Figure 6.

Properties of heterologously expressed α2 channels. (a) Current-voltage (I/V_m) relations of α2a channels in the presence of different cGMP concentrations. (b) Dose-response curves for α2a (solid lines) and α2b (dashed lines) at V_m = +60 mV. All currents were normalized to currents at saturating cGMP. For clarity, data points and error bars were omitted from dashed traces. (c) α2 channels are modulated by CaM. V_m was switched from −40 mV to +40 mV in 1-s intervals. The inside-out patch (α2b) was superfused with 100 μM cGMP to record saturating currents, followed by superfusion in 0 μM cGMP. During superfusion with 3 μM cGMP for 1 min, the current stayed constant. With 3 μM cGMP and 1 μM CaM, the current decreased by roughly 50% within 30 s. The current at saturating cGMP (100 μM) was not altered by CaM.