Related Experiment Video
Updated: Oct 16, 2026

Single-channel Analysis and Calcium Imaging in the Podocytes of the Freshly Isolated Glomeruli
Published on: June 27, 2015
Increased proximal tubule NHE-3 and H+-ATPase activities in spontaneously hypertensive rats
K L Aldred1, P J Harris, E Eitle
1The Department of Physiology, The University of Melbourne, Parkville, Australia.
Objective:
To investigate renal proximal tubular sodium-hydrogen exchanger 3 (NHE-3) and H+-ATPase activities in young (5-week-old) spontaneously hypertensive rats (SHR) and normotensive Donryu (DRY) rats, in the period during which high blood pressure is developing.
Methods:
Five-week-old SHR and DRY rats were weighed and systolic blood pressure recorded. Proximal tubule cells were isolated, loaded with the intracellular pH dye, 2'-7'-bis-carboxyethyl-5(6)-carboxyfluorescein-acetoxymethyl-ester and acidified with a NH4+/NH3 prepulse. Na+-independent intracellular pH recovery rate (H+-ATPase activity) and initial Na+-dependent intracellular pH recovery rate (NHE-3 activity) were assessed. NHE-3 activity was assessed during inhibition of H+-ATPase with Bafilomycin A1 and during inhibition of any possible NHE-1 activity with Hoe 694.
Results:
Mean body weight and systolic blood pressures of 5-week-old SHR and DRY rats were not significantly different. NHE-3 activity was higher in SHR, 1.08 +/- 0.1 pH units/min compared with DRY rats, 0.73 +/- 0.1 pH units/min (P < 0.05) H+-ATPase activity was also higher in SHR, 0.119 +/- 0.02 pH units/min, compared with DRY rats, 0.051 +/- 0.02 pH units/min (P < 0.05).
Conclusions:
Proximal tubule cells of 5-week-old SHR have higher NHE-3 and H+-ATPase activities compared with age-matched DRY rats. Enhanced proximal tubular fluid reabsorption is likely to contribute to development of high blood pressure in young SHR.
Related Concept Videos
Hypertension II: Pathophysiology
Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion
Hypertension and Regulation of Blood Pressure
Antihypertensive Drugs: Angiotensin-Converting Enzyme Inhibitors
Antihypertensive Drugs: Angiotensin II Receptor Blockers
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...

