By Amy Lin, REU intern 2012
Research is formalized curiosity. It is poking and prying with a purpose.
-Zora Neale Hurston
I don’t think I could have expressed as aptly my motivations for becoming involved in research through the Superfund Center as Zora Neale Hurston has just done. Even though the famous American anthropologist may have formulated this quote for reasons entirely unrelated to neurotoxicology research, I think it applies quite well in this context.
I have always been the girl with a lot of questions. When my Neuroscience professors lectured about certain theories, concepts and referred to various research studies, I always inadvertently inundated myself with waves upon waves of questions, stemming from curiosity, skepticism, plain confusion or a little bit of each. The problem was that I didn’t know what to do with all of it. My head almost became numb from the swirl and chaos of question marks incessantly pounding against my frontal cortex.
Research was the perfect solution. It channeled my hyperactive curiosity into the real world. It allowed me to find answers that I could never find in a textbook or in a lecture hall, at least not in the way I wanted to find them. The nicotine self-administration research I helped with during my sophomore year really opened my eyes to the promising state of drug development for smoking cessation treatment. Having grown up watching my dad and uncle struggle to quit smoking, it was a relief to see that others like them may have an easier time of quitting in the near future. It made my relationship with science a little bit more intimate, and a little bit more meaningful. There was a definite purpose to it. During this summer, I have been actively involved in research that pertains to another issue that I feel very strongly towards: how commonly used or produced toxins in the environment can do irreparable damage (particular on a neurological level) to the environment, animals and most of all, to humans.
I have always been interested (or perhaps a better word is wary) about the long-term effects of exposure to toxins in humans. In particular, it is at once puzzling and alarming that many toxins, which are widely used and produced, can be so utterly underestimated and overlooked in its ability to be harmful to humans and animals alike. Perhaps we can attribute this ironic behavior to the fact that today, we live in a highly industrialized society, a fast-paced sort of world that has little patience for anything other than optimal efficiency and in turn, maximum output of product. One important example lies in agriculture. In order to increase agricultural productivity to support the rapidly growing world population, pesticides are conventionally used to rid crops of insects, thereby increasing harvest yield. While pesticides may be beneficial for many reasons, there are also caveats when it comes to using what are essentially poisonous substances, so frequently and ubiquitously.
How could we be so indifferent or unaware of inhaling and ingesting (as they are in our fruits, and vegetables) these toxic substances?! Well, this summer, before embarking on this Superfund internship in Dr. Levin’s lab, I had two general questions in mind: “At what levels of exposure to these pesticides do observable behavioral deficits appear?” and “Specifically what kinds of behavioral deficits are induced as a result of a determined threshold exposure of these toxins and how does it affect the overall functioning capacity of the organism?” In order to answer these questions (as well as many others!), I dived straight into the world of neurobehavioral teratology, in particular the study of how environmental chemicals and certain drugs of use can trigger brain-behavioral changes during embryonic and fetal development.
In Dr. Levin’s lab, we are specifically looking at two drugs: chlorpyrifos and dexamethasone. Chlorpyrifos is a commonly used organophosphate pesticide that is known to have negative effects on brain development. On the other hand, dexamethasone is a drug often given to babies born prematurely with lungs that have not fully developed. However, recent studies seem to suggest that dexamethasone can also cause developmental delay. Approximately 10-20% of people are exposed to dexamethasone.
Because both drugs have been linked to causing persisting impairments in cognitive and emotional responses, we decided to take a closer look at whether double exposure could intensify the severity of these neurological deficits. With the necessary controls in place, we subjected the rats to a series of behavioral assays. Through these behavioral assays, we can assess the cognitive functioning level of the exposed rats and compare the results to those of rats that have not been exposed to either drug or have only been exposed to one of the two drugs. This summer, I was primarily involved with running the rats in the radial arm maze.
For the maze, we would bait 12 of the 16 arms with fruit loops, and time how long it takes the rat to visit all of the baited arms. The radial arm tests both working memory (Mr. Whiskers: Have I already visited this arm?) and reference memory (Mr. Whiskers: Which arms are baited and which are not baited?). After getting the rats accustomed to this task, we began a series of drug-injection trials to determine the specific neural pathways that the rats are using when they are running the maze. Each drug targets certain receptors in the brain and blocks their function. Hence, if a certain drug really impaired their performance in the maze, we can be pretty confident that the neural pathway the drug is blocking has a role in the rats working and reference memory. So far, we are still in the process of analyzing the data derived from the radial arm tests, but whatever the results, I am sure that they will be very interesting and telling.
One important thing I have realized this summer as a Superfund research trainee, is that the research we are doing extends beyond the boundaries of the scientific field, and into the lives of ordinary people. It is a powerful tool for both environmental and social reform. Not only is research about poking around a maelstrom of hypotheses. It is also about “poking” legislators to adopt stricter regulations on these toxins, to incessantly motivate ourselves, as scientists, to devise techniques to clean up polluted sites or find safer ways to treat our crops. It is about “poking and prying” at the general public, to make certain that people know what their bodies are being exposed to: to inform. I think that is the most important thing of all.
If ever we had proof that our nation’s pollution laws aren’t working, it’s reading the list of industrial chemicals in the bodies of babies who have not yet lived outside the womb.
-Louise Slaughter, member of the US House of Representatives
