GABA-A is a type of receptor in the brain that responds to the neurotransmitter GABA (gamma-aminobutyric acid). It plays a crucial role in inhibiting nerve activity, helping to regulate anxiety, mood, and sleep. When GABA binds to the GABA-A receptor, it opens channels that allow negatively charged ions to enter the neuron, making it less likely to fire. These receptors are important targets for various medications, including benzodiazepines and barbiturates, which enhance the effects of GABA. By increasing inhibition in the brain, these drugs can help treat conditions like anxiety disorders and epilepsy, promoting relaxation and reducing seizures.