Nuclear magnetic resonance measurements of intracellular pH: Biomedical implications

The measurement of intracellular pH is of crucial importance in biomedical investigation. Nuclear magnetic resonance (NMR) spectroscopy methods allow investigators to monitor this essential parameter in a variety of experimental conditions. Although a number of NMR spectroscopy methods for measuring intracellular pH have been described, the method of using the chemical shift of inorganic phosphate has been employed most widely. In this review, we discuss the various NMR methodologies which allow for measurement of intracellular pH as well as selected topics where these measurements have been employed. Because of the volume of work which has been published using NMR to monitor intracellular pH, we have not attempted to be exhaustive in our review, but rather have tried to highlight the importance of this methodology by reviewing several topics in biology and medicine where NMR measurements of intracellular pH have played an important role in improving our understanding.