Glycinergic Inhibitory Synaptic Currents and Related Receptor Channels in the Zebrafish Brain
Glycinergic Inhibitory Synaptic Currents and Related Receptor Channels in the Zebrafish Brain
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斑马鱼大脑中的甘氨酸抑制性突触电流和相关受体通道
DOI：
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发表时间：
1994
影响因子：
3.4
通讯作者：
Henri Korn
中科院分区：
文献类型：
--
作者：
P. Legendre;Henri Korn
为了扩展我们对抑制性突触网络的研究，我们开发了一种 52 小时龄斑马鱼 (Brachydanio redo) 的分离全脑制剂，其中保留了大脑结构和功能的完整性。我们报告了量子抑制事件的特征及其特性与潜在激活通道特性的相关性。在 Mauthner 细胞的全细胞记录过程中，10−6 M 河豚毒素的应用大大降低了自发发生的突触事件的频率和幅度，这些事件主要由 Cl−依赖性抑制性突触后电流 (IPSC) 主导。在含河豚毒素的溶液中降低 Ca2+ 并添加 Mg2+ 会导致记录的突触电流振幅进一步降低，其余的被认为是微型 IPSC（mISC）。在河豚毒素存在的情况下应用 0.5–1 μMM 士的宁可消除制剂中 > 90% 的抑制电流。这些 mIPSC 的振幅直方图显示出两个初始等距峰值，随后出现较高值的偏态分布。前两个分量通过两条高斯曲线的总和很好地拟合，给出了第一个峰值的平均量子幅度为 35.7 pA（保持电位为 50 mV）和变化系数为 0.25。外部记录显示至少两类甘氨酸受体通道，一类具有多个电导水平，主状态为 81-86 pS，另一类仅显示一个开放水平 41-43 pS。这两种平均电导状态具有相似的平均开放时间，分别为 0.6-1 和 4.5-6 毫秒。此外，观察到 41-43 pS 水平的三个平均闭合时间。最短的组（0.6-1 ms）被认为代表突发内的间隙。突发分析揭示了三种平均突发持续时间，分别为 0.6、4 和 35 毫秒。第一类 mIPSC 的振幅与开放通道电导的比较表明，一个量子打开 14-22 个通道。此外，mIPSC 的平均衰减时间与平均开放时间或中等爆发持续时间（4-5 ms）之间的对应关系表明，甘氨酸激活的通道仅响应单次胞吐作用而开放一次。在多囊泡释放与突触后受体饱和假设的背景下讨论了 mIPSC 振幅波动的突触前和突触后起源。
To extend our study of the inhibitory synaptic network we have developed an isolated whole‐brain preparation of the 52‐h‐old zebrafish (Brachydanio redo) in which the structural and functional integrity of the brain is preserved. We report the characterization of quantal inhibitory events and the correlation of their properties with those of the underlying activated channels. During whole‐cell recordings of the Mauthner cells, applications of 10−6 M tetrodotoxin greatly reduced the frequency and amplitude of the spontaneously occurring synaptic events, which were dominated by Cl−‐dependent inhibitory postsynaptic currents (IPSCs). Lowering Ca2+ and adding Mg2+ to tetrodotoxin‐containing solutions resulted in a further decrease in amplitude of the recorded synaptic currents, the remaining ones being considered as miniature IPSCs (mISCs). Applications of 0.5–1 μMM strychnine in the presence of tetrodotoxin eliminated > 90% of the inhibitory currents in the preparation. The amplitude histograms of these mIPSCs exhibited two initial equally spaced peaks, followed by a skewed distribution for higher values. The first two components were well fitted by the sum of two Gaussian curves, giving a mean quantal amplitude of 35.7 pA (at a holding potential of‐50 mV) and a coefficient of variation of 0.25 for the first peak. Outside‐out recordings showed at least two classes of glycine receptor channels, one having multiple conductance levels with a main state of 81–86 pS and another displaying only one opening level of 41–43 pS. These two mean conductance states had similar mean open times, of 0.6–1 and 4.5–6 ms respectively. In addition, three mean closed times were observed for the 41–43 pS level. The shortest group (0.6–1 ms) was considered as representing gaps within bursts. Burst analysis revealed three mean burst durations, of 0.6, 4 and 35 ms. Comparisons of the amplitude of the first class of mIPSCs and of the open channel conductances indicated that one quantum opens 14–22 channels. Moreover, the correspondence between the mean decay time of mIPSCs and the mean open time or medium burst duration (4–5 ms) suggests that glycine‐activated channels open only once in response to a single exocytosis. The pre‐and postsynaptic origins of mIPSCs amplitude fluctuations are discussed in the context of multivesicular release versus the hypothesis of postsynaptic receptor saturation.
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膈运动核中的量子突触传递。
影响因子：
2.5
作者：
Liu,G;Feldman,JL
通讯作者：
Feldman,JL
影响因子：
5.5
作者：
JACKSON, MB
通讯作者：
JACKSON, MB
影响因子：
2.5
作者：
JOHNSTON, D;BROWN, TH
通讯作者：
BROWN, TH
DOI：
10.1073/pnas.87.14.5359
发表时间：
1990-07-01
影响因子：
11.1
作者：
BEKKERS, JM;RICHERSON, GB;STEVENS, CF
通讯作者：
STEVENS, CF
影响因子：
3.4
作者：
SIGWORTH, FJ;SINE, SM
通讯作者：
SINE, SM