Effects of hippocampal lesions on striatolimbic ionotropic glutamatergic receptors

Abstract

Changes in ionotropic N-methyl- d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate glutamatergic (Glu) receptor binding in rat caudate putamen (CPu) and nucleus accumbens (NAc) and hippocampal CA 1 and CA 3 regions were examined after unilateral injections of kainic acid (KA) into hippocampus to degenerate local intrinsic neurons and remove the glutamatergic afferents projecting to CPu and NAc. KA injections produced large losses of NMDA, AMPA and kainate receptors in hippocampal CA 1 and CA 3 regions. In addition, NMDA and kainate, but not AMPA, receptors were significantly reduced in NAc and CPu. These results suggest that a large proportion of NMDA, AMPA and kainate receptors in rat hippocampus arise on intrinsic postsynaptic neurons, and that some NMDA and kainate, but not AMPA, receptors also occur on presynaptic terminals of hippocampostriatal afferents innervating the CPu and NAc.