Complete autonomic blockade reveals nitric oxide contribution to blood pressure regulation in obese Black women.

Autor: Rahman S; Department of Medicine, Epidemiology, Vanderbilt University School of Medicine, Nashville, TN, 37212-8802, USA., Gamboa A; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA., Saleem M; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA., Kulapatana S; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA.; Department of Physiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand., Diedrich A; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA., Biaggioni I; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA., Kirabo A; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, P415C Medical Research Building IV, 2215 Garland Avenue, Nashville, TN, 37232, USA. annet.kirabo@vumc.org., Shibao CA; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Room 536 Robinson Research Building, Nashville, TN, 37212-8802, USA. cyndya.shibao@vumc.org.
Jazyk: angličtina
Zdroj: Clinical autonomic research : official journal of the Clinical Autonomic Research Society [Clin Auton Res] 2024 Aug; Vol. 34 (4), pp. 427-436. Date of Electronic Publication: 2024 Aug 01.
DOI: 10.1007/s10286-024-01050-3
Abstrakt: Purpose: Hypertension is one of the major causes of cardiovascular morbidity and mortality in the USA and disproportionately affects Black women. Endothelial-derived nitric oxide (eNO) substantially regulates blood pressure in humans, and impaired NO-mediated vasodilation has been reported in the Black population. Previous studies using an NO synthase inhibitor, N G -monomethyl-L-arginine (L-NMMA) did not fully determine the NO contribution to blood pressure because of baroreflex buffering. Therefore, in the present study we used trimethaphan, a ganglionic blocker, to inhibit baroreflex buffering and study NO modulation of blood pressure in Black women during L-NMMA infusion.
Methods: L-NMMA at doses of 250 μg/kg per minute was infused in combination with trimethaphan at doses of 4 mg/min to eliminate baroreflex mechanisms. Heart rate (HR) was obtained with continuous electrocardiogram monitoring, and continuous blood pressure was measured with the volume clamp method. The increase in systolic blood pressure (SBP) during both infusions was used to estimate the contribution of NO to blood pressure.
Results: Ten Black (age range 30-50 years, body mass index [BMI] 30-45 kg/m 2 ), and nine White women (age range 30-50 years, body mass index 30-45 kg/m 2 ) were enrolled in this study. During autonomic blockade, there was no difference in the decrease in SBP between Black and White women (- 20 ± 16.45 vs. - 24 ± 15.49 mm Hg, respectively; P = 0.659). When autonomic blockade was combined with L-NMMA, Black women had a significant increase in SBP compared to White women (54 ± 13.62 vs. 39 ± 09.64 mm Hg, respectively; P = 0.022, respectively).
Conclusion: Autonomic blood pressure regulation was similar between Black and White women. However, NO contribution to blood pressure was significantly greater in Black women compared to White women.
Registration: ClinicalTrials.gov: NCT01122407.
(© 2024. The Author(s).)
Databáze: MEDLINE
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