Researchers at Oregon Health & Science University’s School of Dentistry have discovered an endomorphin in the nerve of the ear and throat responsible for middle ear troubles and have developed a way to reliably detect its secretion from nerve cells. These findings could play a significant role in the development of new therapies to treat various ear and throat pain, middle ear infections and the aviation otitis caused by changes in ear pressure during flying. Besides the common cold, ear infections are the most commonly diagnosed childhood illness in the United States.
The research is published online in the European Journal of Neuroscience, one of the leading neuroscience journals. The study also ran in one of the two May 2008 print issues (Volume 27, Issue 10).
“This discovery shows that pain signaling involves many different molecules and complex mechanisms,” said Agnieszka Balkowiec, M.D., Ph.D., senior author of the study, OHSU School of Dentistry assistant professor of integrative biosciences and OHSU School of Medicine adjunct assistant professor of physiology and pharmacology. “Our next step is to better understand how the endomorphin affects pain signaling to the brain during various pain conditions.”
Sensation from the middle ear, the pharynx and the tonsils is signaled to the brain by the glossopharyngeal nerve. Sore throats, ear infections and even changes in ear pressure during flight that lead to inflammation of the middle ear, all are characterized by pain that is transmitted to the brain by cells that form the glossopharyngeal nerve.
The OHSU School of Dentistry researchers discovered an endomorphin, Endomorphin-2, in the glossopharyngeal nerve cells and developed a highly sensitive method of detecting Endomorphin-2 secretion from the cells. Using their method, the scientists showed that Endomorphin-2 is secreted from glossopharyngeal cells onto nerve cells in the brain by electrical impulses. The method can now be used by other researchers and will make possible further study of endomorphins in other parts of the body. Endomorphin-2 has previously been implicated in pain signaling from other parts of the body and is likely to be a key player in the transmission of nerve signals from the ear and throat, explained Dr. Balkowiec
Dr. Balkowiec’s research team included Heather Scanlin, B.S., an OHSU doctoral student in neuroscience; Elizabeth Carroll, M.S., a Riverdale High School teacher; and Victoria Jenkins, B.A., an OHSU research assistant.
The research at OHSU was supported by grants from the National Institutes of Health, American Heart Association, and M.J. Murdock Charitable Trust’s Partners in Science program.