Amphibian myocardial angiotensin II receptors are distinct from mammalian AT1 and AT2 receptor subtypes

FEBS Letters

Millan, Monica A.¹  Sandberg, Kathryn¹  Catt, Kevin J.¹  Ji, Hong¹ 

[1] Endocrinology and Reproduction Research Branch National Institutes of Child Health and Human Development, N1H, Bethesda, MD 20892, USA

关键词: Angiotensin receptor;    Angiotensin;    Angiotensin receptor antagonist;    Xenopus laevis;    Myocardium;    Heart;    AII;    angiotensin II;    Ca2+;    calcium;    DTT;    dithiothreitol;   

DOI  :  10.1016/0014-5793(91)80704-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

High-affinity receptors for angiotensin II were identified on Xenopus laevis cardiac membranes and characterized by binding-inhibition studies with peptide and non-peptide AII antagonists. Scatchard analysis of the binding data identified a high-affinity site with K _d1 =1.6 nM and B _max1=3.7 pmol/mg protein and a low-affinity site with K _d2=22 nM and B _max2 =9.5 pmol/mg protein. Treatment with dithiothreitol reduced the number of binding sites by > 70%. The rank order of potency for AII analogs was (agent, IC₅₀) [Sar¹,Ile⁸]AII, 0.91 nM > AII, 2.0 nM > AI, 5.3 nM > [Sar¹, Ala⁸]AII, 19 nM > CGP42112A, 1.2 μM ⋙ DuP 753≈PD-123177, > μM. The relative potencies of these compounds differ markedly from their activities on the two known mammalian AII receptor subtypes, AT₁ and AT₂. These results indicate that amphibian AII receptors are pharmacologically distinct from both the AT₁ and AT₂ receptors characterized in mammalian tissues.

【 授权许可】

Unknown