Figure 7. Effects of Rp-cAMPS on pH_i recovery from acid loads in low pH_i neurons.

A, an acid load was imposed on a low pH_i neuron under HCO₃⁻/CO₂-buffered conditions at RT and, after recovery of pH_i, 50 μm Rp-cAMPS was applied. Rp-cAMPS increased both steady-state pH_i and the rate of pH_i recovery from the second acid load. B, the pH_i dependence of the rate of pH_i recovery from acid loads imposed under HCO₃⁻/CO₂-buffered conditions at RT in the absence (•) and presence (○) of 50 μm Rp-cAMPS; data points were obtained from 12 experiments of the type shown in A. C, the same experiment as shown in A, but conducted at 37 °C. D, the pH_i dependence of the rate of pH_i recovery from acid loads performed at 37 °C in the absence (•) and presence (○) of 50 μm Rp-cAMPS; data points were obtained from eight experiments of the type shown in C. In contrast to observations made in the nominal absence of HCO₃⁻/CO₂, Rp-cAMPS applied to low pH_i neurons in the presence of HCO₃⁻/CO₂ increased rates of pH_i recovery at all absolute values of pH_i and shifted the pH_i dependence of the rate of pH_i recovery in an alkaline direction.