Effect of amiloride analogues on sodium transport in renal brush border membrane vesicles from Milan hypertensive rats.
The effect of ethylisopropyl-amiloride (EIPA) and phenamil on sodium uptake in renal brush border membrane vesicles from prehypertensive rats of the Milan strain (MHS) and their normotensive controls (MNS) was investigated. In the presence of both a membrane potential and a pH gradient a differential effect of EIPA and phenamil was evidenced between the two rat strains. In the absence of a pH gradient, but in the presence of a membrane potential, EIPA was about two-fold more potent than phenamil in inhibiting sodium transport in both rat strains, excluding the presence of epithelial sodium channels in our BBMV preparations. Taken together these results support the hypothesis that a structurally different Na+/H+ exchanger located on the brush border membrane may be involved in the increased tubular sodium reabsorption observed in vivo in hypertensive rats.
Parenti
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Dipartimento di Fisiologia e Biochimica Generali, Università degli Studi di Milano, Italy.
Ferrari
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Ferrandi
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Hanozet
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GM
Bianchi
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G
D000584:Amiloride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D006973:Hypertension / Q000378:metabolism*; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008564:Membrane Potentials; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011922:Rats, Mutant Strains; D012964:Sodium / Q000378:metabolism*
C047088:phenylamil; D000584:Amiloride; D012964:Sodium; C039614:ethylisopropylamiloride