Effects of pH and of Bicarbonateand CO2 on the Respiration and Anaerobic Glycolysis of Rat Brain Tissue.

The main aim of this study was to determine the effects of hydrogen ions, and of bicarbonate and CO2 on the respiration and anaerobic glycolysis of brain tissue in vitro. Such an investigation is of interest since these substances are important components of tissue fluids, and are known to vary in concentration. Observations on the effects of pH and of bicarbonate and CO2 on aspects of in vitro metabolism might, therefore, aid in an understanding of their functions in vivo. Further, it is important to know precisely the effects of these factors in order to judge the validity of experiments in which these factors have varied. For instance, The pH control in many experiments in the literature was poor, and one needs to know how significant results may be. Similarly, it is common practice to compare results obtained in bicarbonate-and phosphate-buffered media, and the validity of these comparisons has been somewhat uncertain. Respiration in the biochemical sense, “tissue respiration”, means the sum of the processes whereby a tissue consumes oxygen in the combustion of various organic compounds. Respiration is the main source of energy for life processes. With brain tissue, glucose may be considered the predominant physiological substrate for respiration (Kety, Lukens, Woodford, Harmel, Freyhan and Schmidt, 1948; for earlier references see Elliott, Scott and Libet, 1942), and it was, therefore, added to all media in this work.[...