POST MORTEM CHANGES IN EXTRACTABLE PROTEIN AND IN TISSUE pH IN THE GUINEA PIG BRAIN

—Guinea pigs were killed by asphyxiation with nitrogen and the soluble proteins were extracted from the brain at various times post mortem. The quantity of extractable brain protein decreased by 21 per cent when the animals remained at room temperature for 2 h post mortem. This decrease was not a consequence of extensive proteolysis or variations in blood volume but was probably a result of precipitation. After death, the pH of the brain fell rapidly to a minimum of ∼6CE4 within about 35 min. Examination of the patterns of brain proteins after acrylamide gel electrophoresis showed a concomitant decrease in the content of several protein bands.