Lesion-induced changes in NMDA receptor subunit mRNA expression in rat visual cortex

Focal lesions in the visual cortex are well known to induce pronounced peri lesional reorganization of the neuronal circuitry. Since NMDA receptors cru cially control synaptic plasticity and reorganization, we studied lesion-in duced changes in their subunit expression and biophysical properties. Betwe en 8 and 10 days after focal thermolesioning, pyramidal neurones in the nea r surround of the lesion were studied in acute brain slices. We found a sig nificant decrease in the ratio of NR2A and NR2B subunit mRNA as compared to neurones from sham operated animals. Interestingly, no significant differe nces in the properties of NMDA receptor-mediated postsynaptic currents (NMD A PSCs) were observed between lesioned and sham operated animals. Thus, the observed perilesional changes in the NR2A/NR2B mRNA ratio appear to be sub threshold to result in significant changes in the functional properties of NMDA receptors. NeuroReport 11:4021-4025 (C) 2000 Lippincott Williams & Wil kins.