Which of the following is an example of an inhibitory neurotransmitter?

Gamma-aminobutyric acid (GABA) is recognized as the primary inhibitory neurotransmitter in the central nervous system. Its main function is to reduce neuronal excitability throughout the nervous system. When GABA binds to its receptors on neurons, it typically results in an influx of chloride ions or an efflux of potassium ions, leading to hyperpolarization of the neuron. This makes it less likely to fire and reduces overall activity in the brain, which is crucial for regulating anxiety, muscle tone, and overall brain excitability.

In contrast, dopamine, serotonin, and norepinephrine are primarily associated with excitatory effects or modulating norepinephrine's excitatory or inhibitory actions depending on the context. These neurotransmitters play significant roles in various functions, such as mood regulation and arousal, but do not predominantly function to inhibit neural activity like GABA does.