Fig. 7. Removal of Na⁺ from the bath causes an alkalinization (A). (A,E) Under Na⁺-free conditions, 10 nmol l^–1 5-HT induces a small intracellular alkalinization (^*P<0.05). (B,E) In the continuous presence of 50 µmol l^–1 EIPA, 10 nmol l^–1 5-HT induces a significantly smaller acidification than under control conditions (^**P<0.01). (C,E) In the absence of extracellular Cl^–, 10 nmol l^–1 5-HT induces a small alkalinization, which is significantly different from the control stimulation (^**P<0.01). (D,E) Application of 500 µmol l^–1 DIDS causes a strong acidification but does not significantly influence the 5-HT-induced acidification (^*P>0.05). Data in E are means ± s.e.m. The number of replicates is given in parentheses.