Immunolocalization of CaMKII and NR2B in hippocampal subregions of rat during postnatal development

Developmental regulation and lateralization of N-methyl-d-aspartate (NMDA) receptors in the rat hippocampus

N-methyl-d-aspartate receptors (NMDARs) are expressed abundantly in the brain and play a crucial role in the regulation of central nervous system (CNS) development, learning, and memory. During early neuronal development, NMDARs modulate neurogenesis, neuronal differentiation and migration, and synaptogenesis. The present study aimed to examine the developmental expression of NMDARs subunits, NR1 and NR2B, in the developing hippocampus of neonatal rats during the first two postnatal weeks. Fifty-four male offspring were randomly divided into three age groups, postnatal days (P) 0, 7, and 14. Real-time-PCR, western blotting, and immunohistochemistry (IHC) analyses were employed to examine and compare the hippocampal expression of the NMDA receptor subunits. The highest mRNA expression of NR1 and NR2B subunits was observed at P7, regardless of its laterality. The mRNA expression of both subunits in the right hippocampus was significantly higher than that of the left one at P0 and P7. Similarly, the highest protein level expression of NR1 and NR2B subunits was also observed at P7 in both sides hippocampi. Although the protein expression of NR1 was significantly higher on the right side in all studied days, the NR2B was significantly higher in the right hippocampus only at P7. The analysis of optical density (OD) has shown a marked increase in the distribution pattern of the NR1 and NR2B subunits at P7 in all hippocampal subregions. In conclusion, there is a marked right-left asymmetry in the expression of NR1 and NR2B subunits in the developing rat hippocampus, which might be considered as a probable mechanism for the lateral differences in the structure and function of the hippocampus in rats.

Gad1-promotor-driven GFP expression in non-GABAergic neurons of the nucleus endopiriformis in a transgenic mouse line

Transgenic animals have become a widely used model to identify and study specific cell types in whole organs. Promotor-driven reporter gene labeling of the cells under investigation has promoted experimental efficacy to a large degree. However, rigorous assessment of transgene expression specificity in these animal models is highly recommended to validate cellular identity and to isolate potentially mislabeled cell populations. Here, we report on one such mislabeled neuron population in a widely used transgenic mouse line in which GABAergic somatostatin-expressing interneurons (SOM^pos INs) are labeled by eGFP (so-called GIN mouse, FVB-Tg(GadGFP)45704Swn/J). These neurons represent a subpopulation of all SOM^pos INs. However, we report here on GFP labeling of non-GABAergic neurons in the nucleus endopiriformis of this mouse line.

A novel mouse model of the aged brain: Over-expression of the L-type voltage-gated calcium channel CaV1.3

The aged population is growing rapidly, which has sparked tremendous interest in elucidating mechanisms of aging in both the body and the brain. Animal models have become an indispensable tool in biomedical science, but because of the cost and extended timeframe associated with aging animals to appropriate time points, studies that rely on using aged animals are often not feasible. Somewhat surprisingly, there are relatively few animal models that have been specifically engineered to mimic physiological changes known to occur during "normal" aging. Developing transgenic animal models that faithfully mimic key aspects of aging would likely be of great utility in studying both age-related deficits in the absence of overt pathology as well as an adjunct for transgenic models of diseases where aging is a primary risk factor. In particular, there are several alterations in the aged brain that are amenable to being modeled genetically. We have focused on one key aspect that has been repeatedly demonstrated in aged animals - an increase in the L-type voltage-gated calcium channel Ca_V1.3. Here we present a novel transgenic mouse line in which expression of Ca_V1.3 is increased by approximately 50% in the forebrain of young mice. These mice do not display any overt physical or non-cognitive deficits, exhibiting normal exploratory behavior, motor function, and affective-like responses, suggesting that these mice can be successfully deployed to assess the impact of an "aged brain" in a variety of conditions.