Time‐matched pre‐ and postsynaptic changes of GABAergic synaptic transmission in the developing mouse superior colliculus
Time‐matched pre‐ and postsynaptic changes of GABAergic synaptic transmission in the developing mouse superior colliculus
复制标题
发育中的小鼠上丘中 GABA 能突触传递的时间匹配的突触前和突触后变化
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
R. Grantyn
中科院分区：
文献类型：
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作者：
S. Kirischuk;R. Jüttner;R. Grantyn
GABA能突触后电流动力学的发育变化已被报道用于各种脑结构。然而，目前还不清楚这些修改是否与突触前变化相匹配。我们解决了这个问题，通过分析诱发的IPSC（eIPSC）在小鼠上级丘切片出生后（P）1和22天。通过电刺激引发eIPSC，并在全细胞膜片钳配置中测量。使用突触传递的二项式模型分析IPSC。根据50-Hz刺激期间的累积eIPSC振幅直方图估计易释放池（RRP，N）。中位延迟IPSC（dIPSC）振幅用作量子振幅（q）估计值。平均释放概率（p）确定为平均eIPSC振幅除以RRP和q的乘积。实验表明，GABA能突触经历两个不同的功能调节时期：（i）P1-3（与多巴胺能自发活动的发作和从去极化到超极化GABA作用的转换一致）显示p显著降低，与成对脉冲比增加相关。（ii）P6-15（睁眼前和睁眼后不久的时期）的特征在于IPSC持续时间的急剧减少。在突触前，它伴随着异步释放的下调，有利于刺激锁定的同步释放。我们的结论是，在上级丘（SC）的GABA能突触传递的突触后修饰确实伴随着突触前的变化，这可能保证在SC的突触网络的发育重建过程中的抑制的必要效力。
Developmental changes in the kinetics of GABAergic postsynaptic currents have been reported for various brain structures. However, it has remained unclear whether these modifications are matched by presynaptic changes. We addressed this question by analysing evoked IPSCs (eIPSCs) in mouse superior colliculus slices between postnatal day (P) 1 and 22. eIPSCs were elicited by electrical stimulation and measured in the whole‐cell patch‐clamp configuration. IPSCs were analysed using the binomial model of synaptic transmission. The readily releasable pool (RRP, N) was estimated from the cumulative eIPSC amplitude histograms during 50‐Hz stimulation. Median delayed IPSC (dIPSC) amplitude was used as a quantal amplitude (q) estimate. The mean release probability (p) was determined as the mean eIPSC amplitude divided by the product of RRP and q. The experiments revealed that GABAergic synapses pass through two distinct periods of functional adjustment: (i) P1–3 (coincidental with the onset of glutamatergic spontaneous activity and a switch from depolarizing to hyperpolarizing GABA action) displayed a significant decrease of p, associated with an increase in the paired‐pulse ratio (eIPSC2/eIPSC1); and (ii) P6–15 (the period before and shortly after eye opening) is characterized by a drastic reduction of IPSC duration. On the presynaptic side, it was accompanied by a down‐regulation of asynchronous release in favour of stimulus‐locked synchronous release. We conclude that postsynaptic modifications of GABAergic synaptic transmission in the superior colliculus (SC) are indeed accompanied by presynaptic changes, and this may guarantee the necessary efficacy of inhibition during the developmental reconstruction of the synaptic network in the SC.
猫上丘视觉和动眼神经功能的神经化学微电路。
影响因子：
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作者：
Mize,RR
通讯作者：
Mize,RR
影响因子：
56.9
作者：
LLINAS, R;SUGIMORI, M;SILVER, RB
通讯作者：
SILVER, RB