Cerebral microvascular endothelial cell Na/H exchange: evidence for the presence of NHE1 and NHE2 isoforms and regulation by arginine vasopressin

Lam, Tina I.; Wise, Phyllis M.; O’Donnell, Martha E

doi:10.1152/ajpcell.00093.2009

Cited by 76 publications

(83 citation statements)

References 76 publications

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“…Several recent studies have provided evidence that NHE-1 is present in rat and bovine brain endothelial cells (Sipos et al, 2005;Lam et al, 2009 sabiporide (73.6 ± 3.07%, 64.0 ± 7.75% and 58.1 ± 7.87%, respectively) ( Fig. 2A).…”

Section: 2mentioning

confidence: 89%

The effect of Na+/H+ exchanger-1 inhibition by sabiporide on blood–brain barrier dysfunction after ischemia/hypoxia in vivo and in vitro

2010

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Section: 2mentioning

confidence: 89%

The effect of Na+/H+ exchanger-1 inhibition by sabiporide on blood–brain barrier dysfunction after ischemia/hypoxia in vivo and in vitro

2010

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“…19 In addition, AVP seems to be involved in brain edema formation by stimulation of the V1a receptors and influencing blood-brain barrier sodium transporters. 20,21 V1a receptor activation might also involve platelet activation, 22 thereby additionally increasing the risk of stroke.…”

Section: Discussionmentioning

confidence: 99%

Copeptin Levels Associate with Cardiovascular Events in Patients with ESRD and Type 2 Diabetes Mellitus

Fenske

Wanner

Allolio

et al. 2011

Journal of the American Society of Nephrology

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In ESRD, the neurohormone arginine vasopressin (AVP) may act primarily through V1a and V1b receptors, which promote vasoconstriction, myocardial hypertrophy, and release of adrenocorticotropic hormone. The preanalytical instability of AVP limits the investigation of whether this hormone associates with cardiovascular events, but the stable glycopeptide copeptin may serve as a surrogate because it is co-secreted with AVP from the posterior pituitary. Here, we studied whether copeptin predicts cardiovascular risk and mortality in ESRD. We measured copeptin at baseline in 1241 hemodialysis patients with type 2 diabetes participating in the German Diabetes and Dialysis Study. The median copeptin level was 81 pmol/L (interquartile range, 81 to 122 pmol/L). In Cox regression analyses, compared with patients with copeptin levels in the lowest quartile (Յ51 pmol/L), patients with copeptin levels in the highest quartile (Ͼ122 pmol/L) had a 3.5-fold increased risk for stroke (HR, 3.48; 95% CI: 1.71 to 7.09), a 73% higher risk for sudden death (HR, 1.73; 95% CI: 1.01 to 2.95), a 42% higher risk for combined cardiovascular events (HR, 1.42; 95% CI: 1.06 to 1.90), and a 48% higher risk for all-cause mortality (HR, 1.48; 95% CI: 1.15 to 1.90). In contrast, we did not detect significant associations between copeptin levels and risks for myocardial infarction or death caused by congestive heart failure. In conclusion, copeptin levels strongly associate with stroke, sudden death, combined cardiovascular events, and mortality in hemodialysis patients with type 2 diabetes. Whether vasopressin receptor antagonists will improve these outcomes requires further studies. 22: 782-790, 201122: 782-790, . doi: 10.1681 Arginine vasopressin (AVP) is a key neurohormone in the human body, with numerous important physiologic activities including regulation of BP, fluid volume, and serum osmolality. AVP acts via three G protein-coupled receptors, namely the V1a (vasoconstriction and myocardial hypertrophy), the V1b (release of adrenocorticotropic hormone), and the V2 receptor (water retention in the renal collecting duct). Despite its suggested importance in the pathogenesis of cardiovascular disorders, 1,2 the evaluation of AVP secretion is difficult because of its preanalytical instability. Copeptin, a 39-amino acid glycopeptide that comprises the Cterminal part of the AVP precursor, is co-secreted with AVP from the neurohypophysis and is a stable and sensitive surrogate marker for AVP release, making it much easier to measure. 3 Dialysis patients are at a very high risk of death (about 20% per year) 4 . Thus, the identification of new risk factors with the potential of applying inter- J Am Soc Nephrol

