Oral contraceptive pill phase alters mechanisms contributing to cutaneous microvascular function in response to local heating

• DOI: 10.1152/ajpregu.00159.2024
• Publication Date: 2025-02-13T01:11:30Z
• Authors: Casey G. Turner; Anna E. Stanhewicz; Karen E. Nielsen; Jeffrey S. Otis; Rafaela G. Feresin; Brett J. Wong
• Keywords: Microdialysis; Tetraethylammonium; Reactive hyperemia

The purpose of this study was to investigate the effect oral contraceptive pill (OCP) phase on in vivo microvascular endothelium-dependent vasodilation and contributions nitric oxide (NO), cyclooxygenase (COX), endothelial-derived hyperpolarizing factors (EDHF). Participants completed two experimental visits random order, during 1) low 2) high hormone OCP cycle. Endothelium-dependent dilation assessed cutaneous microvasculature via local heating at four intradermal microdialysis sites treated with: lactated Ringer's (control), 10 mM ketorolac (Keto, COX inhibitor), 3) 50 tetraethylammonium (TEA, calcium-activated potassium channel 4) + TEA (Keto+TEA). Perfusion 20 L-NAME each site used quantify sensitive component dilation, suggesting NO contribution. There no ( p=0.75) or response p=0.09, d=0.7) control sites. Inhibition increased baseline blood flow regardless (all p<0.01). Control Keto elicited greater than Keto+TEA both phases p<0.0001). During phase, compared with Within-participant differences between support a phase-dependent restraint activity pathways p=0.01). These findings demonstrate that affects underlying mechanistic contributing endothelial function.