在单个海马突触突触节点的突触传播的特性
1Department of Molecular and Cellular Physiology, Stanford University Medical Center, California 94305, USA.
Nature
|June 1, 1995
概括
研究人员在培养的海马神经元中研究了单个突触前神经元,揭示了突触囊泡池如何补充和突触电流幅度的变化. 这项工作揭示了神经元通信中突触强度的协调.
科学领域:
- 神经科学是一个神经科学.
- 细胞生物学 细胞生物学
背景情况:
- 突触传输对于中枢神经系统 (CNS) 神经元通信至关重要.
- 在单个突触前开关水平上理解神经传递是有限的.
研究的目的:
- 在培养的海马神经元中表征单个前突触突起的功能性质.
- 研究在单突触水平上唤起的神经传递和突触强度调节.
主要方法:
- 引起的刺激后突触电流 (e.p.s.c) 是通过局部K+/Ca2+应用于单个突触引发的.
- 使用重要染料FM1-43.3识别了扣子.
- 重复刺激评估了囊泡池动态和恢复.
主要成果:
- 重复刺激耗尽了可释放的囊泡,恢复时间约为40秒.
- 一个单个囊泡池可以支持大约90个e.p.s.c.没有回收.
- 突触电流的幅度有所不同,但在单个神经元上的突触中显示出类似的分布.
- 平均突触电流大小在细胞之间有所不同,并且随着突触内置的密度增加而减少.
结论:
- 个别的前突触点在囊泡释放和回收方面表现出不同的功能特征.
- 突触强度调节机制可以协调神经元上多个突触之间的活动.
- 这些发现表明,平衡突触输入密度的潜在恒常机制.
相关概念视频
The Synapse
Neurons communicate with one another by passing on their electrical signals to other neurons. A synapse is the location where two neurons meet to exchange signals. At the synapse, the neuron that sends the signal is called the presynaptic cell, while the neuron that receives the message is called the postsynaptic cell. Note that most neurons can be both presynaptic and postsynaptic, as they both transmit and receive information.
Synaptic Signaling
Neurons communicate at synapses, or junctions, to excite or inhibit the activity of other neurons or target cells, such as muscles. Synapses may be chemical or electrical.
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
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...
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...
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...


