Fig. 3
Changes in MQAE fluorescence and cell volume induced by osmotic stresses in the Cl−-containing control solution. The hypo- or hyper-osmotic stress was applied by removing NaCl (30 mM) from or adding it to the Cl−-containing control solution, respectively. a–c Hypo-osmotic stress (− 30 mM NaCl). a Changes in MQAE fluorescence intensity normalized by the value before the application of the hypotonic stress (F/F0). The application of hypo-osmotic stress increased the F/F0, unlike its effect in the Cl−-free NO3− solution (*significantly different at p < 0.05; unpaired Student’s t test). b Increases in cell volume normalized by the value before the application of the hypotonic stress (V/V0). The hypo-osmotic stress increased the V/V0 (*significantly different at p < 0.05; paired Student’s t test). c Relative changes in total MQAE fluorescence intensity. The hypo-osmotic stress increased the total MQAE fluorescence intensity, unlike its effect in the Cl−-free NO3− solution (*significantly different at p < 0.05; paired Student’s t test). d–f Hyper-osmotic stress (+ 30 mM NaCl). d The application of hyper-osmotic stress deceased the F/F0 (*significantly different at p < 0.05). e Hyper-osmotic stress decreased the V/V0 (*significantly different at p < 0.05). f Hyper-osmotic stress decreased the total MQAE fluorescence intensity (*significantly different at p < 0.05). Symbols in a and d represent the mean; bars and whiskers in b, c, e, f are the mean and SEM, respectively