cGMP dissociates from CNG channels

As cGMP is hydrolysed during the activation phase of phototransduction, its intracellular concentration decreases leading to the closure of CNG channel (the closed status is designated as CNG channel) (Dhallan et al. 1992, Chen et al. 1993). Channel closure reduces the inward flux of sodium and calcium (also known as the 'dark current') resulting in cell hyperpolarisation. Cooperative binding of cGMP to the CNG channel confers additional amplification to the phototransduction cascade (Pugh & Lamb 1993, Yau & Baylor 1989).

随着光感受器激活阶段中cGMP的水解，其细胞内浓度降低，进而导致CNG通道（封闭状态被标记为CNG通道）的关闭（参见Dhallan等，1992年，Chen等，1993年）。通道的关闭减少了钠离子和钙离子的内向流动（亦称为'暗电流'），从而导致细胞的超极化。cGMP与CNG通道的协同结合为光感受器级联反应提供了额外的放大作用（Pugh & Lamb，1993年，Yau & Baylor，1989年）。