Modulation of the gene expression of N-methyl-D-aspartate receptor NR2B subunit in the rat neostriatum by a single dose of specific antisense oligodeoxynucleotide

N-methyl-D-aspartate receptors (NRs) are a group of ionotropic glutamate re ceptors in the brain and they are composed of heteromeric subunits (NR1. NR 2A-D and NR3). In the neostriatum, a brain region that is associated with m ovement in animals, NMDA channels are known to involve in the motor control . Our previous report (Lai et al., 2000, Neuroscience 98. 493-500) has show n that a single dose of antisense oligodeoxynucleotides that are specific t o NR1 subunit results in blockage of the gene expression of NR1 as well as NR2A subunits in the neostriatum. In the present study, antisense oligodeox ynucleotides that are specific to NR2B (ANR2B) were then employed as molecu lar tools to further investigate the molecular interactions of NMDA recepto r subunits in the neostriatum. A single dose of ANR2B was injected unilater ally into the rat neostriatum. After one day of injection, no modification of motor behavior was found in the ANR2B-injected rats. The mRNA level of N R2B in the ANR2B-injected neostriatum was found to be decreased (-20.4%) by reverse transcriptase polymerase chain reaction (RT-PCR). However, the mRN A levels of NRL NR2A, NR2C and NR2D in the ANR2B-treated neostriatum were f ound to be unchanged. After two days of injection, NR2B immunoreactivity wa s found to decrease in the ANR2B-treated neostriatum by immunofluorescence (-35.1%). At higher magnification, NR2B immunoreactivity was found to decre ase in presumed spiny neurons of the neostriatum (-23.4%). No change in NR1 immunoreactivity was observed. These results indicate that a single dose o f ANR2B can successfully block the gene expression of NR2B in neurons of th e neostriatum and there is less effect on NR1 and other NR2 subunits. The b lockage of the gene expression of NR2B is therefore specific and the presen t results may provide important implications in applications of antisense i n research and in clinical therapy of neurological diseases. (C) 2001 Elsev ier Science Ltd. All rights reserved.