A Concentration-response curve to ACh for oocytes expressing α9α10 injected in a 1:3 ratio in Ca2+ free, 1.8mM Ba2+ solution (n=4). Normalized data is shown as a solid line that fitted to a monophasic curve (●, solid line). B Concentration-response curve to ACh for oocytes expressing α9α10 injected in a 10:1 ratio in Ca2+ free, 1.8mM Ba2+ solution (n=4). A biphasic regression line is fitted through the normalized data shown as a solid line (○, solid line). C An overlay of α9α10 1:3 (●, solid line) and 10:1 (○, solid line) ratios from A and B.