IONIC AND SPECTRAL BASIS OF VISUAL RESPONSES

我们提出实验来测量局部敏感性和局部视紫红质 虎蝾螈离体视网膜视杆细胞和视锥细胞中的浓度 采用细胞外抽吸电极和显微分光光度法， 分别 两次测量都将在同一个单元上进行， 相同的光学系统。 具体问题如下： 1.漂白适应的影响是否可以自由地纵向传播， 杆外节，或他们局限于该地区的外节 含有漂白视紫红质的光盘 2.漂白适应的影响是否可以自由地纵向传播， 锥体外节？ 漂白适应的时间依赖性扩散是否 观察到这与漂白颜料的纵向扩散一致 在膜的脂质基质中 3.在分离的细胞中，11-顺式维甲酸的内源性库的程度如何？ 视杆细胞和视锥细胞，视紫红质可以在黑暗中再生 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 视紫红质的敏感性和再生 5.漂白适应能逆转低钙诱导的脱敏吗 视杆细胞和视锥细胞的反应 最近的实验表明，我们可以应用膜片钳技术， 从扇贝视网膜酶促分离的光感受器细胞， 利马粗糙。 我们提出了以下实验来检查效果 单通道和宏观膜的兴奋和适应 这些细胞中的电流： 1.什么是基本性质（即单通道电导，离子 选择性、门控、动力学等）光诱导和非光诱导 光诱导的受体反应是由哪些电流组成的？ 2.光适应对时间、光线、电压有什么影响 这些单离子通道的依赖性？ 3.什么是激发的空间传播的性质和程度， 这些细胞的适应性？

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?