Microspectrophotometry of visual pigments and oil droplets in a marine bird, the wedge-tailed shearwater Puffinus pacificus:: topographic variations in photoreceptor spectral characteristics
Microspectrophotometry of visual pigments and oil droplets in a marine bird, the wedge-tailed shearwater Puffinus pacificus:: topographic variations in photoreceptor spectral characteristics
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DOI：
10.1242/jeb.00857
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发表时间：
2004-03-01
影响因子：
2.8
通讯作者：
Hart, NS
中科院分区：
文献类型：
--
作者：
Hart, NS
通过对太平洋楔尾海雀的视网膜进行显微分光光度检查，发现七种不同类型的光感受器中存在五种不同类型的基于维生素A(1)的视觉色素。一类单一的棒包含一种中等波长敏感的视觉色素，其最大吸收波长(最大吸收波长)为502 nm。四种不同类型的单锥体含有视觉色素，在紫色(vs，lambda(Max)406 nm)、短(SWS，lambda(Max)450 nm)、中等(MWS，lambda(Max)503 nm)或长(LWS，lambda(Max)566 nm)光谱范围内最敏感。在外周视网膜，SWS、MWS和LWS单锥的内段含有色素油滴，其截止波长(波长)分别为445(C型)、506(Y型)和562 nm(R型)。VS视觉色素与透明(T型)油滴配对，在至少370次以上没有表现出明显的吸收。与LWS单锥体一样，双锥体对的主要和辅助成员都含有566 nm的最大波长的视觉色素，但只有主要成员含有一个油滴，其波长为413 nm。视网膜有一个水平条带或“视觉条纹”，光感受器密度增加，穿过视网膜，大约在果胶顶端背部1.5毫米处。水平条纹中心的圆锥体较小，油滴要么透明/无色，要么比外围少得多的色素。有人提出，视网膜区域视锥油滴色素沉着的减少与高视力有关，这是一种适应，以补偿那里发现的较窄光感受器的光子捕获能力的降低。对眼睛介质的光谱透过率的测量表明，波长低至至少300纳米的波长将被传输到视网膜。
Microspectrophotometric examination of the retina of a procellariiform marine bird, the wedge-tailed shearwater Puffinus pacificus, revealed the presence of five different types of vitamin A(1)-based visual pigment in seven different types of photoreceptor. A single class of rod contained a medium-wavelength sensitive visual pigment with a wavelength of maximum absorbance (lambda(max)) at 502 nm. Four different types of single cone contained visual pigments maximally sensitive in either the violet (VS, lambda(max) 406 nm), short (SWS, lambda(max) 450 nm), medium (MWS, lambda(max) 503 nm) or long (LWS, lambda(max) 566 nm) spectral ranges. In the peripheral retina, the SWS, MWS and LWS single cones contained pigmented oil droplets in their inner segments with cut-off wavelengths (lambda(cut)) at 445 (C-type), 506 (Y-type) and 562 nm (R-type), respectively. The VS visual pigment was paired with a transparent (T-type) oil droplet that displayed no significant absorption above at least 370 run. Both the principal and accessory members of the double cone pair contained the same 566 nm lambda(max) visual pigment as the LWS single cones but only the principal member contained an oil droplet, which had a lambda(cut) at 413 nm. The retina had a horizontal band or 'visual streak' of increased photoreceptor density running across the retina approximately 1.5 mm dorsal to the top of the pecten. Cones in the centre of the horizontal streak were smaller and had oil droplets that were either transparent/colourless or much less pigmented than at the periphery. It is proposed that the reduction in cone oil droplet pigmentation in retinal areas associated with high visual acuity is an adaptation to compensate for the reduced photon capture ability of the narrower photoreceptors found there. Measurements of the spectral transmittance of the ocular media reveal that wavelengths down to at least 300 nm would be transmitted to the retina.