(a–f) HEK293 cells heterologously expressing TRPC4DR-EGFP (a,c,e) and untransfected control cells (b,d,f) were investigated by voltage-clamp experiments in the whole-cell configuration. The membrane potentials were clamped to values ranging from −90 to +90 mV in the absence (a,b) and in the presence (c,d) of 50 nM (-)-Englerin A. Upon addition of 50 nM of (-)-Englerin A, the current density at −60 mV increased from −3.1 ± 1.9 pA/pF (n = 6) to −16.7 ± 10.7 pA/pF (n = 6). In untransfected control cells, the current density in the absence and presence of the activator was virtually the same with values of −2.1 ± 1.2 pA/pF (V = - 60 mV, n = 5) and −1.8 ± 0.9 pA/pF (V = −60 mV, n = 5) respectively. (e,f) Current-voltage curves in the absence (black squares) and in the presence (red circles) of 50 nM (-)-Englerin A. Currents were normalized to the current value in the absence of (-)-Englerin A at a membrane potential of +80 mV. Note that the measurements in the absence and in the presence of (-)-Englerin A were performed on the same cells. Shown are the normalized mean currents of 6 (e) and 5 (f) different cells. Error bars are ± SEM. The measurements were performed as described in Materials and methods.