GABA A receptor, short for gamma-aminobutyric acid type A receptor, is a type of ionotropic receptor within the central nervous system (CNS). It is a protein complex that responds to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The GABA A receptor plays a critical role in regulating neuronal excitability, maintaining the balance between excitation and inhibition in the brain.
In its most common form, the GABA A receptor consists of five subunits that come together to form a functioning receptor. There are multiple subunit types, including alpha, beta, gamma, delta, epsilon, theta, and pi, which form diverse receptor combinations throughout the CNS. These receptor combinations have varying affinities for GABA and influence the receptor's overall function.
When GABA, the primary inhibitory neurotransmitter in the brain, binds to the GABA A receptor, it triggers the opening of an ion channel. This allows negatively charged chloride ions to flow into the neuron, leading to hyperpolarization, calming the activity of the cell. Consequently, GABA A receptors are heavily involved in regulating anxiety, sedation, muscle relaxation, and motor coordination.
The GABA A receptor is the primary target of several important drugs, including benzodiazepines, barbiturates, and certain anesthetics. These substances work by enhancing the receptor's response to GABA, increasing its inhibitory effects and producing sedative, anxiolytic, and hypnotic effects.
Overall, the GABA A receptor is a vital component of the brain's inhibitory system, helping to control neuronal excitability and maintain balance within the CNS.
