NEURAL SIGNALLING IN THE RETINA

脊椎动物光感受器的电信号是由 调节外段处钠离子的内向电流。 的 Na进入外节的机制尚不清楚， 关于光如何控制毛孔的传导性， 或介导Na流入的载体分子。 我们建议研究 光敏电导的性质及其机理 对照，使用膜片钳和吸引电极记录，光学的 测量，以及将物质注入分离的杆中。 我们打算 探讨以下问题： 1)什么是电导，温度依赖性和动力学 的表面膜中的光敏“通道”的行为， 棒外节段？ 2)通道如何响应可能的内部发射器， CA离子与环鸟苷酸 3)在一个棒的生长过程中， 对光的反应？ 4)电暗的连续分量的起源是什么 噪音棒？ 5)锥细胞暗噪声的幅度和功率谱是多少， 噪音是如何产生的？ 6)在暗适应杆的外节中， 内钠浓度梯度？ 钠梯度是否负责 外膜顶端和底部的不同转导动力学 片段？

The electrical signals of vertebrate photoreceptors are generated by modulation of an inward current of sodium ions at the outer segment. The mechanism by which Na enters the outer segment is not known, and there is little solid evidence about how light controls the conductance of the pores or carrier molecules that mediate the Na influx. We propose to examine the properties of the light-sensitive conductance and the mechaism of its control, using patch clamp and suction electrode recording, optical measurements, and injection of substances into isolated rods. We intend to approach the following questions: 1) What is the electrical conductance, temperature dependence and kinetic behaviour of the light-sensitive "channel" in the surface membrane of the rod outer segment? 2) How does the channel respond to possible internal transmitters such as CA ions and cyclic GMP? 3) How does the internal concentration of free Ca change during a rod's response to light? 4) What is the origin of the continuous component of the electrical dark noise of rods? 5) What is the magnitude and power spectrum of the dark noise of cones, and how is the noise generated? 6) In the outer segment of a dark-adapted rod is there a longitudinal gradient of internal Na concentration? Is a Na gradient responsible for the different kinetics of transduction at the tip and base of the outer segment?