Fig. 5

Transporter-mediated changes in choroidal [Na⁺]_i and pH. a Representative SBFI fluorescence image of the lateral choroid plexus taken with a wide-field fluorescence microscope. Scale bar = 40 µm. b Changes in SBFI fluorescence ratio, reporting changes in the intracellular [Na⁺] in choroid plexus in control solution (n = 5) or upon treatment with S0859 (NBCe2 inhibition, n = 5), bumetanide (NKCC1 inhibition, n = 7), ouabain (NKA inhibition, n = 6), or cariporide (NHE1 inhibition, n = 6) for 5 min. c Quantification of the change of the SBFI signal (in b) as a function of time by linear regression, n = 5–7. d Representative Western blot illustrating the protein expression of NHE1 in rat choroid plexus from lateral and 4th ventricles. GAPDH was included as a loading control. e Peak-normalized changes in BCECF ratio (arbitrary units) upon application NH₄Cl, illustrating differences in the rate of recovery from acidification after removal of NH₄Cl. Choroid plexus was perfused with aCSF containing 5 mM NH₄Cl (indicated with black line) in the presence or absence of cariporide (NHE1 inhibitor). f pH recovery rates determined from linear regression analysis of the period right after the maximal acid load in the presence (n = 6) and absence of cariporide (n = 5). Statistical significance determined with Student’s t-test. *P < 0.05