Skip to comments.Secret of Prozac's Success Revealed (increases neural stem cell progeny)
Posted on 05/17/2006 10:24:44 PM PDT by neverdem
New research in specially bred mice has elucidated how the antidepressant Prozac works. Scientists have long known that in addition to discouraging synapses from reabsorbing the neurotransmitter serotonin, Prozac (known generically as fluoxetine) also increases the number of neurons (neurogenesis) in the adult brain. But exactly how the drug manages this multiplication trick has proved difficult to pin down. Now researchers have traced the development cascade of new neurons and determined where fluoxetine exerts its multiplying--and beneficial--effect.
Grigori Enikolopov at the Cold Spring Harbor Laboratory and his colleagues bred a new strain of mice that allowed them to track the development of mature neurons from stem cells using the different marker proteins expressed. Of the six stages of neuron development observed in this process, the scientists found that more than two weeks of fluoxetine treatment boosted the number of so-called amplifying neural progenitors (ANPs) by nearly 50 percent (a migratory stream of which is shown in the image above).
Subsequent testing in mice allowed to live for a month after fluoxetine treatment showed a similar increase in the overall number of neurons. "Together, these results suggest that the fluoxetine-induced increase in the number of ANP precursors in the [brain] later translates into an increase in the number of new neurons," the researchers write in the paper presenting the findings in the Proceedings of the National Academy of Sciences.
By isolating the step in neuron development that fluoxetine influences, the scientists have identified a new target for antidepressants that may have fewer side effects. The research also unveils the links in the chain leading from stem cells to new neurons as well as provides an animal tailor-made to investigate the mechanisms of other medicines and treatments, permitting a ray of hope into the darker regions of brain dysfunction.
del shannon knows...
Those must be some really happy mice on drugs (what, with all the experiments and the lab they are stuck in)
I don't know, but my sister-in-law is weird, whether she's on Prozac or off...
Hope at last, my two surviving neurons might settle down and breed . . .
Microbes Convert Wastewater into Useable Electricity For anyone that's interested, I linked what I believe is the original, actual article on that thread.
FReepmail me if you want on or off my health and science ping list.
*Pant pant* Image....too....big....
Cheers? What's the point of a monster size cartoon and screwing up the thread and comments display?
I forgive him... They are wearing Tarheels caps!!!
This is sort of an urban myth put forward by the Scientologists. Like all urban myths, it has anectdotal evidence to support it.
Some people on Prozac have committed suicide, true, but often people who are suffering from depression commit suicide. Virtually everyone being treated with Prozac has some form of depression. If Prozac had been shown to have a causal link with suicide, it would be off the market.
Of course, Tom Cruise would disagree with that, but he eats placenta...
Are you kidding? Have you seen the profit margin?
1: Pak J Pharm Sci. 1999 Jul;12(2):11-6. Related Articles, Links
Inhibition of rat liver tryptophan pyrrolase activity by fluoxetine.
Bano S, Morgan CJ, Badawy AA, Buckland PR, Guffin PM.
Cardiff Community Health Care NHS Trust, Biomedical Research Laboratory, Witchurch Hospital, Cardiff CF4 7XB, UK.
The present study has demonstrated the effectiveness of acute administration of fluoxetine to inhibit rat liver tryptophan pyrrolase activity. The maximum inhibition of basal liver tryptophan pyrrolase activity at 2 h after administration was observed with 1 mg/kg dose for the total enzyme and apoenzyme activities and that significant inhibition of these two activities was evident with a dose of the drug as small as 0.5 mg/kg. Serum free tryptophan concentrations were also increased using 10 mg/kg dose of fluoxetine. In view of the role of tryptophan depletion and thus 5-HT in pathophysiology of depression, it is strongly suggested that the inhibition of liver tryptophan pyrrolase activity may be a major mechanism of antidepressant action.
PMID: 16414828 [PubMed]
I wonder if they ever take into account what impact this has on their little mice studies?
Who paid for this little smoke and mirrors study? I could never find it in the PDF doc.
I'm not a scientologist or believe it is a urban myth. Take a look at the site I provided.
What concerns me most about prozac is the fact it is showing up in water supplies.
Maybe it is at such a low level that it could never make any difference but it sure seems like something to keep track of.
Personally I am against FDA drugs but I understand that they help some people and those folks should have access to them if they want to.
It scares me to think that massive numbers of people could get their daily dose of prozac without even realizing it.
I heard an MD who worked on Prozac and has since regretted that she did so say that suicide and/or violence are attendant side effects.
Virtually every kid who has shot up classrooms was proven to have been taking it or it's cousins.
