GABA Receptor

The GABA receptor is an inhibitory receptor because it functions as a ligand-gated chloride ion channel.
When GABA binds to its receptor, it permits chloride ions ( $Cl^-$ ) to enter the cell.
As chloride ions are negatively charged, their influx causes the neuron to become hyperpolarized.
Hyperpolarization makes it more difficult for the neuron to generate an action potential.
- The neuron needs to have a lot more positive charges come in to reach the threshold.
- Thus, GABA receptors inhibit neuron activity by making it harder to generate action potentials.

Benzodiazepines, such as Valium, enhance the effects of GABA on its receptor.
This enhancement leads to a greater influx of chloride ions, increasing the inhibitory effect.
The tranquilizing effects of benzodiazepines are mediated through the GABA receptor.

The GABA receptor is considered to have a genetic component related to alcoholism.
Some individuals with alcoholism have a mutation in their GABA receptor, reducing the receptor's response to alcohol.
This mutation allows them to tolerate higher amounts of alcohol and still function relatively normally compared to individuals without the mutation.
The reduced sensitivity to alcohol allows them to build up a tolerance, requiring increasingly higher doses to achieve the same effects.
This tolerance contributes to the development of addiction.
Alcoholics with this mutation may have very high blood alcohol levels (e.g., 25%) and still maintain functionality.
In most people, alcohol induces effects like slurred speech and impaired walking due to signaling through the GABA receptor.
However, in individuals with the GABA receptor mutation, these effects manifest only at extremely high alcohol doses.