The John B. Pierce Laboratory

Dr. Usselman’s published work chosen as an APSselect Paper

Charlotte Usselman, PhD has been a Post Doctoral Fellow in Dr. Nina Stachenfeld’s laboratory since November, 2015.  Before coming to the Pierce Laboratory, Dr. Usselman trained in Kevin Shoemaker’s laboratory at Western University (Canada), one of the most prestigious laboratories in the world studying neurovascular control of blood pressure.  A paper recently published from her work in that laboratory, Hormone phase influences sympathetic responses to high levels of lower body negative pressure in young healthy women was recently published in Am J Physi – Reg, Integrative Comp Physiol (  This paper was chosen by the Journal as an APSselect Paper.

APSselect: The editorial team carefully selects from the top articles nominated each month across the 10 APS (American Physiological Society) research journals that highlight, promote, and rapidly disseminate some of the most stimulating original research.  This is a rare and exciting honor, especially for a scientist in the early phase of what is obviously a promising career in physiology.

This study examined the role that circulating sex hormones play on maintaining blood pressure during orthostatic challenges.  Orthostatic challenges are those which encourage the pooling of blood in the lower body, such as standing for a long time, or moving from seating or lying to standing.  Usselman et al. found that high female sex hormone conditions were associated with greater peripheral blood pooling, likely the result of estrogen as a dilator of peripheral blood vessels. One unexpected finding was that women taking hormonal contraceptives experienced a fall in blood pressure at the highest level of lower body negative pressure, implying that hormone exposure may reduce orthostatic tolerance in young women. Together, these data improve our understanding of the role of sex hormones on the regulation of blood pressure, and provide some insight into the mechanisms by which young women have an increased risk for orthostatic intolerance but are protected from hypertension.