Negishi K, Kato S, Sugawara K
Pflugers Arch. 1978 Jun 21;375(1):53-60. doi: 10.1007/BF00584148.
Experiments were performed on isolated retinas of teh carp (Cyprinus carpio) to investigate the effects of locally applied amino acids on the transretinal potential and the membrane potential of horizontal cells. A minute quantity of each solution of an amino acid was applied locally at different layers by means of pressure-microinjection. The responses were induced by alternating central and annular stimuli of white light. Amino acids applied locally at the distal layer (receptor surface or outer plexiform layer) in the centrally stimulated area, caused, at concentrations of 25--50mM, rapid changes in the light-induced potential, whereas those microinjected into the inner plexiform layer did not. When applied locally at the distal layer, amino acids abolished the proximal PIII response and reduced the amplitude of S-potentials, particularly in response to a central stimulus. However, the resting potential of horizontal cells was depolarized only slightly by acidic amino acids. The results suggest that the passive membrane properties of horizontal cells are not altered significantly by the amino acids applied. Differential susceptibilities of the PII component to acidic and neutral amino acids were found; the former did not change or, in some cases, enlarged, whereas the latter abolished it. Possibly, neutral amino acids interfere with a neural mechanism generating the PII component.
实验在鲤鱼（鲤属鲤科）的离体视网膜上进行，以研究局部应用氨基酸对跨视网膜电位和水平细胞膜电位的影响。通过压力微注射在不同层局部施加微量的每种氨基酸溶液。通过交替的中央和环形白光刺激诱导反应。在中央刺激区域的远端层（受体表面或外网状层）局部施加的氨基酸，在浓度为25 - 50mM时，会引起光诱导电位的快速变化，而注入内网状层的氨基酸则不会。当在远端层局部应用时，氨基酸消除了近端PIII反应并降低了S电位的幅度，特别是对中央刺激的反应。然而，水平细胞的静息电位仅被酸性氨基酸轻微去极化。结果表明，所应用的氨基酸并未显著改变水平细胞的被动膜特性。发现PII成分对酸性和中性氨基酸的敏感性不同；前者不变或在某些情况下增大，而后者则消除了它。中性氨基酸可能干扰产生PII成分的神经机制。
