Protein shown to rally biological clockNovember 30, 2006'Pony Express' protein A biologist at Washington University in St. Louis and his collaborators have identified the factor in mammalian brain cells that keeps cells in synchrony so that functions like the wake-sleep cycle, hormone secretion and loco motor behaviors are coordinated daily over a 24-hour period. Erik Herzog, Ph.D., Washington University associate professor of Biology in Arts & Sciences, Sara Aton, Ph.D., a graduate student in Herzog's lab who is now a postdoctoral researcher at the University of Pennsylvania, James Huettner, Ph.D., associate professor in cell biology and physiology at the Washington University School of Medicine, and Martin Straume, a biostatistician, have determined that VIP ¬- vasoactive intestinal polypeptide - is the rallying protein that signals the brain's biological clock to coordinate daily rhythms in behavior and physiology. The finding clarifies the roles that both VIP and a neurotransmitter GABA play in synchronizing biological clocks, and sheds light on how mammals, in this case mice and rats. regulate circadian rhythm. Results were published in the Nov. 27- Dec. 1 online issue of the Proceedings of the National Academy of Sciences. Neurons in the biological clock, an area called the suprachiasmatic nucleus (SCN), located at the base of the brain right across the optic nerve, keep 24-hour time and are normally highly synchronized. The SCN is composed of 10,000 neurons on one side of the hypothalamus, and 10,000 on the other. Together these neurons are intrinsic clocks in communication with each other to keep 24-hour time. It had been thought that GABA was the prime candidate for the rallying role. All SCN neurons make this inhibitory neurotransmitter, and it had been shown that giving GABA daily at 8 a.m. to SCN cells synchronizes them. "The surprise was that GABA was not needed," said Herzog. "VIP synchronizes even when we block all GABA signaling. When we blocked GABA, synchrony was perfectly fine. Instead, the oscillations got bigger." Herzog likens VIP to the Pony Express rider telling all the SCN cells to synchronize their ; GABA, he says, is like the marshal that prevents he cells from being too active. Herzog and Aton recorded neuron activity from the SCN using a multielectrode array with 60 electrodes upon which they place SCN cells, a "clock in a dish." They also recorded gene expression in real-time using a bioluminescent reporter of gene activity. Using drugs or genetic knock out mice, they negated the role of GABA and recorded the electrical activity of many neurons, what Herzog calls the "hands of the clock," and the gene activities, "the cogs of the clock," of many SCN cells. They found that, without GABA, the cells marched together, but without VIP, they lost synchrony, indicating that VIP is the coordinator. Washington University in St. Louis |
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| Related Biological Clock Current Events and Biological Clock News Articles Java and nighttime jobs don't mix: study Night-shift workers should avoid drinking coffee if they wish to improve their sleep, according to research published in the journal Sleep Medicine. The food-energy cellular connection revealed Our body's activity levels fall and rise to the beat of our internal drums-the 24-hour cycles that govern fundamental physiological functions, from sleeping and feeding patterns to the energy available to our cells. U-M discovery about biological clocks overturns long-held theory University of Michigan mathematicians and their British colleagues say they have identified the signal that the brain sends to the rest of the body to control biological rhythms, a finding that overturns a long-held theory about our internal clock. WUSTL research finds individual cells isolated from the biological clock can keep daily time, but are unreliable Alexis Webb enters a small room at Washington University in St. Louis with walls, floor and ceiling painted dark green, shuts the door, turns off the lights and bends over a microscope in a black box draped with black cloth. Through the microscope, she can see a single nerve cell on a glass cover slip glowing dimly. Chemotherapy for breast cancer is associated with disruption of sleep-wake rhythm in women A study in the Sept.1 issue of the journal Sleep shows that the sleep-wake activity rhythms of breast cancer patients are impaired during the administration of chemotherapy. Biological clocks of insects could lead to more effective pest control Researchers at Oregon State University have discovered that the circadian rhythms or biological "clocks" in some insects can make them far more susceptible to pesticides at some times of the day instead of others. Biological Timekeeper Studies Reveal New Temperature Regulator and Track Clock Protein across a Day Dartmouth Medical School geneticists have made new inroads into understanding the regulatory circuitry of the biological clock that synchronizes the ebb and flow of daily activities. Balancing hormones may help prevent preterm births The relationship between two different types of estrogen and a hormone produced in the placenta may serve as the mechanism for signaling labor, according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM). Children of older fathers perform less well in intelligence tests during infancy Children of older fathers perform less well in a range of cognitive tests during infancy and early childhood, according to a study published this week in the open-access journal PLoS Medicine. In contrast, the study finds that children with older mothers gain higher scores in the same tests - designed to measure the ability to think and reason, including concentration, learning, memory, speaking and reading skills. School-based intervention is a promising model for improving adolescent sleep habits A study in the March 1 issue of the journal SLEEP shows that a school-based sleep intervention is a promising model for addressing adolescent sleep problems, given its high retention rate, cost-effectiveness and potential for promoting healthy sleep knowledge and practice. More Biological Clock Current Events and Biological Clock News Articles |
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