Fluoxetine (Prozace6) has been shown to reduce depression primarily by which of the following mechanisms?

• A. Enhancing the reuptake of norepinephrine
• B. Increasing the availability of serotonin in the synaptic cleft
• C. Blocking dopamine receptors in the brain
• D. Inhibiting the release of gamma-aminobutyric acid (GABA)

Answer: (B)

Verified step by step guidance

1. Understand that Fluoxetine (Prozac) is classified as a selective serotonin reuptake inhibitor (SSRI), which means it primarily affects serotonin neurotransmission.
2. Recall that serotonin is a neurotransmitter involved in mood regulation, and increasing its availability in the synaptic cleft can help alleviate symptoms of depression.
3. Recognize that SSRIs work by blocking the reuptake (reabsorption) of serotonin into the presynaptic neuron, thereby increasing the amount of serotonin available to bind to postsynaptic receptors.
4. Eliminate options that do not align with the mechanism of SSRIs: enhancing norepinephrine reuptake, blocking dopamine receptors, or inhibiting GABA release, as these are not the primary actions of Fluoxetine.
5. Conclude that the correct mechanism is increasing the availability of serotonin in the synaptic cleft by inhibiting its reuptake.