Burnside B, Basinger S
Invest Ophthalmol Vis Sci. 1983 Jan;24(1):16-23.
The retinal pigment epithelium (RPE) and photoreceptors of teleosts exhibit dramatic examples of cell motility (called retinomotor movements) in response to diurnal changes in lighting conditions. In darkness the pigment granules of the RPE migrate to the scleral base of the RPE cell and cone photoreceptors elongate. In the light these movements are reversed; pigment granules disperse into the long apical projections of the RPE cell and cones contract. It is reported here that treatments that elevate cytoplasmic cyclic AMP induce dark-adaptive movements (pigment aggregation and cone elongation) in light-adapted retinas cultured in the light. Treatments designed to elevate cGMP had no effect. In dose-response studies with the cAMP analog, dibutyryl cyclic AMP (dbcAMP), we found that the RPE pigment did not exhibit intermediate states of aggregation with increasing concentrations of dbcAMP but instead changed abruptly from the fully light-adapted to the fully dark-adapted retinomotor positions between 10 microM and 50 microM exogenous dbcAMP concentrations. Cones, on the other hand, elongated to intermediate extents in proportion to increasing dbcAMP concentration between 10 microM and 500 microM. These observations suggest that cytoplasmic cAMP plays a role in regulating retinomotor position in both RPE and cones.
硬骨鱼的视网膜色素上皮（RPE）和光感受器表现出显著的细胞运动实例（称为视网膜运动），以响应光照条件的昼夜变化。在黑暗中，RPE的色素颗粒迁移到RPE细胞的巩膜基部，视锥光感受器伸长。在光照下，这些运动则相反；色素颗粒分散到RPE细胞的长顶端突起中，视锥收缩。本文报道，在光照条件下培养的适应光的视网膜中，提高细胞质环磷酸腺苷（cAMP）的处理会诱导暗适应运动（色素聚集和视锥伸长）。旨在提高环磷酸鸟苷（cGMP）的处理没有效果。在用cAMP类似物二丁酰环磷酸腺苷（dbcAMP）进行的剂量反应研究中，我们发现，随着dbcAMP浓度的增加，RPE色素并未表现出聚集的中间状态，而是在外源dbcAMP浓度在10微摩尔至50微摩尔之间时，从完全适应光的状态突然转变为完全适应暗的视网膜运动位置。另一方面，视锥在10微摩尔至500微摩尔之间随着dbcAMP浓度的增加而伸长到中间程度。这些观察结果表明，细胞质cAMP在调节RPE和视锥的视网膜运动位置中发挥作用。
