Histochemical characterization of neuronal NADPH-diaphorase

We examined the properties of neuronal NADPH-diaphorase in sections of rat striatum, using histochemical procedures. NADPH-diaphorase histochemistry stained discrete populations of central neurons and provided a Golgi-like image of the neurons exhibiting this activity. The NADPH-diaphorase reaction...

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Bibliographic Details
Published in:The journal of histochemistry and cytochemistry 1989-05, Vol.37 (5), p.653-661
Main Authors: Hope, BT, Vincent, SR
Format: Article
Language:English
Subjects:
Analytical, structural and metabolic biochemistry
Animals
Biological and medical sciences
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
Histocytochemistry - methods
Male
Microscopy, Electron
NADH, NADPH Oxidoreductases - metabolism
NADPH Dehydrogenase - metabolism
Neurons - enzymology
Neurons - ultrastructure
Oxidoreductases
Rats
Rats, Inbred Strains
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Summary:We examined the properties of neuronal NADPH-diaphorase in sections of rat striatum, using histochemical procedures. NADPH-diaphorase histochemistry stained discrete populations of central neurons and provided a Golgi-like image of the neurons exhibiting this activity. The NADPH-diaphorase reaction appeared to be enzyme catalyzed, since it was abolished by pre-treatment with proteases, heat, and acid or alkaline denaturation. Under anaerobic conditions, any tetrazolium salt with a redox potential more positive than NADPH could be reduced by the enzyme. NADPH-diaphorase activity was sensitive to inhibition by sulfhydryl reagents but was unaffected by metal chelators, superoxide dismutase, and catalase. Therefore, the enzyme is unlikely to be a metalloenzyme or to reduce tetrazoliums by producing superoxide anions or hydrogen peroxide. Various analogues of beta-NADPH could be used by the enzyme; however, beta-NADH, which can be used by DT-diaphorase, was ineffective. The enzyme was also resistant to dicumarol, an inhibitor of DT-diaphorase activity. Electron microscopy indicated that the NADPH-diaphorase reaction resulted in staining of various membranous organelles. We conclude that neuronal NADPH-diaphorase is a membrane-bound enzyme distinct from DT-diaphorase and other known enzymes with diaphorase activity. The histochemical characteristics presented here should now enable meaningful biochemical studies of neuronal NADPH-diaphorase to be undertaken.
ISSN:0022-1554
1551-5044
DOI:10.1177/37.5.2703701