在爬纤维-普尔金耶细胞突触处的 postsynaptic 谷氨酸运输
T S Otis1, M P Kavanaugh, C E Jahr
1Vollum Institute, L-474, Oregon Health Sciences University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97201, USA.
概括
后突触谷氨酸转运体在中央突触中清除神经递质方面发挥着关键作用. 这项研究表明,它们对大脑爬纤维突触的信号终止有着显著的贡献.
科学领域:
- 神经科学是一个神经科学.
- 突触传输是突触传输的过程.
- 分子生物学分子生物学
背景情况:
- postsynaptic神经元谷氨酸转运体在中央刺激突触的信号终止中的精确功能仍然不清楚.
- 谷氨酸转运体对于调节神经递质水平和突触功能至关重要.
研究的目的:
- 为了研究后突触谷氨酸转运体在终止大脑皮尔金耶细胞突触信号中的作用.
- 量化这些载体在爬纤维突触中对谷氨酸清除的贡献.
主要方法:
- 刺激爬纤维输入到小脑Purkinje细胞.
- 记录由谷氨酸转运体介导的阳离子电流.
- 使用来自普尔金尼细胞的外外膜贴片与受控的谷氨酸脉冲.
- 将突触传递器电流与Xenopus卵细胞表达的电流进行比较.
主要成果:
- 突触刺激产生了一种由谷氨酸转运体介导的阳离子电流.
- 分析显示,后突触吸收消除了在爬纤维突触中释放的至少22%的谷氨酸.
- 神经元传送器电流是由于众多传送器的同步激活而产生的,其数量超过了激活的AMPA受体.
结论:
- 后突触谷氨酸转运体在中央刺激突触中显著参与谷氨酸清除.
- 这种吸收机制在登纤维突触中对突触信号的终止作出了重大贡献.
- 这项研究提供了对神经元传递器在突触可塑性和功能中的作用的定量见解.
相关概念视频
Excitatory and Inhibitory Effects of Neurotransmitters
When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of specific...
Long-term Potentiation
Long-term potentiation, or LTP, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTP is the process of synaptic strengthening that occurs over time between pre and postsynaptic neuronal connections. The synaptic strengthening of LTP works in opposition to the synaptic weakening of long-term depression (LTD) and together are the main mechanisms that underlie learning and memory.
Hebbian LTP
LTP can occur when presynaptic neurons...
Hebbian LTP
LTP can occur when presynaptic neurons...
Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Integration of Synaptic Events
Synaptic integration mainly includes the summation of graded potentials. Graded potentials, regardless of their type, cause subtle alterations in membrane voltage, resulting in either depolarization or hyperpolarization. These incremental changes, when combined or summed, can propel the neuron toward its threshold. Consider, for example, a membrane experiencing a +15 mV shift, causing it to depolarize from -70 mV to -55 mV. In this scenario, graded potentials govern the membrane's ability to...


