What GABA Receptors Are Responsible for Calming?

GABA, or gamma-aminobutyric acid, is the main inhibitory chemical which passes signals along the nerve cell. Studies have shown that alterations in the level of GABA in the brain are linked to anxiety. GABA has three receptors, GABA-A, GABA-B and GABA-C, which allow GABA to achieve its biological action.

Anxiety

• The normal response to stress is anxiety, allowing an individual to manage. However, when anxiety becomes excessive and impacts on everyday life it becomes a disorder. Kessler and colleagues in 2005 and published a study in "Archives of General Psychiatry" that showed that in a 12-month period 18.1 percent of the population in the United States suffered from an anxiety disorder. A number of treatments are available to improve anxiety, including drugs and therapy.

GABA Receptors

• GABA-A and GABA-C receptors are ionotrophic receptors, which are ion channels. Ionotrophic receptors are either open or closed depending on whether the chemical messenger, GABA, is available. A GABA-B receptor is a metabotrophic receptor which, when activated, sets up a signaling process within the cell.

GABA-A Receptor

• GABA-A receptor regulates the excitability of the nerve cell and rapid changes can result in anxiety and panic attacks. Binding of GABA opens the channel and makes the nerve cell, neuron, less prone to excitation. This receptor has a secondary binding site for molecules which modulate the GABA effect. They alter the receptor by a change in the protein architecture, and this modifies the size of the ion channel. Modulators include alcohol, benzodiazepines and steroids.

Progesterone and GABA

• Progesterone is known to alter mood, by causing negative moods. The breakdown products of progesterone bind to the GABAA receptor and acts like benzodiazepines. However, in animal studies progesterone treatment can induce anxiety which is related to an increase in a subunit of the receptor. Studies show that GABA-A receptor agonists can cause anxiety, irritability and aggression. This happens in low doses of medications, including the breakdown products of progesterone.