COMAT Psychiatry Practice Test

Benzodiazepines enhance the activity of the neurotransmitter gamma-aminobutyric acid (GABA) by increasing the frequency of chloride (Cl-) channel opening in the GABA-A receptor complex. When GABA binds to its receptor, it typically induces a conformational change that opens the associated chloride channel, allowing Cl- ions to flow into the neuron. Benzodiazepines do not directly activate these receptors but rather modulate them by increasing the rate at which the chloride channels open upon GABA binding.

This increase in chloride influx leads to a hyperpolarization of the neuron, making it less likely to fire and thus exerting an overall calming or anxiolytic effect. This mechanism is why benzodiazepines are commonly prescribed for anxiety and panic disorders, as they enhance GABA's inhibitory effect on neuronal excitability.

The other options do not accurately describe the role of benzodiazepines in the context of GABA activity. For instance, decreasing the duration of Cl- channel opening would have the opposite effect of what benzodiazepines actually do. Blocking GABA receptors would inhibit their function entirely, which is not the action of benzodiazepines. Lastly, activating NMDA receptors would be unrelated to the action of benz