Provencio I, Foster R G
Department of Biology, University of Virginia, Charlottesville 22903.
Neurosci Lett. 1993 Jun 11;155(2):223-6. doi: 10.1016/0304-3940(93)90713-u.
Fully terrestrial vertebrates were previously thought to exclusively employ vitamin A1 to generate visual pigments. However, recent studies on the visual system of the lizard Anolis carolinensis have shown that its visual pigments are vitamin A2-based. This unexpected result prompted an investigation of the pineal photopigments in this species [13]. HPLC analysis has shown that this extraretinal photoreceptor also exclusively utilizes a vitamin A2-derived chromophore. The adaptive significance of this chromophore within the pineal is unclear. The extended long wavelength sensitivity characteristic of vitamin A2-based visual pigment systems may enhance important visual tasks such as prey detection or mate selection [13]. A similar argument cannot be made for the pineal, whose role is not image formation, but rather detection of the irradiance changes associated with dawn and dusk. We suggest that the pineal may passively utilize whatever retinoids have been adaptively selected by the visual system.
完全陆生的脊椎动物以前被认为只利用视黄醛（维生素A1）来生成视觉色素。然而，最近对绿安乐蜥视觉系统的研究表明，其视觉色素是以视黄醛（维生素A2）为基础的。这一意外结果促使人们对该物种的松果体光色素进行研究[13]。高效液相色谱分析表明，这种视网膜外光感受器也只利用一种源自视黄醛（维生素A2）的发色团。这种发色团在松果体内的适应性意义尚不清楚。基于视黄醛（维生素A2）的视觉色素系统所具有的扩展的长波长敏感性特征，可能会增强诸如猎物探测或配偶选择等重要视觉任务[13]。对于松果体来说，情况则不同，其作用不是成像，而是检测与黎明和黄昏相关的辐照度变化。我们认为，松果体可能被动地利用视觉系统适应性选择的任何类视黄醇。
