Last Updated Wed, 21 Dec 2005 13:47:38 EST

http://www.cbc.ca/story/science/national/2005/12/21/ms-051221.html
CBC News

The puzzle of how nerve coatings are damaged in the brains of people with multiple sclerosis may have been solved by a Canadian-led research team.

Nerve fibres that send electrical signals in the brain are coated in a fatty sheath called myelin. The myelin acts as an insulator, like a plastic coating covering a copper wire.

Neurologist Dr. Peter Stys of the Ottawa Health Research Institute and his colleagues proposed a reason why myelin becomes damaged and invented a way to test the idea in the lab.

The researchers showed myelin contains specialized receptors for glutamate, a neurotransmitter that transmits signals to brain cells.

They also found chemicals that block the receptor can reduce myelin damage.

"Such a mechanism may represent a potentially important therapeutic target in disorders in which [myelin damage] is a prominent feature," the researchers write in Thursday's online issue of the journal Nature.

The laboratory findings need to be confirmed and tested in animals before a potential drug could be tried in humans.

To make the discovery, Stys's team invented a state-of-the-art laser scanning microscope technique. It allowed the first measurements of changes in calcium levels in the tiny spaces within myelin in a rat model.

Stys suspects glutamate from inflammatory cells may directly injure myelin in immune disorders such as MS.

The findings help fill in the details of what molecules are involved and how they interact in MS, agreed Dr. Stephen Waxman, neurology chair at Yale University School of Medicine. He was not involved in the research.

The research was funded by the the National Institute of Neurological Disorders and Stroke, the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Ontario, the Canadian Institute for Photonic Innovations and private donors.