inhibitory chemical synaptic transmission

Definition

Target type: biologicalprocess

Synaptic transmission that results in an inhibitory postsynaptic potential. [GOC:dos]

Inhibitory chemical synaptic transmission is a fundamental process in the nervous system that reduces the likelihood of a postsynaptic neuron firing an action potential. Here's a detailed breakdown of the process:

1. **Action Potential Arrival:** The process begins with an action potential arriving at the presynaptic terminal of an inhibitory neuron. This action potential triggers the opening of voltage-gated calcium channels at the presynaptic terminal.

2. **Calcium Influx:** The influx of calcium ions (Ca2+) into the presynaptic terminal initiates a cascade of events that leads to the release of neurotransmitters.

3. **Neurotransmitter Release:** Vesicles containing inhibitory neurotransmitters, such as GABA (gamma-aminobutyric acid) or glycine, fuse with the presynaptic membrane and release their contents into the synaptic cleft, the tiny space between the presynaptic and postsynaptic neurons.

4. **Neurotransmitter Binding:** The released neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane. These receptors are typically ligand-gated ion channels.

5. **Postsynaptic Hyperpolarization:** Upon binding to the postsynaptic receptors, inhibitory neurotransmitters trigger the opening of ion channels that allow specific ions to flow across the postsynaptic membrane. In the case of GABA and glycine receptors, these channels are permeable to chloride ions (Cl-) or potassium ions (K+). The influx of negatively charged chloride ions or the efflux of positively charged potassium ions leads to hyperpolarization of the postsynaptic membrane.

6. **Reduced Neuronal Excitability:** Hyperpolarization makes the postsynaptic neuron less likely to fire an action potential. This is because the membrane potential is further away from the threshold required for an action potential to occur.

7. **Neurotransmitter Removal:** After binding to their receptors, inhibitory neurotransmitters are rapidly removed from the synaptic cleft. This removal can occur through several mechanisms, including reuptake by presynaptic transporters or enzymatic degradation by enzymes in the synaptic cleft.

8. **Synaptic Integration:** Inhibitory chemical synaptic transmission plays a crucial role in regulating neuronal activity and shaping the overall output of neural circuits. By reducing the likelihood of postsynaptic neuron firing, inhibitory synapses contribute to a wide range of functions, including controlling muscle movement, regulating sensory input, and modulating cognitive processes.

9. **Importance in Nervous System Function:** Inhibitory chemical synaptic transmission is vital for maintaining balance and stability in the nervous system. Dysregulation of inhibitory transmission can lead to a variety of neurological disorders, such as epilepsy, anxiety, and depression.'
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Proteins (1)

Compounds (8)