Reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase-positive neurons in cat cerebral white matter.

Two populations of neurons in the cat cerebral white matter were detected using histochemistry for reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity. One type was bipolar in shape with two cell processes extending in opposite directions, existed mainly in the subcortical areas and was oriented parallel to fiber bundles. The second type had 4 or 5 very long, prominent and varicose cell processes radiating in various directions. They were round or polygonal in shape and formed networks in the white matter of the frontoparietal area. NADPH-diaphorase-positive neurons were also examined by the modified Golgi-Cox silver impregnation method. With this impregnation method, the same two morphological types could be detected but the detailed morphology of these particular populations of neurons was revealed much more fully by NADPH-diaphorase enzyme histochemistry than by the silver impregnation method.