Kainate receptors (KARs) are highly expressed during postnatal development and are likely to play an important role in the synaptic mechanisms underlying maturation of neural networks. Despite recent advances in our understanding of the molecular biology and pharmacology of KARs comparatively little is known about developmental changes in native receptors and the relative contributions of individual subunits to KAR complexes. Using antibodies specific to GluR6/7 and KA2 subunits Immuno and histoblots were used to demonstrate quantitatively that the mechanisms controlling subunit expression during postnatal development are differentially regulated in a precise temporal and region-specific manner.