Unraveling the Mystery Behind Tourette’s Tics
Researchers at U of U Health may have identified a biological factor that underlies the repetitive tics that characterize Tourette’s syndrome.
Tourette syndrome is a neurological disorder characterized by repetitive tics that worsens under stressful situations. Although the incidence of the disorder remains uncertain, the National Institute of Health suggest that 1 to 10 children in 1,000 have Tourette syndrome.
Marco Bortolato, PhD, associate professor in Department of Pharmacology and Toxicology at the University of Utah Health led a research team that compared the effect of three neuroactive steroids¾progesterone, 5a-dihydroprogesterone, and allopregnanolone¾on the stress response in the brain.
In the study, researchers compared the effect of each steroid in a mouse model for Tourette’s syndrome, to control mice. The Tourette’s rodents display spontaneous tick-like jerks and respond to traditional treatments for the disorder, like haloperidol.
The researchers found that one of the steroids, allopregnanolone, increased the tic-like responses in the transgenic mice. These responses were alleviated when the animals were pre-treated with haloperidol. In addition, another drug called finasteride normalized stress-induced behavioral changes by altering allopregnanolone levels in the transgenic mice.
These results provide the first evidence that stress increases allopregnanolone production, aggravating the tic response. The researchers caution that the results are limited to only one animal model. Future work is necessary to clarify the role of finasteride, as well as other neurosteroids in the stress response.