Research ReportIdentification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain
Introduction
Calcium sensing receptor (CaSR) has been isolated for the first time from bovine and human parathyroid glands (Brown, 1991, Garrett et al., 1995), and later from rat brain (Ruat et al., 1995). The CaSR is predicted to be glycosylated proteins, with a large extracellular domain and the seven membrane spanning region characteristic of other G-protein-coupled receptors (Brown, 1991, Garrett et al., 1995, Riccardi et al., 1995), and it has been involved in diverse physiological functions (Chattopadhyay and Brown, 2000). Localization of transcripts for CaSR in the adult rat brain has been reported by Rogers KV and coworkers (1997), and more recently by Ferry et al. (2000), which performed an analysis of CaSR mRNA expression in the adult brain and its localization in neurons and oligodendrocytes. CaSR has been also found express both in astrocytes and microglia but these results have been achieved using primary cultures of human and rat brain respectively (Chattopadhyay et al., 1999, Chattopadhyay et al., 2000). Therefore, at present, a complete in vivo work on the identification of CaSR mRNA-expressing cells lacks and this study was undertaken in order to acquire more information on cell type expressing CaSR mRNA in the rat brain and to analyse for the first time the CaSR mRNA expression in different experimental models of brain injury: (a) bilateral lesion of hippocampal CA3 regions by kainate-induced seizure; (b) unilateral hippocampal lesion by a stereotaxic local injection of ibotenic acid; (c) mechanical lesion produced by a needle (30 G) stereotaxically introduced through the rostral cerebral cortex.
Section snippets
Expression of CaSR mRNA
A detailed analysis of CaSR expression in the normal rat brain was performed using in situ hybridization. Cells expressing CaSR mRNA were scattered throughout almost all the brain areas with regional differences in labeled cells density. Brain regions and nuclei that express CaSR mRNAs are listed in Table 1, that report the relative density of CaSR-expressing cells ranked on a scale from one to four, with “+” representing widely scattered cells (5-20%) and “++++” representing the highest cell
Discussion
Results regarding the brain distribution of CaSR transcripts are in agreement with data of previous works (Ferry et al., 2000, Rogers et al., 1997) confirming an expression of CaSR in all brain regions, with a particularly high abundance in subfornical organ, olfactory bulb and hypothalamus. However, we observed different intensity of signal in some brain regions or nuclei (e.g. hippocampal layers, hypothalamus nuclei) in comparison to previously reported data (Rogers et al. 1997). Such minor
Experimental procedures
Wistar adult male rats (250 g b.w.) from local stock have been used for the present study. The rats were kept under controlled temperature and standardized lighting and free access to food and water. Procedures involving animals and their care were conducted in conformity with the institutional guidelines that are in compliance with national and international laws and policies. All efforts were made to minimize the number of animals used and their suffering and all experiments were approved by
Acknowledgments
This work was funded by a grant from Italian M.I.U.R. (Progetti di Ricerca di Interesse Nazionale-PRIN, #9805089988_005), and from the University of Palermo and University of Catania (Finanziamenti Ricerca Scientifica di Ateneo).
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Enhanced expression of the calcium-sensing receptor in reactive astrocytes following ischemic injury in vivo and in vitro
2016, Journal of the Neurological SciencesCitation Excerpt :In addition, our data revealed that activated microglia within the vulnerable region of the post-ischemic hippocampus were devoid of any specific labeling for CaSR, despite there being evident microglial reactivity in this area. These results contrast with a previous finding of microglial expression in cultured rat microglia [29], but agree well with findings showing an absence of CaSR in microglia/macrophages [11,20]. Astrocytic CaSR expression was evident on days 3–7 after reperfusion and increased progressively until day 28, which was the last time point examined in the present study.
Differential expression of the calcium-sensing receptor in the ischemic and border zones after transient focal cerebral ischemia in rats
2015, Journal of Chemical NeuroanatomyCitation Excerpt :It is unclear why CaSR expression is induced in a subset of neurons in the border zone, and thus, characterization of these neurons using neurotransmitters or calcium-binding proteins is needed to further elucidate the functional significance of neuronal CaSR expression. However, in contrast to our findings, Mudo et al. (2009) reported the expression of CaSR mRNA in neurons and oligodendrocytes (but not in astrocytes and microglia), in normal animals and in those with kainate-induced seizures. In addition, Kim et al. (2011) demonstrated the induction of CaSR in hippocampal neurons, but not in astrocytes and microglia/macrophages, after global forebrain ischemia.
Roles of the calcium sensing receptor in the central nervous system
2013, Best Practice and Research: Clinical Endocrinology and MetabolismCitation Excerpt :On the other hand, the developmental expression profile of CaSR in the hippocampus revealed time-dependent changes in expression in the cell bodies of the pyramidal cell layer.11 Detailed mapping of CaSR transcripts showed expression at different levels in several regions of the developing and adult brain in both the grey and white matter (Refs. 13–15 and Fig. 1). In the grey matter, many areas displayed isolated, widely scattered CaSR-expressing cells.
The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism
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