本实验室以前曾报道,视网膜电图 b 波的敏感度在明适应过程中的变化因背景光强而异:在较弱背景光时随时间逐渐降低,当背景光强达到一定水平后,则在明适应过程中出现一定程度的回复。本工作应用分离、灌流的鲤科鱼视网膜,详细地考察了用...本实验室以前曾报道,视网膜电图 b 波的敏感度在明适应过程中的变化因背景光强而异:在较弱背景光时随时间逐渐降低,当背景光强达到一定水平后,则在明适应过程中出现一定程度的回复。本工作应用分离、灌流的鲤科鱼视网膜,详细地考察了用谷氨酸分离的感受器电位(PⅡ)的明适应特性。在较弱背景光下,PⅡ敏感度除初始时降低外,不随时间作进一步变化。当背景光强达到一定水平后,与 b 波相似,PⅡ敏感度也随时间而回复。对 PⅡ光谱敏感性和不同波长辨增阈的测定表明,PⅡ的这两型变化交替的光强恰为视杆系统与视锥系统活动交替的光强;当背景光完全压抑视杆系统的活动后(仅接收视杆输入的水平细胞的胞内记录的反应完全被压抑),PⅡ即呈现回复型变化。这些结果提示,b 波的回复型变化部分地反映了视锥细胞的明适应特性。展开更多
Changes in electroretinographic b-wave in the presence of background lights of increas-ing intensity were examined in isolated, superfused carp retinas. Within a certain range ofambient illumination b-waves elicited b...Changes in electroretinographic b-wave in the presence of background lights of increas-ing intensity were examined in isolated, superfused carp retinas. Within a certain range ofambient illumination b-waves elicited by red (695 nm) test flashes against dimmer backgroundlights were smaller in size than against brighter ones. Accordingly, incremental thresholdsfor red flashes decreased as the intensity of background lights increased within this intensityrange. The results suggest that cone pathways may be suppressed by rods in darkness anddim illumination. The phenomenon was absent for photoreceptor potentials(PⅢ components),indicating that the rod-cone interaction occurs in second-order retinal neurons.展开更多
文摘本实验室以前曾报道,视网膜电图 b 波的敏感度在明适应过程中的变化因背景光强而异:在较弱背景光时随时间逐渐降低,当背景光强达到一定水平后,则在明适应过程中出现一定程度的回复。本工作应用分离、灌流的鲤科鱼视网膜,详细地考察了用谷氨酸分离的感受器电位(PⅡ)的明适应特性。在较弱背景光下,PⅡ敏感度除初始时降低外,不随时间作进一步变化。当背景光强达到一定水平后,与 b 波相似,PⅡ敏感度也随时间而回复。对 PⅡ光谱敏感性和不同波长辨增阈的测定表明,PⅡ的这两型变化交替的光强恰为视杆系统与视锥系统活动交替的光强;当背景光完全压抑视杆系统的活动后(仅接收视杆输入的水平细胞的胞内记录的反应完全被压抑),PⅡ即呈现回复型变化。这些结果提示,b 波的回复型变化部分地反映了视锥细胞的明适应特性。
基金Project supported by grants from the National Natural Science Foundation of China (3870203) and from the National Institutes of Health (EY08338) to X. L. Yang.
文摘Changes in electroretinographic b-wave in the presence of background lights of increas-ing intensity were examined in isolated, superfused carp retinas. Within a certain range ofambient illumination b-waves elicited by red (695 nm) test flashes against dimmer backgroundlights were smaller in size than against brighter ones. Accordingly, incremental thresholdsfor red flashes decreased as the intensity of background lights increased within this intensityrange. The results suggest that cone pathways may be suppressed by rods in darkness anddim illumination. The phenomenon was absent for photoreceptor potentials(PⅢ components),indicating that the rod-cone interaction occurs in second-order retinal neurons.
