Question

question 13
1 pts
scenario: a patient with schizophrenia is started on a dopamine d2 receptor antagonist. they develop parkinsonian symptoms.
question: what is the most likely cause of these symptoms?
excessive dopamine activity.
dopamine receptor blockade in the nigrostriatal pathway.
serotonin receptor blockade.
glutamate receptor blockade.

Explanation:

1. Analyze Option 1: Excessive dopamine activity is opposite to what a D2 antagonist does (it blocks dopamine, so activity would be reduced, not excessive). Eliminate this.
2. Analyze Option 2: The nigrostriatal pathway is involved in motor control. Dopamine D2 receptor antagonists block dopamine here, leading to reduced dopamine function, which can cause parkinsonian symptoms (similar to Parkinson's disease, where nigrostriatal dopamine is low). This matches the scenario.
3. Analyze Option 3: Serotonin receptor blockade is not directly related to parkinsonian symptoms from dopamine D2 antagonism. Eliminate.
4. Analyze Option 4: Glutamate receptor blockade is not the cause here, as the drug is a dopamine D2 antagonist. Eliminate.

Answer:

B. Dopamine receptor blockade in the nigrostriatal pathway.