The primary inhibitory neurotransmitter in the nervous system is

The primary inhibitory neurotransmitter in the nervous system is

• A. GABA
• B. Glutamate
• C. Acetylcholine
• D. Norepinephrine

Answer: (A)

Inhibitory signaling in the brain is largely governed by gamma-aminobutyric acid (GABA). When GABA binds to its receptors, it typically opens channels that let negatively charged chloride ions into the neuron or activates pathways that make the neuron more negatively charged. This hyperpolarizes the cell, making it less likely to fire an action potential and thus dampening neural activity. This broad, brain-wide inhibition is essential for regulating excitability, controlling movements, reducing anxiety, and supporting sleep-wake balance. Glutamate, in contrast, is the main excitatory neurotransmitter that increases neuronal firing. Acetylcholine is involved in muscle activation and various brain functions, and norepinephrine modulates arousal and attention. None of these provide the widespread inhibitory effect that GABA does, which is why GABA is the primary inhibitory neurotransmitter.

Inhibitory signaling in the brain is largely governed by gamma-aminobutyric acid (GABA). When GABA binds to its receptors, it typically opens channels that let negatively charged chloride ions into the neuron or activates pathways that make the neuron more negatively charged. This hyperpolarizes the cell, making it less likely to fire an action potential and thus dampening neural activity. This broad, brain-wide inhibition is essential for regulating excitability, controlling movements, reducing anxiety, and supporting sleep-wake balance.

Glutamate, in contrast, is the main excitatory neurotransmitter that increases neuronal firing. Acetylcholine is involved in muscle activation and various brain functions, and norepinephrine modulates arousal and attention. None of these provide the widespread inhibitory effect that GABA does, which is why GABA is the primary inhibitory neurotransmitter.