Influence of intracellular pH on the membrane potential of cultured carotid body glomus cells.

The influence of acidity on the resting potential (Em) of cultured rat glomus cells was studied within a narrow range (7.32-7.54) of extracellular pH (pH0). Under these conditions, the intracellular pH (pHi) ranged from 6.3 to 7.21. Resting potentials were most negative when pHi was lowest, and least negative when pHi was highest. These effects were determined by the equilibrium potential of H+ ions (EH) since Em linearly followed EH. However, EH was little affected by pH0. Therefore, intracellular, and not extracellular, acidity was most important in contributing to the Em of glomus cells.