"Support was provided by the National Alliance for Research on Schizophrenia and Depression, the National Institute of Neurological Disorders and Stroke, The Hartman Foundation, The Ira Hazan Fund, The Seraph Foundation, and The Cody Center for Autism and Developmental Disabilities."
It's at the very end of the text, before the references on the right side of the page. As far as this being a "smoke and mirrors study," from the first paragraph after the abstract:
"However, the cellular basis for the action of SSRIs is not clear. In addition to its effects on neurotransmission, SSRI fluoxetine increases generation of new neurons in the dentate gyrus (DG) of the adult brain (49)."
In the sidebar of the pdf browser, click on "Similar articles in PubMed." You'll get at least 2 of those references, e.g. Malberg et al. (2000) J. Neuroscience and Santarelli et al. (2003) Science.
Thanks, any thoughts on post #19?
That site lists anecdotal data, which is meaningless in terms of science and true causality. I was on prozac for awhile, but it didn't help. I now take effexor and it is much more effective for me. Do I have some side effects? Yes, but in this case, the problem was much worse than the 'cure'.
Did you read the site? Anecdotal data?
The ICFDA BOARD
Dr. Ann Blake Tracy
Dr. Ann Blake Tracy, a Ph.D. in Health Sciences with the emphasis on Psychology, is the director of the International Coalition for Drug Awareness. She has specialized for 14 years in adverse reactions to serotonergic medications (such as Prozac, Sarafem, Zoloft, Paxil, Luvox, Celexa, Lexapro, Effexor, Serzone, Anafranil, Fen-Phen, Redux and Meridia) and has testified before the FDA and congressional subcommittee members on Prozac. She has testified since 1992 as an expert witness in Prozac and other SSRI related court cases around the world.
Dr. Candace B. Pert, PhD
Research Professor, Georgetown University Medical Center, Washington, D.C., Former Chief of Brain Biochemistry at NIH for 13 years. She studied the inner workings of the body with an eye towards identifying and locating peptides and receptors
Dr. Julian Whitaker, MD
Dr. Julian Whitaker, founder of the Whitaker Wellness Institute, is one of the country's foremost advocates of healing through diet, exercise, lifestyle changes, and the principles of orthomolecular medicine.
Dr. Lorraine Day, MD
An internationally acclaimed orthopedic trauma surgeon and best selling author was for 15 years on the faculty of the University of California, San Francisco, School of Medicine as Associate Professor and Vice Chairman of the Department of Orthopedics. She was also Chief of Orthopedic Surgery at San Francisco General Hospital and is recognized world-wide as an AIDS expert
Joyce Riley vonKleist, RN, BSN, Captain, USAF inactive Reserve
Has presented at the National Institutes of Health, medical legal conferences such as the American Trail Lawyers Association, was host of her own radio talk show "NurseTalk Radio-The Truth in Health Care", and has guested on over 1500 radio and television shows, including Art Bell, Chuck Harder and Michael Reagan. Served as a Captain in the United States Air Force and flew on C-130 missions in support of Operation Desert Storm. She now serves as spokesperson for the American Gulf War Veterans Association whose purpose is to provide education and information for the Gulf War veterans and their families and to seek treatment for the illnesses that thousands of Gulf War veterans now suffer from.
Dr. Bradford S. Weeks, MD
Bradford S. Weeks, M.D. is a medical doctor whose practice welcomes people all ages suffering with all illnesses. He offers conventional, as well as complementary, medical and psychiatric care. Dr. Weeks' approach is biochemical in nature. That means he works to correct your underlying biochemical imbalances which create your illnesses and pain, rather than to simply offer you various synthetic drugs designed to suppress your symptoms.
Mark M. Miller, ICFDA Web Administrator
Mark and his wife Cheryl lost their 13-year old son to a Zoloft-induced suicide in 1997, Since then, Mark has been serving as the organization's Regional Director in Kansas and developed the ICFDA website to help connect survivors and educate others about the dangerous and often deadly side effects of prescription medications.
They been working on tryptophan pyrrolase for a long time. It will probably be some time before all the effects of fluoxetine are well understood.
"None of the compounds tested showed the strongly inhibitory action of 5-hydroxytryptophan on the Pseudomonas enzyme (12) or on the liver enzyme (13)."
Check all the names for tryptophan pyrrolase as well as the other entries.
Oh lass, I don't know what to make of your reply to me. The data - anecdotal, not statistical. It has nothing to do with scientific proof or causality. So you copied info about their Board. That has nothing to do with my post whatsoever.
Thanks for the links (((BUMP)))
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