Comparing cutaneous NO-dependent vasodilation between young males and females

Area of Science:

• Physiology
• Vascular Biology
• Dermatology

Background:

• Cutaneous microvascular responses to local heating and acetylcholine (ACh) are commonly studied to assess endothelium and nitric oxide (NO) function.
• However, sex differences in these responses in healthy young adults are not fully understood.

Purpose of the Study:

• To investigate sex differences in cutaneous vasodilation in response to local heating and ACh.
• To determine the role of NO in these sex differences.
• To examine the influence of the menstrual cycle on these responses in females.

Main Methods:

• Eighty healthy young adults (40 females) underwent local heating (39°C and 42°C) and intradermal microdialysis with ACh (10^-10 to 10^-1 mol/L) alone or with L-NAME (NO synthase inhibitor).
• Cutaneous vasodilation was measured using laser-Doppler flowmetry.
• Menstrual cycle phase and hormonal contraceptive use were recorded in females.

Main Results:

• Local heating to 42°C induced greater endothelium- and NO-dependent vasodilation than 39°C, with no sex differences observed.
• ACh-induced endothelium-dependent vasodilation did not differ between sexes.
• The NO-dependent component of ACh-induced vasodilation was greater in females than males (p=0.01).
• Menstrual cycle phase did not influence endothelium- or NO-dependent vasodilation in females.

Conclusions:

• Sex differences in microvascular NO bioavailability are stimulus-dependent in young adults.
• In females, cutaneous vasodilation responses are not significantly affected by menstrual cycle phase or hormonal contraceptive use.