Vision in the southern hemisphere lamprey Mordacia mordax:: Spatial distribution, spectral absorption characteristics. and optical sensitivity of a single class of retinal photoreceptor
Vision in the southern hemisphere lamprey Mordacia mordax:: Spatial distribution, spectral absorption characteristics. and optical sensitivity of a single class of retinal photoreceptor
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DOI：
10.1017/s0952523804215103
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发表时间：
2004-09-01
影响因子：
1.9
通讯作者：
Potter, IC
中科院分区：
文献类型：
--
作者：
Collin, SP;Hart, NS;Potter, IC
背外侧位于眼睛的南半球七鳃鳗Mordacia mordax（无颌）包含一个单一的形态类型的视网膜光感受器，具有超微结构的特点，杆和锥。这种光感受器在内节中具有大的可触椭圆体，并且由包含两种类型的绒毡层反射器的视网膜色素上皮包围的长圆柱形外节。光感受器形成六边形阵列，并在腹颞视网膜中达到其峰值密度（33，200个感受器/mm 2）。使用光感受器的尺寸和间距以及孔径尺寸和眼睛尺寸的直接测量，估计峰值空间分辨能力和光学灵敏度分别为1.7 cycle deg（-1）（最小可分离角为34 ′ 7 ″）和0.64 μ m（2）球面度（白色光）以及1.38 μ m（2）球面度（优选波长或λ（max））。显微分光光度法显示，位于外节内的视色素是具有在514 nm处的最大吸收波长（λ（max））的视紫红质。椭圆体具有非常低的吸收率（
The dorso-laterally located eyes of the southern hemisphere lamprey Mordacia mordax (Agnatha) contain a single morphological type of retinal photoreceptor, which possesses ultrastructural characteristics of both rods and cones. This photoreceptor has a large refractile ellipsosome in the inner segment and a long cylindrical outer segment surrounded by a retinal pigment epithelium that contains two types of tapetal reflectors. The photoreceptors form a hexagonal array and attain their peak density (33,200 receptors/mm(2)) in the ventro-temporal retina. Using the size and spacing of the photoreceptors and direct measures of aperture size and eye dimensions, the peak Spatial resolving power and optical sensitivity are estimated to be 1.7 cycles deg(-1) (minimum separable angle of 34'7") and 0.64 mum(2) steradian (white light) and 1.38 mum(2) steradian (preferred wavelength or lambda(max)), respectively. Microspectrophotometry reveals that the visual pigment located within the outer segment is a rhodopsin with a wavelength of maximum absorbance (lambda(max)) at 514 nm. The ellipsosome has very low absorptance (