- In the central nervous system (CNS), neurons that release gamma-aminobutyric acid (GABA) are primarily responsible for mediating inhibitory signals.
- GABA is the main inhibitory neurotransmitter, which functions to reduce neuronal excitability and prevent overstimulation.
- This inhibitory action is crucial for maintaining the balance between excitation and inhibition, thereby ensuring proper neural circuit function and preventing conditions such as seizures.

- In contrast, cholinergic neurons release acetylcholine and are mainly involved in excitatory signaling and modulation, especially in the peripheral nervous system and regions like the neuromuscular junction.
- Glutamatergic neurons release glutamate, the principal excitatory neurotransmitter in the CNS, which promotes neuronal activation.
- Dopaminergic neurons release dopamine, which primarily acts as a modulatory neurotransmitter involved in reward, motivation, and motor control.

Therefore, the dominant mediator of inhibition within the CNS is GABAergic neurons due to their release of the inhibitory neurotransmitter GABA.

Reference: Principles of Neural Science, 5th Edition, Chapter 4, Page 130