Women with high levels of estrogen are more active than women with low estrogen. The same is true for female mice. Cold Spring Harbor Laboratory (CSHL) Assistant Professor Jessica Tollkuhn and her collaborators discovered a small cluster of estrogen-sensitive neurons in the mouse brain that drive physical activity. They found that manipulation of these neurons alone is sufficient to increase activity in the absence of estrogen.
To mimic the effects of estrogen, the scientists developed a mouse with a synthetic receptor (MC4R::hM3Dq) on neurons that normally respond to estrogen (top video). The mouse was fed a drug called CNO that was designed to activate the synthetic receptor. The mouse became highly active, even at a time of the day when it usually would be inactive.
In contrast, the mouse in the bottom video had no synthetic receptors. The drug CNO had no effect on the mouse’s activity; it remained inactive.
The video was sped up twenty times and was provided by the lead author of this study, William C. Krause, a postdoctoral researcher in Holly Ingraham’s lab at University of California, San Francisco.
For humans, this finding may be relevant for post-menopausal women: when estrogen levels decline during menopause, many people become less active. The discovery suggests that there may be new ways to increase activity after menopause.