Which neurotransmitter is the major inhibitory transmitter in the CNS?

Which neurotransmitter is the major inhibitory transmitter in the CNS?

• A. GABA
• B. Glutamate
• C. Dopamine
• D. Serotonin

Answer: (A)

The brain relies on a balance between excitation and inhibition to regulate neuron activity, and the major inhibitory transmitter in the CNS is GABA. It dampens neuronal firing by opening chloride channels (GABA-A), which hyperpolarizes the cell and makes it harder for neurons to fire. GABA-B receptors further suppress excitability by opening potassium channels and reducing calcium influx. This broad inhibition helps prevent overexcitation, stabilizes neural networks, and underpins functions like controlling anxiety, muscle tone, and preventing seizures. Glutamate is the main excitatory transmitter, promoting depolarization through NMDA and other receptors. Dopamine and serotonin modulate many pathways but are not the primary inhibitory system. Clinically, boosting GABAergic signaling provides anticonvulsant and sedative effects.

The brain relies on a balance between excitation and inhibition to regulate neuron activity, and the major inhibitory transmitter in the CNS is GABA. It dampens neuronal firing by opening chloride channels (GABA-A), which hyperpolarizes the cell and makes it harder for neurons to fire. GABA-B receptors further suppress excitability by opening potassium channels and reducing calcium influx. This broad inhibition helps prevent overexcitation, stabilizes neural networks, and underpins functions like controlling anxiety, muscle tone, and preventing seizures. Glutamate is the main excitatory transmitter, promoting depolarization through NMDA and other receptors. Dopamine and serotonin modulate many pathways but are not the primary inhibitory system. Clinically, boosting GABAergic signaling provides anticonvulsant and sedative effects.