The mechanism of action of haloperidol is the blockage of
**Core Concept**
Haloperidol is a typical antipsychotic medication primarily used to treat schizophrenia and other psychoses. Its mechanism of action involves modulating neurotransmitter systems in the brain, specifically targeting dopamine receptors.
**Why the Correct Answer is Right**
Haloperidol exerts its therapeutic effects by blocking dopamine D2 receptors in the mesolimbic pathway, which is involved in the regulation of emotions and cognition. This blockade reduces the positive symptoms of schizophrenia, such as hallucinations and delusions. Additionally, haloperidol's blockade of dopamine D2 receptors in the nigrostriatal pathway contributes to its extrapyramidal side effects, including dystonia and parkinsonism.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because haloperidol's primary mechanism of action is not the blockage of serotonin receptors. While serotonin receptors are involved in the pathophysiology of schizophrenia, haloperidol's selective blockade of dopamine D2 receptors is its primary therapeutic effect.
**Option B:** This option is incorrect because haloperidol is not an NMDA receptor antagonist. NMDA receptor antagonists, such as ketamine and phencyclidine, produce distinct pharmacological effects that are different from those of haloperidol.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the blockade of dopamine D2 receptors in the nigrostriatal pathway by haloperidol contributes to its extrapyramidal side effects, which can be mitigated with anticholinergic medications or benzodiazepines.
**Correct Answer:** C.