Gamlin Paul D R, McDougal David H, Pokorny Joel, Smith Vivianne C, Yau King-Wai, Dacey Dennis M
Department of Vision Sciences, University of Alabama at Birmingham, AL 35294, USA.
Vision Res. 2007 Mar;47(7):946-54. doi: 10.1016/j.visres.2006.12.015. Epub 2007 Feb 22.
Melanopsin, a novel photopigment, has recently been localized to a population of retinal ganglion cells that display inherent photosensitivity. During continuous light and following light offset, primates are known to exhibit sustained pupilloconstriction responses that resemble closely the photoresponses of intrinsically-photoreceptive ganglion cells. We report that, in the behaving macaque, following pharmacological blockade of conventional photoreceptor signals, significant pupillary responses persist during continuous light and following light offset. These pupil responses display the unique spectral tuning, slow kinetics, and irradiance coding of the sustained, melanopsin-derived ganglion cell photoresponses. We extended our observations to humans by using the sustained pupil response following light offset to document the contribution of these novel ganglion cells to human pupillary responses. Our results indicate that the intrinsic photoresponses of intrinsically-photoreceptive retinal ganglion cells play an important role in the pupillary light reflex and are primarily responsible for the sustained pupilloconstriction that occurs following light offset.
黑视蛋白是一种新型光色素，最近已被定位到一群具有内在光敏性的视网膜神经节细胞中。在持续光照期间以及光照结束后，已知灵长类动物会表现出持续的瞳孔收缩反应，这与内在光感受性神经节细胞的光反应非常相似。我们报告称，在行为猕猴中，在对传统光感受器信号进行药理学阻断后，持续光照期间以及光照结束后仍存在明显的瞳孔反应。这些瞳孔反应表现出持续的、源自黑视蛋白的神经节细胞光反应所特有的光谱调谐、缓慢动力学和辐照度编码。我们通过使用光照结束后的持续瞳孔反应将观察扩展到人类，以证明这些新型神经节细胞对人类瞳孔反应的贡献。我们的结果表明，内在光感受性视网膜神经节细胞的内在光反应在瞳孔光反射中起重要作用，并且主要负责光照结束后发生的持续瞳孔收缩。
