Gene Linked to Pain

   Johns Hopkins University Researchers have said that the discovery of a single pain sensitivity gene may someday allow doctors to prescribe drugs to match the pain threshold of their patients.
    In their study they have found that the difference in pain perception is due to a variation on the surface of nerve cells of a molecule called the mu opiate receptor.  Studies of humans and mice show that the number of these receptors directly affects the sensitivity to pain and that the receptors are linked to a single gene called the mu opiate receptor gene.
    The researchers have found that the receptor works by bonding with peptides that help to diminish the sensation of pain.  When there are lots of receptors, the perception of pain is diminished.  The number of these receptors is controlled by the action of the mu opiate receptor gene. 
    "People have long been skeptical that pain has a genetic basis," said neuroscientist George R. Uhl, MD, PhD who led the study.  However, PET scans have shown that some people have almost tow times the number of opiate receptors in certain brain areas than others.  People with the larger number of receptors respond to natural pain-killing opiates in the body.  Now people can think of pain as a genetically regulated problem with little voluntary component," Uhl said.
    The number of opiate receptors can also help predict a person's risk of addiction to opiate drugs, including morphine, researchers say.
----John Hopkins Medical Institutions, July 19, 1999.