By Daniela Kaufer, Alon Friedman | 

It was the middle of the night in Jerusalem, and we were watching mice swim. The year was 1994, and the two of us were crouching over a pool of cold water in a laboratory at the Hebrew University. The room was chilly, our hunched backs ached, and we had been repeating this routine over many nights, so we were tired and uncomfortable. So were the mice. Mice really dislike swimming, especially in cold water—but we wanted to stress them out.

We humans were on the night shift because both of us had other things to do during the day. Kaufer was working on a doctorate in molecular neurobiology, and Friedman was an Israel Defense Forces physician and was often on call. What brought us together with the mice every evening was an attempt to understand a medical mystery: Gulf War syndrome. After the conflict ended in 1991, there were an increasing number of reports of soldiers from the U.S.-led coalition who were afflicted with chronic fatigue, muscle pain, sleep problems and cognitive deterioration, and those soldiers were hospitalized at higher rates than nondeployed veterans. Some doctors suspected that pyridostigmine, a drug that had been given to soldiers to protect them from chemical weapons, could cause these ailments if it made it into their brains.

There was a big problem with this theory, however: pyridostigmine in the bloodstream was not supposed to reach the brain. Blood vessels that course through this vital organ have walls made of specialized cells, packed very closely and with abilities to control what can get in and out. They form a shield that keeps toxins, pathogens such as bacteria, and most drugs safely within the vessels. This structure is called the blood-brain barrier, or BBB for short, and the drug should not have been able to pass through it.

Read the entire source article from Scientific American here.