N-methyl-D-aspartate antagonist inhibits NR-1 subunit phosphorylation of the spinal N-methyl-D-aspartate receptor induced by low frequency electroacupuncture

We investigated whether the 2 Hz electroacupuncture (EA) analgesia is associated with phosphorylation of N-methyl-D-aspartate receptor (NMDAR) NR-1 subunits and NMDAR antagonism in the lumbar spinal cord of rats. EA stimulation produced an increase of serine phosphorylation of NMDAR NR-1 subunits in the spinal cord as compared with normal conditions. However, the intrathecal injection of NMDAR antagonist D-2-amino-5-phosphonopentanoic acid significantly prevented serine phosphorylation of NMDAR NR-1 subunits induced by EA stimulation in the dorsal horn of spinal cord. These results indicate that EA analgesia by stimulation of peripheral nerves may be involved in an increase of NR-1 serine phosphorylation in the dorsal horn of the spinal cord.