The sensitivity and spectral identity of the cones driving the b-wave of the rat electroretinogram
The sensitivity and spectral identity of the cones driving the b-wave of the rat electroretinogram
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DOI：
10.1017/s0952523803202029
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发表时间：
2003-03-01
影响因子：
1.9
通讯作者：
Naarendorp, F
中科院分区：
文献类型：
--
作者：
Akula, JD;Lyubarsky, AL;Naarendorp, F
在大鼠视网膜中，视锥细胞约占光感受器总数的0.85%：其中93%的视锥细胞含有中波敏感色素，其余的表达短波敏感色素（Szel & Rohlich, 1992）。我们用正常成年Long Evans大鼠测定了视锥驱动视网膜电图（ERG） b波的光谱灵敏度和视锥色素在λ (max)处的绝对灵敏度。在适应黑暗和光的条件下，记录麻醉动物角膜的眼电图。棒子反应被稳定的饱和棒子的橙色背景和/或闪光的“白色”背景所抑制。不同强度的“白色”或窄带全场刺激可诱发锥体驱动的b波。锥形b波的作用谱表明在510 nm处存在一个吸光度峰；在360 nm处发现了第二个低两倍的峰（经过透镜的透射率校正）。色适应实验强烈表明视网膜对中波和紫外线刺激的反应是由单一的视锥细胞介导的。在产生类似17000 R*杆（-1）s（-1）的背景下，完全抑制了饱和a波。锥形b波在510 nm处的绝对灵敏度为18 nV光子（-1）mum(2)，在360 nm处的绝对灵敏度为4 nV光子（-1）mum(2)，比小鼠高20-30倍。提示大鼠视网膜中相对较多的视锥上双极细胞是造成视锥b波具有显著敏感性的原因。
In the retina of rat, cones make up similar to0.85% of the photoreceptor population: 93% of these cones contain a midwave-sensitive pigment, the rest expresses a short-wave-sensitive pigment (Szel & Rohlich, 1992). We used normal adult Long Evans rats to determine the spectral sensitivity of the cone-driven electroretinogram (ERG) b-wave and its absolute sensitivity at lambda(max) of the cone pigments. ERGs were recorded at the cornea of anesthetized animals under dark- and light-adapted conditions. Rod responses were suppressed by steady rod-saturating orange backgrounds and/or by a flashed "white" background. Cone-driven b-waves were evoked by "white" or narrowband full-field stimuli of varying intensity. The action spectrum for the cone b-wave indicates the presence of an absorbance peak at 510 nm; a second, twofold lower, peak was found at 360 nm (after correction for transmittance by the lens). Chromatic adaptation experiments strongly suggest that retinal responses to midwave and UV stimuli are mediated by a single cone type. On a background producing similar to17,000 R* rod(-1) s(-1), which completely suppressed the saturated a-wave. the absolute sensitivity of the cone b-wave was 18 nV photon(-1) mum(2) at 510 nm and 4 nV photon(-1) mum(2) at 360 nm which is 20-30 times higher than for the mouse. It is suggested that the relatively large number of on-cone bipolar cells in the retina of rat is responsible for the remarkable sensitivity of the cone b-wave.