What Initiates the Pressor Effect of Salt in Salt-Sensitive Humans?
| Autor: | Olga Schmidlin, Alex Forman Anthony Sebastian, R. Curtis Morris |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Adult
Male medicine.medical_specialty Sodium Drug Resistance Black People Salt (chemistry) chemistry.chemical_element Blood Pressure Body weight Plasma volume Cardiography Impedance Article Reference Values Internal medicine Internal Medicine medicine Humans Sodium Chloride Dietary chemistry.chemical_classification Chemistry Extramural Middle Aged Endocrinology Salt sensitivity Reference values Female Vascular Resistance |
| Zdroj: | Hypertension. 49:1032-1039 |
| ISSN: | 1524-4563 0194-911X |
| DOI: | 10.1161/hypertensionaha.106.084640 |
| Popis: | We tested the traditional hypothesis that an abnormally enhanced renal reclamation of dietary NaCl alone initiates its pressor effect (“salt sensitivity”). Under metabolically controlled conditions, we grouped 23 normotensive blacks as either salt-sensitive (SS) or salt-resistant (SR), depending on whether or not dietary NaCl loading did or did not increase mean arterial blood pressure (MAP) by ≥5 mm Hg. We determined whether dietary NaCl loading induces greater increases in external Na + balance, plasma volume, and cardiac output in SS, compared with any in SR subjects, and differential changes in systemic vascular resistance (SVR) that could account for the pressor differences between SS and SR subjects. Using impedance cardiography, we measured cardiac output and SVR daily at 4-hour intervals throughout the last 3 days of a 7-day period of low NaCl intake (30 mmol per day) and throughout a subsequent 7-day period of NaCl loading (250 mmol per day). In the 11 SS subjects, compared with the 12 SR subjects, NaCl loading induced no greater increases in Na + balance, body weight, plasma volume, and cardiac output. Yet, from days 2 to 7 of NaCl loading, changes of MAP in SS diverged progressively from those in SR. From days 2 to 4, progressive increases of MAP in SS subjects reflected importantly impaired decreases of SVR, as judged from “normal” decreases of SVR in SR subjects. In SS and SR subjects combined, changes in both MAP and SVR on day 2 strongly predicted changes in MAP on day 7. In many normotensive blacks, vascular dysfunction is critical to the initiation of a pressor response to dietary NaCl. |
| Databáze: | OpenAIRE |
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