nNOS expressing neurons in the entorhinal cortex and hippocampus are affected in patients with Alzheimer's disease.
Nitric oxide is a multifunctional molecule that acts as messenger/modulator in synaptogenesis and potential neurotoxin and is synthesized by three isozymes of Nitric oxide synthase (NOS). The role of NOS in Alzheimer's disease (AD) is unclear. For example, neurons in the entorhinal cortex (EC) that are highly vulnerable to neurodegeneration in AD express low levels of NOS and while it has been suggested that the inducible form of NOS is upregulated in AD, it is still not clear if the constitutive expressed isozyme (nNOS) is involved in the process of neurodegeneration. In order to better understand the role of nNOS in the pathogenesis of AD, sections from the EC and hippocampus (HC) of AD and control cases were immunohistochemically analyzed by single- and double-immunolabeling using antibodies against nNOS and PHF-tau. Semiquantitative assessment of numbers of nNOS expressing neurons in different areas of the HC and EC showed a remarkable loss of nNOS expressing neurons in the entorhinal cortex layer II and--less severe--CA1 and CA3 of the hippocampus in patients with AD. In addition, double-immunolabeling studies revealed that nNOS is strongly associated with neurofibrillary tangles and plaques. These findings indicate that nNOS expressing neurons are highly susceptible to neurodegeneration and that nNOS might contribute to the pathogenesis of AD.
Thorns
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Department of Neurosciences, University of California at San Diego, La Jolla 92093-0624, USA.
Hansen
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L
Masliah
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E
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology / Q000473:pathology*; D015153:Blotting, Western; D018450:Disease Progression; D018728:Entorhinal Cortex / Q000201:enzymology / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000201:enzymology / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000032:analysis*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009410:Nerve Degeneration; D009419:Nerve Tissue Proteins / Q000032:analysis*; D016874:Neurofibrillary Tangles / Q000201:enzymology; D009474:Neurons / Q000201:enzymology* / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000032:analysis*; D052248:Nitric Oxide Synthase Type I; D012720:Severity of Illness Index
D007527:Isoenzymes; D009419:Nerve Tissue Proteins; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I