Abstract
We used patch-clamp and Western blot analysis to test whether PGF2α stimulates the basolateral 10-pS Cl- channel and thiazide-sensitive Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT) via a prostaglandin F receptor (FP-R). Single channel and whole cell recordings demonstrated that PGF2α stimulated the 10-pS Cl- channel in the DCT. The stimulatory effect of PGF2α on the Cl- channel was mimicked by a FP-R agonist, latanoprost, but was abrogated by blocking FP-R with AL8810. Also, the effect of PGF2α on the Cl- channel in the DCT was recapitulated by stimulating PKC but was blocked by inhibiting PKC. Furthermore, inhibition of p38 MAPK but not ERK blocked the effect of PGF2α on the 10-pS Cl- channel. Inhibition of NADPH oxidase also abrogated the stimulatory effect of PGF2α on the 10-pS Cl- channel, while the addition of 10 μM H2O2 mimicked the stimulatory effect of PGF2α on the 10-pS Cl- channel. Moreover, superoxide-related species may mediate the stimulatory effect of PGF2α on the 10-pS Cl- channel because the stimulatory effect of PGF2α and H2O2 was not additive. Western blot analysis showed that infusion of PGF2α in vivo not only increased the expression of FP-R but also increased the expression of total NCC and phosphorylated NCC. We conclude that PGF2α stimulates the basolateral 10-pS Cl- channel in the DCT by activating FP-R through PKC/p38 MAPK and NADPH oxidase-dependent pathways. The stimulatory effects of PGF2α on the Cl- channel and NCC may contribute to PGF2α-induced increases in NaCl reabsorption in the DCT.
Highlights
PGF2␣ infusion increases blood pressure, whereas blood pressure is reduced in FPϪ/Ϫ mice [36]
PGF2␣ is one of the major metabolites of arachidonic acid, and FP receptor (FP-R) is highly expressed in the distal convoluted tubule (DCT) and cortical collecting duct (CCD) [8, 36]; no FP mRNA has been detected in glomeruli, proximal tubules, or thick ascending limbs [20]
The 10-pS ClϪ channel (ClC-K2) is the key reabsorption pathway for ClϪ in the DCT, because no ClϪ channel activity could be detected in the DCT and no immunofluorescence staining for ClC-K could be observed in the DCT of the Clcnk2Ϫ/Ϫmouse [9]
Summary
PGF2␣ infusion increases blood pressure, whereas blood pressure is reduced in FPϪ/Ϫ mice [36]. The increase of PGF2␣ level or FP gene expression is associated with susceptibility to essential hypertension [33].On the other hand, downregulation of PGF2␣-FP receptor (FP-R) ameliorates myocardial fibrosis and has protective effect on diabetic cardiomyopathy [3]. They have been considered to be the new targets for the treatment of hypertension-related diseases [6, 39]. We have found that PGF2␣ stimulates the basolateral Kir4.1/5.1 channel in the DCT at low concentration and inhibits the Kϩ channel at high concentration [28], suggesting a role of FP-R in regulating membrane transport in the distal nephron
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
