As a homothermal animal, the human body temperature is regulated at approximately 37°C. Even at resting state, the muscles, liver, brain, heart, kidneys, and other organs generate constant heat. Body temperature is maintained at homeostasis by dissipating this generated excess heat outside the body. Moreover, we must respond to temperature changes caused by the environment. The nervous system is the biological thermostat that responds to such changes.
Temperature information from the skin is transmitted to the cerebral cortex via the spinothalamic cortical tract, leading to conscious perception of temperature. Temperature information is also transmitted to the preoptic area via the lateral parabrachial nucleus, modulating the sympathetic nerves and protecting the body from temperature changes in the external environment; the preoptic area is the thermoregulatory center, and this defense mechanism is an essential mechanism for homeothermic animals, including humans, to survive in a changing temperature environment. In addition, the preoptic area is also the command center that causes fever during infection. Thus, the thermoregulatory mechanism centering on the preoptic area is a very important system that protects the living body from environmental changes and infections.
However, the recent abnormal weather and the emergence of unknown viruses are extremely dangerous for living organisms because they cause body temperature changes that exceed the capabilities of biological thermostats. For example, extreme heat due to global warming and long-term fever generation cause heat stress and damage living organisms. Heat stress induces neuroinflammation, leading to memory impairment and exacerbation of neurodegenerative diseases. In addition, cold stress caused by extreme cold or cooler disease (a modern disease) causes excessive activity of sympathetic nerves and induces mental stress and chronic pain. Furthermore, fever of unknown origin and psychogenic fever due to mental stress may lead to abnormalities in the biological thermostat and its system collapse.
On the other hand, factors that are not directly related to temperature, such as heat and cold stress, can also affect thermoregulation. For example, one of the symptoms of diabetes is burning feet syndrome, a fever in the soles of the feet caused by poor blood circulation; in starvation, decreased metabolism also reduces heat production and cause hypothermia; intermittent hydrarthrosis often develops in women and induces hyperthermia due to physiological stress such as ovulation and menstruation.
We are constantly exposed to external and internal factors that disturb the homeostasis of body temperature, so the thermoregulatory mechanism is essential as an organism's defense. In addition, there are currently no appropriate therapeutic drugs for autoinflammatory diseases, which are often intractable diseases such as familial Mediterranean fever, TNF receptor-related periodic syndrome, and cryopin-related periodic fever syndrome. As the biological thermostat, the brain plays a central role in this defense mechanism, so it is important to understand its mechanism. Recently, the mechanism of body temperature regulation has been clarified, and it has become possible to grasp the brain temperature by MRI analysis. However, the detailed mechanism of fever caused by various factors such as neuroinflammation due to heat stress and hypothermia due to anesthesia is still not well understood.
This topic focuses on the relationship between the nervous system controlling thermoregulation and the factors that disrupt body temperature homeostasis. We hope that this topic will contribute to the discovery of new neuroregulatory mechanisms of body homeostasis based on thermoregulation and the development of treatments for intractable febrile diseases.
As a homothermal animal, the human body temperature is regulated at approximately 37°C. Even at resting state, the muscles, liver, brain, heart, kidneys, and other organs generate constant heat. Body temperature is maintained at homeostasis by dissipating this generated excess heat outside the body. Moreover, we must respond to temperature changes caused by the environment. The nervous system is the biological thermostat that responds to such changes.
Temperature information from the skin is transmitted to the cerebral cortex via the spinothalamic cortical tract, leading to conscious perception of temperature. Temperature information is also transmitted to the preoptic area via the lateral parabrachial nucleus, modulating the sympathetic nerves and protecting the body from temperature changes in the external environment; the preoptic area is the thermoregulatory center, and this defense mechanism is an essential mechanism for homeothermic animals, including humans, to survive in a changing temperature environment. In addition, the preoptic area is also the command center that causes fever during infection. Thus, the thermoregulatory mechanism centering on the preoptic area is a very important system that protects the living body from environmental changes and infections.
However, the recent abnormal weather and the emergence of unknown viruses are extremely dangerous for living organisms because they cause body temperature changes that exceed the capabilities of biological thermostats. For example, extreme heat due to global warming and long-term fever generation cause heat stress and damage living organisms. Heat stress induces neuroinflammation, leading to memory impairment and exacerbation of neurodegenerative diseases. In addition, cold stress caused by extreme cold or cooler disease (a modern disease) causes excessive activity of sympathetic nerves and induces mental stress and chronic pain. Furthermore, fever of unknown origin and psychogenic fever due to mental stress may lead to abnormalities in the biological thermostat and its system collapse.
On the other hand, factors that are not directly related to temperature, such as heat and cold stress, can also affect thermoregulation. For example, one of the symptoms of diabetes is burning feet syndrome, a fever in the soles of the feet caused by poor blood circulation; in starvation, decreased metabolism also reduces heat production and cause hypothermia; intermittent hydrarthrosis often develops in women and induces hyperthermia due to physiological stress such as ovulation and menstruation.
We are constantly exposed to external and internal factors that disturb the homeostasis of body temperature, so the thermoregulatory mechanism is essential as an organism's defense. In addition, there are currently no appropriate therapeutic drugs for autoinflammatory diseases, which are often intractable diseases such as familial Mediterranean fever, TNF receptor-related periodic syndrome, and cryopin-related periodic fever syndrome. As the biological thermostat, the brain plays a central role in this defense mechanism, so it is important to understand its mechanism. Recently, the mechanism of body temperature regulation has been clarified, and it has become possible to grasp the brain temperature by MRI analysis. However, the detailed mechanism of fever caused by various factors such as neuroinflammation due to heat stress and hypothermia due to anesthesia is still not well understood.
This topic focuses on the relationship between the nervous system controlling thermoregulation and the factors that disrupt body temperature homeostasis. We hope that this topic will contribute to the discovery of new neuroregulatory mechanisms of body homeostasis based on thermoregulation and the development of treatments for intractable febrile diseases.
