Different expression of NR2B and PSD‐95 in rat hippocampal subregions during postnatal development

Abstract

The different expressions of NR2 and synaptic-associated proteins have been studied by protein and mRNA level with immunoblotting, in situ hybridization, or immunogold analysis. But the relationship between NR2 subunits and PSD-95 family proteins is still controversial. In this study, we used immunofluorescent staining to assess NR2B and PSD-95 expressions and the relationship between them in CA1, CA3, and DG of rat hippocampus on different postnatal day. In CA1, NR2B expression decreased with age. It was high at birth, reached a plateau at P4, and declined gradually after P7. In CA3, NR2B expression was similar to that in CA1. But the stratum lucidum was devoid of staining. In DG, the NR2B expression retained a higher level. From P0 to P2, the PSD-95 expression in CA1 increased gently, and then declined slightly. After P7, the PSD-95 expression increased sharply till P28, and decreased again. In CA3 and DG, the PSD-95 expression is very similar except that low-level of PSD-95 was found in the CA3 stratum lucidum. The expression of NR2B did not correlate with that of PSD-95 in CA1 and the DG granular and molecular layer. Only in CA3 and DG polymorphic layer, there was a negative correlation. The results suggested in hippocampal subregions, CA3 and DG may be more plastic than CA1.The NR2B and PSD-95 expression have distinct regional and cell specific distribution. The different regional distribution pattern may relate to the different physiological functions during postnatal development.

Prenatal ketamine exposure causes abnormal development of prefrontal cortex in rat

“…Synaptophysin is one of the most abundant synaptic vesicle integral proteins that regulates the formation and trafficking of synaptic vesicles47. Our Western blot and immunohistochemistry data showed that the expression of PSD-95 and synaptophysin at P0 and P30 was similar to what was reported elsewhere4849. The higher levels of PSD-95 and NR2B expression in ketamine-treated than in the control samples presumably reflects increased synapse concentration, which is consistent with the overbranched dendritic phenotype in mature neurons39.…”

Proteomic Analysis of Postsynaptic Protein Complexes Underlying Neuronal Plasticity

“…22 In rats, GluN2B levels decreased in both Cornu Ammonis (CA)1 and CA3 regions of the hippocampus beginning 4 days after birth and reaching adult levels (∼40% decrease) by postnatal day 21. 23 Similar results were observed in humans, where the GluN2A:GluN2B mRNA ratio increases in the CA1 and CA3 region, but not the dentate gyrus. 24 Despite age-dependent reductions in GluN2B levels, recent studies suggest that triheteromeric NMDARs containing GluN1/GluN2A/GluN2B may be the most abundant form in dissociated hippocampal neurons and adult hippocampal synapses.…”

N-methyl-d-aspartate receptor subunit expression in adult and adolescent brain following chronic ethanol exposure

“…A number of studies have shown that NMDAR subunit expression is differentially regulated during development (Watanabe et al, 1992, 1993; Monyer et al, 1994; Zhong et al, 1995; Jin et al, 1997; Wenzel et al, 1997; Hsieh et al, 2002; Magnusson et al, 2002; Law et al, 2003; Chang et al, 2009). Most of these studies have demonstrated in the rat that NR2A expression is generally low at birth but then increases up to about P21–P28, whereas NR2B is high at birth and then peaks around P10–21.…”

“…Evidence has shown that NMDA receptor subunit expression is developmentally regulated during brain maturation (Watanabe et al, 1992, 1993; Jin et al, 1997; Wenzel et al, 1997; Barria and Malinow, 2002; Magnusson et al, 2002; Law et al, 2003; Chang et al, 2009). This regulation, which has been demonstrated both in vivo and in vitro, leads to changes in the functional and pharmacological properties of NMDAR.…”