Ottawa team unravelling brain damage in multiple sclerosis Last Updated Wed, 21 Dec 2005 13:47:38 EST 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, which acts as an insulator, like a plastic coating covering a copper wire. The myelin coating on nerves is damaged in people with MS. If myelin gets damaged in multiple sclerosis or spinal cord injuries, the electrical circuit may misfire or not fire at all. 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 can be tried by humans. To make the discovery, Stys's team invented a state-of-the-art laser scanning microscope technique to look closely at living myelin from a rat model. They discovered the surface of myelin has tiny open pores that provide a gateway for calcium to enter. If too much calcium enters, it can injure the myelin and affect our ability to walk, talk or see. Stys and his team also found a drug already on the market to treat brain disease can block the pores of the myelin sheath. "When we put these drugs on it, it greatly reduced the injury to the myelin and greatly improved the ability of these nerve fibres to conduct and transmit nerve impulses," Stys said. 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.