Antidepressant which is a Presynaptic a-2 receptor blocker which enhance secretion of both norepinephrine and serotonine ?
**Core Concept**
Mirtazapine (not Miazapine, a common typo) is a unique antidepressant that acts as a presynaptic α2 receptor antagonist. This action increases the release of both norepinephrine and serotonin from their respective nerve terminals, thereby enhancing their neurotransmission in the brain.
**Why the Correct Answer is Right**
Mirtazapine's mechanism of action involves blocking the presynaptic α2 receptors, which are inhibitory autoreceptors on the nerve terminals. By blocking these receptors, mirtazapine reduces the negative feedback inhibition of norepinephrine and serotonin release, leading to an increase in the secretion of both neurotransmitters. This dual action is thought to contribute to its antidepressant effects.
**Why Each Wrong Option is Incorrect**
**Option A:** Trazodone is a serotonin antagonist and reuptake inhibitor (SARI), which primarily acts by increasing serotonin levels. It does not have significant presynaptic α2 receptor blocking activity.
**Option C:** Mianserine is a tetracyclic antidepressant that acts as a serotonin antagonist and reuptake inhibitor (SARI), similar to trazodone. It does not have significant presynaptic α2 receptor blocking activity.
**Option D:** Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI) that primarily acts by increasing norepinephrine and dopamine levels. It does not have significant presynaptic α2 receptor blocking activity.
**Clinical Pearl / High-Yield Fact**
Mirtazapine is known for its unique sedative and anxiolytic properties, making it a good option for patients with anxiety-related depression. Its sedative effects are thought to be due to its antagonism of central histamine H1 receptors.
**✓ Correct Answer: B. Mirtazapine**