Cervetto L, Torre V, Rispoli G, Marroni P
Exp Biol. 1985;44(3):147-57.
A steady illumination equivalent to about 1000 or more photoisomerizations per s per rod completely abolishes the dark current and induces a total desensitization of toad rods. Under these conditions, however, both current and sensitivity recover from the initial suppression and reach a new steady level within about 30 s. Both extent and time course of recovery depend on the intensity of the conditioning light. The ability of rods to respond to light stimuli under light saturating conditions is enhanced by procedures aimed at increasing the sodium gradient across their surface membrane. The results suggest that rods can also contribute significantly to vision at photopic levels of ambient light. The mechanisms underlying this adaptational property of rods are discussed.
相当于每根视杆每秒约1000次或更多次光异构化的稳定光照会完全消除暗电流，并使蟾蜍视杆产生完全脱敏。然而，在这些条件下，电流和敏感度都会从最初的抑制状态恢复，并在约30秒内达到新的稳定水平。恢复的程度和时间进程取决于调节光的强度。通过旨在增加视杆表面膜上钠梯度的程序，可以增强视杆在光饱和条件下对光刺激的响应能力。结果表明，在环境光的明视觉水平下，视杆对视也有显著贡献。文中讨论了视杆这种适应性特性背后的机制。
