Fig. 3

Inhibitors of ion-transport mechanisms exert influence on the pH_i in the FCE during S10b (WFM-experiment; CFDA). a WFM-fluorescence images were used to measure the fluorescence intensity in the columnar FCE (marked yellow) of every single follicle. While glibenclamide (ATP-sensitive K⁺-channels) and furosemide (Na⁺/K⁺/2Cl⁻-cotransporters) led to strong alkalisation, the alkalising effects of verapamil (L-type Ca²⁺-channels) and 9-anthroic acid (Cl⁻-channels) were smaller. Amiloride (NHEs and Na⁺-channels) and bafilomycin (V-ATPases) showed no significant effects. To analyse and compare the effects of the inhibitors, averaged values (of 12 time points during 60 min of inhibition) of three experiments per inhibitor were summed up and normalised (mean intensity ratio). Mean values, shown with their standard deviation (cf. Additional file 2: Table S3), were compared using an unpaired t-test (* p < 0.05; ** p < 0.01; *** p < 0.001). b Pseudocolour fluorescence images after 60 min of incubation. Furosemide led to strong alkalisation of the whole follicle. In contrast to the control (DMSO), the columnar FCE exhibits an even stronger fluorescence intensity than the germ-line cells