English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Using ion-selective microelectrode technique, we investigated acid-induced changes of peritubular membrane potential (EM) and intracellular activity of Na+ and H+ ((Na)i and pHi) in the proximal tubule of perfused bullfrog kidney in vivo. When peritubular pH was reduced at constant PCO2, EM was depolarized in two steps: i.e., an initial sharp fall followed by an additional deeper fall. This was termed as the acid-induced two-step depolarization. During this change, pHi was decreased gradually from 7.4 to 6.9 in response to 1/10 HCO3- reduction (pH from 7.7 to 6.7), whereas (Na)i was increased after a transient decrease. This result supports the peritubular rheogenic HCO3- exit coupled to Na+ movement during the initial depolarization period. Complete removal of peritubular HCO3- at constant pH produced a less marked initial depolarization with a transient rise of pHi, followed by a partial repolarization without appreciable change in (Na)i. Peritubular SITS administration inhibited these depolarization responses to the acid perfusion. The above findings suggest that 1) the initial part of the two-step EM depolarization produced by low HCO3- or HCO(3-)-free perfusion resulted mainly from the peritubular rheogenic exist of HCO3-, 2) the magnitude of initial depolarization would also be affected by pHi, and 3) the subsequent delayed changes of EM were mainly determined by the pHi-sensitive K+ conductance of the peritubular membrane.

Acid-Induced Two-Step Depolarization in the Peritubular Membrane of Bullfrog Kidney Proximal Tubules.