Abstract
Measurements of 5'-nucleotidase in mouse spinal cord showed that enzymic activity was unequally distributed, being twice as high in dorsal gray as in ventral gray matter, and that white matter had still lower activity. Similar determinations with cat spinal cord revealed no corresponding regional difference in 5'-nucleotidase activity in the gray matter and, again, a lower activity in white matter. In cat spinal cord the enzyme activities were lower than in corresponding areas of mouse cord. Essentially all of the 5'-nucleotidase activity was associated with particulate fractions of spinal cords of both species as well as with sedimentable proteins from mouse brain. Phosphatase activity in fresh mouse brain homogenates was much higher in the supernatant than in the particulate fraction; however, no appreciable phosphatase activity could be detected in either freshly homogenized or lyophilized spinal cord sections obtained from cat or mouse. The effects of some histochemical reagents and inhibitors on both enzymic activities were also measured.