Hippocampal SH2-containing protein-tyrosine phosphatases are involved in extinction of contextual fear.

Contextual fear memory is attenuated by re-exposure of animals to a context alone without pairing it with an unconditioned stimulus, and this phenomenon is referred to as fear extinction. In this study we demonstrated that stereotaxic injection of an inhibitor of Src homology 2-containing protein-tyrosine phosphatases 1 and 2 (SHP1/2), NSC87877, into the hippocampus significantly suppressed extinction of contextual fear in the mouse. Intra-hippocampal injection of NSC87877, however, had no effect on the initial memory formation in contextual fear conditioning. These findings suggest that SHP1/2 activity in the hippocampus is involved in the control of contextual fear extinction.