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Inositol 1,4,5 trisphosphate receptor and chromogranin B are concentrated in different regions of the hippocampus
Author(s) -
Nicolay Nils H.,
Hertle Daniel,
Boehmerle Wolfgang,
Heidrich Felix M.,
Yeckel Mark,
Ehrlich Barbara E.
Publication year - 2007
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21328
Subject(s) - dentate gyrus , inositol , hippocampal formation , hippocampus , biology , phosphatidylinositol , inositol trisphosphate receptor , microbiology and biotechnology , chromogranin a , intracellular , kinase , endoplasmic reticulum , inositol phosphate , inositol trisphosphate , receptor , neuroscience , biochemistry , immunohistochemistry , immunology
Calcium (Ca 2+ ) release from intracellular stores plays a crucial role in many cellular functions in the brain. These intracellular signals have been shown to be transmitted within and between cells. We report a non‐uniform distribution of proteins essential for Ca 2+ signaling in acutely prepared brain slice preparations and organotypic slice cultures, both made from rat hippocampus. The Type I inositol‐1,4,5 trisphosphate receptor (InsP 3 R1) is the main InsP 3 R subtype in neurons. Immunohistochemistry experiments showed a prominent expression of InsP 3 R1 in the CA1 region of the hippocampus whereas the CA3 region and dentate gyrus (DG) showed only moderate immunoreactivity. In contrast, chromogranin B (CGB), a protein binding to the InsP 3 R1 on the luminal side of the endoplasmic reticular membrane was enriched in the CA3 region whereas DG and the CA1 region showed only faint CGB signals. The neuronal kinases leading to the formation of inositol‐1,4,5 trisphosphate (InsP 3 ), phosphatidylinositol‐4‐kinase (PI4K), and phosphatidylinositol‐4‐phosphate‐5‐kinase (PIPK), showed strong immunoreactivity throughout all hippocampal cell fields with differences in the subcellular distribution. Moreover, a distinct band of strong CGB and PIPK immunoreactivity was observed in the CA3 region that coincides with the mossy fiber tract (stratum lucidum). These data show differential expression of the components of the signaling toolkit leading to InsP 3 ‐mediated Ca 2+ release in cells of the hippocampus. The regulation of these differences may play an important role in various neuropathologic conditions such as Alzheimer's disease, epilepsy, or schizophrenia. © 2007 Wiley‐Liss, Inc.