Dopamine

Dopamine

by Tobias on May 31, 2010

I am doing a lot of research on the brain, stress, depression, etc. Many things point back to dopamine.

I have been reading and watching lectures and documents about brain chemistry.  Lately I have been running into many that discuss how dopamine is a key element in happiness, reward, etc. mechanics in the brain.  Seeing charts descriping how dopamine levels in the brain reinforce data got me thinking:

How can I test myself for dopamine levels?

As far as I can tell, the only solution is trepanation. Sadly, I don’t think this is a way to go.

If there is a viable way to accurately and safely test for dopamine levels, then shouldn’t we be actively integrating this into our mental health care system?

If you or someone you know has more information about the research involved in collecting dopamine data on human subjects, please enlighten me.

{ 7 comments… read them below or add one }

john adams May 31, 2010 at 4:13 am

You can get this from a urine test for catecholamines.

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Tobias May 31, 2010 at 4:22 am

My understanding is that urine tests only test for levels in the blood stream and do not directly reflect the amount that make to the neurons. i.e., It is a test that can give you a few hints, but not a direct correlation to what is going on inside the brain.

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Tbias May 31, 2010 at 11:30 am

In addition, if there is an easy and viable urine test, then why are people not tested prior, during and after antidepressant administration?

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Colin May 31, 2010 at 11:26 am

You can test dopamine activity via Eye Blink Rate (EBR). It's used as a measure in Parkinson's (low blink rate indicating low dopamine disfunction) and high blink rate has been connected with schizophrenia, and when the blink rate is high but not too high it correlates to creativity. Also low blink rate has been connected with cocaine drug withdrawl. And then there is ADHD which has a complicated relationship.

You seem to be mostly interested in dopamine's relationship to depression. There is no direct correlation between EBR and depression though there is an interesting study with sleep deprivation, depression, and EBR. The study showed a correlation between heightened EBR and the mood uplift in depressed individuals following with sleep deprivation, which did not occur in controls. This indicates that there is heightened dopamine activity happening; however, we don't know if the dopamine is the cause of this mood uplift or if there is a third factor which is triggering both the dopamine activity and the mood uplift.

In any case, depression is a complicated beast. Dopamine activity certainly plays a roll as does serotonin activity and norepinephrine, but what a lot of depression researchers are looking at these days is the relation to stress: specifically the damage extended cortisol release does to the hippocampus and the related reduction in neurogenesis. There is evidence that tricyclic anti-depressants up-regulates the expression of glucocorticoid receptor which helps regulate the levels of cortisol. SSRIs don't on the other hand, but there is evidence that SSRIs somehow positively effect neurogenesis. Not sure where DRIs like wellbutrin fit into this.

You'll notice that I mentioned "dopamine activity" rather than "dopamine levels." It's a mistake to think of depression, schizophrenia, etc as a "chemical imbalance" as if everything would be better if only I had the right amount of neurotransmitters pumping around in there. The neurons ability to produce and properly regulate the amount of neurotransmitters through transmission and reuptake is only part of the equation. On the other side of the synapse are the receptors for these neurotransmitters. If these transmitters are not working properly or there aren't the correct number of them this also causes changes to the activity of the system as a whole.

There is also a difference between tonic dopamine levels (the baseline low level amount of dopamine floating around) and phasic dopamine (the bursts of dopamine that correlate with learning/reward/motivation). Further complicating matters is the difference between the phasic release of dopamine prior to an award and the release after the award. The difference between these two levels is potentially what creates learned responses—if the reward is higher than the what it was assumed to be prior than it encourages you to do it again.

So yeah complicated. Though as neurotransmitters go the dopamine system is the most understood. Unlike serotonin which is an even more complicated beast.

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A. Tobias Tenney June 1, 2010 at 4:57 pm

One problem I have is that the test you site is EBR. It would seem to me that this is test when you haven't been able to find a way to do actual scientific data collection. Eye blinking is not a metabolic behavior uncontrolled by any conscious brain activity. To base a slew of scientific resolution on such a study is mildly disingenuous. The study you reference even states a "possible relationship," instead of a "direct relationship".

I am not saying that your argument has no merit. Instead I suggest that these findings should be added as potentially empirical data rather than dogmatic scientific findings.

The problem is that there are far too many pathways that lead to the blinking of eyes; If eye blinking was caused purely by, for example, dopamine, then I'd put more weight in your suggestions.

It seems that we don't actually have a good way for data collection in this department and we are merely doing the best we can. That being said, we should be sure to add a large grain of salt for such analysis.

As for your comment regarding dopamine in correlation with reward/motivation, the latest research shows that dopamine levels increase at the onset of the task at hand and drop once the task has been accomplished, prior to the actual reward. In addition, if the probability of reward goes down, then the dopamine release during said tasks goes up. This is why humans become so heavily addicted to gambling.

To be clear, my interest is not specifically about depression, although I do have a heavy interest in that department. I am also quite interested in the way we get excited about tasks, such as work projects, in relation to the expectation of reward and interest.

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Kristen May 31, 2010 at 12:58 pm

Interesting. There are many meds that essentially suppress dopamine, but no testing as far as I know. "Tests" are done by verbal question.

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Tbias June 2, 2010 at 12:09 am

"Verbal question" testing is generally a completely unscientific method.

I am hoping that we no longer throw medications at people for various mental conditions and instead have tests in place to hone in on the actual problems and treat those problems accordingly.

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