Histochemical mapping of NADPH-diaphorase in monkey and human eyes

Abstract

Purpose. To localize nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in normal human and monkey eyes.

Methods. NADPH-d activity in ocular tissue sections was revealed by histochemical staining.

Results. NADPH-d staining was found in the anterior and posterior ocular segment of both species. In the anterior segment, reaction product was present in the corneal epithelium and endothelium, iris dilator and sphincter, lens capsule, ciliary muscle, and non-pigmented epithelial cells and stroma of the ciliary processes. Staining density in the longitudinal ciliary muscle was higher than in the other ciliary muscle regions in the human; such regionalization was less apparent in the monkey. The trabecular meshwork stained minimally if at all in both species. In the posterior segment, staining was seen around choroidal blood vessels and choroidal nerves, and in the retinal pigment epithelial, photoreceptor, bipolar, inner plexiform and ganglion cell layers.

Conclusions. NADPH-d is widespread in human and monkey eyes, indicating significant and presumably functionally relevant NO production in the various ocular structures. Curr. Eye Res. 17: 370–379, 1998.

Key words:

• NADPH-diaphorase
• eye
• human
• monkey
• nitric oxide
• nitric oxide synthase
• enzyme histochemistry