Fig. 4. Effects of the Nigella arvensis (NA) extract on short-circuit current (I_sc), single-channel current (i_Na), transepithelial conductance (G_T), total number of channels (N_T) and open-channel probability (P_o). (A) Pulse protocol of 6-chloro-3,5-diaminopyrazine-2-carboxamide (CDPC)-induced noise before and after addition of the NA extract basolaterally. CDPC-induced noise was recorded by switching the apical CDPC concentration ([CDPC]_Ap) alternately from 10 µmol l^-1 to 40 µmol l^-1 every 5 min. 50 µmol l^-1 amiloride (Ami) was administered apically at the end of the experiment. Solution conditions were as in Fig. 1. (B) I_sc, i_Na, N_T and P_o during control (open bars) and after exposure to NA extract (filled bars). The values were calculated using a three-state model. ^* The values of the control and the NA extract are significantly different (P<0.05) for all parameters.