National Certified Addiction Counselor, Level I (NCAC I) Practice Exam

What neurotransmitter's activity is increased by barbiturates?

1. Dopamine

2. Serotonin

3. Norepinephrine

4. GABA

The correct answer is: GABA

Barbiturates primarily enhance the activity of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter in the central nervous system. They bind to the GABA_A receptor, increasing the duration that the chloride channel remains open when GABA is present. This leads to greater inhibitory effects on neuronal excitability, resulting in sedation, relaxation, and anxiolytic effects. In contrast, other neurotransmitters like dopamine, serotonin, and norepinephrine have different roles and interactions in the brain that are not primarily enhanced by barbiturates. For instance, dopamine is largely associated with mood regulation and reward-seeking behaviors, serotonin is involved in mood and anxiety regulation, and norepinephrine mainly impacts attention and responding actions. Therefore, while barbiturates may have complex interactions with various neurotransmitter systems, their most significant action is to enhance GABA's inhibitory activity, making it the correct choice in this context.