IONIC AND SPECTRAL BASIS OF VISUAL RESPONSES

我们提出了测量局部敏感度和局部视紫红质的实验。 虎鳗离体视网杆和视锥中的浓度 使用胞外吸气电极和显微分光光度法， 分别进行了分析。这两个测量将在相同的单元格上进行， 同样的光学系统。具体问题包括： 1.漂白适应的影响是否在纵向上传播 杆段，还是仅限于外段的区域 含有漂白视紫红质的光盘？ 2.漂白适应的影响是否在纵向上传播 圆锥体外段？漂白适应的时间依赖性传播能否 这与漂白颜料的纵向扩散一致 在膜的脂质基质中？ 3.11-顺式维甲酸内源池的范围有多大 视紫红质可在黑暗中再生的视杆和视锥 在视紫红质漂白之后？ 4.外源性应用11-顺式维甲酸能否促进脑出血患者的康复 视紫红质在这些细胞中的敏感性和再生？ 5.漂白适应能否逆转低钙诱导的脱敏 像背景光一样的杆状和圆锥状？ 最近的实验表明，我们可以将膜片钳技术应用于 用酶法从扇贝的视网膜分离光感受器细胞， 利马结痂。我们建议通过以下实验来检验这些影响 单通道和宏观膜中的激发和适应 这些电池中的电流： 1.基本性质是什么(即单通道电导、离子 选择性、门控、动力学等)光和非光诱导的 光感受器反应是由哪些电流组成的？ 2.光适应对时间、光和电压有什么影响 这些单离子通道的依赖性吗？ 3.激励和空间传播的性质和程度是什么？ 在这些细胞中适应吗？

We propose experiments to measure local sensitivity and local rhodopsin concentration in isolated retinal rods and cones of tiger salamander employing extra-cellular suction electrodes and microspectrophotometry, respectively. Both measurements will be made on the same cell with the same optical system. Specific questions are: 1. Are the effects of bleaching adaptation free to spread longitudinally in rod outer segments, or are they confined to areas of the outer segment containing discs with bleached rhodopsin? 2. Are the effects of bleaching adaptation free to spread longitudinally in cone outer segments? Can time dependent spread of bleaching adaptation be observed which is consistent with longitudinal spread of bleached pigment within the lipid matrix of the membrane? 3. What is the extent of the endogenous pool of 11-cis retinoid in isolated rods and cones from which rhodopsin can be regenerated in darkness following rhodopsin bleaching? 4. Can exogenous application of 11-cis retinoids promote recovery of sensitivity and regeneration of rhodopsin in these cells? 5. Can bleaching adaptation reverse low calcium induced desensitization in rods and cones in the same way background light does? Recent experiments have shown that we can apply patch clamp techniques to enzymatically isolated photoreceptor cells from the retina of the scallop, Lima scabra. We propose the following experiments to examine the effects of excitation and adaptation in single channel and macroscopic membrane currents in these cells: 1. What is the elementary nature (i.e. single channel conductance, ion selectivity, gating, kinetics, etc.) of light and non-light induced currents of which the light induced receptor response is composed? 2. What are the effects of light adaptation on the time, light, and voltage dependence of these single ion channels? 3. What is the nature and extent of spatial spread of excitation and adaptation in these cells?