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how can serotonin be removed? thought it was an essential brain chemical? ----- Original Message ----- From: "mschild" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, July 01, 2010 1:21 AM Subject: Serotonin solves decades-old mystery in Parkinson's disease > The study sheds light on the long term consequences of brain tissue > transplants and may help improve future trials that consist of > transplanting > cells from other sources, such as bioengineered cells or stem cells. > Pioneering surgeries performed with aborted fetal tissue in the 1980’s in > patients with Parkinson’s proved that the diseased brain could be > repaired, at > least in some cases. The treatment aimed to replace decayed dopamine cells > in > the brain’s of Parkinson’s patients. Some transplanted patients showed > remarkable improvement but eventually the majority developed dyskinesias. > > The controversy surrounding the transplantation of fetal cells into adults > put > an end to human trials in the United States in the late 1980’s when the > U.S. > government temporarily banned fetal tissue research, though research > continued > in other parts of the world. The U.S. ban was lifted in the early 1990’s, > but > the cause of dyskinesias in these patients remained a mystery, and no > effective > treatment has been found. > > Now, Marios Politis and colleagues in the United Kingdom and Sweden have > discovered that the neurotransmitter serotonin is the culprit. Using > imaging > scans and radioactive tracers, the researchers were able to visualize the > function of different chemicals in the two patient’s brains. Taking a > closer > look, they found that previously decayed dopamine neurons—a hallmark of > Parkinson’s disease—were still restored and fully functional over a decade > after transplantation. But Politis and colleagues also saw unexpectedly > high > amounts of serotonin neurons in the transplanted tissue. > > The finding is puzzling because the usual dyskinesias in Parkinson’s are > thought to be a result of dopamine action, not serotonin. The researchers > discovered that the deceptive ability of serotonin neurons to switch to a > different neurotransmitter—to adopt and pump out dopamine—causes the > dyskinesias. Administering a drug to block this action almost immediately > eliminated the dyskinesias in both patients. The authors also suggest that > removing serotonin in any future cell-based therapies might prevent this > crippling side effect. Recently, a new trial launched under the name > TRANSEURO > plans to use fetal cell therapy to treat Parkinson's disease, with the > first > surgeries planned in 2012. > > More information: "Serotonergic Neurons Mediate Dyskinesia Side Effects in > Parkinson’s Patients with Neural Transplants," by M. Politis et al. > Science > Translational Medicine. > > Provided by AAAS > > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: > mailto:[log in to unmask] > In the body of the message put: signoff parkinsn > ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn