The regulation of proximal tubular salt transport in hypertension: an update

Abstract

Purpose of review Renal proximal tubular sodium reabsorption is regulated by sodium transporters, including the sodium glucose transporter, sodium amino acid transporter, sodium hydrogen exchanger isoform 3 and sodium phosphate cotransporter type 2 located at the luminal/apical membrane, and sodium bicarbonate cotransporter and Na+/K+ATPase located at the basolateral membrane. This review summarizes recent studies on sodium transporters that play a major role in the increase in blood pressure in essential/polygenic hypertension. Recent findings Sodium transporters and Na+/K+ATPase are segregated in membrane lipid and nonlipid raft microdomains that regulate their activities and trafficking via cytoskeletal proteins. The increase in renal proximal tubule ion transport in polygenic hypertension is primarily due to increased activity of NHE3 and Cl/HCO3 exchanger at the luminal/apical membrane and a primary or secondary increase in Na+/K+ATPase activity. Summary The increase in renal proximal tubule ion transport in hypertension is due to increased actions by prohypertensive factors that are unopposed by antihypertensive factors.

Renal aging in WKY rats: Changes in Na+,K+-ATPase function and oxidative stress

“…In the kidney, Na + ,K + -ATPase catalyzes active transport of Na + in exchange for K + , maintains intracellular ion balance and membrane potential and is also responsible for maintaining Na + gradient (Bengele et al, 1983;Wang et al, 2009). In proximal tubules, glucose and aminoacid reabsorption is achieved due to Na + ,K + -ATPase generated Na + gradient.…”

Renal Redox Balance and Na+, K+-ATPase Regulation: Role in Physiology and Pathophysiology

“…Moreover, as recently reviewed by Wang and co-workers (Wang et al, 2009) it is well known that altered renal proximal tubular sodium reabsorption is implicated in the development of essential hypertension.…”

“…Given the key role of Na + ,K + -ATPase for normal renal function changes in Na + ,K + -ATPase regulation are associated with the development of several conditions such as hypertension, obesity-associated hypertension and diabetes as well as during the ageing process (Jaitovich et al, 2010;Silva et al, 2010;Vague et al, 2004;Wang et al, 2009). As such understanding the mechanisms involved in regulation of Na + ,K + -ATPase throughout the nephron is of major importance.…”

Renal Sodium Transporters and Water Channels

“…[5][6] The increase in renal proximal tubule ion transport in polygenic hypertension is primarily due to increased activity of NHE-3 and Cl/HCO 3 exchanger at the luminal/apical membrane. 5) There are persistent changes in NHE-3 and NaPi2 distributions and activity in response to chronic hypertension in spontaneous hypertensive rat.…”