GABA-ergic synapse

Definition

Target type: cellularcomponent

A synapse that uses GABA as a neurotransmitter. These synapses are typically inhibitory. [GOC:dos]

GABAergic synapses are specialized junctions between neurons that utilize the neurotransmitter GABA (gamma-aminobutyric acid) for signal transmission. These synapses play a crucial role in regulating neuronal activity, inhibiting excitatory signals, and maintaining proper brain function. The cellular component of a GABAergic synapse comprises several key structures, including:

**Presynaptic Terminal:**
* **Presynaptic Vesicles:** These spherical structures are filled with GABA molecules, the neurotransmitter responsible for inhibitory signaling. They are clustered near the presynaptic membrane, ready to be released into the synaptic cleft.
* **Active Zones:** Specialized regions on the presynaptic membrane where synaptic vesicles dock and fuse, allowing for the release of GABA into the synaptic cleft.
* **Calcium Channels:** Voltage-gated calcium channels located near the active zones. When an action potential arrives at the presynaptic terminal, it triggers the opening of these channels, leading to a rapid influx of calcium ions.
* **Synaptic Proteins:** A variety of proteins that regulate the formation, trafficking, and release of synaptic vesicles. These include SNARE proteins, which mediate vesicle fusion, and synapsins, which tether vesicles to the cytoskeleton.

**Synaptic Cleft:**
* **Extracellular Matrix:** A specialized extracellular space that separates the presynaptic and postsynaptic membranes. It contains various molecules, including proteins, carbohydrates, and lipids, that contribute to the structure and function of the synapse.
* **Neurotransmitter Receptors:** Located on the postsynaptic membrane, these receptors bind to GABA, initiating a signaling cascade that modulates neuronal activity.

**Postsynaptic Terminal:**
* **Postsynaptic Density (PSD):** A dense protein scaffold located directly opposite the active zone on the postsynaptic membrane. It contains a diverse array of proteins involved in signal transduction, including GABA receptors, scaffolding proteins, and signaling molecules.
* **GABA Receptors:** These transmembrane proteins are responsible for mediating the inhibitory effects of GABA. There are two major types of GABA receptors: GABA-A receptors, which are ionotropic and allow chloride ions to enter the postsynaptic neuron, and GABA-B receptors, which are metabotropic and activate intracellular signaling pathways.

The interplay of these cellular components ensures the efficient transmission of GABAergic signals. The arrival of an action potential at the presynaptic terminal triggers the release of GABA into the synaptic cleft, where it binds to postsynaptic receptors, leading to the inhibition of neuronal activity. These synapses are essential for regulating brain function, maintaining neuronal balance, and mediating a wide range of cognitive processes, including learning, memory, and behavior.
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Proteins (30)

Compounds (893)