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Mysterious Melatonin December 18, 2010

Posted by Kyle in Biology, Chemistry, Health, Medicine, Neuroscience, Nutrition, Physiology.
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I am sure everyone has already heard of a little compound known as melatonin. Melatonin is a hormone that can be found in many different organisms including plants, although most people know melatonin for its actions in mammals. In humans, melatonin is produced in the brain by the pineal gland. Circulating melatonin levels have been found to be high at night and low during the day, which is consistent with research that has shown that light suppresses melatonin. Because melatonin plays a role in controlling the circadian rhythm, it has received much interest for its use as a treatment for various sleep disorders. Because melatonin is a hormone, supplementing melatonin can present some issues.

Many people have used melatonin supplements to help them sleep at night. If you take a trip to your local drug store you are likely to find melatonin on the shelf. The first time I came across melatonin supplements I couldn’t help but think about the potential negative aspects to selling melatonin over the counter, unregulated. As many of you know, the human body likes to maintain homeostasis. When this delicate balance is interrupted, the body will react to return to homeostasis. I started to wonder what happens when someone takes melatonin supplements. The first thing that comes to mind is a decrease in the amount of melatonin receptors or a decrease in the production of melatonin itself, or both. I also wondered about possible side effects of increasing melatonin levels. As we have seen with many other hormones, multiple pathways and mechanisms can be influenced by a single hormone. So someone taking melatonin to help them sleep could inadvertently throw off other pathways, like those involved in reproduction for example.

Melatonin has been shown protect against reactive oxygen species, which can wreak havoc inside cells. This could potentially be an obvious benefit to taking melatonin supplements, especially if it helps an individual sleep at night. While sifting through the literature, I was unable to find any studies specifically looking at the negative effects of taking melatonin supplements, if any. But just because it isn’t proven that something is bad, doesn’t mean the potential for bad isn’t there. Also, other countries have taken action to stop over the counter sale of melatonin. Of course, there is also the question, do melatonin supplements even work?  How much of the melatonin present in a melatonin pill is denatured by stomach acids or excreted in urine before it even has an effect?

I am skeptical of melatonin supplements, if you haven’t noticed yet. To each his own, but I don’t think I will be purchasing or taking any melatonin supplements in the near future.  Good luck to everyone on their upcoming finals. Make sure to get plenty of sleep, although if your to-do list looks like mine, that won’t be happening.

Stress and the GI Tract December 17, 2010

Posted by ljsteele in Behavior, Biology, Chemistry, Ecology, Environment/Conservation, Health, Neuroscience.
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The mechanics of stress and the gut.

Stress is shown to have a huge effect on the body, whether or not it is experienced as an acute or chronic stress.  A major topic of interest is what effects stress has on the gastrointestinal tract in organisms.  According to a multi-part scientific paper entitled “Stress and the Gastrointestinal Tract”, there are many different stressors that can be examined within a variety of organisms.  Examples of the stressors explored include food deprivation, fearful sounds, weather changes, and water avoidance ( an acute stressors explored in lab organisms such as mice, rats, and guinea pigs).  It has also been shown that acute stressors in humans, such as pain exposure, anger, fear, and intense exercise can cause gastrointestinal shut down.

From the stressors listed above, research has explored how stress influences gastro muscles to slow contraction,  thus inhibiting the processing of food.  An interesting reaction to this slowing of peristaltic movement is the fact that many organisms lose control of their colon, showing defecation in response to certain stimuli such as fear and water avoidance.  Corticotropin releasing hormone, also known as CRH  (or CRF, as identified in the aforementioned paper), is released from the hypothalamus, and blocks the effects of the vagas nerve, while also traveling through the solar plexus, and attaching to receptors in the stomach.

