Contribution of the Na+-K+-2Cl−cotransporter NKCC1 to Cl− secretion in rat OMCD
SM Wall, MP Fischer, P Mehta… - American Journal of …, 2001 - journals.physiology.org
SM Wall, MP Fischer, P Mehta, KA Hassell, SJ Park
American Journal of Physiology-Renal Physiology, 2001•journals.physiology.orgIn rat kidney the “secretory” isoform of the Na+-K+-2Cl− cotransporter (NKCC1) localizes to
the basolateral membrane of the α-intercalated cell. The purpose of this study was to
determine whether rat outer medullary collecting duct (OMCD) secretes Cl− and whether
transepithelial Cl− transport occurs, in part, through Cl− uptake across the basolateral
membrane mediated by NKCC1 in series with Cl− efflux across the apical membrane.
OMCD tubules from rats treated with deoxycorticosterone pivalate were perfused in vitro in …
the basolateral membrane of the α-intercalated cell. The purpose of this study was to
determine whether rat outer medullary collecting duct (OMCD) secretes Cl− and whether
transepithelial Cl− transport occurs, in part, through Cl− uptake across the basolateral
membrane mediated by NKCC1 in series with Cl− efflux across the apical membrane.
OMCD tubules from rats treated with deoxycorticosterone pivalate were perfused in vitro in …
In rat kidney the “secretory” isoform of the Na+-K+-2Cl− cotransporter (NKCC1) localizes to the basolateral membrane of the α-intercalated cell. The purpose of this study was to determine whether rat outer medullary collecting duct (OMCD) secretes Cl− and whether transepithelial Cl− transport occurs, in part, through Cl− uptake across the basolateral membrane mediated by NKCC1 in series with Cl− efflux across the apical membrane. OMCD tubules from rats treated with deoxycorticosterone pivalate were perfused in vitro in symmetrical HCO/CO2-buffered solutions. Cl− secretion was observed in this segment, accompanied by a lumen positive transepithelial potential. Bumetanide (100 μM), when added to the bath, reduced Cl− secretion by 78%, although the lumen positive transepithelial potential and fluid flux were unchanged. Bumetanide-sensitive Cl− secretion was dependent on extracellular Na+ and either K+ or NH, consistent with the ion dependency of NKCC1-mediated Cl− transport. In conclusion, OMCD tubules from deoxycorticosterone pivalate-treated rats secrete Cl−into the luminal fluid through NKCC1-mediated Cl− uptake across the basolateral membrane in series with Cl− efflux across the apical membrane. The physiological role of NKCC1-mediated Cl− uptake remains to be determined. However, the role of NKCC1 in the process of fluid secretion could not be demonstrated.
American Physiological Society