INVESTIGADORES
JEREZ Susana Josefina
congresos y reuniones científicas
Título:
Effect of angiotensin antagonists in the osmotic water flow response to angiotensin-(1-7) in toad skin.
Autor/es:
SANTOS, J.C., PERAL DE BRUNO, M., JEREZ, S. AND COVIELLO, A
Lugar:
Buenos Aires
Reunión:
Congreso; XV International Congress of Nephrology; 1999
Resumen:
In previous experiments we demosntrated that angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability (Posm) in isolated toad skin, a tissue with functional properties similar to the distal mammalian nephron. The objective of the present work was to test the action of different agiotensin antagonists in this response. Osmotic water permeability ( Posm) was measured by a gravimetrical method in paired pieces of isolated pelvic ventral skin of the toad (Bufo arenarum). Results were expressed in mg.cm-2.h-1 as the mean ± S.E. After an equilibration period of one hour control measurements were performed and a antagonist of angiotensin was added to the dermal side of one half (experimental) 10 min before adding Ang-(1-7) 10-7 M to both halves. A-779 the specific antagonist of Ang-(1-7), [7-D-Ala-Ang-(1-7)] 10-6 did not inhibited the response to Ang-(1-7),  control 34.2 ± 6.4 vs experimental 43.3 ± 5.6, difference 8.3 ± 8.1, N=12, N.S. The AT1 receptor antagonist Losartan  10-6 produced an inhibition of 61.8 % of the response to Ang-(1-7), control 29.2 ± 5.6 vs 11.2 ± 6.3, difference 18.0 ± 7.9, N=12, p<0.05. The AT2 antagonist PD 123319 completely inhibited the response to Ang-(1-7), control 22.8 ± 2.7 vs –2.8 ± 6.1, difference 25.6 ± 5.2, N=12, p<0.001.These results show that Ang-(1-7) may stimulate Posm through AT1 and AT2 receptors and its specific inhibitor A-779 has no effect in toad skin, at variance with results reported by others authors in rat tissues.