title: Regulation of NMDA receptor subunit mRNA expression in the rat brain during postnatal development.
abstract: Different NMDA receptor subunits have been recently cloned. The present paper describes the developmental profile of expression of the NR-1 subunit and three NR-2 subunits (A, B, C) in the rat central nervous system. A sensitive RNase protection assay was employed to determine simultaneously the mRNA levels of these receptor subunits. We found low levels of NR-1 mRNA (comprising all different splicing isoforms) in newborn rats with a progressive increase of its expression in the following 2-3 weeks. NR-2 subunits can be regarded as 'modulatory' since their expression can produce differences in the properties of NMDA receptors. More than one NR-2 subunits can be expressed in the same brain region. NR-2A and NR-2C are concomitantly expressed in the cerebellum and during development their mRNAs increase with a similar profile from low levels in P-8 rats to maximal expression in P-21 animals. NR-2A and NR-2B are concomitantly expressed in several brain regions with a different ontogenetic profile. In the hippocampus NR-2B mRNA increases rapidly during the first week of life as compared to the NR-2A subunits which at this time is expressed to low levels indicating that NR-2B will probably be dominant in determining the NMDA properties during the first period of life. Our data can provide a molecular correlate with properties of NMDA receptors such as voltage dependent Mg2+ block and deactivation kinetics which undergo significant changes during development and have been shown to depend upon the NR-2 subunit co-expressed with the common NR-1 subunit in various brain regions.
authors: DIBIT, San Raffaele Hospital, Milan, Italy.
authors: M A
authors: MA
authors: Riva
authors: F
authors: F
authors: Tascedda
authors: R
authors: R
authors: Molteni
authors: G
authors: G
authors: Racagni
mesh_terms: D000818:Animals; D001481:Basal Metabolism; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D005260:Female; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*; D012260:Ribonucleases
chemical_list: D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D012260:Ribonucleases