The linking of pain sensitivity and regulation to reproductive hormones--particularly estrogen--makes some "evolutionary" sense, Zubieta says. Women require more flexible, adaptive mechanisms to protect themselves from injury during their reproductive years to preserve the reproductive function of the species, he says. At the same time, women also have to adapt to the body changes and pain that takes place during pregnancy and childbirth--a time when reproductive hormones are at an all-time high. "So they have to develop mechanisms, like the mu-opioid neurotransmitter system, that promote that type of flexibility," Zubieta says. "Interestingly, this neurotransmitter system is also involved in maternal-offspring attachment behavior, another area where estrogens may play a role."
At McMaster University , Meir Steiner, MD, PhD, and his colleagues have been studying the role that estrogen and other reproductive hormones may play in gender differences in depression. Women are two to three times more likely than men to experience a major depressive episode during their lifetime.
"The underlying cause of the gender difference in depression and other mood disorders is not entirely clear," says Steiner, "but the differences, which begin rather dramatically at puberty and become less marked after menopause, strongly suggest a link to fluctuating estrogen and progesterone levels." Although hormones fluctuate in both men and women, the fluctuations are much more pronounced in women, particularly around their menstrual cycles, during the weeks immediately after pregnancy (postpartum), and in the period leading up to menopause (perimenopause). These fluctuations, Steiner has proposed, cause disturbances along the hypothalamic-pituit
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Contact: Leah Ariniello
dawn@sfn.org
202-462-6688
Society for Neuroscience
24-Oct-2004