Gene expression of AMPA, kainate, and NMDA receptor subunits in the pigeon spinal cord

This study examined the localization of postsynaptic neurons having three types of iGluRs in the pigeon spinal cord. Nine mRNAs of iGluR subunits – namely GluA1, GluA2, GluA3, and GluA4 for AMPA receptors; GluK1, GluK2, and GluK4 for kainate receptors; and GluN1 and GluN2A for N-methyl-D-aspartate (NMDA) receptors – were analyzed by in situ hybridization. All three types of iGluRs were found in gray matter, with GluK4 and GluN1 subunits strongly expressed in laminae I–IX. GluA1 and GluA2 subunits were expressed in glial cells of white matter. In general, AMPA receptors were more weakly expressed than kainate and NMDA receptors. Among the four segments of the spinal cord, no significant differences were observed between the hybridization signals of the various iGluRs. Neurons with strong expression of GluK4 and GluN1 (but not the other subunits) were present in the marginal nucleus of cervicothoracic segments and in the accessory lobe of Lachi in lumbosacral segments, while GluA1, GluA2, and GluK2 were expressed in glycogen cells of the accessory lobe. Taken together, these results suggest that multiple subunits of iGluRs are responsible for glutamate transmission in the avian spinal cord.
Source: Journal of Chemical Neuroanatomy - Category: Neuroscience Source Type: research