PHOSPHOLIPASE A(2) ENHANCES [H-3] AMPA BINDING TO A PUTATIVE HOMOMERIC GLUR-B RECEPTOR IN THE RAT SPINAL-CORD

[H-3]AMPA and [H-3]kainate binding to rat spinal cord was localised most densely in the substantia gelatinosa of the dorsal horn. Phospholipase A(2) elicited a dose-dependent increase in specific [H-3]AMPA binding but not in [H-3]kainate binding. The enhancement of [H-3]AMPA binding was blocked by bromophenacyl bromide and at O'C and was not mimicked by arachidonic acid. Since GluR-B is the only AMPA receptor subunit detectable in the rat spinal cord, and recombinant homomeric GluR-B assemblies do not bind [H-3]kainate, these results suggest phospholipase A(2) may modulate [H-3]AMPA binding to putative homomeric GluR-B receptors.