Effect of pre- and postmortem variables on specific mRNA levels in human brain

The method of polymerase chain reaction was used to investigate the pre- and postmortem factors which affect the stability of specific mRNAs in the C₁ region of human autopsy brain. Eight premortem and 4 postmortem factors were correlated to levels of phenylethanolamine N-methyltransferase (PNMT), three splice forms of amyloid precursor protein (APP) and actin mRNAs in 10 control brains using Pearson's correlation coefficient. Significant negative correlations were found between hypoxia and PNMT mRNA, and between postmortem and storage intervals and APP₇₅₁ and β-actin mRNAs. A positive correlation was found between death-refrigeration interval and total APP and APP₆₉₅ mRNAs. There was also a positive correlation between seizure activity and APP₇₇₀ mRNA. The results indicate that a variety of pre- and postmortem factors can affect mRNA levels. The possible effect of pre- and postmortem factors on specific mRNA levels should be investigated prior to comparing mRNA levels in different disease states.