Figure 3.
Effect of Rp-8-pCPT-cGMPS and 8-pCPT-cGMP on retinal CNG channels. (A,B) Efficacy of Rp-8-Br-pCPT-cGMPS and 8-pCPT-cGMP when activating rod and cone CNG channels. The CNG-channel currents triggered by the respective cGMP analogues were related to the maximal cGMP-induced current measured at +100 mV (3 mM and 1 mM cGMP for rod and cone channels, respectively; n = 4–16). The gray symbols represent individual measurements. (C,D) Concentration–activation relationships for rod and cone CNG channels obtained in the presence of cGMP (black), 8-pCPT-cGMP (gray) and cGMP + Rp-8-pCPT-cGMPS (50 µM, orange). The experimental data points, representing means of several measurements were fitted with Equation (1) (for EC50, H and n see Table S1).