Researchers have discovered a neurological target that may lead to the development of a medication to control a common and distressing symptom of menopause – hot flashes.
The effect is caused by the dilation of blood vessels just beneath the skin, leading to sweating and a flushed face. They are experienced by about two-thirds of women during and sometimes before menopause, and can be a troublesome feature of life for as long as 11 years.
The purpose of hot flashes remains mysterious, but now scientists from the University of Washington in the US may have at least pinned down the cause – a type of neuron, called Kiss1, found in an area of the brain known as the hypothalamus.
Using mice, a team led by Stephanie Padilla established that activation of Kiss1 cells in mice from whom sex organs had been removed produced hot flashes – and did so in males as well as females.
In pre-menopausal women, and men, the neurons are regulated by hormones released by sex organs. As the level of hormones diminishes with age, the regulation becomes less stringent, leading to temperature fluctuations.
Although more research needs to be done, Padilla and her colleagues suggest that the link between Kiss1 and sex hormones and its effect on body temperature may be linked to the demands of carrying offspring. It may represent an additional, or auxiliary, temperature control system.
The Kiss1 neurons express two types of peptides, called kisspeptin and neurokinin B. The researchers found that if they used a pharmacological barrier to block neurokinin B receptors, hot flashes could not be induced.
Kiss1 neurons are also present in humans. Although rodent models do not always represent accurate analogues for people, the results suggest that blocking neurokinin B receptors represents a treatment target for controlling the menopause symptom.
“Hormonal states such as menopause and prostate cancer treatment that give rise to hot flash susceptibility are very complex,” says Padilla.
“That we were able to reliably generate such a robust physiological response by manipulating one population of sex-hormone-sensitive cells in a specific region of the brain validated a decade of research by groups investigating this phenomenon.”
The research is published in the journal Cell Reports.