سلول های مغزی ستاره شکلی که پیش تر تصور می شد نقش درجه دومی را در فعالیت های مغزی بر عهده دارد ممکن است نقش کلیدی در کنترل تنفس عهده دار باشد، این مطلب را مطالعه جدیدی بر روی موش های صحرایی القا می کند.
در هنگام تنفس، ما اکسیژن حیاتی را به درون می بریم و کربن دی اکسید زاید را بیرون می دهیم. نتیجه های این پژوهش نشان می دهد که سلول های به نام استروسایتز می تواند تغییرات در میزان کربن دی اکسید در خون را حس کرده و آنگاه به دیگر شبکه های مغز علامت دهد تا تنفس را تنظیم کنند.
الکساندر گورین، پژوهشگر این مطالعه از دانشگاه کالج لندن، گفت: "این پژوهش استروسایتز های مغز را به عنوان عوامل پیش تر ناشناخته ای از مدارهای مغزی شناسایی کرده است که عملکردهای جسمی اساسی و حیاتی برای ادامه زیست، مانند نفس کشیدن، را کنترل می کند، و نشان می دهد که آنها [استروسایتزها] در واقع ستارگان واقعی مغز است."
ممکن است که این سلول های مغزی و یا دیگران [سلول های دیگر] مانند آنها در بروز اختلال های مرتبط با از کار افتادگی تنفسی، مانند سندروم مرگ ناگهانی نوزادان، دخالت داشته باشد. با این حال، پژوهشگران گفتند: پژوهش های بیشتری نیاز است تا این رابطه ثابت شود. همچنین، با این که موش های صحرایی مدل خوبی برای مطالعه بر مغز انسان محسوب می شود، پژوهش آتی لازم است اطمینان یابد که نتایج به دست آمده در مورد انسان ها نیز صادق است.
این مطالعه قرار است این هفته در شماره زودهنگام آنلاین مجله علمی ساینس انتشار یابد ...
[به دنبال متن کامل انگلیسی خبر بالا، مطلب دیگری که توضیحی در مورد انواع سلول های مغزی است آورده می شود.]
Brain Cells that Help Us Breathe Revealed
Rachael Rettner LiveScience Staff Writer
LiveScience.com – Thu Jul 15, 2:10 pm ET
Star-shape brain cells previously thought to take a back seat in terms of the brain's activity might play a key role in controlling breathing, a new study in rats suggests.
When we breathe, we take in vital oxygen and expel waste carbon dioxide. The study results show brain cells known as astrocytes can sense changes in blood carbon dioxide levels and then signal other brain networks to adjust breathing.
"This research identifies brain astrocytes as previously unrecognized crucial elements of the brain circuits controlling fundamental bodily functions vital for life, such as breathing, and indicates that they are indeed the real stars of the brain," said study researcher Alexander Gourine of University College London.
It's possible that these brain cells or others like them contribute to disorders associated with respiratory failure such as Sudden Infant Death Syndrome (SIDS). However, more research is needed to prove the links, the researchers say. Also, while rats are considered a good model for studies on the human brain, future research is needed to make sure the results hold true for humans as well.
The study will be published this week in an early online edition of the journal Science.
The other brain cells
Astrocytes belong to a group of brain cells known as glial cells (glia is Greek for "glue"). Until recently, glial cells were thought to be minor players in the brain, providing structural and nutritional support to neurons, which did the heavy lifting.
"It's called neuroscience because it's neuro-centric," Gourine said. "Astrocytes and other glial cells, they were considered to not be as exciting to study previously."
However, Gourine and his colleagues found that astrocytes directly respond to decreases in blood carbon dioxide levels. Once activated, astrocytes send out a chemical messenger called ATP, which in turn stimulates other networks in the brain involved in respiration. Breathing in the study rats was increased when astrocytes indicated levels of carbon dioxide were too high, a reflex to get rid of the extra gas, and decreased when carbon dioxide levels were too low.
Role in disease?
While no one knows what causes SIDS, previous research has suggested abnormalities in the brain stem or an inappropriate response to low blood oxygen levels could play a role.
"This basic science information has to be used rapidly in order to determine whether glial dysfunction contributes to serious disorders of central control of breathing underlying Sudden Infant Death Syndrome." Gourine said. "If this hypothesis is correct astrocytes may be considered as potential targets for therapy in preventing respiratory failure".
The study was funded by the Wellcome Trust and the British Heart Foundation.
Original Story: Brain Cells That Help Us Breathe Revealed
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Environmental News Network (ENN)
Andy Soos, Published July 16, 2010 12:40 PM
Brain Cells
The brain has always been a bit mysterious. How does it all work so that a human being can live, breathe and talk. The brain is composed of two broad classes of cells: neurons and glia. These two types are equally numerous in the brain as a whole, although glial cells outnumber neurons roughly 4 to 1 in the cerebral cortex. Glia come in several types, which perform a number of critical functions, including structural support, metabolic support, insulation, and guidance of development. Astrocytes (brain cells named after their characteristic star-shape) that were previously thought to act only as the glue between neurons have a central role in the regulation of breathing.
The finding provides a new dimension for research into fundamental principles of brain organization and function and may be relevant for understanding causes of respiratory failure such as Sudden Infant Death Syndrome.
The research was carried out by Dr Alexander Gourine and colleagues at University College London, and Professor Sergey Kasparov and colleagues in Bristol University's Department of Physiology and Pharmacology. They demonstrate that brain astrocytes are able to sense the levels of carbon dioxide in the blood. They then activate brain neuronal respiratory networks to increase our breathing in accord with prevailing metabolism and activity.
Astrocytes are a subtype of a group of brain cells known as glia (which means 'glue’ in Greek). Glial cells are the most abundant cells in the human brain — outnumbering neurons by a factor of ten to one. Until very recently, glial cells have been thought to be the less exciting sisters of neurons, merely providing them with structural and nutritional support.
The four traditional functions of glial cells are to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons.
Astrocytes perform many functions, including biochemical support of endothelial cells which form the blood brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, and a principal role in the repair and scarring process of the brain and spinal cord following traumatic injuries. They have now been found to have a unique ability to sense the composition of arterial blood entering the brain by sensing increases in arterial levels of carbon dioxide. When activated they release a chemical messenger called ATP which stimulates brain respiratory centers to increase breathing rates in order for extra carbon dioxide to be removed from the blood and exhaled.
This observation places astrocytes as a key automatic role for respiratory adjustment due to changing conditions. Normally no one thinks to breathe more rapidly. This may be the way the brain makes that adjustment.
This newly realized brain cell function may be critical to understanding and then treating certain respiratory diseases such as Sudden Infant Death Syndrome and Ondine's curse (a sleep disorder where the body stops breathing for a moment.
For further information: http://www.bristol.ac.uk/news/2010/7133.html