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Updated: Aug 6, 2026
Intradermal Microdialysis: An Approach to Investigating Novel Mechanisms of Microvascular Dysfunction in Humans
Published on: July 21, 2023
Comparing cutaneous NO-dependent vasodilation between young males and females
Madison G Evering1, Kelsey S Schwartz2,3, Claire E Goebel2
1Department of Health Behavior and Nutrition Sciences, University of Delaware, Newark, DE.
Background:
Despite the common use of local heating and intradermal microdialysis perfusion of acetylcholine (ACh) to probe cutaneous endothelium and nitric oxide (NO)-dependent dilation, sex differences in microvascular responsiveness to these stimuli in healthy young adults remain incompletely understood.
Methods:
Cutaneous vasodilation was assessed in response to local heating to 39°C and 42°C and graded perfusion of ACh (10-10 to 10-1 mol/L) alone or concurrently with 15 mM NG-nitro-L-arginine methyl ester (L-NAME; NO synthase inhibitor) using laser-Doppler flowmetry coupled with intradermal microdialysis in 80 young adults (40 females).
Results:
Local heating to 42°C elicited greater endothelium- and NO-dependent dilation than heating to 39°C in both groups (p<0.001), but no sex differences were observed at either temperature (p=0.65). ACh-induced endothelium-dependent dilation also was not different between sexes (p=0.08), but the NO-dependent component was greater in females than in males (p=0.01). In young females, menstrual cycle day (range: day 2-33) was not associated with endothelium- or NO-dependent dilation in response to any stimulus (all p≥0.19), regardless of hormonal contraceptive use.
Conclusions:
Taken together, these findings suggest that sex differences in microvascular NO bioavailability in healthy young adults depend on the stimulus used to elicit cutaneous vasodilation and, in females, microvascular endothelium- and NO-dependent dilation are not meaningfully influenced by menstrual cycle phase.
