title: Pyridine-silver methods for the study of optic axons in retinal whole mounts.
abstract: The optic fibers in the retinas of diverse species may be selectively stained and viewed en bloc in the embryonic and adult states. Treat the eye as follows: 1) 50% pyridine for at least 16 hr, 2) distilled water 3--4 hr, 3) 20% H2O2 until the eye is a light brown, 4) 95% ethanol overnight, 5) 1.5% AgNO3 for 2--6 days at 37 C, 6) in water, remove the vitreous, then direct 0.25% pyrogallic acid in 1.25% formalin against the retina for 2--5 secs until the optic fibers are reduced to a coffee-copper color (1--4 minutes), 7) dissect the retina and mount flat on a glass slide, 8) cover with glycerin, apply a coverslip, and fix in place with nail polish. Variants for particular species are given. The technique offers an advantage over Golgi and methylene blue methods which tend to stain only a small percentage of fibers and frequently do not work at the earliest stages of development.
mesh_terms: D000818:Animals; D001001:Anura; D001369:Axons / Q000032:analysis*; D006054:Goldfish; D006651:Histocytochemistry; D009900:Optic Nerve / Q000166:cytology*; D011725:Pyridines; D012160:Retina / Q000166:cytology*; D012455:Salamandridae; D012834:Silver; D013194:Staining and Labeling
chemical_list: D011725:Pyridines; D012834:Silver