Measurement of Dopamine levels in vivo

[solumanculver]

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Is there a method to measure the dopamine levels in a living persons brain? I didn't think that there was, but I did a google search and now I'm not really sure. I didn't devote too much time to the search, since I'm not really an expert at reading neuroscience journal articles, but I thought I would ask you guys.

It seems like such a test would show schizophrenics to have an abundance in some region and a deficit in another region... but my sources on this type of thing might be a bit dated. Is that how it's supposed to work?

If there isn't such a test, then what is the major stumbling block?

 

[manwhoisthursdy]

Is there a method to measure the dopamine levels in a living persons brain? I didn't think that there was, but I did a google search and now I'm not really sure. I didn't devote too much time to the search, since I'm not really an expert at reading neuroscience journal articles, but I thought I would ask you guys.

It seems like such a test would show schizophrenics to have an abundance in some region and a deficit in another region... but my sources on this type of thing might be a bit dated. Is that how it's supposed to work?

If there isn't such a test, then what is the major stumbling block?

How would you test it? You can't really do a blood test, because that will only tell you about dopamine in the blood. What you could theoretically do is on brain imaging, look at the structures that we know, from basic research, to contain dopaminergic cells/tracts. Abnormality may be related to dopamine level in some way.

Neurotransmitter theories of mental illness are, IMHO, very simplistic however, and largely inferred from the fact that certain drugs that affect neurotransmitters have psychiatric effects. Really the pathology is probably more complex, involving not just the levels of neurotransmitters but also the amount of receptors, the genetic variants of receptors and their distribution, modifications to those receptors, neuronal circuitry involving the relevant neurons, hypertrophy/hyperplasia and atrophy of certain structures involving the relevant neurons, etc etc etc.

 

[solumanculver]

Hi,
I think you're right that neurotransmitter theories of mental illness are simplistic. But neurotransmitter theories of mental symptoms seems right on the money. Of course schizophrenia isn't primarily a disorder of dopamine... but psychosis is intimately linked to dopamine.

Yeah, blood test is no good, has to be imaging. I think you could do it with radioactive L-Dopa and MRI... Well that's my idea, but it has problems I guess.

Is your point that dopamine levels would probably be the same in schizophrenics and non-schizophrenics alike, that the dopamine receptor might be the thing that varies? That's possible... Well I'd like to know. I think that there is some data on this, though, isn't there? Maybe from post mortem analysis...?

 

[nitemagi]

There's actually data on dopamine receptor abnormalities and expression in peripheral leukocytes of schizophrenics, and possibly in family members of schizophrenics. Could be a screening technique down the road if more research is done.

 

[Anasazi23]

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1471-4159.1983.tb00893.x

http://www.sciencemag.org/cgi/content/abstract/221/4617/1264

 

[whopper]

Good old evidence based medicine eh Anasazi?

Slightly off topic, but when I was in college, taking some neuropharm classes, the methods of how NTs were measured were mentioned. Its been over 10years, and I'm sure I'm not remembering everything 100% correctly.

Some of the very interesting studies chemically linked gold atoms to neurotransmitter or NT analogs to bind to receptors so receptors could be located in the brain (gold shows up on radiological scans, NTs don't). Others involved studying amounts in CSF.

Unfortunately not a topic we often hit in our clinical practice but one that is very important since we should know the foundations of why we know what we know.