LONG-TERM POTENTIATION INCREASES TYROSINE PHOSPHORYLATION OF THE N-METHYL-D-ASPARTATE RECEPTOR SUBUNIT 2B IN RAT DENTATE GYRUS IN-VIVO

Long-term potentiation (LTP) is a form of synaptic memory that may sub serve developmental and behavioral plasticity. An intensively investig ated form of LTP is dependent upon N-methyl-D-aspartate (NMDA) recepto rs and can be elicited in the dentate gyrus and hippocampal CA1. Induc tion of this type of LTP is triggered by influx of Ca2+ through activa ted NMDA receptors, but the downstream mechanisms of induction, and ev en more so of LTP maintenance, remain controversial. It has been repor ted that the function of NMDA receptor channel can he regulated by pro tein tyrosine kinases and protein phosphatases and that inhibition of protein tyrosine kinases impairs induction of LTP. Herein we report th at LTP in the dentate gyrus is specifically correlated with tyrosine p hosphorylation of the NMDA receptor subunit 2B in an NMDA receptor-dep endent manner. The effect is observed with a delay of several minutes after LTP induction and persists in vivo for several hours. The potent ial relevance of this post-translational modification to mechanisms of LTP and circuit plasticity is discussed.