The study objective of this project is to examine the mechanisms of the venous distension
reflex (VDR) in humans. We hypothesize that COX blockade with ketorolac tromethamine, an
intravenous NSAID, will attenuate the muscle sympathetic nerve activity (MSNA) response to
limb venous distension. To gain further insight into whether the COX byproducts directly
stimulate chemically-sensitive afferents, or enable venodilation and indirectly evoke
afferent stimulation, we will measure vein size using 3T MRI during venous distention with
and without ketorolac infusions.