Intracellular pH, H ion flux and H ion permeability coefficient in bullfrog toe muscle

Abstract

1. The dimethyloxazolidinedione (DMO) technique was used to estimate intracellular pH (pH_i) in bullfrog toe muscles incubated in vitro. The control value of pH_i was 7·16 + ± 0·01 ( S.D.).2. pH_i was affected by changes in PCO₂ and external bicarbonate ion concentration ([HCO₃⁻]₀). At a given PCO₂, decreasing the external [HCO₃⁻] was more effective in lowering pH_i than increasing the external [HCO₃⁻] was in increasing pH_i.3. On the assumption that the changes in pH_i were due to hydrogen ion [H⁺) movements across the membrane, a H⁺ flux of 10⁻¹³ mole/cm². sec was calculated. The corresponding H⁺ permeability coefficient was 10⁻³ cm/sec.4. The variability of the tissue CO₂ buffer value was examined.