Fig. 9

The MT-organisation is affected by alterations of both pH_i and V_mem. Using inhibitors of ion-transport mechanisms, we modified pH_i and/or V_mem as well as the MT-pattern. The results obtained with living αTub84B-GFP follicles (right columns) were similar to those obtained with fixed wild-type follicles using an antibody against acetylated α-tubulin (left columns). Typical follicles of S10b are shown. For summary, see Fig. 10. Scale bars refer to all pictures in the same column. The inhibitor verapamil (voltage-dependent L-type Ca²⁺-channels), which had the strongest impact on V_mem (strong hyperpolarisation, reduction of the angles of the a-p and the d-v gradient, cf. Figure 2) and led to alkalisation, stabilised the longitudinal alignment of MT. In addition, the MT-bundles appeared to be thicker than in the control (ethanol). On the other hand, the MT of follicles treated with either furosemide (Na⁺/K⁺/2Cl⁻-cotransporters; no clear effect on V_mem; strong alkalisation, cf. Figure 2) or glibenclamide (ATP-sensitive K⁺-channels; moderate hyperpolarisation; strong alkalisation, cf. Figure 2) lost their longitudinal alignment and became partially disintegrated. This coincided with a spherical FC shape, which was especially noticeable in αTub84B-GFP (control DMSO). With 9-anthroic acid (Cl⁻-channels; no clear effect on V_mem; slight alkalisation, cf. Figure 2), this effect was weaker (control ethanol)