美西螈视网膜中的致敏作用与中心-外周拮抗作用。

Sensitization and centre-surround antagonism in Necturus retina.

Burkhardt D A

J Physiol. 1974 Feb;236(3):593-610. doi: 10.1113/jphysiol.1974.sp010454.

Abstract

The impulse discharge of ganglion cells and the proximal negative response were recorded with extracellular micro-electrodes in Necturus retina and spatial influences of background illumination studied.2. When a steady background of constant illuminance was extended in diameter from 0.25 to 1 mm, the response to a small concentrically placed test flash was enhanced (sensitization).3. This sensitization was tonic, showed marked spatial summation, was also found by surrounding a central background with an annulus, and when quantified by threshold measurements, closely resembled the sensitization effect found psychophysically in human vision.4. Sensitization was prominent in intracellular recordings from bipolar cells and usually apparent in horizontal cells. In bipolar cells, a background change which produced sensitization evoked a large but predominantly transient potential whose polarity was opposite to that evoked by a central flash.5. The tonicity and large spatial extent of the sensitization effect strongly suggest that it is mediated by horizontal cells. They might do this by either acting upon receptors, bipolar cells, or both.

摘要

用细胞外微电极记录了美西螈视网膜神经节细胞的冲动发放和近端负反应，并研究了背景光照的空间影响。
当恒定照度的稳定背景直径从0.25毫米扩大到1毫米时，对小的同心放置的测试闪光的反应增强（敏化）。
这种敏化是紧张性的，表现出明显的空间总和，通过用一个环包围中央背景也能发现，并且当通过阈值测量进行量化时，与在人类视觉中通过心理物理学发现的敏化效应非常相似。
敏化在双极细胞的细胞内记录中很突出，在水平细胞中通常也很明显。在双极细胞中，产生敏化的背景变化会诱发一个大的但主要是短暂的电位，其极性与中央闪光诱发的电位相反。
敏化效应的紧张性和大的空间范围强烈表明它是由水平细胞介导的。它们可能通过作用于受体、双极细胞或两者来做到这一点。