What is the mechanism of action of benzodiazepines in seizure control?

• A. They enhance GABA-A receptor activity, increasing inhibitory chloride influx and neuronal inhibition.
• B. They block NMDA receptors.
• C. They inhibit sodium channels.
• D. They antagonize GABA receptors.

Answer: (A)

Benzodiazepines control seizures by boosting the brain’s inhibitory signaling. They are positive allosteric modulators of the GABA-A receptor, binding to a specific site and increasing the receptor’s response to GABA. This raises the likelihood that the chloride channel opens when GABA binds, allowing more chloride ions to enter the neuron, causing hyperpolarization and reduced neuronal excitability. Because their effect depends on GABA being present, they amplify inhibitory signaling rather than directly activating neurons, which makes them effective for acutely stopping seizures. Other mechanisms like blocking NMDA receptors, inhibiting sodium channels, or antagonizing GABA receptors would not explain how benzodiazepines work and would either act differently or reduce inhibition.