Stomach ulcer

Once bound, this hormone has been shown to inhibit gastro movement, and thus preventing emptying of the stomach. The difference between the stomach and the colon is that the stomach requires contraction of the muscles to push food through, whereas the colon requires contraction to keep bowel movements inside the body.  With the effect of CRH binding to the receptors, relaxation in gastrointestinal muscles occur, which is why the release of the colon sphincter results.  However, the results explored here were in response  to short term stressors.  The effects of long-term stressors have yet to be studied.

Stress and Ulcers

What does this research mean to you?  Well, the results we glean from research like this offer powerful implications for human medicine and today’s society.  Many people not only experience acute stress, but chronic stress as well.   Short term affects of acute stress include accelerated of heartbeat and an increase in metabolism, but it is only natural to ponder the long term effects of chronic stress.    We can extrapolate from the results of  acute stress that it would make sense that we, as humans, would not want these effects to be long lasting.  Major problems would arise with the decrease of gastro movement.  Problems manifest from a build up of bile and stomach acids in the stomach.  Since gut motility is decreased when stressed, less movement would mean that more bile, which is highly acidic, would sit in the stomach longer and could lead to stomach or intestinal ulcers.

Sympathetic Nervous System

Chronic stress can also lead to a decrease in the immune system of the organism as well as a decrease in the second messenger systems within the body.  An example of this effect on a second messenger system is the attachment of CRH to CRH-receptors in the solar plexus.  The binding of these receptors causes the effect of the decrease in gastro movement.

How much stress is too much stress?

Lastly, with chronic stress and chronic stimulation of the CRH/CRF system, we might see a scenario in that the more that these receptors are activated, the more desensatized they can become. This could cause problems for people and their response to stress.  If the are “desensitized” this may mean that these people have a problem when trying to   properly responding to an acute stressors when needed.

Decreasing Ageing affect on Memory October 15, 2010

Posted by zach in Health, Medicine, Neuroscience, Physiology.
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Have you recently misplaced your car keys and spent hours trying to find them? A resent article from Science Daily explains how misplacing your keys may be a thing of the past.  A promising new drug candidate is currently being developed at the  University of Edinburgh to reverse age-related memory loss.  The researchers have developed a compound that has improved cognitive function and memory in aging mice. This compound works by blocking an enzyme known as 11beta-HSD1.  As we age our body changes, with these changes comes changes in the concentration of the enzymes in our body.  The cause of these enzymatic changes is not fully known but it can be linked to physiological effects such as stress.

The aging enzyme

11beta-HSD1 is an enzyme that is found in the brain which can produce stress hormones such as the glucocorticoids.  When there are high levels of glucocorticoids in the brain negatively affect memory.  Therefore, if we can find a way to block 11beta-HSD1 we could increase our memory by decreasing the negative pressure on memory. The problem with blocking 11beta-HSD1 is that until now it hasn’t been possible to find a molecule that has a high specificity for blocking only 11beta-HSD1.  After ingesting a synthetic compound that blocks 11beta-HSD1,  mice show a dramatic increase in memory after only ten days.  The increase in memory was quantified by the time it took mice to complete a Y maze.

A burgeoning field of research

The research in the biomedical world is very concentrated on developing medicines that will reduce or even try to eliminate the effects of aging.  In the past I have blogged about how targets of rapamycin act as a master regulator for protein synthesis.  If we could find a drug to regulate that regulated TOR we could in turn regulate aspects of how our body ages.  Maybe some day we will have a set of anti-aging drugs that will allow us to combat all the negative effects that come with growing old.  If researchers can keep developing synthetic compounds to stop memory loss there may be a day when you will never forget where you misplaced your keys.

