Hot flushes - also called hot flashes - affect millions of people, and not just women. Yet, it is still unclear what causes the episodes of temperature discomfort, often accompanied by profuse sweating.
Now, a team of researchers including Dr Naomi Rance from the University of Arizona College of Medicine, has come closer to understanding the mechanism of hot flushes, a necessary step for potential treatment options.
The team identified a group of brain cells known as KNDy neurons as a likely control switch of hot flushes. KNDy neurons (pronounced "candy") are located in the hypothalamus, a portion of the brain controlling vital functions that also serves as the switchboard between the central nervous system and hormone signals.
"Although the KNDy neurons are a very small population of cells, our research reveals that they play extremely important roles in how the body controls its energy resources, reproduction and temperature. They are true multitaskers," said Melinda Mittelman-Smith, who led the study.
By studying KNDy neurons in rats, the research team created an animal model of menopause to elucidate the biological mechanisms of temperature control in response to withdrawal of the hormone estrogen, the main trigger of the changes that go along with menopause.
They discovered that tail skin temperature was consistently lower in rats whose KNDy neurons were inactivated, suggesting the neurons control a process known as vasodilation, or widening of the blood vessels to increase blood flow through the skin.
"The hallmark of hot flushes is vasodilation. When you flush, your skin gets hot and you can see the redness of the skin. It is an attempt of the body to get rid of heat, just like sweating. Except that if you were to measure core temperature at that point, you would find it is not even elevated," Rance explained.
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Although the results are not yet directly applicable in helping individuals affected by hot flushes, they mark a necessary first step, Rance said in a statement.
"Right now the only effective way of treating flushes is estrogen-replacement therapy. If we could figure out what is causing those flushes, we could try to develop a better, more targeted therapy," Rance added.
Rance said hot flushes usually last for four or five years and occur in up to 80 per cent of women but also in men undergoing certain hormone treatments for prostate cancer.
The research was published in the Proceedings of the National Academy of Sciences.