mutant mice.
±: no change; ⇓: significant decrease versus control or wild-type mice; N.D.: not determined.
Modified from [13–15, 21].