Angiotensin-(1-7) reverts the stimulatory effect of angiotensin II on the proximal tubule Na(+)-ATPase activity via a A779-sensitive receptor.
Recently, we demonstrated that the stimulatory effect of Ang II on the Na(+)-ATPase activity in proximal tubules is reversed, in a dose-dependent manner, by Ang-(1-7) [Biochim. Biophys. Acta 1467 (2000) 189]. In the present paper, we characterized the receptor involved in this phenomenon. The preincubation of the Na(+)-ATPase with 10(-8) M Ang II increases the enzyme activity from 7.50+/-0.02 (control) to 12.40+/-1.50 nmol Pi mg(-1) min(-1) (p<0.05). Addition of 10(-9) M Ang-(1-7) completely reverts this effect returning the ATPase activity to the control level. This effect seems to be specific to Ang-(1-7) since Ang III (10(-12)-10(-8) M) does not modify the stimulation of the renal proximal tubule Na(+)-ATPase activity by Ang II. Saralasin abolishes the Ang-(1-7) effect in a dose-dependent manner being the maximal effect obtained at 10(-11) M. The increase in A779 concentration (from 10(-12) to 10(-7) M), a specific Ang-(1-7) antagonist, also abolishes the Ang-(1-7) effect. On the other hand, PD123319 (10(-8)-10(-6) M), an AT(2) antagonist receptor, and losartan (10(-12)-10(-7) M), an AT(1) antagonist receptor, does not modify the effect of Ang-(1-7). Taken together, these data indicate that Ang-(1-7) reverts the stimulatory effect of Ang II on the Na(+)-ATPase activity in proximal tubule through a A779-sensitive receptor.
Lara
Lucienne S
LS
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, RJ, Rio de Janeiro, Brazil.
Bica
Rafael B S
RB
Sena
Sílvia L F
SL
Correa
Juliana S
JS
Marques-Fernandes
Maria F
MF
Lopes
Aníbal G
AG
Caruso-Neves
Celso
C
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D000805:Angiotensin III / Q000494:pharmacology; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000201:enzymology; D019808:Losartan / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000819:agonists; D012504:Saralasin / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013552:Swine
C092006:7-Ala-angiotensin (1-7); D057911:Angiotensin Receptor Antagonists; D000959:Antihypertensive Agents; D007093:Imidazoles; D010446:Peptide Fragments; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000805:Angiotensin III; C073402:PD 123319; D000803:Angiotensin I; D000254:Sodium-Potassium-Exchanging ATPase; D012504:Saralasin; C118790:angiotensin I (1-7); D019808:Losartan