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- Title
Luminal arginine vasopressin stimulates Na<sup>+</sup>-H<sup>+</sup> exchange and H<sup>+</sup>-ATPase in cortical distal tubule via VI receptor.
- Authors
Barreto-chaves, M.L.M.; Mello-Aires, Margarida De
- Abstract
Bicarbonate reabsorption was evaluated by stationary microperfusion of <em>in vitro</em> early distal (ED) and late distal (LD) segments of rat kidney intratubular pH was recorded by double-barreled H ion-exchange resin/reference (1M KCl) microelectrodes for the determination of HCO3- reabsorption. In the presence of luminal arginine vasopressin (AVP, 10-9 M) a significant increase in HCO3-reabsorption was observed both in ED (from 0.931 ± 0.061 to 2.12 ± 0.171 nmol cm-2 s-1 and LD segments [from 0.542 ± 0.086 to 1.67 ± 0.111 nmol cm-2, s-1 The addition of the V1-receptor antagoinist [(d (CH2)5. Tyr (Et)²) argine vasopressin] (10-5 M) to luminal perfusion blocked luminal AVP mediated stimulation in ED and LD segments. 5-(N,N-hexamethylene). amiloride (10-4 M) addedto luminal perfusion inhibited luminal AVP-mediated stimulatton in ED (by 63.7%) and LD (by 34.1% ) segments The addition of Bufilomycin A1 (2 ×10-7 M) to the luminal perfusion did not affect luminal AVP-mediated stimulation in ED sements, but reduced it (by 31.7%) in LD segments. Our results indicate that luminal AVP acts to stimulate die Na+ H+ exchange in ED and LD segments via activation of V1 receptors, as well as the vacuolar H+ -ATPase in LD segments.
- Subjects
ADENOSINE triphosphatase; AMINO acids; ARGININE; VASOPRESSIN; ORGANIC acids; ELECTRODES
- Publication
Kidney International, 1997, Vol 52, Issue 4, p1035
- ISSN
0085-2538
- Publication type
Article
- DOI
10.1038/ki.1997.425