Relationships between salt sensitivity of blood pressure and sympathetic nervous system activity: a short review of evidence.
Experimental and clinical studies provided evidence in favor of complex relationships between sympathetic nervous system activity and salt-sensitivity of blood pressure. Genetic and acquired metabolic alterations associated with a tendency to retain salt and water may generate salt-sensitivity of blood pressure and shift the pressure-natriuresis curve to the right, promoting an increase in blood pressure. Sympathetic activation is a factor contributing to this result. Chronic high dietary salt intake is followed by a derangement in mechanisms of central sympathetic inhibition and then by an enhanced peripheral sympathetic tone. This, in turn, may generate salt-sensitivity of blood pressure by affecting renal hemodynamics, tubular sodium and water handling. Insulin resistance and sodium and water retention are prompted by high-fat (as well as high carbohydrate) diets, and by an increase in body fat mass. Also, aging is a condition of impaired interactions of the above factors. A gain in weight due to reduced physical activity, not followed by a parallel decrease in calorie intake, brings to a fall in insulin sensitivity. In many cases, the natural age-related decline of renal function is associated with a reduced physical exercise, hyperinsulinemia and sodium retention; sympathetic nervous system activity is enhanced and causes an increase in blood pressure.
Department of Clinical and Experimental Medicine, Federico II University of Naples Medical School, Napoli, Italy. strazzul@vnina.it
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Strazzullo
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Barbato
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Vuotto
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Galletti
D000375:Aging / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D004351:Drug Resistance; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000235:genetics / Q000503:physiopathology; D007668:Kidney / Q000502:physiology; D009318:Natriuresis / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000009:adverse effects; D013564:Sympathetic Nervous System / Q000502:physiology*
D012982:Sodium, Dietary; D012965:Sodium Chloride