Fig. 10.

hβ4 protects hSlo from block by iberiotoxin (a) and charybdotoxin (b). Experiments were done in the whole-cell patch-clamp mode, and toxins were applied from the extracellular side. hSlo currents recorded in the presence of different concentrations of toxins were normalized to the control current in the absence of toxin. The filled symbols with solid lines show the block of current by toxins in the absence of hβ4, and the open symbols with dashed lines show that current is not blocked, even by high concentrations of toxin, in the presence of hβ4 (n = 3; holding potential of −85 mV, steps to +105 mV, 10 μm free internal calcium). Note the different concentration axes in a andb.