title: A topographic measurement of brain pH.
abstract: The ability of neutral red to serve as an internal pH indicator in biological systems was tested in the rat brain after parenteral adminstration of the dye. The injected dye is avidly taken up by the brain cells and is distributed mainly in intracellular organelles. The ratio of optical signals recorded from the frozen brain at 445 and 530 nm and compared with calibration curves provides pH values. Color transition of neutral red ranges from 6.0 to 8.0 pH units. Topographic application of this method is particularly useful in studying local pH changes in brains with developing ischemic foci.
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism; D002560:Cerebrovascular Circulation; D006863:Hydrogen-Ion Concentration; D002542:Intracranial Embolism and Thrombosis / Q000378:metabolism; D008297:Male; D009499:Neutral Red; D051381:Rats
chemical_list: D009499:Neutral Red