Scientists have identified neurons responsible for regulating the body temperature of mammals, paving the path for technological development that can artificially modify it to assist cure heat stroke, hypothermia, and even obesity, news agency PTI reported quoting a recent study.
A group of researchers from Nagoya University in Japan discovered that EP3 neurons in the preoptic area of the brain play an important role in controlling body temperature in animals. The preoptic region is a portion of the hypothalamus that regulates important functions in the body.
When the preoptic area receives signals from a mediator called prostaglandin E (PGE2), which is created in response to infections, the preoptic area sends out a command to raise body temperature in order to combat viruses, bacteria, and other disease-causing organisms.
The results have been published in the journal Science Advances.
Humans and many other mammals control their body temperature at roughly 37 degrees Celsius, or 98.6 degrees Fahrenheit, which maximises all regulatory functions. When their body temperature deviates significantly from the normal range, their functions are hampered, potentially leading to heat stroke, hypothermia, and, in the worst-case scenario, death. However, if body temperature can be artificially changed to the usual range, these disorders may be treated.
It was unknown which neurons in the preoptic region sent orders to raise or lower body temperature.
Professor Kazuhiro Nakamura and his colleagues used rats in their research to find these neurons. According to the study, they focused on EP3 neurons in the preoptic area, which express EP3 PGE2 receptors, and explored their involvement in regulating body temperature.
According to the study, Professor Nakamura and his colleagues initially explored how the activity of EP3 neurons in the preoptic area alters in response to changes in ambient temperature.
For rats, a comfortable temperature is roughly 28 degrees Celsius. The rats were subjected to cold (4 degrees Celsius), room (24 degrees Celsius), and hot (36 degrees Celsius) temperatures for two hours.
The results showed that exposure to 36 degrees Celsius activated EP3 neurons but not 4 or 24 degrees Celsius.
The researchers next examined nerve fibres of EP3 neurons in the preoptic region to determine where EP3 neuron signals are delivered. The discovery revealed that nerve fibres are scattered throughout the brain, particularly in the dorsomedial hypothalamus (DMH), which activates the sympathetic nervous system.
The sympathetic nervous system is always operating at the most fundamental level in order to maintain homeostasis, which is the state of optimal functioning for the organism and encompasses several factors such as body temperature and fluid balance.
According to the study, the chemical used by EP3 neurons for signal transmission to DMH is gamma-aminobutyric acid (GABA), a strong inhibitor of neuronal excitation.
To learn more about the role of EP3 neurons in temperature regulation, researchers used a chemogenetic technique to modify their activity. They discovered that stimulating the neurons decreased body temperature while suppressing their activity increased it.
This study found that EP3 neurons in the preoptic area play an important role in controlling body temperature by sending inhibitory signals to DMH neurons, which control sympathetic responses.
"Probably, EP3 neurons in the preoptic area can precisely regulate the signal strength to fine-tune body temperature," said Nakamura, the lead author of the study was quoted as saying by PTI.
"For example, in a hot environment, signals are augmented to suppress sympathetic outputs, resulting in increased blood flows in the skin to facilitate the radiation of the body's heat to prevent heat stroke, PTI reported.
"Signals are lowered in a cold environment to activate sympathetic outputs, which boost heat production in brown adipose tissue and other organs to prevent hypothermia. Furthermore, during infection, PGE2 acts on EP3 neurons to decrease their activity, resulting in sympathetic output activation and fever "Nakamura stated.
According to the study, technological advancements capable of artificially altering body temperature can be applied to a wide range of medical sectors, including the treatment of obesity, by keeping body temperature slightly higher than normal to increase fat burning.
"Additionally, this technology could lead to new techniques for human survival in hotter global conditions, which is becoming a critical global challenge," Nakamura said.
(With Inputs From PTI)