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“…To date, nine isoforms of NHE have been identified in different tissues (Lam et al, 2009). Experiments with isolated sheep rumen epithelial cells (RECs) have shown that the specific inhibitors HOE 694 and S3226 of NHE-1 and NHE-3, respectively, are able to inhibit an acid-induced pH i recovery in these cells (Schweigel et al, 2005).…”

Section: Electroneutral Namentioning

confidence: 99%

Transport of cations and anions across forestomach epithelia: conclusions from in vitro studies

Leonhard-Marek

Stumpff

Martens

2010

Animal

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Secretion of saliva as well as absorptive and secretory processes across forestomach epithelia ensures an optimal environment for microbial digestion in the forestomachs. Daily salivary secretion of sodium (Na 1 ) exceeds the amount found in plasma by a factor of 2 to 3, while the secretion of bicarbonate (HCO 3 2 ) is 6 to 8 times higher than the amount of HCO 3 2 in the total extracellular space. This implies a need for efficient absorptive mechanisms across forestomach epithelia to allow for an early recycling. While Na 1 is absorbed from all forestomachs via Na 1 /H 1 exchange and a non-selective cation channel that shows increased conductance at low concentrations of Mg 21 , Ca 21 or H 1 in the luminal microclima and at low intracellular Mg 21 , HCO 3 2 is secreted by the rumen for the buffering of ingesta but absorbed by the omasum to prevent liberation of CO 2 in the abomasum. Fermentation provides short chain fatty acids and ammonia (NH 3 ) that have to be absorbed both to meet nutrient requirements and maintain ruminal homeostasis of pH and osmolarity. The rumen is an important location for the absorption of essential minerals such as Mg 21 from the diet. Other ions can be absorbed, if delivered in sufficient amounts (Ca 21 , P i , K 1 , Cl 2 and NH 4 1 ). Although the presence of transport mechanisms for these electrolytes has been described earlier, our knowledge about their nature, regulation and crosstalk has increased greatly in the last years. New transport pathways have recently been added to our picture of epithelial transport across rumen and omasum, including an apical non-selective cation conductance, a basolateral anion conductance, an apical H 1 -ATPase, differently expressed anion exchangers and monocarboxylate transporters.Keywords: ruminants, sodium potassium magnesium and calcium, short chain fatty acids, chloride and bicarbonate, channels transporters and exchangers ImplicationsThe improved knowledge of ruminal ion transport clearly underlines its physiological meaning for the whole animal. For example, magnesium absorption is markedly reduced at low Mg and high K intake and the effect of potassium is diminished at high Mg intake. This variable interaction has been quantified recently permitting the prediction of Mg absorption. Great progress has also been made in understanding the interactions between the absorptive pathways for Na, short chain fatty acids and ammonium. The new findings on structure and regulation of various ion transporters will allow a better understanding of the challenges that different diets pose to the maintenance of homeostatic conditions within the rumen and within the cells of the surrounding epithelium, with the implications for the investigation of ruminal adaptation to different diets. Future studies on transport pathways should include the barrier function of rumen epithelium and its possible impairment under harsh feeding conditions.

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Cerebral microvascular endothelial cell Na/H exchange: evidence for the presence of NHE1 and NHE2 isoforms and regulation by arginine vasopressin

Cited by 76 publications

References 76 publications

The effect of Na+/H+ exchanger-1 inhibition by sabiporide on blood–brain barrier dysfunction after ischemia/hypoxia in vivo and in vitro

The effect of Na+/H+ exchanger-1 inhibition by sabiporide on blood–brain barrier dysfunction after ischemia/hypoxia in vivo and in vitro

Copeptin Levels Associate with Cardiovascular Events in Patients with ESRD and Type 2 Diabetes Mellitus

Transport of cations and anions across forestomach epithelia: conclusions from in vitro studies

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