A topographic quantitative method for measuring brain tissue pH under physiological and pathophysiological conditions.

A technique was developed for the quantitative regional assessment of brain pH by a modification of the umbelliferone method. Twenty micron thick sections were brought into contact with umbelliferone-soaked paper strips and the fluorescence (450 nm) following excitation at 370 nm and 340 nm was recorded photographically. The 340 nm excitation image was subtracted from 370 nm picture, using a computerized image-processing system. Regional pH values were measured in rats and cats under normal and ischemic conditions.