Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

Calcium sensing receptor (CaSR), isolated for the first time from bovine and human parathyroid, is a G-protein-coupled receptors that has been involved in diverse physiological functions. At present a complete in vivo work on the identification of CaSR mRNA-expressing cells in the adult brain lacks and this investigation 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 its expression in different experimental models of brain injury. The expression of CaSR mRNAs was found mainly in scattered cells throughout almost all the brain regions. A double labeling analysis showed a colocalization of CaSR mRNA expression in neurons and oligodendrocytes, whereas it was not found expressed both in the microglia and in astrocytes. One week after kainate-induced seizure CaSR was found in the injured CA3 region of the hippocampus and very interestingly it was found up-regulated in the neurons of CA1-CA2 and dentate gyrus. Similarly, 1 week following ibotenic acid injection in the hippocampus, CaSR mRNA expression was increased in oligodendrocytes both in the lesioned area and in the contralateral CA1-CA3 pyramidal cell layers and dentate gyrus. One week after needle-induced mechanical lesion an increase of labeled cells expressing CaSR mRNA was observed along the needle track. In conclusion, the present results contribute to extend available data on cell type-expressing CaSR in normal and injured brain and could spur to understand the role of CaSR in repairing processes of brain injury

Cellular localization of mGluR3 and mGluR5 mRNAs in normal and injured rat brain

In order to understand the role of metabotropic glutamate receptors (mGluRs) in the brain, it is important to know how the mGluRs are differentially expressed among the different cell types. At present, the cellular expression of mGluR3 and mGluR5 has been mostly studied in terms of proteins with observations suggesting the expression of both mGluR3 and mGluR5 in neuronal and in glial cells. In order to verify the brain cell type-expressing mGluR3 and mGluR5 mRNAs, both in normal and injured brain, we performed a double labeling analysis, by in situ hybridization for mGluR3 or mGluR5 mRNA and immunohistochemistry for specific cellular markers

Fibroblast growth factor-2 and its receptor expression in proliferating precursor cells of the subventricular zone in the adult rat brain

Several findings have suggested the existence in the subventricular zone (SVZ) from sagittal sections of adult rat brain of a trophic mechanism, mediated by fibroblast growth factor-2 (FGF-2) and its multiple high-affinity FGF receptors (FGFRs), regulating neurogenesis mainly by controlling precursor cell proliferation. However, no clear data are available on the expression of FGF-2 and FGFRs in proliferating precursor cells of the SVZ. To address these questions we examined FGF-2 mRNA and its FGFR mRNA expression in proliferating precursor cells of the SVZ by using a double labeling procedure, combining in situ hybridization for FGF-2 and its FGFR mRNA with immunohistochemistry for bromodeoxyuridine (BrdU), a marker for proliferating cells. The results showed that FGFR1 and FGFR2 mRNAs were expressed in BrdU-labeled proliferating precursor cells, whereas FGFR3 and FGF-2 mRNAs were not, suggesting that in the SVZ the proliferating precursor cells express FGFR1 or FGFR2 and they may respond to FGF-2 released by non-proliferating cells. The FGFR4 mRNA was not found expressed in the SVZ. In the future, by identifying the cell types expressing FGFRs, it will be possible to gain insight into the functional activity of FGF2 within the SVZ