Sleep and stress May 3, 2010

Posted by Colleen in Health, Neuroscience.
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tired and stressed

Finals week has arrived which includes late nights in the library, lots of caffeine and not enough sleep. We all know it’s bad for us, yet we continue to deprive ourselves of sleep just to get that extra hour of work in. We feel so stressed out that we think depriving ourselves of this vital function will help in some way, shape or form.

sleeping helps retention

Science Daily posted an article about stress and its connection to sleep. Studies have shown that “people with chronic stress report shorter sleep duration, worse sleep quality, and more daytime functioning impairments.” The problem is that lack of sleep can also cause more stress upon the person which could lead to an unfortunate and potentially never-ending cycle.  How should someone with this problem begin to address it? Make some lifestyle changes: don’t drink too much caffeine, don’t try to stay up all night studying for a final (I should take my own advice!), make sure you have a wind-down period before bed, etc. This way sleep deprivation won’t be the cause of the stress in your life!

Do sick people trigger immune responses in people that are not sick? May 2, 2010

Posted by Jill in Behavior, Biology, Health, Neuroscience.
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Chicken pox

The answer to this question is apparently, yes. A new study suggests that when people see someone that is blowing their nose, coughing, sneezing, or generally looking under the weather, could potentially trigger an immune response. In the study, participants were shown images of people with cold-like symptoms or other infectious diseases, such as pox or skin lesions, while another group of participants were not shown images of people feeling or looking sick. Among the two groups, blood samples were taken from all of the individuals to determine the extent of an immune response. Researchers found that the participants that were shown the images of the sick people mounted a stronger immune response against bacteria that had been added to each blood sample.

Similar photo to what study participants viewed that triggered an immune response

According to Lindsay Lyon, a reporter for U.S. News, reported seven ways to prevent from getting a cold. One of these ways was actually broadening one’s social network—those with larger and more diverse social networks tend to have less colds or are able to fight off colds better than those with smaller social circles. Sheldon Cohen, professor of psychology at Carnegie Mellon University, backs this theory with a line of evidence saying that people who are socially connected tend to live much longer than those with weak or a small number of relationships. Most experts would argue that the quality of a relationship beats the quantity of relationships, but Cohen argues that his data indicates the two factors are relatively similar, but either one has a positive impact on longevity.

The full study can be found in the Journal of Psychological Science.

 

Take Naps and Dream! May 1, 2010

Posted by Kyle in Biology, Neuroscience, Physiology.
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As finals are quickly approaching many students are spending a lot of time studying.  No matter how much you study, it is important to remember to get a decent amount of sleep.  A recent study by scientists at Beth Israel Deaconess Medical Center has shown that people who sleep right after attempting to learn a new task, more specifically those who dream about the task, perform better in later attempts.  Researchers hypothesized that by dreaming about a learning experience individuals would have improved performance on tasks relying on spatial memory. Researchers tested this hypothesis on 99 individuals by having them attempt a virtual maze.  They then had some individuals sleep while others stayed awake.  Individuals that slept and dreamed about some aspect of the maze performed 10 times better than other individuals. Individuals who remained awake and reviewed the path of the maze showed no improvement if they did not sleep.  These results show that something is happening while a person dreams that helps the brain sort out memory.

In another study related to learning and memory, researchers looked at how individuals evaluate their learning skills and memorization.  The researchers tested individuals by showing them a list of words and having them memorize the words. The individuals participating in the test predicted how well they would be able to remember the words.  The study showed that most of the participants underestimated their learning abilities and were over confident in their memories.  According to the researchers who performed these tests, Nate Kornell, an assistant professor of psychology at Williams College, and Robert A. Bjork of the University of California, Los Angeles, understanding how you learn and what supports learning is important to effectively manage the conditions of learning.

According to a separate study out from the University of California, Berkeley, napping can help restore brain power. The study showed that just 90 minutes of nap time can greatly improve learning ability later in the day. Past studies by the same research team have shown that pulling an all-nighter to study can decrease your ability to learn new information by roughly 40 percent. So as everyone prepares to finish off the semester, remember to not only study wisely but to also get plenty of sleep.  Hopefully I will be able to dream about organic chemistry and molecular genetics over the next couple nights, since this will apparently help me remember more. If not, at least maybe I can dream about golf and nap, and then maybe I wouldn’t be so bad at it.

