McNaughton P A
Department of Physiology, King's College London, UK.
Cell Calcium. 1995 Oct;18(4):275-84. doi: 10.1016/0143-4160(95)90024-1.
A transduction cascade in the outer segments of vertebrate photoreceptors amplifies the visual signal, resulting in the metabolism of cGMP and the closure of ionic channels. The intracellular calcium concentration declines after a light response, and this decline is the key regulator responsible for controlling the gain of the transduction cascade. Calcium turnover in the outer segment is determined by three processes: influx through light-sensitive channels; buffering within the outer segment; and extrusion by a Na/Ca,K exchange mechanism.
脊椎动物光感受器外段中的转导级联反应放大视觉信号，导致cGMP代谢和离子通道关闭。光反应后细胞内钙浓度下降，这种下降是控制转导级联反应增益的关键调节因子。外段中的钙周转由三个过程决定：通过光敏感通道流入；在外段内缓冲；以及通过钠/钙、钾交换机制排出。
