Astrocytes, Perhaps more Important than we Thought
As we know, astrocytes are glial cells within the Central Nervous System that support other neurons as well as help to form the Blood Brain Barrier, but new research suggests we still do not know all of the functions of astrocytes. In the study, scientists discovered a correlation between the amount of CO2 in the blood, due to exercise, and a chemical release of neurotransmitters from astrocytes to nearby nerve cells. This means that the astrocytes in our Central Nervous System, specifically astrocytes near the medulla oblongata, are capable of detecting decreased pH levels in our blood and are capable of sending neurotransmitter information to nearby neurons to increase breathing, which effectively expels CO2 and increases the pH levels in our blood.
The scientists were able to prove this by inserting calcium sensitive fluorescent protein into the brains of rats, specifically into the astrocytes. They then shone the light on the brain to see how bright the calcium sensitive protein shone as the levels of calcium changed due to the fluctuating levels of pH in the blood. As the pH in the blood decreased, calcium in the astrocytes increased, indicating the release of neurotransmitters to nearby cells within the medulla oblongata.
Researchers hope that this discovery will help to explain cot death, the sudden death of babies due to lack of breathing, and Ondine's curse, a disease we are familiar with.
I thought that the detection of the decreased pH levels within the blood by the medulla was a pretty obvious evaluation, as the medulla is responsible for the homeostasis of chemicals within our blood, but the fact that astrocytes were responsible is unique. This makes me wonder what else do we not know about the functions of other glial cells? I was also curious about the relation between the signaling of astrocytes to regulate breathing and Ondine's curse, as I thought Ondine's curse was a result of the separation of an afferent nerve that controlled the involuntary action of breathing, then forcing it to become a voluntary action. It maybe that the afferent nerve crosses the medulla and thus does not interact with astrocytes as the connection has been severed, or maybe not, we'll see.
Below: An astrocyte glowing due to the injection of chemical sensitive proteins.
source: http://www.nature.com/news/2010/100715/full/news.2010.355.html
The scientists were able to prove this by inserting calcium sensitive fluorescent protein into the brains of rats, specifically into the astrocytes. They then shone the light on the brain to see how bright the calcium sensitive protein shone as the levels of calcium changed due to the fluctuating levels of pH in the blood. As the pH in the blood decreased, calcium in the astrocytes increased, indicating the release of neurotransmitters to nearby cells within the medulla oblongata.
Researchers hope that this discovery will help to explain cot death, the sudden death of babies due to lack of breathing, and Ondine's curse, a disease we are familiar with.
I thought that the detection of the decreased pH levels within the blood by the medulla was a pretty obvious evaluation, as the medulla is responsible for the homeostasis of chemicals within our blood, but the fact that astrocytes were responsible is unique. This makes me wonder what else do we not know about the functions of other glial cells? I was also curious about the relation between the signaling of astrocytes to regulate breathing and Ondine's curse, as I thought Ondine's curse was a result of the separation of an afferent nerve that controlled the involuntary action of breathing, then forcing it to become a voluntary action. It maybe that the afferent nerve crosses the medulla and thus does not interact with astrocytes as the connection has been severed, or maybe not, we'll see.
Below: An astrocyte glowing due to the injection of chemical sensitive proteins.
source: http://www.nature.com/news/2010/100715/full/news.2010.355.html
posted by vincent.zaballa at 11:35 AM
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