AP Biology class blog for discussing current research in Biology

Tag: neurotransmitters

Newly Discovered Neurons and Their Role in Maintaining Normal Body Temperature

The internal body temperature in humans and mammals is maintained at 37℃/96℉, unless disrupted by a force like an illness or heat exhaustion. Regulating the body to stay in the normal range is crucial for survival and for enzyme function.  Our internal body temperature is constantly being regulated by our hypothalamus, located at the base of our brain. The hypothalamus uses sensors from a mediator known as prostaglandin E which is brought about when an infection is present in the body. After PGE2 is present, it signals for the body to raise its temperature and combat the infection. If temperature levels are abnormal, the enzymes in our body have trouble functioning because they need specific temperature conditions to carry out reactions. Therefore, maintaining homeostasis throughout the body by regulating internal temperature is key to human survival.

Prostaglandin E

A team of researchers at Nagoya University in Japan were inspired by this process and decided to focus on the unknown neurons that make up the receptors of PGE2 and how this regulation process functions. The group of professors and colleagues successfully discovered key neurons that work to regulate the body temperature of mammals. This finding can be highly useful for creating future technology that can artificially fix body temperature related conditions such as hypothermia, heat stroke, and obesity.  



By using rats as a subject for their research, they exposed the rats to cold (4°C), room (24°C) and hot (36°C) temperatures to observe the effect of temperature changes on EP3 neuron response. After conducting the experiment, the researchers were able to conclude that exposure to the hot temperature led to an activation of EP3 neurons and the cold temperatures did not. Once they made this conclusion, they dug deeper into the neurons and analyzed the nerve fibers of the neurons to discover where the signal transmission occurs after sensing an infection. The researchers were able to conclude that the neuron fibers are spread out in different areas of the brain, mainly the dosomedial hypothalmus, which works to activate the sympathetic nervous system. Not only did they discover these fibers, but they also discovered the substance that EP3 neurons utilize to send signals to DMH. By observing the structure and chemical makeup, they found that this substance is a neurotransmitter known as gamma-aminobutyric acid (GABA), which inhibits neuron excitation. 

Finally, their findings support the idea that EP3 neurons are a major component of regulating internal body temperature and that they send out the GABA substance to signal to DMH neurons for a proper response. Their research proves that intiating a neural response decreases body temperature and inhibiting neurons leads to an increase in body temperature. Furthermore, their strong research in this area can support future development of advanced technology that will be capable of artificially adjusting internal body temperature. The anticipated technology could help prevent hypothermia, treat obesity to keep body temperature slightly higher and initiate fat burning, and be a key method of survival in hot environments. 


Epigenetics and Dopamine Activity

Researchers at the University of California in Irvine have correlated erratic dopamine activity as an underlying cause of complex neuropsychiatric disorders, specifically because of the epigenetic alterations caused by low levels of dopamine. This study, overseen by Emiliana Borelli, a UCI professor of microbiology & molecular genetics, provides clues to the possible causes of complicated disorders like schizophrenia.

Dopamine is a neurotransmitter (and hormone) that fuels our daily life, acting as our prime motivator and pleasure inducer, while also being linked to memory, and cognitive function. Many addictive drugs increase the amounts of dopamine released to exhausting levels, eventually wearing out the neurotransmitters notwithstanding the negative effects of the drugs themselves. High dopamine levels can also be achieved via everyday pleasures like exercise or sex, which can also spur addiction.


Dopamine, therefore, has an irrefutable role in our everyday lives, and according to Borelli, “Genes previously linked to schizophrenia seem to be dependent on the controlled release of dopamine at specific locations in the brain. Interestingly, this study shows that altered dopamine levels can modify gene activity through epigenetic mechanisms despite the absence of genetic mutations of the DNA.”

In short, it is quite likely that Dopamine is an epigenetic hub of sorts, that can cause powerful changes in gene regulation when functioning in a disrupted or excessive manner. Borelli, knowing the consequences of excess dopamine release, tested the opposite effect on mice, hindering dopamine release by turning off mid brain dopamine receptors in rats, leading to mild dopamine synthesis. The results were profound, as Borelli found there to be decreased expression in approximately 2,000 genes in the prefrontal cortex. This epigenetic surge of decrease in genetic expression was reinforced by the increase in change of DNA proteins called histones, which are associated with reduced gene activity. The now mutated mice suffered from ranging psychotic behavior and episodes, and were then treated with dopamine activators for a duration of time before seeing their behavior normalize.

Borelli’s and others’ work will provide useful clues for understanding these complex neurological disorders, while serving to reinforce the newfound importance of comprehending gene regulation and expression. These studies seem to point to a new era in which it is not just your genetic make up that determines your future, but also the regulation of your genes.



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