Benzodiazepines exert their effects by binding to which receptor?

• A. NMDA receptors
• B. Dopamine receptors
• C. GABA receptors
• D. Adrenergic receptors

Answer: (C)

Benzodiazepines work by modulating the GABA system. They bind to a specific site on the GABA-A receptor, which is a pentameric ligand-gated chloride channel. When GABA binds to its own site, the channel opens and chloride ions enter the neuron, dampening excitability. Benzodiazepines don’t open the channel by themselves; they are positive allosteric modulators, meaning they increase the frequency of channel openings in response to GABA. This amplifies the inhibitory effect and produces the drug's characteristic calming, anti-anxiety, anticonvulsant, and sedative actions. The other receptors listed—NMDA (glutamate receptor), dopamine receptors, and adrenergic receptors—aren’t the targets of benzodiazepines, which is why the GABA-A receptor is the correct choice.