DEMONSTRATION OF NITRIC-OXIDE SYNTHASE (NOS) IN MARMOSETS BY NADPH DIAPHORASE (NADPH-D) HISTOCHEMISTRY AND NOS IMMUNOREACTIVITY

Since species interdiversity often prevents the extrapolation of labor atory rodent data to man and similar problems may exist for nitric oxi de synthase (NOS), NADPH-d activity and immunohistochemistry of NOS we re investigated in the New World monkey Callithrix jacchus (marmoset), which has been shown to be close to the human situation in many respe cts. Using the NADPHd reaction with beta-NADPH and nitroblue tetrazoli um (NET) on acetone-chloroform pretreated cryosections, NET formazan w as found in many neural and non-neural (e.g. diverse epithelia, striat ed muscle fibers, vascular endothelium) cells in numerous tissues and. organs. Prefixation with formaldehyde lowered the number of NADPH-d a ctive sites and the amount of formazan with the exception of neuronal NADPH- d as did incubation of fresh or acetone-chloroform-pretreated s ections for NADPH-d in the presence of 0.5% formaldehyde. When 1% form aldehyde or 0.5 mM permanganate were used significant amounts of forma zan appeared only in central and peripheral neurons, vasal endothelial cells, small intestinal enterocytes, plasma membrane region of striat ed muscle fibers as well as arteriolar cells in the kidney; except for enterocytes, these observations were confirmed by NOS-immunohistochem istry which revealed in addition reactive cells in the thymus and inte stinal lamina propria.