Postmenopausal vasomotor symptoms are associated with heightened cutaneous vasodilation despite preserved nitric oxide–mediated endothelial function

Objective: To evaluate whether postmenopausal females with vasomotor symptoms (VMS) exhibit altered nitric oxide synthase (NOS)-dependent cutaneous vasodilation during local heating, and whether these responses vary by body region. Methods: Cutaneous vascular conductance normalized to maximum vasodilation (percentage of the maximal conductance %CVC max ) was assessed at the chest, abdomen, forearm, and calf using laser-Doppler flowmetry in 18 postmenopausal females (9 with current VMS, 9 without VMS). Local skin temperature was increased from 33 °C to 42 °C (~30 min) to elicit a vasodilatory plateau. NG-nitro-L-arginine methyl ester (20 mM), a NOS inhibitor, was then perfused during continued heating (~40 min). The NOS contribution was assessed by the difference in %CVC max mediated by NG-nitro-L-arginine methyl ester. Results: Baseline %CVC max was higher at the chest compared with the calf across groups (10.0 3.3, 16.6%; P = 0.0013). During the 42 °C heating plateau, females with VMS exhibited greater %CVC max than those without VMS when responses were pooled across regions (7.2 1.7, 23.5%; P = 0.013), and at the abdomen (8.7 0.6, 18.4%), chest (10.3 2.3, 18.4%), and calf (8.4 0.4, 16.5%; all P 0.15). Conclusion: Although postmenopausal females with VMS exhibit heightened cutaneous vasodilatory responses to local heating, NOS-dependent vasodilation is preserved. These findings suggest that enhanced microvascular reactivity in VMS is not attributable to altered endothelial NOS function.