Many drugs produce their effects by facilitating or interfering with neurotransmitters at synapses. Which of the following drugs would most likely increase the effect of serotonin? A)a drug that binds to directly coupled serotonin receptors but does not change membrane permeability to ions B)a drug that prevents the activity of an enzyme that breaks down serotonin molecules in the synaptic cleft C)a drug that blocks the effect of Ca²⁺ ions D)a drug that blocks the effect of a conditional neurotransmitter that normally facilitates the effect of serotonin

Question

Quizplus · Accepted Answer

If a drug prevents the breakdown of serotonin molecules in the synaptic cleft, then the concentration of serotonin in the synaptic cleft will increase, leading to increased activation of serotonin receptors and increased serotonin effects. Therefore, option B is the correct answer. Option A describes a drug that binds to serotonin receptors without affecting membrane permeability to ions and may or may not increase serotonin effects. Option C describes a drug blocking the effect of Ca2+ and IP3 ions, which are not directly related to serotonin effects. Option D describes a drug blocking the effect of a conditional neurotransmitter, which may or may not affect serotonin effects depending on the specific neurotransmitter and pathway involved.

Many Drugs Produce Their Effects by Facilitating or Interfering with Neurotransmitters