Developments in Brief : Histamine in Rats May Provide Allergies Clue
French scientists have discovered two new drugs that appear to affect the natural production of histamines in rats, a development that they say could lead to new treatments for human allergies and cardiovascular disorders.
The drugs have already helped them discover how the production of histamines are regulated by the brain, according to the researchers from the Centre Paul Broca de l’Inserme in Paris. Their report appears in the current issue of the British science journal Nature.
Histamines are amino acids--released in vast quantities by the body during allergic reactions--that cause inflammation of tissues and hives. One of histamine’s jobs is to signal the body to produce allergy symptoms such as runny eyes and sneezing. Histamines also appear to play a role in communication between brain cells and control of sleep and wakefulness.
The French researchers reported in Nature that tests in laboratory animals show that one new drug, alphamethylhistamine, increases the body’s production of histamines while the other drug, thioperamide, blocks its production.
Dr. J. C. Schwartz said the drugs interact with a previously unknown receptor on brain cells that appears to regulate the production of histamines.
The receptor, known as H3, seems to sense when there is an overabundance of histamines in the body and messages the brain to stop production, he said. Antihistamine drugs already available interfere with the release of histamines, but at a different site in the body than the new drugs do.
Scientists from the Cincinnati College of Medicine in Ohio have independently produced additional evidence that the H3 receptors exist in organs other than the brain, including the lungs, skin and spleen.
Because histamines play such a wide range of roles in the body, the drugs may eventually be useful as sedatives, stimulants and treatments for allergies, asthma and migraine headaches.
