01.09.08
Posted in Biology at the University of Virginia, Body Clock, Nocturnin, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, biology, circadian rhythms, evolution, hypothalamus, metabolism, physical health at 12:15 pm by Jacob Canon
In today’s show, adapted from an article published on the Oscar web site written by Fariss Samarrai, we discuss the research of Carla Green, associate professor of biology at the University of Virginia, and a study she headed which says that the gene Nocturnin, working within the network of the body’s circadian clock, appears to be particularly important in the control of metabolism.
The body’s biological clock has been shown to regulate life’s activity/rest cycles by controlling energy levels, alertness, growth, moods and the effects of aging. Further study has revealed that these internal clocks are controlled by circadian rhythms. Rhythms that were established early in the history of life on the planet and evolved associated with the astronomical cycles that effect Earth’s environment such as the rise and setting of the sun and the passing of seasons. What is now being discovered is that certain elements, already known to be part of the body’s circadian network, may have a broader influence on the life of an individual.
In a study published in the journal, Proceedings of the National Academy of Sciences, Associate Professor of Biology at the University of Virginia Carla Green and her colleagues discovered that the gene Nocturnin, which participates in the regulation of the body’s biological rhythms, may also be a major control in regulating metabolism. The study showed that mice lacking the gene were resistant to weight gain when put on a high fat diet and also were resistant to the accumulation of fat in the liver.
Professor Green, said, “It’s been known for some time that there are many links between the circadian clock and various aspects of physiology and metabolism. This study suggests that Nocturnin is part of the network that the circadian clock uses to control important aspects of metabolism.”
In the study, Green and her colleagues, Nicholas Douris, a U.Va. graduate student who designed the study, U.Va. post-doctoral fellow Shihoko Kojima and Joseph Besharse of the Medical College of Wisconsin, used regular mice and genetically altered mice in which the Nocturnin gene was not present. The Nocturnin-deficient mice were divided into two groups; one group fed a normal diet, the other a very high fat diet. A group of normal mice were also fed a high fat diet.
The researchers found that both groups of genetically altered mice maintained normal weight and activity levels, and, of particular interest, the ones fed the high fat diet exhibited only slight weight gains, even over long periods of time. However, the normal mice on the high fat diet ballooned, gaining more than twice the weight of the Nocturnin-deficient mice. And, when the mice were dissected, the researchers found that the normal mice had, as expected, large concentrations of fat in their livers, whereas the altered mice had normal levels of fat.
Green said, “We were quite amazed at what we found. We thought that over time, as we continued to feed the mutant mice the high fat diet that they would eventually gain weight at some expected rate, but it never happened. These mice continued to stay slim while the normal mice nearly doubled in weight and developed fatty livers.”
Clock genes in the body’s organs operate in conjunction with a central time keeper in the brain, the hypothalamic suprachiasmatic nucleus, but also work somewhat independently, resulting in a complex system of oscillators regulating various functions of the body. Scientists are working to better understand how the genes and proteins of the circadian clock in mammals affect not only activity cycles but also rates of metabolism, which are tied to feeding cycles. Green said it is possible that, “A better understanding of Nocturnin’s function could eventually lead to medical treatments that could counteract the problems of obesity, which has become a major issue in modern society.”
We look forward to the continued study of this important new finding in the hope that its potentially far reaching health benefits will be realized in our lifetime.
You’ve been listening to the Oscar Show… I’m Jacob Canon. Join us next week when our topic will be UVa professor and chair of biomedical engineering Thomas Skalak and his efforts to develop real scientific evidence about the effectiveness of magnetic therapy.
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11.22.07
Posted in Jacob Canon, James Coan, MRI, Psychology, Relationships, The Oscar Show, University of Virginia, anxiety, brain, emotions, environmental conditions, happiness, hypothalamus, immune, nervous system, neurobiology, neurophysiology, physical health, physiology, sensory inputs, stress at 3:46 pm by Jacob Canon
How did you react the last time you had a fight with that significant someone in your life? With couples, the woman might apologize, or the man might make a joke or express understanding. By doing this, they subtly and briefly lighten the tension as they work their way through a disagreement.
Psychology Professor James Coan discovered a long time ago that by doing this, even when couples fight, they take care of each other. This interplay was significant when Coan designed a study exploring what happens in people’s brains when they behave emotionally or observe other people’s emotions. Coan said, “what we are learning is our emotions are more heavily involved in our day-to-day physical health than we previously thought.
How we deal with our relationships is closely tied to how long we live, how frequently we go to the doctor, how rapidly we recover from injury, how happy we tend to be in our lives.” With his colleagues, Hillary Schaefer and Richard J. Davidson from the University of Wisconsin, Coan sought to demonstrate the neurobiological basis of emotional expression and regulatory processes.
In the study, they used MRI technology to view these responses at the level of glucose metabolism and blood oxygenation in the brain. Because of the importance of emotional connectedness to the study, 16 happily married, heterosexual couples were recruited as test subjects. Wives were placed in the scanner so brain activity could be recorded as each was exposed to the anxiety-producing possibility of an electric shock to the ankle.
Researchers wanted to see what effect different types of emotional support would have in areas of the brain related to the body’s normal fight-or-flight stress response. Readings were taken when the woman was alone in facing this challenge, When a stranger, a male, was present to support her And when her husband offered support. Coan stated, “the scanning environment is pretty hostile to looking at interactions between people.” The MRI machine surrounds the subject’s body and restricts movement. The women weren’t even able to see the support person during the scanning process.
Having the man offer his hand for the woman to hold was about the only intervention possible in this setting. Not surprisingly, the results show there was a healthy reduction in the stress response when test subjects were supported. Stimulation in the regions of the brain that regulate physiological arousal and coordinate large muscles and joints was significantly decreased, no matter who was holding the woman’s hand. However, when it was her husband’s hand she was holding, the response was significantly greater.
Coan said, “When you’re holding a spouse’s hand, you get down-regulation in all of those same systems. But all the other systems that have to do with the conscious regulation of your emotions — having to pay attention to what’s happening with your body and having to become more vigilant for future dangers — all of these other systems come down as well. Your brain doesn’t work as hard when it’s your spouse. What surprised Coan and his colleagues most was the relaxation response demonstrated by what they called “super couples.” In those couples with exceptionally high-quality relationships, “Hand-holding had a significantly greater effect on soothing their brains.”
Tests showed differences involving two structures that were not affected at all in other test subjects. They observed evidence of reduced release of stress hormones by the hypothalamus. These hormones are responsible for inhibiting immune response and other activities that have critical implications for health and well-being.
Of greater interest was the reduction of activity in the right anterior insula. This brain structure modulates the amount of pain stimulus one experiences subjectively. Reduction of activity in this area means test subjects actually felt less pain when they held their husband’s hand.
So it can be said, having someone you love hold your hand really can take the hurt away.
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