Coupled ATP and potassium efflux from intercalated cells.
Am J Physiol Renal Physiol
; 300(6): F1319-26, 2011 Jun.
Article
em En
| MEDLINE
| ID: mdl-21454249
ABSTRACT
Increased flow in the distal nephron induces K secretion through the large-conductance, calcium-activated K channel (BK), which is primarily expressed in intercalated cells (IC). Since flow also increases ATP release from IC, we hypothesized that purinergic signaling has a role in shear stress (τ; 10 dynes/cm(2)) -induced, BK-dependent, K efflux. We found that 10 µM ATP led to increased IC Ca concentration, which was significantly reduced in the presence of the P(2) receptor blocker suramin or calcium-free buffer. ATP also produced BK-dependent K efflux, and IC volume decrease. Suramin inhibited τ-induced K efflux, suggesting that K efflux is at least partially dependent on purinergic signaling. BK-ß4 small interfering (si) RNA, but not nontarget siRNA, decreased ATP secretion and both ATP-dependent and τ-induced K efflux. Similarly, carbenoxolone (25 µM), which blocks connexins, putative ATP pathways, blocked τ-induced K efflux and ATP secretion. Compared with BK-ß4(-/-) mice, wild-type mice with high distal flows exhibited significantly more urinary ATP excretion. These data demonstrate coupled electrochemical efflux between K and ATP as part of the mechanism for τ-induced ATP release in IC.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Trifosfato de Adenosina
/
Cálcio
/
Canais de Potássio Cálcio-Ativados
/
Néfrons
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Renal Physiol
Assunto da revista:
FISIOLOGIA
/
NEFROLOGIA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos