Pharmacological properties and physiological function of a P2X-like current in single proximal tubule cells isolated from frog kidney.
Although previous studies have provided evidence for the expression of P2X receptors in renal proximal tubule, only one cell line study has provided functional evidence. The current study investigated the pharmacological properties and physiological role of native P2X-like currents in single frog proximal tubule cells using the whole-cell patch-clamp technique. Extracellular ATP activated a cation conductance (P2X(f)) that was also Ca²+-permeable. The agonist sequence for activation was ATP = αβ-MeATP > BzATP = 2-MeSATP, and P2X(f) was inhibited by suramin, PPADS and TNP-ATP. Activation of P2X(f) attenuated the rundown of a quinidine-sensitive K+ conductance, suggesting that P2X(f) plays a role in K+ channel regulation. In addition, ATP/ADP apyrase and inhibitors of P2X(f) inhibited regulatory volume decrease (RVD). These data are consistent with the presence of a P2X receptor that plays a role in the regulation of cell volume and K+ channels in frog renal proximal tubule cells.
Department of Biomedical Science, University of Sheffield, Sheffield S102TN, UK.
John P
JP
Davies
Louise
L
Robson
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D007668:Kidney / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D058913:Purinergic Agonists / Q000494:pharmacology; D058914:Purinergic Antagonists / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D011896:Rana temporaria; D058469:Receptors, Purinergic P2X / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology
D058913:Purinergic Agonists; D058914:Purinergic Antagonists; D058469:Receptors, Purinergic P2X; D013873:Thionucleotides; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D011732:Pyridoxal Phosphate; C045674:2',3'-O-(2,4,6-trinitro-cyclohexadienylidine)adenosine 5'-triphosphate; D000255:Adenosine Triphosphate; C008501:2-methylthio-ATP