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Ringing in a Possible Cure

January 23, 2004

Heather Heilman
Phone: (504) 865-5714

hheilman@tulane.edu

Tinnitus is a major public health problem, and it's only going to get worse as those of us who went to rock concerts and walked around with Walkmans get older," said

ringingMeredith Garcia, professor of otolaryngology. She should know--she was a teenager in southern California in the 1960s, surrounded by loud cars and loud music.

Today, like 50 million other Americans, she has tinnitus. Tinnitus is the perception of sound when no external sound is present. It's often referred to as ringing in the ears, although those who have it can hear many different sounds--hissing, roaring, whistling or even clicking sounds.

About 12 million Americans have tinnitus severe enough to require medical attention and two million are so debilitated that they can't function on a day-to-day basis.

"There's not just one condition called tinnitus. Some forms originate in the peripheral auditory system and some in the central auditory system," said Garcia. "And there are no good pharmacological therapies--nothing you can give a patient that will work any better than a placebo."

But Garcia believes modulation of the nitric oxide pathway could be a therapy for tinnitus. In 1998, Louis Ignarro shared the Nobel Prize for medicine for his work showing that nitric oxide transmits signals in the body. Ignarro is a professor at the University of California-Los Angeles, but did much of his prize-winning work while at Tulane. Nitric oxide dilates blood vessels, improving blood flow, and is used to help control blood pressure.

And the popular drug Viagra works by increasing the effect of nitric oxide. A few years ago, Garcia had a graduate student in her lab named Douglas Webber, who is now a postdoctoral fellow at UCLA. He wanted to study the role of nitric oxide in the auditory system.

"His hypothesis was that the inhibition of the nitric oxide pathway would attenuate response to sound, which it did," Garcia said. "But the most interesting thing he found was that in the absence of sound, inhibition of this pathway caused neuronal activation only in the auditory system, which is fascinating because there are nitric oxide receptors all over the brain."

What that means is that nitric oxide seems to have a tonic inhibitory effect, lessening the perception of sound that isn't really there. Garcia is hopeful that this will lead to a drug treatment for tinnitus. In the meantime, she gets a lot of e-mail from tinnitus sufferers who wonder if Viagra could help their hearing.

"I tell them I don't dispense medical advice, but they could take the abstract of my research and show it to their doctor," said Garcia, whose career has been less than traditional. She first moved to New Orleans in the late 1960s with her first husband, who was a student at Tulane's medical school. She finished her bachelor's degree at St. Mary's Dominican College in 1984, the year the school closed.

And she worked as a lab technician at Tulane, primarily in the laboratory of Tulane's own Nobel Laureate, Andrew V. Schally, before doing her graduate work here. She also is studying the ways signaling molecules in the auditory system change in response to loss of hearing or to surges of sound. Her research is sponsored by the National Institutes of Health, the American Tinnitus Association and by Louisiana's Health Excellence Fund.

Citation information:

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