Regulation of Na+/H+ exchange by diadenosine polyphosphates, angiotensin II, and vasopressin in rat cortical collecting duct.
In principal cells of rat cortical collecting ducts (CCD) cellular pH (pHi) is regulated by basolateral Na+/H+ exchange. The influence of various agonists on pHi and cellular Ca2+ activity ([Ca2+]i) in freshly isolated CCD cells was examined with BCECF and fura-2 fluorescence ratios. The recovery of pHi per minute (delta pH/min) after an acid load was 0.26 +/- 0.03 (N = 53) in control conditions and was increased by the diadenosine polyphosphates Ap4A, Ap5A, Ap6A, the phorbol ester phorbol 12-myristat 13-acetate (PMA) (each 5 mumol/L) and angiotensin II (100 nmol/L) by 0.05 +/- 0.02 (N = 10), 0.11 +/- 0.05 (N = 13), 0.09 +/- 0.02 (N = 24), 0.10 +/- 0.03 (N = 7), and 0.09 +/- 0.03 (N = 8), respectively. Vasopressin (10 nmol/L) decreased delta pH/min by 0.11 +/- 0.03 (N = 9); ATP and Ap3A (each 5 mumol/L) had no significant effect. The increase in delta pH/min with Ap6A was abolished in the presence of an inhibitor of protein kinase C, calphostin C (0.1 mumol/l, N = 8). Fura-2 fluorescence ratio was not significantly changed with angiotensin II, Ap3A, or Ap4A but increased with vasopressin, ATP, Ap5A, and Ap6A by 0.08 +/- 0.02 (N = 13), 0.04 +/- 0.02 (N = 13), 0.03 +/- 0.01 (N = 14), and 0.03 +/- 0.01 (N = 10), respectively. These data indicate that Na+/H+ exchange in rat CCD is activated by the stimulation of a Ca(2+)-independent protein kinase C and inhibited by protein kinase A.
Schlatter
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Westfälische Wilhelms-Universität Münster, Medizinische Poliklinik, Germany.
Haxelmans
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Ankorina
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Kleta
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D000227:Adenine Nucleotides / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D005260:Female; D005452:Fluoresceins; D005456:Fluorescent Dyes; D016257:Fura-2; D006146:Guanidines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007672:Kidney Cortex; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013450:Sulfones / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology*
D000227:Adenine Nucleotides; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006146:Guanidines; D017923:Sodium-Hydrogen Exchangers; D013450:Sulfones; D014667:Vasopressins; D000804:Angiotensin II; C074107:3-methylsulfonyl-4-piperidinobenzoyl guanidine; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D002118:Calcium; D016257:Fura-2