Developmental profile of GABAA-mediated synaptic transmission in pyramidal cells of the somatosensory cortex
Developmental profile of GABAA-mediated synaptic transmission in pyramidal cells of the somatosensory cortex
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DOI：
10.1111/j.1460-9568.2008.06401.x
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发表时间：
2008-09-01
影响因子：
3.4
通讯作者：
Kang, Youngnam
中科院分区：
文献类型：
--
作者：
Kobayashi, Masayuki;Hamada, Tomohiro;Kang, Youngnam
由γ-氨基丁酸（GABA）（A）受体介导的抑制性突触传递参与了经验依赖性皮质可塑性的调节。然而，关于其突触前和突触后发育概况的信息很少。本研究旨在研究小鼠桶状皮质中微型和单一抑制性突触后电流（mIPSC 和 uIPSC）的发育变化。从颗粒上锥体神经元记录的 mIPSC 频率在出生后 6-15 天 (PD6-15) 期间逐渐增加，随后在 PD16-20 时显着增加，并且 mIPSC 频率在大约 PD21-30 时达到平台。 mIPSCs 的振幅在 PD10-12 时呈现短暂下降，随后在 PD13-30 期间增加，并在 PD30 左右达到平台。它们的衰减时间常数在出生后的前 30 天内逐渐下降，并在 PD30 左右达到稳定水平。来自中间神经元和突触耦合的目标锥体细胞的配对记录显示，uIPSC 振幅随着年龄的增长而增加，直至 PD30。相反，故障率和变异系数在PD7-15期间下降，并且在后期变化不大。 33 Hz突触前刺激引起的短期抑制在PD6-20期间逐渐减少，并稳定在PD21-30左右。定量分析显示，直到PD30，释放位点的数量随着年龄的增长而增加，而在PD6-12期间释放概率增加，然后达到平台水平。这些结果表明，GABA 和 GABA(A) 介导的 IPSC 动力学的释放位点数量和释放概率显示出不同的发育特征，这可能在调节经验依赖性皮质可塑性关键时期的开始和抵消中发挥作用。
Inhibitory synaptic transmission mediated by gamma-aminobutyric acid (GABA)(A) receptors is involved in regulation of experience-dependent cortical plasticity. However, little information is available on their presynaptic and postsynaptic developmental profiles. The present study aims to investigate the developmental changes of miniature and unitary inhibitory postsynaptic currents (mIPSCs and uIPSCs) in mouse barrel cortex. mIPSCs recorded from supragranular pyramidal neurons showed a gradual increase in frequency during postnatal days 6-15 (PD6-15) followed by a marked increase at PD16-20, and mIPSCs frequency reached a plateau at about PD21-30. The amplitude of mIPSCs showed a transient decrease at PD10-12 followed by an increase during PD13-30, and reached a plateau at about PD30. Their decay time constant progressively decreased during the first 30 days postnatally, and reached a steady level at about PD30. Paired recordings from interneurons and synaptically coupled target pyramidal cells revealed that uIPSC amplitude increased with age up to PD30. In contrast, failure rate and coefficient of variation decreased during PD7-15 and showed little change at a later stage. Short-term depression induced by presynaptic stimulation at 33 Hz progressively decreased during PD6-20, and was stabilized at about PD21-30. Quantal analysis revealed that the number of release sites increased with age up to PD30, while the release probability increased during PD6-12 and then reached a plateau level. These results suggest that the number of release sites and release probability of GABA and GABA(A)-mediated IPSC kinetics show distinct developmental profiles, which could play roles in regulating the onset and offset of critical periods for experience-dependent cortical plasticity.