HOUSTON -- Headlines usually tell the story. A young athlete who seems no different from his colleagues on the football field dies suddenly during exercise under the baleful sun of a blistering summer day.
Some of these young, physically fit young people may have a gene mutation that makes them particularly sensitive to heat, and now researchers led by those at Baylor College of Medicine (http://www.bcm.edu) may have identified a molecule that could reduce that threat. A report on their work appears online today in the journal Nature Medicine (http://www.nature.com/nm/index.html).
It all begins in the laboratory of Dr. Susan Hamilton (http://www.bcm.edu/physio/hamilton/?pmid=6654), chair of molecular physiology and biophysics at BCM, who studies the ryanodine receptor 1(RyR1) that is implicated in a particularly deadly disorder called malignant hyperthermia. People with this disorder suffer life-threatening elevations of temperature during a particular kind of general anesthesia. When mice with this mutation exercise in a hot room or are even exposed for a short time to the temperatures of a Houston summer, they suffer all the hallmarks of malignant hyperthermia before they die. Recent evidence suggests that this heat sensitivity is also found in humans with comparable RyR1 mutations.
In her studies of muscle fatigue (another focus of the laboratory), Hamilton and her colleagues studied a compound called AICAR (5-aminoimidazole-4-carboxamide ribonucleoside) recently shown by Vihang Narkar, Ronald Evans and colleagues at the Salk Institute to slow muscle fatigue and improve muscle endurance without exercise making it popularly known as "exercise in a pill," said Hamilton.
"When we gave AICAR to the (heat-sensitive) mice, it was 100 percent effective in preventing heat-induced deaths, even
|Contact: Graciela Gutierrez|
Baylor College of Medicine