BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: serotonin

Why We Should Embrace the Bacteria in our Gut

Surprisingly enough, through research conducted in the California Institute of Technology, it was discovered that EC cells depend on Microbes found in the gut to produce Serotonin. EC Cell stands for Enterochromaffin Cell, and they can typically and easily be found in the small intestine, colon and appendix. They are shaped like polygons or cones. Serotonin is a neurotransmitter, with defects related to diseases ranging from Osteoporosis, Cardiovascular Disease, and even depression. According to Merriam Webster, a famous online dictionary, Microbes are microorganisms and “germs”. This oversimplified understanding of the significance of a microbe is representative of the overall population’s ignorance on the matter. Bacterium are forms of Microbes, and thus have very negative connotations. That is why this discovery regarding the correlation between the germs in EC cells and Serotonin (a neurotransmitter we can attribute much of our good mood) levels is so important.

To begin with, the peripheral Serotonin levels in mice with standard EC cells, and peripheral Serotonin levels in mice with microbe/bacteria/germ free cells were tested and compared. Astonishingly, the mice with standard EC cells had 60% higher levels of Serotonin than mice with germ free EC cells. The newly tested levels of Serotonin were affirmed by the side effects typically associated with increased levels of Serotonin. For example, the mouse’s gastrointestinal motility would increase overtime if their EC cells were unaltered, as opposed to if their EC cells were germ-free. Overall, it is safe to conclude that having Bacteria in the gut can actually make someone less depressed, and healthier all in all.

Love and happiness really do come from the bottom of your… gut?

Serotonin is the famous neurotransmitter oft attributed to causing joyous type emotions.  Unlike most neurotransmitters, which are produced predominately in the brain and nervous system, a recent study mentioned in a review article estimate that, “90 percent of the body’s serotonin is made in the digestive tract. […] [C]ertain bacteria in the gut are important for the production of peripheral serotonin.”

uBiome - Microbiome Sequencing Gut Bacteria Sample Kit

 

Interesting play on words of the “Microbiome.” The gut microbiome comprises most of our body but very little of our mass… It outnumbers our cells 10 to 1! [Source]

 

Researchers at the California Institute of Technology (Caltech) sought to identify a link between the gut microbiome and the production of the serotonin neurotransmitter. Peripherally made serotonin is already understood as a product of the digestive tract, however, is there a link between the myriad of bacteria that compose our gut microbiomes and the neurotransmitter? What they found, was surprising; notwithstanding the known communicative link between the nervous system and the microbiome, the researchers found that the microbiome is not directly responsible for most of the production of the neurotransmitter.  The bacteria interact and stimulate the production of serotonin by the intestinal cells.

 

To arrive at this conclusion, the researchers studied the effects of “germ-free” mice.  They found that the mice that exhibited a dearth of flora within. Experimental results indicated that the mice produced around 60% less serotonin than mice with normal gut microbiomes.  The experiments also demonstrated an interesting result that may lead to future studies on the serotonin deficiency treatments–the researchers found that when augmenting the gut microbiomes with bacteria responsible with serotonin production stimulation, the levels of the neurotransmitter increased. Of course, the subject is vastly complicated, and will therefore require extensive research to more fully understand.

Original Article

Study from Article

Serotonin Wikipedia Page

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Bullying and its Epigenetic Effect

Unfortunately, bullying is commonplace in most schools in America.  Most people are aware of the mental and psychological harm that bullying can cause, but not until very recently have they been aware of the lasting physical changes it can cause.  With the discovery of epigenetics, or the study of genetic traits or expressions that are not caused by DNA, but rather by the methylation or concealing of genes, a new door into the effects of bullying was opened. A group of researches from the UK and Canada performed a study on identical twins.  At age 5, the twins had not been exposed to bullies and expressed almost all of the same traits, physically and emotionally.  The researchers then waited until the twins were 12, imageand revisited only the twins that had different experiences with bullying (one twin was bullied when the other was not).  The researches found big disparities in the twins epigenome, or the way they express their genes.

 

The bullied twin’s protein that codes for a protein that helps move the neurotransmitter serotonin into neurons called SERT had significantly more DNA methylation in its promoter region.  This change is thought to dial down the amount of proteins that can be made from the SERT gene — meaning the more it’s methylated, the more it’s “turned off.”  Therefore, the bullied twin is unable to produce as much serotonin.  This effect is thought to persist through a person’s life.  The effects of bullying will persist an entire lifetime.

 

The researchers also tested how the twins responded to stressful situations differently.  The bullied twin had a much lower cortisol response than the twin that had not experienced bullying.  Cortisol is a hormone that helps people through stressful situations, like being bullied.  However, having too much cortisol is harmful to the body.  The bullied twin’s body turned off the gene that aids in cortisol production because they were being put in stressful situations so often by bullies that their body couldn’t tolerate the amount of cortisol they were producing.

 

This study is not only interesting from a scientific standpoint, but it is also very important in the movement against bullying.  These scientists proved that bullying not only does immense psychological harm, but it also effects people’s well being in a very real and lasting way.

 

 

 

Link to article: http://www.huffingtonpost.com/sharon-moalem/bullyings-terrible-legacy_b_5142857.html

 

Hypocretin: A New Avenue for Antidepressants

Depression is a major psychiatric disorder in the United States, affecting about six percent of the population. However, antidepressants in common use such as selective serotonin reuptake inhibitors (SSRIs) and other drugs have only flimsy evidence to support their efficacy. Recent studies suggest that positive results with these medications may be the result of the placebo effect rather than an effective treatment. Critics of current remedies for depression point out that they aren’t linked to observed deficiencies in certain hormones affect mood.

Scientists at the University of California Los Angeles Semel Institute recently discovered a new chemical, a peptide called hypocretin, directly linked to happiness and alertness. In their study, the scientists monitored patients undergoing treatment for severe epilepsy. “Piggy-backing” on the implanted electrodes from the patients’ treatment, the team monitored levels of hypocretin and MCH (or melanin concentrating hormone) throughout the day at 15 minute intervals. Notes of the patients’ activities were made simultaneously. Patients answered a questionnaire asking about their mood every hour they were awake. In analyzing their data, the scientists discovered that hypocretin was highest when patients experienced “positive emotions, anger, social interactions, and awakening.” In contrast, the MCH was highest during sleep lowest when hypocretin was high.

According to Professor Segel of the Semel Institute, who led the team that made this discovery, “The findings suggest that abnormalities in the pattern of activation of these systems may contribute to a number of psychiatric disorders.” Chemicals that counteract hypocretin are already being developed as sleeping pills, and hypocretin could provide the foundation for a new kind of antidepressant.

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