ULTRASTRUCTURAL-LOCALIZATION OF GLUTAMATE-RECEPTOR SUBUNITS (NMDAR1, AMPA GLUR1 AND GLUR2 3) AND SPINOTHALAMIC TRACT CELLS/

THE associations of glutamate receptor subunits (NMDAR1, AMPA GluR1 an d GluR2/3) and spinothalamic tract neurons in the rat lumbar spinal co rd dorsal horn were investigated. Staining for NMDAR1 and AMPA GluR1 a nd GluR2/3 receptor subunits was observed throughout the spinothalamic tract soma and dendrites, particularly in association with the rough endoplasmic reticulum and some postsynaptic membrane sites. Immunostai ning for NMDAR1 and AMPA GluR2/3 was also noted in presynaptic membran e sites. Localization of both NMDA and AMPA glutamate receptor subunit s in association with spinothalamic tract neurons provides anatomical evidence in support of the various interactions reported for glutamate receptors in nociception. Presynaptic localization of the AMPA GluR2/ 3 receptor subunit suggests that spinothalamic tract cells may also be affected presynaptically by AMPA glutamate receptor interactions.