Astrocytes, it was long believed, were little more than the scaffolding of the brain—they provided a support structure for the stars of the show, the neurons. But a study out in this week’s Science is the latest to suggest that this is far from the whole story. The study says that astrocytes (whose “astro” name come from their star-shape) may in fact play a critical role in the process of breathing.
Astrocytes are a type of glial cell — the most common type of brain cell, and far more abundant than neurons. “Historically, glial cells were only thought to ‘glue’ the brain together, providing neuronal structure and nutritional support but not more,” explains physiologist Alexander Gourine of University College London, one of the authors of the study. “This old dogma is now changing dramatically; a few recent studies have shown that astrocytes can actually help neurons to process information” [Nature].
Gourine’s team peeked into the brains of rats to figure out the connection between astrocytes and breathing. In humans and in rodents, the level of carbon dioxide in the blood rises after physical activity. The brain has to adjust to this, setting the lungs breathing harder to expel that CO2.
Astrocytes, the scientists found, are key players in this process. When the cells sensed a decrease in blood pH (because the carbon dioxide made it more acidic), they immediately released calcium ions, which the researchers could detect because they’d given the rats a gene encoding a protein that shone fluorescent in the presence of calcium. The astrocytes also released the chemical messenger ATP. That ATP appeared to trigger the nearby neurons responsible for respiration, kicking them into gear.
The astrocytes are no one-trick ponies, though. They could be important not only for breathing, but also for brain circulation, memory formation, and other activities.
The next step is to find a way to inhibit astrocytes in vivo, said Gourine. Then, researchers will be able to test the numerous hypotheses for the functions of astrocytes in the brain. It is likely astrocytes in various regions of the brain serve different functions, said [Cendra] Agulhon, just as many different types of neurons do many different jobs. “Depending on where they are and what kind of neurons they are surrounded by, they will function differently,” she added. “We are just starting to understand how important astrocytes can be” [The Scientist].
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Image: Wikimedia Commons
July 21st, 2010 at 3:07 am
I doubt there is much in the brain that does little. There are many secrets waiting to be unlocked within our wetware.
July 21st, 2010 at 5:24 am
nothing wasted anywhere in this body, or this universe … wish western science had a bit less hubris
July 21st, 2010 at 10:28 am
Hmm, do fish have astrocytes? After all they don’t exactly breathe in the sense that our lungs are not related to fish’s gills.
July 21st, 2010 at 11:30 am
#3 – Yes they do. And fruit flies have them too.
I would suspect – repeat s u s p e c t – they work basically the same way in fish, because blood acidity as a function of CO2 would have the same effect on calcium concentrations in fish astrocytes and release ATP, but then of course the excited neurons in fish would starting from that level and above effect completely different physiological mechanisms to “normalize” blood acidity.
And also #2 western science doesn’t exist. There is only one kind of science, which is science.
July 22nd, 2010 at 10:19 am
Junk DNA turns out not to be junk…and now the brain’s “scaffolding” turns out to be integral to the neural network. Next you’re going to tell me that physicists could drop the idea of dark matter if they stopped rounding off their calculations. (Really? you’re explanation for why you’re measurements don’t add up is because there is some invisible matter than you can’t prove exists? That’s more plausible than “you’re wrong”?)
There is nothing “insignificant” in this world. Everything has a place, and everything has a purpose.
And I would call this philosophy an eastern-type philosophy, Mr. Bakker. Western philosophies (including scientific schools of thought) tend to be a little more over-reaching in their assumptions, wouldn’t you agree?
July 22nd, 2010 at 1:43 pm
#5 – No sir/ ma’am, I would not agree. And even though it is completely irrelevant to the subject here, which is about new scientific discoveries (not philosophies) about glia I think your proclamations about dark matter are even more funny than over-reaching.