Temperature fluctuations: due to weather seasons or seasons of change within you?

The changeThe seasons have just changed and temperatures have dropped.  Everyone feels comfortable at different temperatures, and right now in Wisconsin, it’s not uncommon to see some people wearing winter jackets while others are wearing shorts.  During menopause, a woman’s temperature comfort range changes and is the main cause of hot flashes.  Hot flashes are commonly blamed on the sudden change in hormone levels, but neurotransmitters also play a major role in hot flashes and temperature regulation.

One of the most significant connections is estradiol and serotonin.  Serotonin and estrogen receptors are present together in many of the same tissues throughout the body.  Activation of the estradiol receptor E2-β increases the number of the serotonin receptor 5-HT2A.  This is important because the 5-HT2A receptor is involved in mood, cognitive function, and temperature regulation.

Figure 1. At reproductive age, the temperature range that women feel comfortable is wide because of the abundance of serotonin and estradiol.  As women age, estrogen levels decrease, leading to a smaller comfort range for temperatures.  The smaller comfort range can easily lead to hot flashes.

Figure 1. At reproductive age, the temperature range that women feel comfortable is wide because of the abundance of serotonin and estradiol. As women age, estrogen levels decrease, leading to a smaller comfort range for temperatures. The smaller comfort range can easily lead to hot flashes.

5-HT2A receptors found in the hypothalamus regulate body temperature and work in conjunction with estradiol to influence the thermoregulatory set point (Figure 1).  For example, a pre-menopausal, “healthy” individual should have an abundance of estradiol and serotonin in circulation leading to estrogen binding and an upregulation of 5-HT2A receptors and a wide thermoregulatory set point.  As women age estrogen levels decline, resulting in less 5-HT2A receptors and a narrowing of the thermoregulatory set point.  This narrowing of the temperature range at which women feel comfortable is thought to be a change that leads to hot flashes.

So when you look to open a window when others reach for a sweater, consider your estrogen and serotonin levels. For more information on the role neurotransmitters can play in hot flashes, please watch the webinar “The Science of Being Hot: Clinical Neuroendocrinology for Hot Flashes and Night Sweats” on the NeuroScience YouTube channel.

References:
Blum I, et al. (1996). The effect of estrogen replacement therapy on plasma serotonin and catecholamines of postmenopausal women. Isr J Med Sci, 32:1158-62.
Roepke, T, et al. (2011). Front Biosci, 16:125-34.
Rybaczyk, LA, et al. (2005). An overlooked connection: serotonergic mediation of estrogen-related physiology and pathology. BMC Women’s Health.
This entry was posted in Endocrinology and tagged , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s