Scientists in Springfield believe a specific part of the brain will become a useful tool in developing medicines to treat tinnitus, a chronic ringing in the ears that affects millions of Americans.
“We’re looking at this one structure, which we believe is very important in trying to identify tinnitus-related pathology,” said Donald Caspary, professor of pharmacology at Southern Illinois University School of Medicine.
Caspary and colleagues at SIU and the University of Illinois at Urbana-Champaign will use a recently awarded $ 942,500 grant from the federal government to investigate properties of a brain chemical called GABA and how it plays a role in tinnitus.
The three-year grant from the U.S. Office of Naval Research will allow SIU’s auditory research group to specifically focus on the auditory thalamus, a small section of the central brain that is inches from inner-ear structures on both sides of the head.
Caspary, principal investigator for the project, said scientists believe this region of the brain may determine the severity of tinnitus, a condition that affects 22.7 million Americans, or 10 percent of the adult population of the United States.
Often caused by loud noises, tinnitus can result in debilitating ringing, hissing and buzzing for about 10 percent of tinnitus sufferers.
Tinnitus is “one of the most common service-related disabilities among veterans returning from Iraq and Afghanistan,” according to the National Institute on Deafness and Other Communication Disorders.
More than 200 drugs also are known to cause tinnitus, and symptoms of the condition usually get worse with age.
In experiments that use live rats and rat brain tissue, scientists at SIU and the U of I will look for differences in brain chemistry among rats with tinnitus and those without the condition.
“If we can identify differences, and I think we can, between those populations, then we can try to normalize responses from cells in the tinnitus animal using drugs and therefore have a screening tool for effective tinnitus drugs,” Caspary said.
“We can flow the drugs in and see whether we can make the cells in the tinnitus animal behave like the cells in the normal animal,” he said.
Caspary said he has a list of drugs that will be used but wouldn’t identify them.
“We have one or two unique compounds that are most promising,” he said.
New drug treatments may be years away, he said, but, “The progress in tinnitus research over the past 10 years has been dramatic.”
15 years of research
SIU isn’t a newcomer to research on tinnitus.
Caspary, a member of SIU’s faculty since 1973, and other members of the auditory research group have received grants totaling almost $ 30.4 million since 1978, and SIU has conducted tinnitus-related research for at least 15 years.
SIU scientist Jeremy Turner, another principal investigator in the grant from the Office of Naval Research, helped invent a patented method for testing rats that have been exposed to noise in such a way as to give them a moderate case of tinnitus.
SIU’s expertise helped the medical school land the grant, Caspary said.
Caspary said his team also will benefit from the expertise of Evgeny Sametskiy, a research assistant professor of pharmacology. Sametskiy will evaluate how various drugs affect the electrical responses of individual living rat brain cells as he observes the cells under a microscope.
SIU scientists also will track the way live rats with and without tinnitus respond when the auditory thalamus regions of their brains are exposed to certain drugs.
“To be able to do it, both on a cellular level and a whole-animal level, and to be able to manipulate that environment … is very important,” Caspary said.
Tinnitus in humans often begins with damage to the inner ear, followed by the brain trying but failing to compensate for the injury, Caspary said.
The end result can be noise that prevents people from working or sleeping. The condition can cause depression and in extreme cases make people suicidal.
Some treatments — such as hearing aids, counseling, sound-related devices —help people deal with the symptoms, but there’s no cure.
That’s why research pinpointing a part of the brain that may regulate tinnitus could lead to better treatments, Caspary said.
“We’re trying to figure out how and where it’s working,” he said. “Then, developing a drug becomes a lot easier.”
Dean Olsen can be reached at 788-1543. Follow him at twitter.com/deanolsen.
More information on tinnitus
Members of the research team that will use a $ 942,493 grant from the U.S. Office of Naval Research to look into new drug treatments for tinnitus:
*Donald Caspary, SIU professor of pharmacology
*Thomas Brozoski, SIU professor of surgery
*Jeremy Turner, SIU part-time associate professor of surgery
*Evgeny Sametskiy, SIU research assistant professor of pharmacology
*Boris Odintsov, senior research scientist at University of Illinois at Urbana-Champaign
*Lynne Ling, SIU laboratory manager