Dose response curves for THG113.31 and spontaneous myometrial contractions. Graphical representation of the effects of cumulatively increasing tissue bath concentrations of THG113.31 (1 nM, 10 nM, 100 nM, 1 μM and 10 μM) at 20 min intervals on spontaneous (shaded circle) contracting pregnant myometrium in the presence (shaded triangle) and absence (shaded square) of IbTX. A control trace showing uninterrupted spontaneous contractions in pregnant myometrium in the presence (open square) and absence (shaded circle) of IbTX, are shown for comparison. The symbols used represent the mean values (n = 6) within each group. Vertical error bars represent the standard error of the mean.