The chemical morphology of the retina

Abstract

Recent investigations of the chemistry of rod vision (Wald, '51) suggest the desirability of exploring the retina by histochemical means in an attempt to relate structure with chemical function. To this end we have applied a number of histochemical techniques to retinas of frogs and rhesus monkeys. The results of these procedures are described and illustrated with reference to the several retinal layers. The significance of the histochemical reactions is discussed and an interpretation of some of them offered with respect to the structural and possible functional organization of the photoreceptor cells. MATERIALS AND METHODS The material consisted of about 40 eyes of normal young adult rhesus monkeys (Jlacaca mulatta) and about twice that number of eyes of frogs (Rana p i p i e m ) .More methods of fixation and modification of histochemical procedure were carried out on frogs' than on monkeys' retinas, because frogs' retinas are more readily available. Furthermore, the rods of the frog are very much larger than those of the monkey, which favors their use for a number of histochemical procedures.The monkeys' eyes were removed from freshly killed animals, bisected equatorially with a razor blade into anterior and posterior segments, and fixed in different ways. I n 'This investigation was aided by a grant from the Eugene Higgins Fund of Harvard University. The cost of reproducing the colored plate was met through a special gift to the Department of Anatomy for that purpose.

Electron Microscopy of Retinal Photoreceptors

“…Sj5strand (25) postulated that the existence of dense bands in the outer segments is due to the osmium deposition at the level of protein layers. This interpretation is consistent with the fact that the protein of the visual cells outer segments has a high content of sulfhydryl groups (4,23,35) which are known to be very reactive with OsO4 (1). However, recent work in pure lipid models (30) has resulted in the detection of layered structures in phospholipid myelin figures; the dense bands observed seem to be a product of the reaction of OsO4 with double bonds in the fatty acid chains.…”

Nitric oxide synthase in tiger salamander retina

“…The first studies on diaphorase reactions in the retina appeared some 40 years ago, at a time when no one suspected a relationship between NADPH-d activity and an unknown nitric oxide-generating enzyme (Wislocki and Sidman, 1954;Kuwabara, 1959, 1960;Cogan, 1959, 1960;Berkow and Patz, 1961;Bhattacharjee, 1977). This early body of work described the species of electron donor required for a diaphorase reaction, the degree of the diaphorase reaction in different classes of retinal neurons, and the changing pattern of NADPH-d activity during retinal development.…”

The interphotoreceptor matrix, a space in sight

“…SHORT HISTORY The IPM was described by Henle (1855) as a carbohydrate rich compartment. With the use of mostly cationic dyes such as Alcian blue and colloidal iron, it was seen that the compartment was fibrous and rich in mucopolysaccharides (among others: Day, 1950;Lillie, 1952;Ocumpaugh and Young, 1966;Sidman, 1958;Wislocki and Sidman, 1954;Zimmerman, 1958;Zimmerman and Eastham, 1959). Electron microscopic characterization of the extracellular material was performed by Rohlich (19701, who named it interphotoreceptor matrix, and also by Feeney (1973a,b) and Yamada (1985).…”