As allergy sufferers we know all too well that although many over-the-counter antihistamines relieve symptoms, we’re are often too groggy to enjoy the respite. Now, thanks to some sleuth work by a team of international scientists, the way has been paved for antihistamines with fewer side-effects.
An international team of scientists has successfully cracked the code for the complex 3-D structure of the human histamine H1 receptor protein. Using an X-ray beam 100 billion times stronger than normal, at Diamond Light Source, the UK’s national synchrotron facility, researchers were able to get a 3D picture of the shape of H1 receptors.
Published this week in Nature, this discovery opens the door for the development of ‘third-generation’ antihistamines.
The H1 receptor protein is found in the cell membranes of various human tissues including airways, vascular and intestinal muscles, and the brain. It binds to histamine and has an important function in the immune system. However, in susceptible individuals it can cause allergic reactions such as hay fever, food allergies and pet allergies. Antihistamine drugs work because they prevent histamine attaching to H1 receptors.
Dr. Simone Weyand, postdoctoral scientist at Imperial College London, who conducted much of the experimental work at Diamond, said: “First-generation antihistamines are effective, but not very selective, and because of penetration across the blood-brain barrier, they can cause side-effects including sedation, dry mouth and arrhythmias.”
Professor So Iwata, Director of the Membrane Protein Laboratory at Diamond, said: “It took a considerable team effort but we were finally able to elucidate the molecular structure of the histamine H1 receptor protein and also see how it interacts with antihistamines. This detailed structural information is a great starting point for exploring exactly how histamine triggers allergic reactions and how drugs act to prevent this reaction.”
Word on Health’s allergy prone bloggers will be eagerly awaiting developments and will bring you news as it happens…assuming of course we can stay awake to do so!