Faculty Collaboration Database

Direct inhibition of basolateral Kir4.1/5.1 and Kir4.1 channels in the cortical collecting duct by dopamine. Am J Physiol Renal Physiol 2013 Nov 01;305(9):F1277-87

Date

08/30/2013

Pubmed ID

23986512

Pubmed Central ID

PMC3840222

DOI

10.1152/ajprenal.00363.2013

Scopus ID

2-s2.0-84887009013 (requires institutional sign-in at Scopus site)   44 Citations

Abstract

It is recognized that dopamine promotes natriuresis by inhibiting multiple transporting systems in the proximal tubule. In contrast, less is known about the molecular targets of dopamine actions on water-electrolyte transport in the cortical collecting duct (CCD). Epithelial cells in the CCD are exposed to dopamine, which is synthesized locally or secreted from sympathetic nerve endings. Basolateral K(+) channels in the distal renal tubule are critical for K(+) recycling and controlling basolateral membrane potential to establish the driving force for Na(+) reabsorption. Here, we demonstrate that Kir4.1 and Kir5.1 are highly expressed in the mouse kidney cortex and are localized to the basolateral membrane of the CCD. Using patch-clamp electrophysiology in freshly isolated CCDs, we detected highly abundant 40-pS and scarce 20-pS single channel conductances, most likely representing Kir4.1/5.1 and Kir4.1 channels, respectively. Dopamine reversibly decreased the open probability of both channels, with a relatively greater action on the Kir4.1/5.1 heterodimer. This effect was mediated by D2-like but not D1-like dopamine receptors. PKC blockade abolished the inhibition of basolateral K(+) channels by dopamine. Importantly, dopamine significantly decreased the amplitude of Kir4.1/5.1 and Kir4.1 unitary currents. Consistently, dopamine induced an acute depolarization of basolateral membrane potential, as directly monitored using current-clamp mode in isolated CCDs. Therefore, we demonstrate that dopamine inhibits basolateral Kir4.1/5.1 and Kir4.1 channels in CCD cells via stimulation of D2-like receptors and subsequently PKC. This leads to depolarization of the basolateral membrane and a decreased driving force for Na(+) reabsorption in the distal renal tubule.

Author List

Zaika OL, Mamenko M, Palygin O, Boukelmoune N, Staruschenko A, Pochynyuk O

MESH terms used to index this publication - Major topics in bold

Animals
Dopamine
Kidney Cortex
Kidney Tubules, Collecting
Male
Mice
Mice, Inbred C57BL
Patch-Clamp Techniques
Potassium Channels, Inwardly Rectifying
Protein Kinase C
Receptors, Dopamine D2
Signal Transduction
Sodium