TISSUE PH AS AN INDICATOR OF MESSENGER-RNA PRESERVATION IN HUMAN POSTMORTEM BRAIN

The relationship between pH and mRNA preservation in post-mortem human brain was examined using in situ hybridization histochemistry and Nor thern hybridization with oligonucleotide probes in a large group of hu man subjects, including control and neuropathological cases. Tissue pH was found to correlate strongly with presentation of four mRNA specie s in three brain areas. Tissue with low pH, assumed to result from pro longed terminal hypoxia, contained reduced or absent mRNA, while tissu e with higher pH was found to contain quantifiable amounts, the values for pathological brain samples being comparable to those for control material of similar pH. Measurement of tissue pH provides a simple mea ns to screen post-mortem brain for mRNA preservation and is suggested as a means to match material in case-control studies of human neurodeg enerative disease.