{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,8,1]],"date-time":"2023-08-01T04:24:34Z","timestamp":1690863874766},"reference-count":0,"publisher":"Cell Physiol Biochem Press GmbH and Co KG","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cell Physiol Biochem"],"abstract":"<jats:p>Background\/Aims: The functional significance of the Na+\/Ca2+ exchanger (NCX) in basolateral membranes in the proximal tubule remains controversial. The key factor in crosstalk between the apical and basolateral sides is not known. Methods: We investigated the basolateral membranes, using double-barreled Ca2+ or pH ion\u2013selective microelectrodes. We used doubly perfused bullfrog kidneys in vivo, and switched the basolateral solution (renal portal vein) to experimental solutions. Results: In the control, cellular pH (pHi) was 7.33 \u00b1 0.032 (mean \u00b1 SE, n = 7) and in separate experiments, cellular Ca2+ activity (aCai) was 249.6 \u00b1 35.54 nM (n = 28). Changing to respiratory acidosis, pHi was significantly acidified by 0.123 pH units on average and the change of aCai was +53.1 nM (n = 9 ns). In metabolic acidosis, pHi was reduced by 0.151 while aCai was reduced by 143.4. Using the 30 mM K+ solution, pHi was increased by 0.233 while aCai was reduced by 203.9, with depolarization. Both ionomycin and ouabain caused aCai to increase. In the 0.5 mM Na+ solution (replaced with BIDAC Cl), pHi was reduced by 0.177. No changes in aCai (+49.8 ns) were observed although we recorded depolarization of 15.2 mV. In the 0.5 mM Na+ solution, replaced with raffinose, no changes in aCai (\u2212126.4 ns) were observed with depolarization (6.5 ns). Conclusion: Our results suggest that thermodynamic calculations of cellular Na+ concentration led to the conclusion that either a Na+\/HCO3\u2212 exchanger (NBC) or NCX could be present in the same basolateral membrane. H+ ions are the most plausible key factor in the crosstalk.<\/jats:p>","DOI":"10.33594\/000000641","type":"journal-article","created":{"date-parts":[[2023,7,31]],"date-time":"2023-07-31T13:19:05Z","timestamp":1690809545000},"page":"238-263","source":"Crossref","is-referenced-by-count":0,"title":["The Absence of an Na+\/Ca2+Exchanger (NCX) in Bullfrog Proximal Tubules and Cellular pH is More Influential Than Cellular Ca2+ on Proximal Na Transport"],"prefix":"10.33594","volume":"57","member":"19235","published-online":{"date-parts":[[2023,7,31]]},"container-title":["Cellular Physiology and Biochemistry"],"original-title":[],"deposited":{"date-parts":[[2023,7,31]],"date-time":"2023-07-31T13:19:06Z","timestamp":1690809546000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cellphysiolbiochem.com\/Articles\/000641\/index.html"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,31]]},"references-count":0,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2023,7,31]]}},"URL":"https:\/\/doi.org\/10.33594\/000000641","relation":{},"ISSN":["1015-8987","1421-9778"],"issn-type":[{"value":"1015-8987","type":"print"},{"value":"1421-9778","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,31]]}}}