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Involvement of Na+/HCO3‐ Cotransporter in Intracellular pH Regulation and Anion Secretion in Cultured Rat Epididymal Epithelia
Author(s) -
Zuo Wulin,
Li Sheng,
Zhang Geng,
Ruan Yechun,
Zhou Wenliang
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.799.5
Subject(s) - dids , cotransporter , intracellular ph , amiloride , extracellular , intracellular , chemistry , hepes , sodium–hydrogen antiporter , ion transporter , secretion , atpase , epithelial polarity , nigericin , biochemistry , biophysics , microbiology and biotechnology , biology , membrane , enzyme , sodium , organic chemistry
Intracellular pH(pHi) plays a critical role in many intracellular processes. Several ion transporters, including Na+/H+ exchanger (NHE), Na+/HCO3‐ cotransporter(NBC) and vacuolar H+‐ATPase(H+‐ATPase), contribute to pHi regulation in different types of cells. The present study examined the mechanisms of pHi regulation by NBC in cultured caput epididymal epithelia by using the fluorescent pH sensitive probe, SNARF‐4F. In the HEPES buffered Krebs‐Henseleit(KH) solution, a pHi recovery from NH4Cl induced acidification was completely inhibited by amiloride, the inhibitor of NHE. Then immediate change of the KH solution from HEPES buffered to HCO3‐ buffered would cause another pHi recovery. The pHi recovery in HCO3‐ buffered KH solution was inhibited by 4, 4'diisothiocyanatostilbene‐2, 2′‐disulfonic acid (DIDS) or removal of extracellualr Na+. However, the pHi recovery was not affected by removal of extracellular Cl‐. In addition, the short circuit current measurement showed that adding DIDS to the basolateral side of epididymal epithelial monolayer could inhibit adrenalin induced anion secretion. In summary, these results indicate that not only does NBC play a functional role in pHi regulation of epididymal epithelia, but also regulate the epididymal fluid microenvironment by affecting anion secretion. This work was supported by the National Natural Science Foundation of China (No.30770817)