NADPH diaphorase histochemistry in the macaque striate cortex

Area of Science:

• Neuroscience
• Enzymology
• Primate Brain Anatomy

Background:

• Dihydronicotinamide adenine dinucleotide phosphate (NADPH) diaphorase is an enzyme with an incompletely understood function.
• Investigating enzyme distribution aids in understanding cortical circuitry and neuronal populations.

Purpose of the Study:

• To map the distribution of NADPH diaphorase activity in the rhesus monkey striate cortex.
• To compare NADPH diaphorase patterns with other markers like cytochrome oxidase.
• To characterize the morphology and laminar distribution of NADPH diaphorase-positive cells.

Main Methods:

• Histochemical staining for NADPH diaphorase in rhesus monkey brain sections.
• Comparative analysis with adjacent sections stained for cytochrome oxidase.
• Assessment of cellular morphology and laminar distribution.

Main Results:

• NADPH diaphorase activity in the neuropil closely matched cytochrome oxidase patterns.
• Monocular deprivation similarly affected both enzyme activities.
• Scattered cells, predominantly in white matter and layers 2/3, were intensely positive for NADPH diaphorase.
• These cells were morphologically diverse, lacking pyramidal or spiny features, and possessed extensive varicose processes.

Conclusions:

• NADPH diaphorase exhibits a distinct distribution within the striate cortex, partially overlapping with cytochrome oxidase.
• The morphology and location of NADPH diaphorase-positive cells suggest a potential colocalization with neuropeptides like somatostatin and NPY.
• Further research is needed to elucidate the specific function of NADPH diaphorase in cortical circuits.