Membrane Ion Transport in Erythrocytes of Salt Hypertensive Dahl Rats and Their F2 Hybrids: the Importance of Cholesterol

Abstract

The possible association of salt hypertension and altered lipid metabolism with abnormalities of particular systems transporting sodium and potassium has been studied in erythrocytes of Dahl rats and their F2 hybrids fed a high-salt diet since weaning. Our attention was paid to the Na -K pump, Na -K cotransport and especially to passive membrane permeability for Na and Rb (Na and Rb leak), because the Na leak was found to be dependent on the genotype, age and salt intake of Dahl rats, whereas the Rb leak was sug-

Relationships between membrane lipids and ion transport in red blood cells of Dahl rats

“…In this study, RBC of SS/Jr rats had higher Na i + content than RBC from SR/Jr rats, which is in accordance with the findings of McCormick et al (1989) and Zicha and Duhm (1990). On the other hand, we did not observe any significant difference between Dahl strains in the activity of the Na + -K + pump, which is in contrast with our previous studies reporting enhanced activity of the Na + -K + pump and Na + -K + cotransport as well as augmented Na + leak and Rb + leak in RBC of Dahl rats with salt hypertension (Zicha and Duhm, 1990;Zicha et al, 2001;Vokurková et al, 2003). Some of these discrepancies could be related to particular physiological factors, namely to the age-dependent kinetic changes of examined transport systems (Furukawa et al, 1981;Rosati et al, 1988;Zicha and Duhm, 1990).…”

“…Relationship between mean cellular hemoglobin content and Na i + content, Na + leak, activity of the Na + -K + pump (ouabain-sensitive Na + net extrusion and Rb + uptake) and activity of the Na + -K + cotransport (bumetanide-sensitive Na + net extrusion and Rb + uptake) in the Dahl salt-sensitive rats on high-salt diet from previous and present study (n = 23). Horizontal bars indicate the distribution of MCHC values in the present study and in the previous study by Vokurková et al (2003).…”

“…Our previous study of Dahl SS/Jr  SR/Jr F 2 hybrids fed a high-salt diet since weaning showed significant associations between blood pressure and RBC intracellular Na + (Na i + ) content and the activity of both Na + -K + pump and Na + -K + -2Cl À cotransport (Vokurková et al, 2003). Moreover, these experiments revealed significant association of ion transport parameters with total plasma cholesterol (Zicha et al, 2001), which is in agreement with findings that salt hypertension of Dahl rats is accompanied by pronounced hypercholesterolemia (Dahl, 1960;O'Donnell et al, 1992).…”

Attenuation of Salt-Loading Induced Cardiomegaly and Dyslipidemia in Wistar Rats by Aqueous Leaf Extract of <i>Chromolaena odorata</i>

“…Dyslipidemia, a disorder of lipoprotein metabolism in the form of either lipoprotein overproduction or deficiency, may be expressed as increased serum total cholesterol, low density lipoprotein cholesterol and/or triglycerides, a decrease in high density lipoprotein cholesterol concentration, or various combinations of these [3]. It usually results in altered membrane micro-viscosity, with the concomitant modifications of membrane properties [4], which, in cells participating in cardiovascular regulation, might be a part of pathogenetic mechanisms responsible for chronic elevation of blood pressure [5] and alterations in the vascular system leading to vessel damage [6]. The lowering of cholesterol concentrations in individuals at high risk of cardiovascular disease improves outcome [7], therefore, any pharmacological intervention that improves or normalizes abnormal lipid metabolism may be useful for reducing the risk of cardiovascular complications in the hypertensive.…”

Hypocholesterolemic effect of aqueous extract of the rhizomes of Sansevieria liberica on salt-loaded rats

“…The dyslipidemia accompanying essential hypertension consists of elevated plasma triglycerides, low high density lipoprotein cholesterol, and increased levels of atherogenic low density lipoprotein cholesterol particles (Lopes et al, 1997;Zicha et al, 1999;Kabakci et al, 2008). It is reflected by altered membrane microviscosity, and is known to modulate the activity of proteins involved in ion transport, signal transduction, cell Ca 2+ handling, intracellular pH regulation, etc (Vokurková et al, 2003); and is closely associated with ion transport abnormalities as well as with impaired control of cytosolic Ca 2+ and pH in various forms of hypertension in both humans and rats. Such lipid-dependent modifications of membrane properties in cells participating in the cardiovascular regulation might be a part of pathogenetic mechanisms responsible for chronic blood pressure elevation (Zicha et al, 1999), as well as alterations in the vascular system leading to vessel damage (Catalano et al, 1991;Bernardes-Silva et al, 1995).…”