Properties of synaptic transmission from photoreceptors to bipolar cells in the mudpuppy retina.
Properties of synaptic transmission from photoreceptors to bipolar cells in the mudpuppy retina.
复制标题
从光感受器到泥小狗视网膜双极细胞的突触传递特性。
DOI：
10.1152/jn.1993.69.2.352
复制
发表时间：
1993
影响因子：
2.5
通讯作者：
Miller,RF
中科院分区：
文献类型：
--
作者：
Kim,HG;Miller,RF
1.同时，全细胞记录从突触耦合的感光细胞/双极细胞对，通过使用直接可视化在灌流，mudpuppy视网膜切片制备。2.当外源性电流注入视杆细胞和视锥细胞时，OFF双极细胞（BP）产生了符号保存反应，而ON BP产生了符号反转反应。当电流注入光感受器时，在响应潜伏期（27.8对80.6 ms）和峰值响应时间（50.5对159.8 ms）方面，OFF-BP（n = 24）比ON-BP（n = 12）响应更快。我们没有检测到任何显着差异杆与锥介导的潜伏期或高峰反应时间在ON和OFF-BP亚型。3.犬尿烯酸（Kyn）可阻断视杆细胞和视锥细胞对OFF-BP的输入，但视杆细胞输入所需的剂量显著更高：Kyn的IC 50（拮抗剂阻断50%反应的浓度）对于视锥细胞输入为0.3 mM，对于视杆细胞输入为1 mM。4.视杆输入OFF-BP表现出相同的Kyn的敏感性视杆输入水平细胞（HC）。然而，对HC的视锥细胞输入（IC 50 < 200 μ M）对Kyn比对OFF-BP更敏感。5.这里提出的药理学研究，以及以前的研究，表明mudpuppy视网膜的外丛状层中的信号保存途径涉及至少三种谷氨酸受体亚型：1）HC的视锥激活受体; 2）OFF-BP的视锥激活受体;和3）HC和BP中发现的视杆激活受体。（250字处删节）
1. Simultaneous, whole-cell recordings were obtained from synaptically coupled photoreceptor/bipolar cell pairs, by the use of direct visualization in a superfused, mudpuppy retinal slice preparation. 2. OFF-bipolar cells (BPs) generated sign-conserving responses when extrinsic current was injected into rods and cones, whereas ON-BPs generated a sign-reversing response. OFF-BPs (n = 24) responded faster than ON-BPs (n = 12), in terms of response latency (27.8 vs. 80.6 ms) and peak response times (50.5 vs. 159.8 ms) when current was injected into photoreceptors. We did not detect any significant difference between rod- versus cone-mediated latency or peak response times in the ON- and OFF-BP subtypes. 3. Rod and cone inputs to OFF-BPs were blocked by kynurenic acid (Kyn), but the doses required were significantly higher for rod inputs: the IC50 (the concentration at which an antagonist blocks 50% of the responses) for Kyn was 0.3 mM for cone inputs and 1 mM for rod inputs. 4. Rod inputs to OFF-BPs showed the same Kyn sensitivity as rod inputs to horizontal cells (HCs). However, cone inputs to HCs (IC50 < 200 microM) were more sensitive to Kyn than those to OFF-BPs. 5. The pharmacological studies presented here, together with previous studies, suggest that the sign-conserving pathway in the outer plexiform layer of the mudpuppy retina involves at least three subtypes of glutamate receptors: 1) cone-activated receptors of HCs; 2) cone-activated receptors of OFF-BPs; and 3) rod-activated receptors found in HCs and BPs.(ABSTRACT TRUNCATED AT 250 WORDS)