National Certified Addiction Counselor, Level 2 (NCAC II) Practice Exam Exam

Which neurotransmitter prevents a neuron from sending a message to its target cell?

1. Acetylcholine

2. Dopamine

3. Inhibitory

4. Epinephrine

The correct answer is: Inhibitory

The correct answer focuses on the role of inhibitory neurotransmitters in the communication between neurons. Inhibitory neurotransmitters are essential because they serve to prevent the firing of action potentials in the postsynaptic neuron. This inhibition occurs when these neurotransmitters bind to their receptors, leading to hyperpolarization of the neuron, making it less likely to initiate a new action potential. In contrast, the other options (acetylcholine, dopamine, and epinephrine) typically function as excitatory neurotransmitters or are involved in processes that enhance neuronal communication. For instance, acetylcholine can elicit both excitatory and inhibitory effects depending on the type of receptor it binds to, while dopamine and epinephrine are primarily considered excitatory neurotransmitters associated with motivation, mood regulation, and the fight-or-flight response. Thus, the role of inhibitory neurotransmitters is crucial in maintaining the balance between excitation and inhibition within the nervous system, helping to regulate various functions like muscle contraction, mood, and the overall excitability of neuronal circuits.