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Ionic Mechanism of Postsynaptic Inhibition.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Eccles, John C. |
| Copyright Year | 1964 |
| Abstract | The body and dendrites of a nerve cell are specialized for the reception and integration of information which is conveyed as impulses that are fired from other nerve cells along their axons. In this diagrammatic drawing of a nerve cell (Fig. 1A) it is seen that impinging on its surface are numerous small knob-like endings or t h e fibres which are, in fact, the terminal branches of axons from other nerve cells. Communication between nerve cells occurs at these numerous areas of close contact or synapses, the name first applied to them by Sherrington, who laid the foundations of what is often called synaptology. We owe to Dale and Loewi the concept that transmission across synapses is effected by the secretion of minute amounts of specific chemical substances that act across the synapse. The cable-like transmission of impulses over the surfaces of nerve cells and their axons ceases abruptly at the synaptic contact between cells, but may begin again on the other side of the synapse. The high resolving power of electron-microscopy gives essential information on those structural features of synapses that are specially concerned with this chemical phase oftransmission. For example in Fig. 1B, C, we can see the membrane, about 70 Å thick, that encloses the expanded axonal terminal or synaptic knob. These knobs contain numerous small vesicular structures, the synaptic vesicles that are believed to be packages of the specific chemical substances concerned in synaptic transmission. Some of these vesicles are concentrated in zones on the membrane that fronts the synaptic cleft, which is the remarkably uniform space about 200 Å across, that is indicated by arrows in Fig. 1B. The chemical transmitter substance is released from the synaptic knob into the cleft and acts on the subsynaptic membrane. Since synaptic transmission has to occur across the synaptic cleft that is interposed between the presynaptic and postsynaptic components of the synapse, it might appear that the synaptic cleft is merely a barrier to transmission; but we shall see later that it must not be too narrow else it will unduly impede the flow of the postsynaptic electric currents that provide the essential expression of synaptic actions of all kinds. In its dimensional design the synaptic cleft approaches to optimal efficiency. The experimental investigation ofsynaptic transmission was transformed 6,7 |
| Starting Page | 767 |
| Ending Page | 771 |
| Page Count | 5 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://neurosci.info/courses/systems/Cortex/ecclesnp.pdf |
| Alternate Webpage(s) | http://neurosciences.us/courses/systems/Cortex/ecclesnp.pdf |
| PubMed reference number | 14173402v1 |
| Volume Number | 145 |
| Issue Number | 3637 |
| Journal | Science |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Axon Concentrate Dosage Form Control knob Dendrites Diagram Dirac delta function Electron Foundations Fractal dimension Ionic Knob Device Component Neuron Neurons SyNAPSE Synapses Synaptic Transmission Synaptic Vesicles Synaptic cleft Tissue membrane Transmitter Device Component Vesicle (morphologic abnormality) Xfig |
| Content Type | Text |
| Resource Type | Article |
