title: Immunoreactivity of calcium binding protein secretagogin in the human hippocampus is restricted to pyramidal neurons.
abstract: Disturbed calcium homeostasis plays a crucial role in the aetiology of Alzheimer's disease (AD) and the aging process. We evaluated immunoreactivity of secretagogin, a recently cloned calcium binding protein, in hippocampus and adjacent entorhinal cortex of 30 neuropathologically examined post mortem brains (m:f=12:18; mean age, 79.8+/-15.1 years). The study group consisted of 15 cases fulfilling the criteria for high probability of AD according to the NIA-Reagan Institute Criteria and 15 cases with no to medium probability. Sections were incubated with secretagogin-specific antibodies and the number of immunoreactive neurons as well as staining intensities in both neurons and neuropil were assessed. Both cellular and neuropil immunoreactivity were restricted to subiculum and Ammons horn. Cellular immunoreactivity was further restricted to pyramidal neurons and showed a hierarchical distribution: the mean percentage of immunoreactive neurons was highest in sector CA3 (64.41%), followed by CA2 (44.09%), CA4 (34.38%), CA1 (10.9%), and the subiculum (2.92%; P<0.001, except CA2-CA4, P>0.05), while it did not differ significantly between groups with different degrees of AD pathology. The pattern of secretagogin immunoreactivity resembles that of calcium sensor proteins as it is restricted to a subset of neurons and therefore secretagogin could serve highly specialized tasks in neuronal calcium signalling.
authors.affiliation: Institute of Pathology, Otto Wagner Hospital, Baumgartner Hoehe 1A-1145, Vienna, Austria. johannes.attemps@wienkav.at
authors.forename: Johannes
authors.initials: J
authors.lastname: Attems
authors.forename: Magdalena
authors.initials: M
authors.lastname: Quass
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Gartner
authors.forename: Anastasiya
authors.initials: A
authors.lastname: Nabokikh
authors.forename: Ludwig
authors.initials: L
authors.lastname: Wagner
authors.forename: Stefan
authors.initials: S
authors.lastname: Steurer
authors.forename: Stefanie
authors.initials: S
authors.lastname: Arbes
authors.forename: Felix
authors.initials: F
authors.lastname: Lintner
authors.forename: Kurt
authors.initials: K
authors.lastname: Jellinger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000276:immunology*; D015153:Blotting, Western / Q000379:methods; D002102:Cadaver; D002135:Calcium-Binding Proteins / Q000276:immunology*; D018891:Dentate Gyrus / Q000276:immunology; D018728:Entorhinal Cortex / Q000276:immunology; D005260:Female; D006624:Hippocampus / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D019581:Neuropil / Q000276:immunology; D017966:Pyramidal Cells / Q000276:immunology*; D064046:Secretagogins
chemical_list: D002135:Calcium-Binding Proteins; C576556:SCGN protein, human; D064046:Secretagogins