NMDAR2 upregulation precedes mossy fiber sprouting in kainate rat hippocampal epilepsy.
Following intrahippocampal (hilar) kainic acid (KA) lesions in rats, NMDAR2A/B receptor proteins are upregulated significantly in the inner molecular layer (IML) of the dentate gyrus by post-injection day 5. By contrast, the aberrant mossy fibers which reinnervate the IML remained in the subgranular zone before sprouting and synapsing in the IML, which occurs at approximately post-KA day 17. For 40 days thereafter, this mossy fiber ingrowth progressed, while the increased NMDAR2A/B (receptors) immunoreactivity remained at the same densities. These results suggest that new NMDAR2A/B proteins in granule cell dendrites are limited to the IML, which is the eventual site for MF hyperinnervation, neosynaptogenesis, and recurrent synaptic hyperexcitability.
Mikuni
N
N
Department of Neurosciences NC-30, The Cleveland Clinic Foundation, OH 44195, USA. mikunin@cesmtp.ccf.org
Babb
T L
TL
Chakravarty
D N
DN
Hadam
J L
JL
Penrod
C E
CE
D000818:Animals; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D006624:Hippocampus / Q000503:physiopathology*; D007608:Kainic Acid; D008297:Male; D019599:Mossy Fibers, Hippocampal / Q000503:physiopathology*; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate; D007608:Kainic Acid