UT Southwestern researchers report that damage to the parasympathetic nervous system may account for nearly half of the typical symptoms including gallbladder disease, unrefreshing sleep, depression, joint pain, chronic diarrhea and sexual dysfunction that afflict those with Gulf War syndrome. Their findings will be published in the October issue of the American Journal of Medicine and are currently available online.

"The high rate of gallbladder disease in these men, reported in a previous study, is particularly disturbing because typically women over 40 get this. It's singularly rare in young men," said Dr. Robert Haley, chief of epidemiology at UT Southwestern and lead author of the new study.

The parasympathetic system regulates primitive, automatic bodily functions such as digestion and sleep, while the sympathetic nervous system controls the "fight or flight" instinct.

"They're sort of the mirror image of each other the yin and the yang of the nervous system that control functions we are not usually aware of. This is another part of the explanation as to why Gulf War syndrome is so elusive and mysterious," said Dr. Haley.

Previously, isolating pure parasympathetic brain function was difficult. In the new study Dr. Haley and his colleagues used a technique that monitors changes in approximately 100,000 heartbeats over 24 hours and measures changes in high-frequency heart rate variability a function solely regulated by the parasympathetic nervous system.

After plotting the subtle changes in heart function using a mathematical technique called spectral analysis, researchers found that parasympathetic brain function, which usually peaks during sleep, barely changed in veterans with Gul
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Contact: Katherine Morales
katherine.morales@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
27-Sep-2004