Fig. 2

Bioelectrical properties were modified using inhibitors of ion-transport mechanisms (summarised according to [16]). a Schematic drawing of a follicle cell showing the analysed ion-transport mechanisms. Na⁺/H⁺-exchangers (NHE) and Na⁺-channels were blocked with amiloride, V-ATPases with bafilomycin, ATP-sensitive K⁺-channels with glibenclamide, voltage-dependent L-type Ca²⁺-channels with verapamil, Cl⁻-channels with 9-anthroic acid and Na⁺/K⁺/2Cl⁻-cotransporters with furosemide. Intracellular pH (pH_i) and membrane potential (V_mem) were analysed in living follicles using the pH-indicator 5-CFDA,AM (5-carboxyfluorescein diacetate, acetoxymethyl ester) and the potentiometric dye DiBAC₄(3) (bis-(1,3-dibutylbarbituric acid) trimethine oxonol). pH_i, V_mem or both parameters were affected by each inhibitor [16]. b Schematic summary of the effects of inhibitors on the electrochemical gradients in the columnar FCE during S10b [16]. The antero-posterior (a-p) and dorso-ventral (d-v) pH_i- and V_mem-gradients are visualised as colour gradients in the FCE. Triangles symbolise directions of the gradients. Increasing pH_i means more alkaline, decreasing V_mem means less hyperpolarised. The effects of inhibitors on the angles of the gradients are represented by width and colour of the triangles. While the strongest effects on pH_i-gradients were generated by furosemide or glibenclamide, the strongest effects on V_mem-gradients were generated by verapamil or glibenclamide (bold letters) [16]