title: BK channels in the kidney: role in K(+) secretion and localization of molecular components.
abstract: Although it is generally accepted that ROMK is the K(+) secretory channel in the mammalian distal nephron, recent in vitro and in vivo studies have provided evidence that large-conductance Ca(2+)-activated K(+) channels (BK, or maxi K) also secrete K(+) in renal tubules. This review assesses the current evidence relating BK channels with K(+) secretion. We shall consider the component proteins of the BK channel, their localization with respect to segment and cell type, and the electrophysiological forces involved in K(+) secretion. Although the majority of studies have focused on a role for BK channels in flow-mediated K(+) secretion, this review also considers a potential role for BK channels in high-K diet-induced K(+) secretion. The division of workload between ROMK and BK is discussed as a mechanism for ensuring a constant plasma K(+) concentration.
authors.affiliation: Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Pluznick
authors.forename: Steven C
authors.initials: SC
authors.lastname: Sansom
mesh_terms: D000818:Animals; D002451:Cell Compartmentation / Q000502:physiology; D004594:Electrophysiology; D006801:Humans; D007668:Kidney / Q000033:anatomy & histology / Q000502:physiology*; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000502:physiology*
chemical_list: C086989:KCNJ1 protein, human; D051036:Large-Conductance Calcium-Activated Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium