ScienceDaily Magazine -- Sustained Use Of Anti-Depressants Increases Cell Growt

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ScienceDaily Magazine -- Sustained Use Of Anti-Depressants Increases Cell Growth

And Protects Cells In The BrainHi List, this is an article about an interesting

Yale study that concludes that long-term use of SSRIs increases cell growth and

protects cells in the brain. :-)

Kathy R. in Indiana

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Reprinted from ScienceDaily Magazine ...

Source: Yale University

Date Posted: Friday, December 15, 2000

Web Address: http://www.sciencedaily.com/releases/2000/12/001215081931.htm

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Sustained Use Of Anti-Depressants Increases Cell Growth And Protects Cells In

The Brain

New Haven, Conn. - Continued use of anti-depressants leads to new cell growth in

an area of the brain known to suffer cell death and atrophy as a result of

depression and stress, a study by Yale researchers shows.

Depression affects an estimated 12 percent to 17 percent of the population at

some point during their lifetime. Anti-depressants are commonly prescribed for

depression and other affective disorders, but the drugs' therapeutic effects on

the molecular and cellular level are not clearly understood.

" The findings of our study are that chronic administration of anti-depressants

increases the number of neurons in the adult hippocampal , " said Duman,

M.D.., professor of psychiatry and pharmacology. " This could explain in part how

anti-depressants produce their therapeutic response. " Duman was senior author of

the study published Dec. 15 in The Journal of Neuroscience.

The hippocampus is part of the limbic brain that is involved in learning,

memory, mood and emotion. It is one of only a few regions of the brain where

production of neurons occurs in the adult brain of animals, including humans.

Several studies have demonstrated that stressful experiences, both physical and

psychological, lead to neuronal loss or atrophy in the hippocampus. Other

studies show that anti-depressants can block this cell loss.

" In humans, brain imaging studies demonstrate that in patients with depression

or post traumatic stress syndrome there is a decrease in volume of the

hippocampus that is thought to be related to the neuronal atrophy and loss, "

Duman said. " The results of our study demonstrate that anti-depressants can

reverse or block further loss of neurons in the hippocampus by increasing

neurogenesis (new cell growth). "

Duman's laboratory has been studying the mechanism of action of anti-depressants

in rodents for over 15 years. The researchers have focused on cellular actions

of anti-depressants, looking at the role of the intracellular signal

transduction pathways that control neuronal function. They have identified

several actions of anti-depressants which indicate that anti-depressants

influence the survival or the number of neurons in the hippocampus.

This study was intended to look at whether the anti-depressants increased the

birth of neurons in the hippocampus. The researchers tested several different

classes of anti-depressant drugs, as well as electroconvulsive seizure therapy

(ECS), and an anti-psychotic medication.

ECS is clinically the most effective treatment for cases of depression that are

resistant to available drug treatments. As expected, chronic, or repeated,

administration of ECS increased the number of neurons in the hippocampus of the

brain by 50 percent. The chemical anti-depressants tested increased the number

of neurons in the same area by 20 percent to 40 percent.

The anti-depressants that were administered included a monoamineoxidase

inhibitor (tranlcypromine), a serotonin-selective reuptake inhibitor

(fluoxetine), and a norepinephrine-selective reuptake inhibitor (reboxetine).

However, brief or " acute " (one to five days) administration of the

anti-depressants did not lead to any significant cell change. Results were seen

after 14 to 28 days of administration, which is consistent with treatment

regimens for the therapeutic response to anti-depressants.

Administration of the anti-psychotic drug haloperidol, which is a

non-antidepressant psychotropic drug, also did not produce any significant cell

change in this area of the brain. In addition, the researchers recently have

demonstrated that morphine, another non-antidepressant psychotropic drug,

decreases the number of cells in the hippocampal area.

Co-authors of the study were Malberg and Amelia Eisch, both postdoctoral

fellows in psychiatry, and Nestler, formerly a professor of psychology,

pharmacology and neurobiology at Yale.

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