Sympathetic transduction at rest and during cold pressor test in young healthy non-Hispanic Black and White women

Abstract

Non-Hispanic Black (BL) individuals have the highest prevalence of hypertension and cardiovascular disease (CVD) compared to all other racial/ethnic groups. Previous work focused on racial disparities in sympathetic control and blood pressure (BP) regulation between young BL and White (WH) adults, have mainly included men. Herein, we hypothesized that BL women would exhibit augmented resting sympathetic vascular transduction and greater sympathetic and BP reactivity to cold pressor test (CPT) compared to WH women. Twenty-eight young healthy women (BL:n=14, 224 years; WH:n=14, 224 years) participated. Beat-to-beat BP (Finometer), common femoral artery blood flow (duplex Doppler ultrasound), and muscle sympathetic nerve activity (MSNA; microneurography) were continuously recorded. In a subset (BL n=10, WH n=11), MSNA and BP were recorded at rest and during a two-minute CPT. Resting sympathetic vascular transduction was quantified as changes in leg vascular conductance (LVC) and mean arterial pressure (MAP) following spontaneous bursts of MSNA using signal-averaging. Sympathetic and BP reactivity was quantified as changes in MSNA and MAP during the last minute of CPT. There were no differences in nadir LVC following resting MSNA bursts between BL (-8.74±3.45%) and WH women (-7.48±3.52%; P=0.431). Likewise, peak increases in MAP following MSNA bursts were not different between groups (BL:+2.80+1.4mmHg; vs. WH: +3.02±1.2mmHg; P=0.623). During CPT, increases in MSNA and MAP were also not different between BL and WH women, with similar transduction estimates between groups (ΔMAP/ΔMSNA; P=0.182). These findings indicate that young, healthy BL women do not exhibit exaggerated sympathetic transduction or augmented sympathetic and BP reactivity during CPT.