Fig. 2.

Changes in intracellular pH (pH_i) of osteoclasts. The pHi of primary osteoclasts labeled with the pH-sensitive dye BCECF-AM (12 μM) was monitored along time in order to evaluate the H⁺ secretion under flow and no-flow conditions after the NH₄Cl prepulse, which causes an acid load to the cells. Experiments were performed in the absence HCO₃ ⁻ to inhibit base transporters. a. Flowing standard HEPES-buffered solution (5 mL/min) after acid loading is related to a discrete H⁺ secretion and a small ΔpH_i. b. Non-flowing HEPES-buffered solution (0 mL/min) after acid loading is related to a transient H⁺ secretion and a higher ΔpH_i than in flow condition