Abstract
Michail and Benetato 1 found a 50 to 70% higher oxygen consumption in degenerated human optic nerves (from glaucomatous and atrophied eyes) than in optic nerves removed shortly after traumatization of the eye. Van Harreveld and Tyler 3 compared the metabolism of normal optic nerves of cats with that of eye nerves severed directly behind the eye 3 to 14 days before. A lower oxygen consumption of the operated nerves was found constantly. As the nerves examined by Michail and Benetato had probably been subject to degeneration much longer than the 2 weeks allowed for degeneration by van Harreveld and Tyler, the metabolism of optic nerves of cats, 6 months after transection was compared with that of the heterolateral normal eye nerves.
Methods. The optic nerve on one side was severed with aseptic precautions directly behind the eyeball. Six months later the oxygen consumption of the normal and degenerated nerves was determined in Warburg respirometers at 38°. The nerves were not minced but were left intact since previous experiments 3 had shown that the highest metabolism is found in undamaged nerves. The dura was removed with as little injury to the nerve as possible. The medium used was a glucose-Ringer, buffered with phosphates to a pH of 7.4. After the metabolism determination one part of each nerve was fixed and stained in osmic acid. The other part was fixed in Zenker's solution and later stained with hematoxyline eosin.
Results. The results of the metabolism determination are shown in Table I. These figures give the oxygen consumption in mm 3 per gram of wet tissue during the hour between the 50th and 110th minute after the removal of the nerve from the animal.
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