Action of ANP on the nongenomic effects of aldosterone on the Na+/H+ exchanger in the S3 segment of proximal tubule of rat: studies in isolated tubules role of cytosolic calcium. / Ação do ANP no efeito não genômico da aldosterona sobre o trocador Na+/H+ no segmento S3 do túbulo proximal de rato - Estudos em túbulos isolados: função do cálcio citosólico.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The effects of aldosterone and ANP(2 min preincubation) on the intracellular pH recovery rate (pHirr) after the acid load induced by NH4Cl and on the [Ca2+]i were investigated in isolated rat S3 segment. The basal pHi was 7.20 + ou - 0.009(n=47/209) and the basal pHirr via the Na+/H+ exchanger was 0.195 + ou - 0.012 pHi/min(n=16/96). Aldosterone(10-12M) caused an increase in the pHirr, but aldosterone(10-6M) decreased it. ANP(10-6M) alone or plus aldosterone(10-12 or 10-6 M) had no effect on pHirr. The basal [Ca2+]i was 100 + ou - 1(n=5)hM. After 1 min of Aldosterone pi there was a transient and dose-dependent increase of the [Ca2+]i and after 6 min pi there was a new increase of [Ca2+]i. ANP alone decreased the [Ca2+]i and prevented the stimulatory effects of aldosterone(10-12 or 10-6M) on this parameter. The data indicate a nongenomic action of aldosterone and ANP on the Na+/H+ exchanger and on [Ca2+]i and are compatible with stimulation of the this exchanger by increases in [Ca2+]i in the lower range (at10-12M aldosterone) and inhibition by increases at high levels (at10-6M aldosterone).

ASSUNTO(S)

cálcio citosólico citosolic calcium anp aldosterone não-genômico trocador na+/h+ non genomic anp na+/h+ exchanger proximal tubule aldosterona túbulo proximal

ACESSO AO ARTIGO

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