Co-localization of N-methyl-D-aspartate receptors and substance P (neurokinin-1) receptors in rat spinal cord

Glutamate, substance P (SP), and their receptors have been implicated in th e initiation and maintenance of persistent pain through an interaction at s econd order spinal cord neurons. Employing well-characterized antibodies to the SP receptor and the N-methyl-D-aspartate receptor (NR1 subunit, splice variant missing exon 22), we demonstrate co localization of these receptor s on second order neurons at cervical, thoracic, lumbar, and sacral spinal cord levels. The co-localization was marked in lamina I of the dorsal horn at all levels and in the intermediolateral nucleus of the thoraco-lumbar sp inal cord nuclei associated with autonomic function. (C) 2000 Elsevier Scie nce Ireland Ltd. All rights reserved.