In experiments on humans and mice, researchers in Australia showed that a class of compounds called nitric oxide donors delays the entry of toxins from potentially deadly snakebites into the blood stream.
Nitric oxide (NO), a molecule involved in regulation of blood pressure and the control of brain activity, has been shown to lower blood pressure in patients who suffer acute strokes.
The new finding is of more than academic interest: every year some 100,000 people worldwide die from snakebites, and another 400,000 must amputate limbs that have been injected with poison.
It has long been known that many snake venoms contain large molecules that transit the human body's lymphatic system before entering the bloodstream.
Separately, scientists have also established that nitric oxide slows down a pumping mechanism within the lymphatic system, a part of the body's immune system that carries a clear fluid -- called lymph -- toward the heart.
Dirk van Helden, a researcher at the University of Newcastle in New South Wales, put these two facts together to suggest a possible treatment for snakebites.
"We hypothesized that a nitric oxide-releasing agent applied topically would slow lymphatic transit time and entry of the venom into the circulation, delaying onset of toxicity," he and his colleagues wrote in the study.
To test their theory, the researchers injected a venom-like substance into one foot of 15 volunteers, and measured the time it took for the toxin substitute to reach lymph nodes in the groin.
The experiment was later repeated, except this time the drug-laced ointment was spread around the puncture within one minute of the injection.
Result: the transit time dropped from an average of 13 minutes to 54 minutes, four times slower.
Further experiments using real toxins in rats yielded roughly the same results.
Read more at Discovery News
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