Scientists reset hamsters’ ‘clocks’

Press, 12 June 1986, Page 32

Scientists reset hamsters’ ‘clocks’

NZPA-AP New York • Scientists have reset the “biological clock” of hamsters by giving them a standard sleeping-pill drug, raising hope that similar medications may help people overcome jet lag. "It’s the first step in trying to identify drugs that could affect the (human) biological clock,” said a professor of neurobiology and physiology at Northwestern University, Fred Twek, who reported the work in the most recent issue of the “British Journal of Nature.” His experiment provides “the strongest hint yet that the elusive jet-lag pill is within reach,” said a visiting research biologist at the University of California-San Diego, Arthur Windfree in an accompanying editorial. The director of the Centre for Insomnia Research at Stanford University, Wesley Seidel said the drug used on the hamsters, triazolam, had already been shown to help travellers fight jet lag for short periods just by helping them sleep.

That study did not look at whether it can reset the biological clock, he said. Professor Turek said scientists still must see whether triazolam affects the human biological clock and find the proper dose and times to take it. “If taken at the wrong time, it might worsen the jet lag by shifting the clock in the wrong direction,” he said. “The body’s sleep-wake cycle is governed by a biological clock in the brain. Cued by the natural alternation of daylight and darkness, the clock runs on a 24-hour day and works smoothly with daily activities. A traveller who crosses time zones or a worker who changes shifts disrupts that co-ordination, and can experience insomnia at bedtime and sleepiness when he wants to be active, until the clock adjusts to the new schedule. Shift workers can also get digestive disorders. Professor Turek’s experiment, done with Susan Losee-Olson, used 80 golden hamsters. It counted on the biological clock’s close regulation of

when the animal exercises on a wheel in its cage, the authors wrote. Hamsters kept for at least two weeks in constant daylight or constant darkness were given injections of triazolam or an inert substance. After injections of triazolam, the hamsters began running sooner or later than before, depending on when the triazolam was given. Results indicated the biological clocks for some of them had been reset by an hour or more. The animals stuck to their new schedules long after the drug had been eliminated from their bodies, suggesting it had reset the biological clock much like a wristwatch, Professor Turek said. “Triazolam evidently affects brain cells in the location of the biological clock, called the suprachiasmatic nucleus,” he said. Apart from jet lag and shift work, a clock-reset-ting drug might help in treating disorders such as depression possibly related to an out-of-synch clock, Professor Turek said.