GABARs

GABARs, or Gamma-aminobutyric acid receptors, are a group of ionotropic and metabotropic receptors found in the central nervous system of vertebrates. They are the primary mediators of inhibitory neurotransmission in the brain, meaning they decrease the excitability of neurons. The main inhibitory neurotransmitter that binds to GABARs is gamma-aminobutyric acid (GABA).

There are two main types of GABARs: GABAA receptors and GABAB receptors. GABAA receptors are ligand-gated ion channels. When GABA binds to a GABAA receptor, it causes a channel to open, allowing chloride ions to flow into the neuron. This influx of negative charge hyperpolarizes the neuron, making it less likely to fire an action potential. GABAA receptors are complex proteins composed of five subunits, with many different subunit types contributing to their diverse properties and functions.

GABAB receptors are G protein-coupled receptors, a type of metabotropic receptor. When GABA binds to a GABAB receptor, it initiates a signaling cascade that can indirectly affect ion channels, typically by opening potassium channels and closing calcium channels. This also leads to neuronal inhibition, but through a slower and more prolonged mechanism than GABAA receptors. GABAB receptors are usually formed by two different subunits, GABAB1 and GABAB2.

Dysfunction of GABARs is implicated in a variety of neurological and psychiatric disorders, including epilepsy, anxiety disorders, depression, and schizophrenia. Many therapeutic drugs, such as benzodiazepines and barbiturates, exert their effects by modulating GABAA receptor activity. Research into GABARs continues to be a significant area of neuroscience, aiming to understand their roles in normal brain function and to develop more effective treatments for associated conditions.

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