What neurotransmitter is enhanced by benzodiazepines to produce a calming effect?

Benzodiazepines primarily enhance the activity of gamma-aminobutyric acid (GABA), which is the chief inhibitory neurotransmitter in the central nervous system. By binding to specific sites on the GABA-A receptor, benzodiazepines facilitate the opening of ion channels in the neuron membranes, allowing more chloride ions to enter the neuron. This hyperpolarization decreases neuronal excitability, resulting in a calming effect. The increase in GABAergic activity is responsible for the anxiolytic, sedative, and muscle relaxant properties of benzodiazepines, making them effective in treating anxiety disorders, insomnia, and certain types of seizures.

In contrast, while dopamine, norepinephrine, and serotonin play roles in various mood and behavioral regulation, they are not the primary targets of benzodiazepines and do not directly mediate the calming effects that benzodiazepines are known for.