(dailyRx News) Opioid receptors in the brain are the target of many legal and illegal drugs, from hospital anesthetics to heroin. Until recently the details of these important receptors has been somewhat of a mystery.
Researchers have been able to discover the 3D atomic structure of one type of opioid receptor, called kappa, using detailed X-Ray imaging. The Kappa receptor may be very useful in the development of new medications, involved with depression, anxiety, addiction, and even irritable bowel syndrome.
"This finding is going to have a major impact on understanding the fundamental principles of opioid receptor recognition and evolution," said Raymond Stevens, Ph.D., molecular biology professor at The Scripps Research Institute.
Many types of molecules, or ligands, bind to the kappa receptor. These binds affect the receptors on the surface of brain cells which can invoke feelings of pleasure, pain, addiction, depression, psychosis, and others. It is for this reason that the researchers targeted the receptors.
Despite the potential of the kappa opioid receptors in medicinal development, there are currently no FDA approved drugs that bind only with them. Now that the structure is known, there is much greater potential to design these drugs.
"Once we see the structure of the receptor, it becomes easier for us to develop drugs that target the receptor in ways that might be beneficial for medical therapy," said Bryan Roth, M.D., Ph.D., the Michael Hooker Distinguished Professor of Pharmacology at UNC. "Drugs that block the receptor are potentially useful for treating a number of serious illnesses including chronic pain, cocaine addiction and other diseases."
The team found that the receptor had a very large area available for binding with other molecules, which may account for its relation to so many mental and physical problems.
"This receptor's binding pocket is much bigger and deeper than any other we've studied; that may explain why so many different types of ligands bind to this receptor. A lot of work remains, though, in understanding opioid selectivity,” notes Stevens. “This is just the beginning and we will see follow up studies take the understanding even further.”
The study was published March 21st, 2012, in the journal Nature and was funded by the National Institutes of Health.