A Second “Lab Rat” has its Genome Mapped April 28, 2010

Posted by ecogeeko10 in Behavior, Biology, Evolution, Genetics, Health, Neuroscience, Physiology.
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Many behavioral ecologists, geneticists, physiologists, etc. are familiar with the zebra finch (Taeniopygia guttata). In fact, many have considered it to be the avian version of the white lab rat. Because of this, these researchers should be excited to hear that scientists have just recently decoded the zebra finch’s genome.

A genome to explore behavior

The zebra finch isn’t the only bird to have its genome mapped (the chicken was completed first) and it’s only about one-third the size of the human genome. However, this was a unique find because it will greatly help behavioral ecologists to understand the underlying mechanisms that help baby songbirds learn how to sing from their parents. This isn’t something that could have been done with the chicken genome because chickens don’t learn how to “cluck” from their parents—they just do it. Zebra finches, on the other hand, are similar to humans because human children also learn how to speak from their parents.

The zebra finch genome gives us the opportunity to explore the influence of genetics on language development.

Researchers are already analyzing the genome and they are finding that a good portion of the bird’s DNA is actively participating in the hearing and singing of songs. What’s more, these short simple songs are rooted in a great deal of genetic complexity. To date, it has been understood that the very act of singing and hearing songs activates large, complex gene networks in the bird’s brain. However, the current genomic research is revealing there to be many more participating genes than once thought. Right now it seems that there may be approximately 800 total genes that are active in this process!

Genes not acting as genes

New evidence is also showing that many of the activated genes aren’t acting like genes in the traditional sense. Rather than coding for proteins, the DNA from these genes is transcribed into short stretches of non-coding RNA that control the expression of other genes involved in the zebra finch’s vocal communication. Since non-coding RNAs are very influential in the developmental processes in animals and since they are thought to be instrumental in the evolution of higher organisms, the vocal learning that is found in the higher organisms may use non-coding RNAs as their driving force.

The evolution of language

It is also worth noting that when comparing the newly mapped zebra finch genome with the chicken genome, there seems to be some obvious differences that may point towards the evolutionary pathway that gave rise to birds that are capable of vocal learning. For instance, the evolution of the ion channel genes—which are important players in behavior and neurological function—in the zebra finch brain were greatly accelerated; the expression of the male sex chromosome genes seems to have been modified; and the production of new variants of neurobiologically important genes have taken place. It is amazing to see how much has learned in such a short period of time!

From birds to humans

It took the combined effort of more than 20 institutions to map out the genome of this song bird and now everyone has the opportunity to reap the benefits from this work. The newly gathered information should prove to be instrumental in helping us to better understand how humans learn language and perhaps it will help neuroscientists to identify the genetic and molecular causes of certain speech disorders that are associated with various illnesses such as Parkinson’s disease, strokeautism, etc. With the parrot genome scheduled to be completed by the end of this year, who knows what all we can learn about our little feathered friends and even ourselves!

Potential assignment for the new Ecological Physiology class April 27, 2010

Posted by Dr. O in Behavior, Biology, Fun, Neuroscience, Physiology, Science Education.
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MU Science Students as possible Guest Bloggers?

What do you think?  Perhaps my students should star as “guest writers” to this blog , the Animal Review, who’s blog owners “grade” animals based on their wacky adaptations.  Seems a perfect way to celebrate the diversity of physiology in the animal world.  I might just use this as an assignment for Physiological Ecology-BIO 305 in the Spring of 2012

Who needs a brain? (this coming from a neuroscientist…)

After checking out the Animal Review, I for one would have given the jellyfish a “B” and the comb jellies (Ctenophora) an “A+” for living in a “society” and incorporating “tool use” with out a true brain.

The beautiful comb jelly

I would also give the angler fish a solid B+ or A-.  The ladies are okay in their own skin and definitely wear the pants in the relationship.  After all… males are basically no better than parasites.

