Charlton J A, Baylis P H
Department of Medicine, Medical School, University of Newcastle upon Tyne.
J Endocrinol. 1990 Nov;127(2):213-6. doi: 10.1677/joe.0.1270213.
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.
在先前的研究中，我们已经证明，当使用细胞化学生物测定法进行测量时，1 - 10飞摩尔精氨酸加压素（AVP）/升在刺激4或10分钟后，能最大程度地刺激大鼠肾髓质亨利氏袢厚升支（MTAL）中Na⁺/K⁺-ATP酶的活性。我们检验了这样一个假说，即这种刺激是由MTAL中的V2受体介导的。采用细胞化学生物测定法来研究特异性V1和V2/V1拮抗剂以及合成的V2激动剂[1-脱氨基，8-D-精氨酸]-加压素（dDAVP）对Na⁺/K⁺-ATP酶活性的影响。V1拮抗剂（1飞摩尔 - 1微摩尔/升）对抑制由1飞摩尔AVP/升刺激的Na⁺/K⁺-ATP酶活性没有作用。相反，100皮摩尔/升的V2/V1拮抗剂显著（P小于0.001）抑制了1飞摩尔AVP/升对Na⁺/K⁺-ATP酶活性的刺激，刺激4分钟后，平均积分消光（MIE）从55.5±4.3（标准误）降至31.9±1.6，刺激10分钟后，从67.0±3.2降至36.9±0.7 MIE。同样，10飞摩尔dDAVP/升对Na⁺/K⁺-ATP酶的刺激在刺激4分钟后被V2/V1拮抗剂从式55.1±1.0抑制至26.1±0.5 MIE。我们得出结论，AVP对Na⁺/K⁺-ATP酶的刺激是由大鼠肾MTAL中的V2受体介导的。
