STRIATAL NMDAR2B MESSENGER-RNA EXPRESSION AFTER BILATERAL CORTICAL AND UNILATERAL NIGRAL DEAFFERENTATION

WE have studied by in situ hybridization histochemistry the regulation of NMDAR2B mRNA expression by dopaminergic (DA) and cortical glutamat ergic afferent fibres in the rat striatum. The effects induced by a un ilateral lesion of the medial forebrain bundle and a bilateral lesion of the sensorimotor cortex were analysed in the dorsal striatum 3 week s after the lesions. Using a S-35-labelled specific oligonucleotide pr obe no change in NMDAR2B mRNA level was found in DA-depleted striatum compared with the normal rat striatum. However, following cortical les ions, the levels of NMDAR2B mRNA were significantly increased, specifi cally in the striatal projection area of the SM cortex. These results suggest that NMDAR2B mRNA expression is regulated by cortico-striatal fibres in a topographic manner.