Benzodiazepines exert their sedative effect by enhancing the activity of GABA receptors, specifically the GABA-A subtype. They bind to a specific site on the receptor complex, increasing the affinity of GABA for its receptor. This action leads to an increase in chloride ion influx into neurons, causing hyperpolarization and decreased neuronal excitability. The result is a calming effect on the central nervous system, producing sedation, anxiolysis, muscle relaxation, and anticonvulsant effects. This mechanism is central to their clinical use in anxiety, insomnia, and seizure management.

Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.