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How does mirtazapine primarily function as an antidepressant?
Serotonin reuptake inhibition
NE reuptake inhibition
α2 Adrenergic receptor antagonism
Partial dopamine antagonism
The correct answer is: α2 Adrenergic receptor antagonism
Mirtazapine primarily functions as an antidepressant through its action as an alpha-2 adrenergic receptor antagonist. This mechanism enhances norepinephrine and serotonin neurotransmission by blocking presynaptic alpha-2 receptors, which normally inhibit the release of these neurotransmitters. By antagonizing these receptors, mirtazapine increases the availability of norepinephrine and serotonin in the synaptic cleft, which is believed to contribute to its antidepressant effects. In addition to its action on alpha-2 receptors, mirtazapine also antagonizes specific serotonin receptors (specifically 5-HT2 and 5-HT3), further balancing the serotonergic system. This unique dual action is what differentiates it from other traditional antidepressants, as it can produce fewer side effects associated with increased serotonin levels, such as anxiety or gastrointestinal issues. The other mechanisms mentioned in the other options are not the primary actions of mirtazapine. For example, serotonin reuptake inhibition and norepinephrine reuptake inhibition are more characteristic of other classes of antidepressants, such as SSRIs and SNRIs, respectively. Partial dopamine antagonism is more relevant to atypical antipsychotic medications than to mirtaz