HISTOCHEMICAL DEMONSTRATION OF PHOSPHORYLASE IN BRAIN TISSUE: ASSOCIATION OF POSTMORTAL NEURON CHANGES WITH PHOSPHORYLASE ACTIVITY

The preparation of brain tissue for the histochemical demonstration of phosphorylase induces postmortal cell changes, such as pycnomorphic, chromophilic neurons and swollen, vacuolated, chromatin depleted neurons. The inconsistent phosphorylase reaction in grey matter is associated with the following changes. A positive phosphorylase reaction is found in pycnomorphic, chromophilic neurons, whereas the swollen, homogenized neurons exhibit negative phosphorylase reaction of the cell body but sometimes a definite pericellular phosphorylase activity. Irregularities in the phosphorylase reaction in the grey matter are therefore related to postmortal cell changes and conclusions on the normal distribution of the enzyme should be drawn with extreme care. There is indication that a positive phosphorylase reaction might result from an adaptive cell change occurring during the treatment of the specimens in vitro.