Activation of splice variant ccCNGCαΔ5-6 by cGMP. Series ofI–V recordings in the presence of different cGMP concentrations. Inside-out patch of HEK 293 cells transfected with plasmid pccCNGCαΔ5-6. The inset shows the dose–response relation at −60 mV. TheK½ value was 30 μm, and the Hill coefficient was n = 1.8. The cGMP concentrations were trace 1, 5 μm; 2, 10 μm; 3, 20 μm;4, 30 μm; 5, 50 μm; 6, 80 μm;7, 100 μm; 8, 300 μm; 9, 1000 μm.