Relationship Between Sympathetic Baroreflex Sensitivity And Vascular Transduction

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Sympathetic baroreflex sensitivity (BRS) is a tool used to quantify how effectively the baroreflex buffers beat‐to‐beat changes in blood pressure. However, current methods of assessment do not take into account vascular transduction, i.e. the response of the peripheral vasculature to vasoconstrictor drive. The aim of the study was to investigate the relationship between sympathetic BRS and vascular transduction. Muscle sympathetic nerve activity (MSNA, microneurography), blood pressure, heart rate and superficial femoral artery blood flow (Doppler ultrasound) were recorded at rest for 5 min in 28 healthy adults (18–31yrs, 13 males, 15 females). Sympathetic BRS was quantified by plotting MSNA burst incidence against mean diastolic pressure using 3 mmHg bins. For vascular transduction, the % change in leg vascular conductance was determined for 15 cardiac cycles following each MSNA burst and the nadir of the response was calculated. Linear regression analysis was used to examine the relationship between sympathetic BRS and vascular transduction in males and females separately. Sympathetic BRS was not significantly different between males (−2.9± 1.8) and females (−3.2 ± 1.6 %bursts/mmHg, p=0.68). However, vascular transduction was significantly lower in males (−5.5 ± 4.1) compared with females (9.1 ± 4.7 %change in ml/min/mmHg, p=0.04). In males there was a significant inverse relationship between sympathetic BRS and vascular transduction (r=0.78, p=0.002), but in females there was no significant relationship (r=0.34, p=0.21). The results suggest that in males those with high sympathetic BRS have low vascular transduction, and vice versa. This may represent a compensatory effect to ensure that blood pressure is regulated effectively. However, this relationship between sympathetic BRS and vascular transduction was not apparent in young females.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.