Aug. 15 (UPI) -- Researchers have found a better way to suppress chronic itches: two experimental drugs that target two receptors in the spinal cord.
In experiments involving mice and dogs, researchers at the University of Zurich in Switzerland alleviated different kinds acute and chronic itches.
For many, the unpleasant itching sensation -- including after being bitten by a mosquito -- can be relieved by drugs on the market. But some patients suffer from unrelenting and debilitating urge to scratch because of skin, kidney or liver diseases. Some 14 percent reported chronic itching in a study of the general population in Germany.
These sufferers are now treated with antidepressants or immune suppressants, but they often are ineffective or have side effects.
The researchers tested an experimental drug to boost the effect of specific neurons in the spine that prevent itch signals from being relayed to the brain.
Three years ago, they located and described these neurons. Later, using genetic tests in mice, they identified two specific receptors that control the effect of the spinal neurons: α2 and α3GABAA. They are among a large group of receptors activated by the amino-acid transmitter gamma-aminobutyric acid, or GABA.
These GABA receptors have been known to interact with benzodiazepines, a class of drugs used to treat insomnia, anxiety or epilepsy.
The experimental drug originally was developed for anxiety. Researchers found the drug not only suppresses acute itches, but is also effective against chronic ones.
In the tests, mice scratched themselves less often and their skin changes healed significantly quicker than in animals given a placebo. This drug then was carried out in dogs by the researchers in cooperation with the University of Zurich's Veterinary Department. In both cases, the drug did not cause obvious undesired side effects.
"We are confident that the substance we've tested will also be effective in humans," Dr. Hanns Ulrich Zeilhofer said in a press release. "Like humans, dogs also often suffer from chronic itch. They too therefore stand to benefit from the approach."
The researchers have filed a patent application and are working with companies to develop the compound for use in human and veterinary medicine.