Hafner G S, Tokarski T R
Department of Visual Science, School of Optometry, Indiana University, Bloomington 47405.
J Comp Physiol A. 1988 Jun;163(2):253-8. doi: 10.1007/BF00612434.
The interrelationship between the diurnal cycle of membrane loss and synthesis of new rhabdom components remains a key element in forming a complete picture of the turnover of photopigment-containing membrane in the crayfish photoreceptor cell. In order to examine this aspect of the turnover process, the diurnal pattern of photopigment synthesis was examined using an in vitro incubation system for incorporation of 3H-leucine into photoreceptor protein. The incorporation of 3H-leucine into total protein and photopigment specifically was measured in photoreceptors isolated from incubated retinas. The results indicate that for both total protein and photopigment there is no significant variation in the rate of synthesis during the 12-12 light-dark cycle. These data combined with earlier data on diurnal membrane loss from the rhabdom suggest that light-stimulated rhabdom membrane loss is superimposed on a diurnally constant level of synthesis and assembly of new rhabdom constituents.
膜丢失与新视杆成分合成的昼夜循环之间的相互关系，仍然是全面了解小龙虾光感受器细胞中含光色素膜更新过程的关键因素。为了研究更新过程的这一方面，利用体外孵育系统，检测了光色素合成的昼夜模式，该系统用于将3H-亮氨酸掺入光感受器蛋白中。在从孵育的视网膜分离出的光感受器中，测定了3H-亮氨酸掺入总蛋白和特定光色素中的情况。结果表明，在12小时光照-12小时黑暗的循环中，总蛋白和光色素的合成速率均无显著变化。这些数据与早期关于视杆昼夜膜丢失的数据相结合，表明光刺激的视杆膜丢失叠加在新视杆成分昼夜恒定的合成和组装水平上。
