Openings of the rat recombinant alpha 1 homomeric glycine receptor as a function of the number of agonist molecules bound.
Openings of the rat recombinant alpha 1 homomeric glycine receptor as a function of the number of agonist molecules bound.
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DOI：
10.1085/jgp.20028530
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发表时间：
2002-05
期刊：
影响因子：
--
通讯作者：
Sivilotti LG
中科院分区：
文献类型：
--
作者：
Beato M;Groot-Kormelink PJ;Colquhoun D;Sivilotti LG
使用大鼠α1亚基cDNA转染的人胚胎肾细胞的全细胞和outside-out记录研究了大鼠同聚α1甘氨酸受体的功能特性。全细胞剂量反应曲线给出的 EC 50 估计值在 30 至 120 μM 之间，希尔斜率约为 3.3。单通道记录是通过将甘氨酸（0.3、1 或 10 μM）稳态应用到外侧斑块上获得的。单通道电导大多为 60-90 pS，但也观察到 ∼40 pS 的较小电导（占事件的 10%），其相对频率不依赖于激动剂浓度。表观开放时间分布的时间常数不随激动剂浓度变化，但在低甘氨酸浓度下短事件更频繁。还有证据表明，先前错过的短暂开放状态在较低甘氨酸浓度下更为常见。发现突发长度分布的不同分量的时间常数在不同浓度下具有相似的值。然而，平均突发长度随着甘氨酸的增加而增加。这是因为每个突发长度成分的相对面积取决于浓度，并且在较低的甘氨酸浓度下有利于短突发。发现相邻打开和关闭时间的持续时间呈强（负）相关。此外，长突发由比平均开口更长且由短间隙分隔的开口组成，而短突发通常由单个孤立的短开口组成。对这些发现最合理的解释是，当受体上五个潜在激动剂结合位点中较高比例的甘氨酸被占据时，就会产生长爆发。基于浓度依赖性和内部爆发结构，我们提供了同聚甘氨酸受体激活的初步动力学方案，其中一到五个任意数量的甘氨酸分子都可以打开通道，尽管效率不同。
The functional properties of rat homomeric α1 glycine receptors were investigated using whole-cell and outside-out recording from human embryonic kidney cells transfected with rat α1 subunit cDNA. Whole-cell dose-response curves gave EC 50 estimates between 30 and 120 μM and a Hill slope of ∼3.3. Single channel recordings were obtained by steady-state application of glycine (0.3, 1, or 10 μM) to outside-out patches. Single channel conductances were mostly 60–90 pS, but smaller conductances of ∼40 pS were also seen (10% of the events) with a relative frequency that did not depend on agonist concentration. The time constants of the apparent open time distributions did not vary with agonist concentration, but short events were more frequent at low glycine concentrations. There was also evidence of a previously missed short-lived open state that was more common at lower glycine concentrations. The time constants for the different components of the burst length distributions were found to have similar values at different concentrations. Nevertheless, the mean burst length increased with increasing glycine. This was because the relative area of each burst-length component was concentration dependent and short bursts were favored at lower glycine concentrations. Durations of adjacent open and shut times were found to be strongly (negatively) correlated. Additionally, long bursts were made up of longer than average openings separated by short gaps, whereas short bursts usually consisted of single isolated short openings. The most plausible explanation for these findings is that long bursts are generated when a higher proportion of the five potential agonist binding sites on the receptor is occupied by glycine. On the basis of the concentration dependence and the intraburst structure we provide a preliminary kinetic scheme for the activation of the homomeric glycine receptor, in which any number of glycine molecules from one to five can open the channel, although not with equal efficiency.
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影响因子：
--
作者：
Colquhoun, HM;Lewis, DF;Williams, DJ
通讯作者：
Williams, DJ
DOI：
10.1073/pnas.86.7.2199
发表时间：
1989-04-01
影响因子：
11.1
作者：
JACKSON, MB
通讯作者：
JACKSON, MB
影响因子：
5.5
作者：
BLATZ, AL;MAGLEBY, KL
通讯作者：
MAGLEBY, KL
影响因子：
2
作者：
KARLIN, A
通讯作者：
KARLIN, A
影响因子：
5.5
作者：
Fucile, S;de Saint Jan, D;Bregestovski, P
通讯作者：
Bregestovski, P