D'Souza Andrew W, Hissen Sarah L, Manabe Kazumasa, Washio Takuro, Annis Meghan C, Sanchez Belinda, Usselman Charlotte W, Fu Qi, Shoemaker J Kevin
Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada.
Am J Physiol Heart Circ Physiol. 2025 Feb 1;328(2):H271-H282. doi: 10.1152/ajpheart.00623.2024. Epub 2025 Jan 7.
Although previous work has demonstrated that oral contraceptive pill (OCP) use does not affect resting muscle sympathetic nerve activity (MSNA), growing evidence indicates that it attenuates neurogenic vasoconstriction. Despite these advances, it remains unknown how OCP use affects the ability of MSNA to dynamically control vascular tone and arterial blood pressure (BP) on a beat-by-beat basis. Thus, we tested the hypothesis that, compared with naturally menstruating females (MC), those using OCPs will exhibit attenuated sympathetic vascular transduction at rest. Forty-three females [MC: = 21, 26 (4) yrs; OCP: = 22, 24 (4) yrs; data are presented as means (SD)] completed 10 min of supine rest with continuous measurements of beat-by-beat BP, femoral artery blood flow (26 females; MC: = 13, OCP: = 13), and MSNA. Spike-triggered averaging was used to determine sympathetic transduction into leg vascular conductance (LVC) and BP for 12 cardiac cycles following MSNA bursts. Overall sympathetic-BP transduction ( = 0.293), as well as sympathetic-BP transduction of MSNA burst quartiles ( = 0.741) and burst firing patterns ( = 0.452) were not different between the MC and OCP groups. Conversely, sympathetic vascular transduction per unit MSNA burst amplitude ( = 0.026) and burst firing pattern ( = 0.014) were attenuated among females using OCPs. In addition, females using OCPs demonstrated progressively smaller leg vasoconstrictor responses as a function of MSNA burst firing pattern compared with MC females ( = 0.021). Collectively, these data indicate that, in premenopausal females, OCP use attenuates the leg vasoconstrictor responses to bursts of MSNA, particularly during periods of increased sympathetic neural drive, without affecting the transduction of MSNA bursts into beat-by-beat changes in BP. This study investigated the impact of OCP use on the transduction of MSNA bursts into regional vasoconstriction and blood pressure in premenopausal females. We demonstrated that females using OCPs exhibit attenuated sympathetic transduction into LVC; however, this does not translate to reductions in sympathetic blood pressure transduction. Collectively, these data indicate that OCP use may alter the local vasoconstrictor response to bursts of MSNA; however, compensatory mechanisms may contribute to maintain sympathetic blood pressure transduction.
尽管先前的研究表明，口服避孕药（OCP）的使用不会影响静息状态下的肌肉交感神经活动（MSNA），但越来越多的证据表明，它会减弱神经源性血管收缩。尽管有这些进展，但OCP的使用如何影响MSNA在逐搏基础上动态控制血管张力和动脉血压（BP）的能力仍不清楚。因此，我们检验了以下假设：与自然月经周期的女性（MC）相比，使用OCP的女性在静息状态下交感神经血管转导会减弱。43名女性[MC组：n = 21，年龄26（4）岁；OCP组：n = 22，年龄24（4）岁；数据以均值（标准差）表示]完成了10分钟的仰卧休息，期间连续测量逐搏血压、股动脉血流量（26名女性；MC组：n = 13，OCP组：n = 13）和MSNA。在MSNA爆发后的12个心动周期中，使用脉冲触发平均法来确定交感神经向腿部血管电导（LVC）和血压的转导。MC组和OCP组之间的总体交感神经-血压转导（P = 0.293），以及MSNA爆发四分位数的交感神经-血压转导（P = 0.741）和爆发发放模式（P = 0.452）没有差异。相反，在使用OCP的女性中，每单位MSNA爆发幅度的交感神经血管转导（P = 0.026）和爆发发放模式（P = 0.014）减弱。此外，与MC组女性相比，使用OCP的女性随着MSNA爆发发放模式的变化，腿部血管收缩反应逐渐减小（P = 0.021）。总体而言，这些数据表明，在绝经前女性中，OCP的使用会减弱腿部对MSNA爆发的血管收缩反应，特别是在交感神经驱动增加的时期，而不会影响MSNA爆发向逐搏血压变化的转导。本研究调查了OCP的使用对绝经前女性MSNA爆发向局部血管收缩和血压转导的影响。我们证明，使用OCP的女性交感神经向LVC的转导减弱；然而，这并没有转化为交感神经血压转导的降低。总体而言，这些数据表明，OCP的使用可能会改变对MSNA爆发的局部血管收缩反应；然而，代偿机制可能有助于维持交感神经血压转导。
