Posts Tagged ‘hippocampus’
Lack of Sleep Leads to Poor Memory
Written by WTJ on October 22, 2009 – 10:55 am -
Neuroscientists from the University of Pennsylvania, University of Glasgow and University of Toronto found that lack of sleep cause people to be forgetful. The neuroscientists study mice and humans and found that sleep deprivation disrupts a specific molecule in the brain’s memory circuitry (hippocampus), which cause the interruption of the storage of episodic memories. Episodic memories are information about who, what, when, and where.
The neuroscientists believes the long-term potentiation (LTP) is the strengthening of connection between neurons that underlies memory. The stimulation of LTP in the brain requires the molecule cyclic adenosine monophosphate (cAMP), which is a molecular messenger involving in regulating activity of memory formation genes by passing signals between proteins. Sleep-deprived mice had 50% less cAMP in their brain cells compared to well-rested mice. The scientists also noticed increased amount of PDE4A5, a type of phosphodiesterase (PDE) enzyme that degrades cAMP, in sleep-deprived mice.
The findings provide a possibility to develop drug that knock out PDE4A5 to enhance the memories of sleepyheads. The results were published in Nature on 22th October 2009. The authors are Christopher G. Vecsey, George S. Baillie, Devan Jaganath, Robbert Havekes, Andrew Daniels, Mathieu Wimmer, Ted Huang, Kim M. Brown, Xiang-Yao Li, Giannina Descalzi, Susan S. Kim, Tao Chen, Yu-Ze Shang, Min Zhuo, Miles D. Houslay, and Ted Abel.
Tags: Andrew Daniels, brain, cAMP, Christopher G. Vecsey, cyclic adenosine monophosphate, Devan Jaganath, episodic, Episodic memories, forget, forgetful, George S. Baillie, Giannina Descalzi, hippocampus, Kim M. Brown, long-term potentiation, LTP, Mathieu Wimmer, memory, Miles D. Houslay, Min Zhuo, Nature, neuroscience, neuroscientist, PDE, PDE4A5, phosphodiesterase, Robbert Havekes, sleep, Sleep-deprivation, Susan S. Kim, Tao Chen, Ted Abel, Ted Huang, University of Glasgow, University of Pennsylvania, University of Toronto, Xiang-Yao Li, Yu-Ze Shang
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Protein Links to Stress and Depression
Written by WTJ on March 1, 2009 – 10:47 am -
Recent studies showed that a protein called kainate receptors response to certain antidepressants, and the protein also involved in depression and suicidal thought.
Scientists at Rockefeller University examined one of the five subunits of kainate receptors, KA1 in rats and the result may help to explain the mechanism of the protein reshaping the brain in response to stress. Researchers at Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology at Rockefeller University studied the impact of stress and steroid on rats. They induce stress to the rats by restraining them 6 hours per day for over three weeks. The production of KA1 in these rats increased in certain parts of hippocampus under the instruction sent by messenger RNA. Hippocampus involved in learning and memory functions. Scientists also tried to inject hormone called corticosteroids into the unstressed rats. Low dose of corticosteroids increased KA1 production but high dose did not.
Fortunately the brains will replace the retracted neurons once the stress is removed. The study was published in the journal PLos ONE. The authors were Richard G. Hunter, Rudy Bellani, Erik Bloss, Ana Costa, Katharine McCarthy, and Bruce S. McEwen.
Tags: adaptive plasticity, Ana Costa, Bruce S. McEwen, corticosteroid, depression, Erik Bloss, Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, hippocampal kainate receptor, hippocampus, HPA, KA1, kainate receptor, Katharine McCarthy, mental health, PLoS ONE, psychology, Richard G. Hunter, richard hunter, Rockefeller University, Rudy Bellani, Steroid, stress
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