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

IF 3.9 3区医学 Q1 CLINICAL NEUROLOGY

Clinical Autonomic Research Pub Date : 2024-08-01 DOI:10.1007/s10286-024-01050-3

Sharla Rahman, Alfredo Gamboa, Mohammad Saleem, Surat Kulapatana, André Diedrich, Italo Biaggioni, Annet Kirabo, Cyndya A Shibao

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Abstract

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/m²), and nine White women (age range 30-50 years, body mass index 30-45 kg/m²) 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.

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完全自律神经阻断揭示了一氧化氮对肥胖黑人妇女血压调节的作用。

目的：高血压是美国心血管疾病发病和死亡的主要原因之一，对黑人妇女的影响尤为严重。内皮源性一氧化氮（eNO）在很大程度上调节着人体的血压，有报道称在黑人群体中，NO 介导的血管舒张功能受损。之前使用一氧化氮合酶抑制剂 NG-单甲基-L-精氨酸（L-NMMA）进行的研究并不能完全确定一氧化氮对血压的影响，因为这会受到气压反射缓冲作用的影响。因此，在本研究中，我们使用神经节阻滞剂曲美沙芬来抑制气压反射缓冲，并研究输注 L-NMMA 期间 NO 对黑人女性血压的调节作用：方法：以每分钟 250 μg/kg 的剂量输注 L-NMMA，同时以每分钟 4 mg 的剂量输注曲美沙芬，以消除气压反射机制。通过连续心电图监测获得心率（HR），并通过容量钳法测量连续血压。两种输注过程中收缩压（SBP）的升高被用来估算 NO 对血压的贡献：本研究共招募了 10 名黑人女性（年龄在 30-50 岁之间，体重指数[BMI] 30-45 kg/m2）和 9 名白人女性（年龄在 30-50 岁之间，体重指数 30-45 kg/m2）。在自律神经阻断过程中，黑人和白人女性的 SBP 降幅没有差异（分别为 - 20 ± 16.45 mm Hg 与 - 24 ± 15.49 mm Hg；P = 0.659）。当自律神经阻断与 L-NMMA 结合使用时，黑人女性的 SBP 比白人女性显著升高（分别为 54 ± 13.62 vs. 39 ± 09.64 mm Hg；P = 0.022）：结论：黑人和白人女性的自主血压调节能力相似。结论：黑人妇女和白人妇女的自主血压调节能力相似，但黑人妇女的氮氧化物对血压的影响明显大于白人妇女：注册：ClinicalTrials.gov：NCT01122407。

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来源期刊

Clinical Autonomic Research 医学-临床神经学

CiteScore

7.40

自引率

6.90%

发文量

审稿时长

>12 weeks

期刊介绍： Clinical Autonomic Research aims to draw together and disseminate research work from various disciplines and specialties dealing with clinical problems resulting from autonomic dysfunction. Areas to be covered include: cardiovascular system, neurology, diabetes, endocrinology, urology, pain disorders, ophthalmology, gastroenterology, toxicology and clinical pharmacology, skin infectious diseases, renal disease. This journal is an essential source of new information for everyone working in areas involving the autonomic nervous system. A major feature of Clinical Autonomic Research is its speed of publication coupled with the highest refereeing standards.