Psychology question from AAMC SB

[SSerenity]

According to AAMC:
D is incorrect because, if the receptors were internalized, dopamine could not be pharmacologically active. Neurotransmitters bind to receptors on the outside, not inside, of neurons. This is a Scientific Reasoning and Problem Solving question because it requires the prediction of a scientific outcome.


I don't understand their logic. The logic clearly states that cocaine affects dopamine functionality. If cociane was found to internalize dopamine receptors, then why can't we call that its pharmacological effect?

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[theonlytycrane]

Dopamine binds to receptors on the outside of the cell. If the receptors are internalized (inside the cell), dopamine can't bind and won't be pharmacologically active.

 

[SSerenity]

Dopamine binds to receptors on the outside of the cell. If the receptors are internalized (inside the cell), dopamine can't bind and won't be pharmacologically active.

Thanks for the reply. But you literally just repeated what AAMC said, which does not help.

The question is asking about cocaine being pharmacologically active.
My question is, if internalization of dopamine receptors is an effect that cocaine has (i.e this may be useful in treating schizophrenia), then why can't we call that a pharmacological effect?

 

[hopefulERdoc251]

So pharmacologically active IMO means that the drug must bind to a receptor to cause an effect. In this case, if cocaine is pharmacologically active while it is in the brain, then the cocaine that is in the brain is binding to the dopamine receptors on the neuron. If the receptors are internalized, then cocaine can't bind to anything, and therefore, will not cause an effect on the neuron at the synapse and is inactive (because it can't do anything).

What you are thinking of is receptor downregulation, which is one step further than what the question is asking. How I interpreted the question was "OK so you administer cocaine and if you were to take a snapshot in time at this time when cocaine binds to receptors, what would you see?". If they asked, if you "repeatedly administer cocaine, if you took an image of the brain at that time, what would you see? The answer would be downregulation of "internalization".