What is the mechanism of action of bupropion?

Bupropion's mechanism of action primarily involves the inhibition of norepinephrine and dopamine reuptake in the brain. This pharmacological activity increases the availability of these neurotransmitters in the synaptic cleft, which can enhance mood and alleviate symptoms of depression. By specifically targeting norepinephrine and dopamine, bupropion is effective in treating major depressive disorder and is also commonly used as an aid for smoking cessation.

Norepinephrine is associated with attention, arousal, and mood, while dopamine plays a key role in reward and pleasure pathways. The effects of bupropion on these neurotransmitters contribute to improved energy levels, motivation, and overall emotional well-being, which can be particularly beneficial for patients experiencing depression with fatigue or anhedonia (loss of pleasure).

The other mechanisms presented in the options do not accurately reflect how bupropion functions. For instance, it does not primarily involve serotonin, GABA transmission, or monoamine oxidase inhibition, which are typical actions of other antidepressant classes, such as SSRIs, benzodiazepines, or MAO inhibitors. Understanding bupropion's specific action helps guide its appropriate use in clinical practice, making option B the accurate choice.