Chemical studies of peripheral nerve during Wallerian degeneration. 4. Phosphatases

Abstract

The rate of hydrolysis of phenylphosphate at pH 4.9 (acid phosphomonoesterase), phenylphosphate at pH 9.9 (alkaline phosphomonoesterase), adenosine-5-phosphate at pH 7.5 (5-nucleotidase) and adenosinetriphosphate at pH 7.2 in the presence of Ca++ (adenosinetriphosphatase) was detd. in the sciatic nerve of the cat at intervals of 2 to 96 days after nerve section and 16 to 600 days after nerve crush. After either nerve section or nerve crush the activity of the acid phosphomonoesterase increased rapidly, reaching a max. at 16 days after the operation and then decreased slowly. The increase was of the same order and occurred at the same time as the increase in the concn. of desoxy-pentosenucleic acid previously reported. After nerve section the activity of the alkaline phosphomonoesterase decreased rapidly during the period 4-16 days after the operation and then remained at a low level until 96 days. After nerve crush the activity decreased during the first 32 days and then increased, so that by 96 and 175 days the activity in the crushed nerves was greater than that in the controls. The activity of the 5-nucleotidase increased after either type of operation, reaching a max. in 32 days after nerve section and 96 days after nerve crush. The rate of hydrolysis of adenosinetriphosphate did not change after nerve section, but increased after nerve crush, reaching a max. 96 days after the operation. These results were discussed in relation to the morphological and histochemical changes known to occur in degenerating and regenerating nerves.