Stimulation of rat renal medullary Na+/K(+)-ATPase by arginine vasopressin is mediated by the V2 receptor.
In previous studies, we have demonstrated that 1-10 fmol arginine vasopressin (AVP)/l maximally stimulates the activity of the enzyme Na+/K(+)-ATPase in the rat renal medullary thick ascending limb (MTAL) of Henle's loop after 4 or 10 min of stimulation when measured using a cytochemical bioassay. We have tested the hypothesis that this stimulation is mediated by the V2 receptor in the MTAL. A cytochemical bioassay was used to investigate the effect of specific V1 and V2/V1 antagonists and a synthetic V2 agonist [1-deamino,8-D-arginine]-vasopressin (dDAVP), on the activity of Na+/K(+)-ATPase. There was no effect of the V1 antagonist (1 fmol-1 mumol/l) in inhibiting the activity of Na+/K(+)-ATPase stimulated by 1 fmol AVP/l. In contrast, 100 pmol of the V2/V1 antagonist/l significantly (P less than 0.001) inhibited the stimulation of Na+/K(+)-ATPase activity by 1 fmol AVP/l from 55.5 +/- 4.3 (S.E.M.) to 31.9 +/- 1.6 mean integrated extinction (MIE) after 4 min of stimulation and from 67.0 +/- 3.2 to 36.9 +/- 0.7 MIE after 10 min of stimulation. Similarly, the stimulation of Na+/K(+)-ATPase by 10 fmol dDAVP/l was inhibited by the V2/V1 antagonist from 55.1 +/- 1.0 to 26.1 +/- 0.5 MIE after 4 min of stimulation. We conclude that the stimulation of Na+/K(+)-ATPase by AVP is mediated by the V2 receptor in the rat renal MTAL.
Charlton
J A
JA
Department of Medicine, Medical School, University of Newcastle upon Tyne.
Baylis
P H
PH
D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007679:Kidney Medulla / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D017483:Receptors, Vasopressin; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013268:Stimulation, Chemical; D014667:Vasopressins / Q000378:metabolism
D057911:Angiotensin Receptor Antagonists; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; D000254:Sodium-Potassium-Exchanging ATPase