Research Conferences are Cool! April 25, 2010

Posted by ecogeeko10 in Behavior, Biology, Ecology, Evolution, Genetics, Neuroscience, Physiology.
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A couple of weeks ago, I was fortunate enough to be able to attend the Association of Southeastern Biologists’ 71st Annual meeting held in Asheville, North Carolina. This is a pretty neat conference because every year over 1000 biologists get together and present the research that they have been working on in the past year.  The reason why I made the trip is because I did a poster presentation for my research on beaver dredged canal function and development. However, the types of questions that other researchers addressed ranged from topics such as the role of estradiol in courtship displays of Collared Manakins to the best management techniques for mountain lions in New Mexico. This conference was definitely geared towards a wide range of interests.

One particular oral presentation that I attended and thought was pretty interesting was by a graduate student named Jennifer Carman from Western Carolina University. In her study, she was investigating the morphological variation in song sparrows. What was so fascinating about this research, though, was that she was seeing real/statistically significant morphological differences between birds in rural areas and birds in urban areas. Just as Charles Darwin saw that there were many variations in the beaks of finches on the Galapagos Islands, Jennifer was seeing that the urban populations of song sparrows had larger and strong beaks than the rural populations that are just a few miles down the road. What’s more, the urban birds seemed to be much bolder than their neighbors. Jennifer was sure to let us know that this is only a preliminary study, but she is hoping to eventually find out what is causing these morphological differences. Are the urban population exposed to different food sources that require stronger beaks? She is also interested in seeing if the urban populations have higher levels of testosterone. If so, how are these populations benefiting from being more aggressive? I am interested to see how this study turns out.

A second talk that I thought was interesting actually relates a lot with what we have been doing in our own molecular genetics class. In the presentation, titled Detection of Misidentified Plants in the International Cocoa Geneback, Trinidad, James Bardsley (Towson University-Maryland) explained how he and his class used SSR analysis in order to find that 31 out of the 123 individual cocoa plants that they brought back from Trinidad were actually mislabeled. The reason for this high level of error comes from the fact that breeders are constantly trying to create new hybrids with desired characteristics. For instance, one person may decide that he was to create a crop that has a high yield and is disease resistant. He would achieve this by obtaining a “high yield” gene and a “disease resistant” gene from the gene bank and then breed them into the crop of interest. This constant intermixing of genes makes for much difficulty when trying to tell plants apart. Many of these hybrids have very similar morphological characteristics! James and his lab proved that the best way to fix this problem is to utilize molecular techniques when trying to identify a species. This is indeed a relatively expensive technique, but it is unfair that the consumers are being sold the incorrect product 25% of the time. Hopefully the cocoa companies takes this information to heart.

I’m really happy about being given the chance to attend one of these meetings. I was able to gain experience in presenting my own work, I was able to network with other scientists in the field, and I was able to learn about some pretty cool studies that are going on around the country. I highly recommend that anyone who is interested in research should go to a conference like this because they are great resources for anyone who wants to get their name out there so that they can obtain a job or go on to graduate school. This meeting was definitely worth the eight-hour drive!

Queer Antelope and the Sex Dreams of Shrew… March 5, 2010

Posted by Dr. O in Behavior, Biology, Genetics, Health, History of Science, Neuroscience.
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Recently Dr. Donna Drucker, a historian studying the work of Alfred Kinsey, came to speak at MU’s new, “Interdisciplinary Seminar Series”.

I found this talk to be quite informative and interesting from the construct of Kinsey’s previous work as an entomologist and animal behaviorist and how it influenced his later work on human sexual behavior.

We had just finished a segment in BIO 326-Animal Behavior, on the influence of the environment on neuroscience as well as a segment in BIO 425-Molecular Genetics, on behavioral genetics and the influence of nature vs. nurture…or more appropriately in my mind, the spectrum of nature vs. nurture on behavior.

You can find a podcast of Dr. Drucker’s seminar here.

Drucker talk