( Drugs that treat depression by manipula...)Commonly used antidepressants may also affect human immune system

That's because the investigators found, for the first time, that serotonin is passed between key cells in the immune system, and that the chemical is specifically used to activate an immune response. They do not know yet, however, whether these SSRI (selective serotonin reuptake inhibitors) drugs "including the brands Prozac, Zoloft, Paxil and others" could have either a beneficial or a damaging effect on human immunity.

"The wider health implication is that commonly used SSRI antidepressants, which target the uptake of serotonin into neurons, may also impact the uptake in immune cells," said Gerard Ahern, Ph.D., assistant professor of Pharmacology at Georgetown and lead researcher on the study.

He said that while it may be possible that SSRI drugs may restore a healthy immune function in people who are depressed and prone to infections, it is possible that they might also bolster immunity to the point that they trigger autoimmune disease. "At this point we just don't know how these drugs might affect immunity, so we really need to clarify the normal role of serotonin in immune cell functioning," Ahern said.

The surprising finding that serotonin is rapidly passed between immune cells in a manner similar to its transmission between brain neurons was revealed in mid-October, when the research team published the findings in the journal Blood. In December, the discovery was highlighted for the general scientific audience by the journal Nature Reviews Immunology, and now the research team is working to produce an animal model that may help describe the precise nature of this interaction.

"The novelty is that we reveal a potential communication, involving the transmitter serotonin
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Source:Georgetown University Medical Center