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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Reelin' in Clues to Schizophrenia
22 March 2002 (All day)
People with schizophrenia have abnormally low levels of a protein called reelin in the brain. Now researchers have found that this protein seems to play an important role in guiding newborn neurons to their final homes. They suggest that a lack of this protein could lead to schizophrenia by impoverishing neural circuits important for normal cognition--although they and other researchers caution that this mechanism is still speculative.
Researchers knew that reelin plays an important role in brain development because mice that lack the reelin gene have a misshapen cerebral cortex and a peculiar gait (thus the nickname "reeler" mice). They also knew that some psychiatric patients, including schizophrenics, have abnormally low levels of reelin. But scientists have had a hard time figuring out exactly what reelin does.
Preliminary experiments suggested to Kiminobu Sugaya, of the University of Illinois, Chicago, that reelin might help guide new neurons to the correct location in the brain. To test this, he and colleagues injected human neural stem cells into the brains of normal mice and reeler mice. A month later they looked at the brains under a microscope. In the normal mice, the introduced cells had migrated to the hippocampus and cortex, areas critical for cognitive functions such as learning and memory. But in reeler mice, the implanted cells failed to migrate, the team reports in the 19 March issue of the Proceedings of the National Academy of Sciences. Sugaya's team also found evidence that reelin guides the migration of the mice's own stem cells: When they injected mice with a compound that labels newborn cells, they found far fewer new neurons in the hippocampus and cortex of reeler mice. A reelin deficiency--like that seen in schizophrenics--could prevent new-formed neurons from migrating properly and integrating themselves into brain circuits, the team concludes.
The study "adds to the evidence that reelin may be important for neural cell migration," says Lalit Srivastava, a psychiatrist at McGill University in Toronto. But Gabriella D'Arcangelo of Baylor College of Medicine in Houston, who discovered reelin in 1995, says that Sugaya's evidence that the mice's own stem cells migrate to the cortex isn't conclusive and warns that the link between reelin and schizophrenia is still speculative.