Friday, May 2, 2003 | 9:07 a.m.
The use of tranquilizers in aging monkeys suggests that the drugs may sharpen the sight, hearing and cognitive skills in aging people, according to a paper published by a Las Vegas resident today in the journal Science.
Audie Leventhal, professor of neurobiology and anatomy at the University of Utah, has studied the visual cortex and normal aging in the brain for 25 years.
His research into brain chemistry in monkeys indicates that supplying a neurotransmitter named GABA or a similar chemical named muscimol to deteriorating nerve cells in the visual cortez may reverse aging.
The research suggests that by boosting the brain's chemicals, doctors may someday help elderly people reverse brain cell aging that can cause declines in vision, hearing, memory and other cognitive and motor skills.
While much modern medical research aims at regenerating injured or lost abilities, such as repairing spinal cord cells damaged by disease or injury, Leventhal said he wants to protect existing brain cells as we age.
"We have to make the same brain cells last a long time," Leventhal said from his Summerlin home.
Tranquilizers from the benzodiazepines group -- including brands such as Valium, Xanax, Librium and Ativan -- increase GABA levels in the brain, Leventhal said.
"So the findings raise the question of whether sedatives or perhaps other medications might help counter brain-related declines in the vision of elderly people," he said.
Scientists from the University of Utah and from China report that they were able to reverse age-related deterioration of nerve cells in the brain's visual cortex for several minutes when researchers administered GABA or a similar chemical. Leventhal has been an honorary professor of biology at the University of Science and Technology of China since 1990.
"The fact that we can fix it is really good news," Leventhal said.
Because brain levels of GABA also play a role in several higher brain functions, such as interpreting what we see and hear, memory formation and movement control, future research should investigate whether tranquilizers or other GABA-enhancing chemicals might help reverse other declining abilities caused by the brain's deterioration as people grow older, he said.
In normal aging, Leventhal said, "Grandpa is able to see you at age 90 when you walk into the room, but he can't recognize you."
In animals such as frogs, with no visual cortex, seeing seems to be almost a reflexive reaction. "A frog will try to eat a fly, but he will also shoot at a moving pebble," he said. "The frog doesn't know the difference."
The way GABA or other tranquilizers operate in the brain seems amazing: slow grandpa's brain and he will move and think better.
Without the help, an older brain may be overloaded with background noise, similar to a driver trying to cross the Las Vegas Strip on Flamingo Road with the traffic signals out. "Everything comes to a dead stop," Leventhal said.
The new study builds on research Leventhal published in 2000 in the journal Nature Neuroscience. The earlier study found as vision declines in elderly monkeys, it is not necessarily from diseases of the eye or the optic nerve. Instead, age caused nerve cells to deteriorate in the brain's visual cortex.
Leventhal and his Chinese colleagues measured electrical activity in 242 visual cortex nerve cells in six young monkeys, ages 7 to 9 years old, comparable to 21- to 27-year-old humans. Then they measured activity in another 257 nerve cells in seven older monkeys, 26 to 32 years in age, equal to 78 to 96 in humans.
"It's premature to run out and take benzodiazepines," Leventhal said. When younger monkeys were fed GABA, the visual cortex cells immediately slowed. "It just put them to sleep."
The older Rhesus monkeys and long-tailed macaques improved with the GABA or muscimol, like a traffic light regulating the flow of nerve impulses.
Leventhal, a research professor who does not have teaching responsibilities, said he moved to Las Vegas from Salt Lake City in the last year after leaving the Las Vegas Strip during a visit and seeing Red Rock Canyon.
"I like to be able to walk across the golf course and go hiking in Red Rock," he said.
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