Thursday, January 12, 2006

Activist Astrocyctes

There is an article in Nature Neuroscience that raised an eyebrow or two at MSNBCs online column, Livescience.  In the Livescience acticle-about-the article, the reporter conveys the following about the significance of the study:
Star-shaped brain cells called astrocytes were traditionally thought of as housekeeping cells that helped nourish the brain under the direction of the neurons. The new study found that the astrocytes can directly control blood flow without being told.
The MSNBC article present the new study as being a big challenge to the traditional way of thinking about astrocytes, stating "The discovery challenges a basic assumption in neuroscience."  Basically, the study show that astrocytes are not merely housekeeping cells; they have important regulatory functions as well.  

An astrocyte shown in (false-color) green

That is fine, except that it has been known for years that astrocytes have important regulatory functions.  In 1998, a different article in Nature Neuroscience (Astrocyte-mediated potentiation of inhibitory synaptic transmission) reported that astrocytes have a role in mediating the synaptic activity of neurons.  In 2001, there was an article in the PNAS entitled New Functions for Glia in the Brain.  (Glia are cells in the brain that are not neurons; astrocytes are a kind of glial cell) In the PNAS article, it is stated:
Ten or twenty years ago, glial cells were considered minor players in the nervous system, even though they outnumber neurons 10-fold. Glia were thought to function as passive support cells, bringing nutrients to and removing wastes from the neurons, whereas the latter carried out the critical nervous system functions of information processing, plasticity, learning, and memory. Recent studies, reviewed here, are changing this view and demonstrating that glial cells play a key role in these essential brain functions [Sharma and Vijayaraghavan (1) and Ullian et al. (2)].
So if the old idea actually was overturned several years ago, why is the MSNBC writer implying that it is a new challenge to the old idea?  I suppose they do that in order to make the current article sound more important than it really is.  

It seems unfortunate to me, that the journalist would resort to that tactic to make the article seem more important.  On the one hand, I do like to see these kinds of articles in the popular press, since there is a chance that members of the general public will take an interest in an obscure topic.  On the other hand, if the mission is to get the public interested in science, wouldn't it do just as well to explain why the study is really important, rather than making up a reason?  It seems to me that the public would be better served by a straightforward explanation of the real significance of the study.  It would be perfectly fair for them to say that the new study is the latest in the past few years to challenge the old conception of astrocytes, and to go on to say that the more we learn about how the brain works, the more likely we are to be able to figure out how to fix it when something goes wrong.  That would be just as captivating to the general public, and more accurate.  

Perhaps some science journalists think the general public can't grasp the subtleties of the implications of the research.  Perhaps they are right, and I am overestimating their readership.  I don't think so, though.  I think that most people can appreciate the fact that not every research study produces a paradigm shift, but that incremental advances are important nonetheless.

Furthermore, the author could take the opportunity to point out that scientists are coming to understand that most things in the body serve more than one function, and that nothing in the body is passive.  Everything constantly communicates with the other anatomical structures in its environment.  For example, your bones aren't just sitting there like so many pieces of concrete.  They actively resculpt themselves in response to weight-bearing activity.  The serve as a buffer in the control of the level of calcium and phosphate in the blood.  The mineral crystals that form the latticework for the bones are constantly broken and reformed.  In other words, bones are an active participant in various physiological processes.  The new study about astrocytes provides confirmation of the general idea, that everything in the body is active all the time.  I think people can appreciate the fact that this is not a revolutionary thought, but that it still is interesting and important.