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Dr. Bob is Robert Hsiung, MD,
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Posted by djmmm on May 16, 2006, at 9:33:18
This really isn't new, news...an interesting read nonetheless
How Prozac affects the brain* 22:00 15 May 2006
* NewScientist.com news service
* Jessica MarshallA new mouse model may help explain exactly what happens in the brain in response to antidepressants like Prozac. The research may hold huge potential for understanding and screening new treatments for depression. And the wide variety of existing treatments may have more in common than was previously thought, the researchers suggest.
Prozac (fluoxetine), one of the most common drug treatments for depression, acts by stimulating the growth of new neurons in the brain’s hippocampus. Grigori Enikolopov and his team from Cold Spring Harbor Laboratory in New York, US, wanted to narrow down which steps in this growth process, called neurogenesis, Prozac was influencing.
So the team engineered mice with nuclei in their nerve cells that glow green during neurogenesis. This made it easy to count and compare the number of developing neurons. By tracking other factors associated with different stages of neurogenesis, Enikolopov’s team found that only one step was influenced by Prozac.
The drug did not promote neuron growth by stimulating stem cells, but rather by stimulating the division of cells just "downstream" of the stem cell, called amplifying neural progenitor cells, which have already committed to becoming neurons.
Tailored treatmentsNow the researchers are testing a range of treatments – from different drugs to deep brain stimulation – to see if they influence the same step in neuron development.
If these different treatments are all acting on the same step, that would provide a precise target for development of new therapies, Enikolopov says, and potential therapies could be screened more quickly.
But if different therapies target different steps in neurogenesis, that could make different treatments appropriate under different conditions, he suggests. For example, Parkinson's disease is associated with depression. Doctors may be better off treating such patients with an antidepressant drug that acts downstream of the step where Parkinson's attacks, in order for the treatment to have an effect.
In either case, Enikolopov asks: "How is the generation of new neurons translated into improved mood? That is the most critical and unanswered question."
The team is also testing mice pups treated with Prozac to see if neurogenesis responds the same way in juveniles as in adults. They hope this may shed light on concerns over whether Prozac is appropriate to give to children.
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0601992103)
http://www.newscientist.com/article/dn9171-how-prozac-affects-the-brain.html
Posted by naughtypuppy on May 16, 2006, at 11:18:58
In reply to How Prozac affects the brain, posted by djmmm on May 16, 2006, at 9:33:18
Thats been my favorite theory for a while. In addition, I think that depression can return shortly after the discontinuation of antdepressants because the new neurons were created with a higher than normal level of neurotransmitter present and require that higher level to function properly.
Posted by linkadge on May 19, 2006, at 22:03:16
In reply to Re: How Prozac affects the brain, posted by naughtypuppy on May 16, 2006, at 11:18:58
Its kindof like steroids. Once you stop, you shrink and whither back to your original self.
You might be able to maintain some of the gains should you replace the AD with other other antidepressant agents such as exercise.
How new neurons actually helps depression is unknown.
The neurogensis theory is probably part of it, but there are some things that it doesn't explain.
Stimulants, for instance, can lift the spirits immediately. It is short lived, but a brief remission nonetheless.
Linkadge
Posted by llrrrpp on May 28, 2006, at 19:01:03
In reply to Re: How Prozac affects the brain » naughtypuppy, posted by linkadge on May 19, 2006, at 22:03:16
If any of you want to be sent a PDF of the full-text article, babble-mail me, and include an e-mail address that will accept an attachment (no viruses, I'm 99.999% confident. I use Mac)
sincerely,
-llrrrppp.s. this is for educational purposes only. Then we can have an online study group meeting :o)
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