Wagner H J, Kröger R H
Anatomisches Institut, Universität Tübingen, Germany.
Philos Trans R Soc Lond B Biol Sci. 2000 Sep 29;355(1401):1249-52. doi: 10.1098/rstb.2000.0677.
To investigate the developmental plasticity of colour vision, we reared fish with a trichromatic cone system (Aequidens pulcher) under three near-monochromatic lights, differentially stimulating each spectral cone type from the larval stage to the age of at least one year. Control conditions comprised white lights of two intensities. The treatments did not affect the visual pigments, hut led to significant changes in cone outer segment lengths. Furthermore, in the blue-reared group the density of single cones within the retina was reduced by two-thirds after 18 months of exposure, while no changes were observed in the other groups. The connectivity of cone horizontal cells with the single cones was influenced by the intensity and spectral composition of the rearing lights: H1 cells were more sensitive to the spectral component, whereas H2 cells responded to intensity cues. In the blue-light group the dynamics of horizontal cell synaptic spinule formation and degradation were severely compromised. These observations show that long-term spectral deprivation leads to significant morphological changes at the level of photoreceptors and horizontal cells. While the reactions of photoreceptors may be interpreted mostly in terms of compensation, the functional consequences of the changes observed on the horizontal cell level remain to be determined electrophysiologically.
为了研究色觉的发育可塑性，我们在三种近单色光下饲养具有三色视锥系统的鱼类（美鲶），从幼体阶段到至少一岁，分别对每种光谱视锥类型进行不同程度的刺激。对照条件包括两种强度的白光。这些处理并未影响视觉色素，但导致视锥外段长度发生显著变化。此外，在蓝光饲养组中，暴露18个月后视网膜内单视锥细胞的密度降低了三分之二，而其他组未观察到变化。视锥水平细胞与单视锥细胞的连接性受饲养光的强度和光谱组成影响：H1细胞对光谱成分更敏感，而H2细胞对强度线索有反应。在蓝光组中，水平细胞突触棘形成和降解的动态过程受到严重损害。这些观察结果表明，长期光谱剥夺会导致光感受器和水平细胞水平上的显著形态变化。虽然光感受器的反应大多可以用补偿来解释，但在水平细胞水平上观察到的变化的功能后果仍有待通过电生理学方法来确定。
