Abstract: | Matrix Metalloproteinase 9 (MMP‐9) has been demonstrated to play a crucial role in maintenance of NMDA receptor‐dependent LTP and in lateral mobility of these receptors. However, the effect of MMP‐9 on NMDA receptor (NMDAR) functional properties is unknown. For this purpose we have investigated the impact of recombinant MMP‐9 on the whole‐cell NMDAR‐mediated current responses in cultured hippocampal neurons. Treatment with MMP‐9 induced a reversible acceleration of desensitization and deactivation kinetics but had no effect on current amplitude. Interestingly, phorbol ester, a PKC activator known to enhance NMDAR lateral mobility, induced kinetic changes of currents similar to those produced by MMP‐9. In conclusion, our results show that MMP‐9 reversibly modulates the NMDAR kinetics and raise a possibility that this modulation could be related to the lateral mobility of these receptors. © 2009 Wiley‐Liss, Inc. |