A correlation between soluble brain nitric oxide synthase and NADPH-diaphorase activity is only seen after exposure of the tissue to fixative

Academic Article


  • In histochemical studies using fixed brain tissue, NADPH-diaphorase has been found to be colocalized with soluble nitric oxide synthase. In the present study, using fresh tissues from eight different regions of rat brain, NADPH-diaphorase activity was found mostly in the particulate fraction, whereas most of the nitric oxide synthase activity was located to the cytosolic fraction. Also, the distribution of NADPH-diaphorase activity among brain regions was different from that of nitric oxide synthase. Pretreatment of the fractions with paraformaldehyde virtually abolished the NADPH-diaphorase activity in the particulate fraction, whereas 40-60% of the NADPH-diaphorase activity remained intact in the cytosolic fraction. These results suggest that during fixation most NADPH-diaphorase activity is inactivated and only some of the NADPH-diaphorase activity associated with soluble nitric oxide synthase remains intact. ¬© 1993.
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    Digital Object Identifier (doi)

    Author List

  • Matsumoto T; Nakane M; Pollock JS; Kuk JE; F√∂rstermann U
  • Start Page

  • 61
  • End Page

  • 64
  • Volume

  • 155
  • Issue

  • 1