Developmental Regulation of mRNAs Encoding Rat Brain Kainate/AMPA Receptors: A Northern Analysis Study

Abstract

Functionally diverse kainate/alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) receptors are generated by assembly of glutamate receptor (GluR)1, 2, and 3 subunits into homomeric and heteromeric channels. We examined GluR1, 2, and 3 gene expression in embryonic, neonatal, and adult rat brain by northern analysis under conditions of high stringency. In the adult, hybridization to a GluR1 riboprobe revealed the presence of an abundant RNA species, 5.2 kb in size, and minor bands of 3.2 and 3.9 kb. GluR2 hybridized to two species, 3.9 and 5.9 kb, of comparable abundance, presumably attributable to alternate splice products. Hybridization to the GluR3 riboprobe showed a major species of 5.2 kb. This pattern of RNA species was invariant over all the brain regions examined. Examination of GluR expression in development revealed that in the postnatal period, GluR1, 2, and 3 mRNAs are regulated as a function of age. In adult rat brain, GluR1 and 2 mRNA expression was highest in hippocampus; GluR3 was expressed at highest density in hippocampus and frontal cortex. The three transcripts were first detected at embryonic day 16 and then exhibited changes in expression levels in a region-specific manner. In hippocampus, all three transcripts exhibited elevated expression in the late neonatal period; in frontal cortex, elevated expression was observed for GluR2 and 3 only. In striatum, all three transcripts were expressed at relatively low levels throughout development, with a modest peak at postnatal day 14. In cerebellum, the GluR1 mRNA level was high from postnatal day 28 to adult.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the eight AMPA receptor subunit genes in the developing central nervous system and sensory organs of zebrafish

“…Expression of all AMPA receptor subunits in the forebrain was detectable at 24 hpf and followed a progressive maturational enrichment. The same pattern of AMPA receptors in the forebrain during development was also observed in other vertebrate systems such as rat and ferret (Durand and Zukin, 1993;Snyder-Keller and Costantini, 1996;Martin et al, 1998;Smith and Thompson, 1999). Furthermore, high levels of glutamate are found in the zebrafish olfactory bulb in the dorsal telencephalon, from 24 hpf onward (Sakata et al, 2003).…”

Age‐related functional changes of the glutamate receptor channels in rat Meynert neurones

“…These results suggest that the native AMPA receptors of Meynert neurones form a mosaic of several subunits which change at various developmental stages while the ratio of Ca¥-permeable GluR-1,3,4 subunits to that of the Ca¥-impermeable GluR-2 subunit may decline gradually during the developmental stages. In fact, the ratio of GluR-1 and GluR-3 to GluR-2 gene expression in the rat brain at various stages of development determined by an in situ hybridization study was high in postnatal CNS neurones but declined monotonically with age (Durand & Zukin, 1993). In the present study, we found that the Meynert neurones became less responsive to NMDA with age, while the KA and AMPA responses gradually increased.…”

Developmental and Activity Dependent Regulation of Ionotropic Glutamate Receptors at Synapses

“…This is in line with the identification of AMPARs at early embryonic stages (E14-15) in other rat brain regions including hypothalamic neurons [12] and raphe cells [13]. AMPA and NMDA receptor mRNAs have also been detected in CA1 early in development by in situ hybridization [14] and Northern analysis [15]. Glutamatergic synaptic transmission in the mammalian brain can be detected electrophysiologically at late prenatal stages and early in postnatal development -for example, in neocortex [16,17,18] and hippocampus [19,20].…”