Mice have Parkinson's non-motor symptoms

ATLANTA, June 23 (UPI) -- U.S. scientists say they have genetically engineered mice to reproduce many of the non-motor symptoms associated with Parkinson's disease in humans.

Emory University researchers said the classic symptoms of Parkinson's disease involve tremor, stiffness and slow movements. But the genetically engineered mouse model sheds light on common non-motor symptoms, such as digestive and sleep problems, loss of sense of smell and depression.

"These mice are very useful for studying the major non-motor symptoms of Parkinson's because they have them together as a package," Professor Gary Miller said, noting the mice were engineered to be deficient in VMAT2 (vesicular monoamine transporter 2), a protein that helps to store the brain chemicals that Parkinson's patients gradually lose the ability to produce.

The VMAT2-deficient mice could become research tools in the search for medications to treat non-motor symptoms, Miller said, since the mice have delayed emptying of the stomach, they fall asleep more quickly and they have a loss of the sense of smell.

The study that included Tonya Taylor Mike Caudle, Kennie Shepherd, Alireza Noorian, Chad Jackson, Mike Iuvone, David Weinshenker and James Greene appears in the Journal of Neuroscience.