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Des-aspartate-angiotensin I and angiotensin AT1 receptors in rat cardiac ventricles.
Regul Pept. 2005 Jul 15; 129(1-3):133-7.RP

Abstract

The binding of 125I-[Sar1,Ile8]angiotensin II and 125I-angiotensin II to ventricular membranes of rat heart was studied. Displacement of bound 125I-[Sar1,Ile8]angiotensin II by its cold equivalents, angiotensin I, angiotensin II, angiotensin III, des-aspartate-angiotensin I, losartan, PD123319 and CGP42112B supports the presence of the AT1 and the near absence of the AT2 angiotensin receptor in adult rat ventricle. The presence of binding sites for des-aspartate-angiotensin I could account for its reported cardioprotective actions. Binding of 125I-angiotensin II but not that of 125I-[Sar1,Ile8]angiotensin II was partially displaced by GppNHp suggesting that a portion of the receptor population was in the active state with dissociated G-protein. Saturation experiments carried out in the absence and presence of 1 mM GppNHp showed similar magnitude of decrease in the number of receptors (Bmax from 26.2+/-1.3 to 15.7+/-1.1 fmol/mg protein) in [125I]-angiotensin II binding. However, the guanine nucleotide had no effect on the binding of 125I-[Sar1,Ile8]angiotensin II as has also been reported elsewhere, and may suggest that Sar1-Ile8-angiotensin II, being a partial agonist, binds to both the G-protein coupled and uncoupled states of the angiotensin receptors. The present study demonstrates that des-aspartate-angiotensin I binds to angiotensin receptors in the heart, and provides further evidence for its involvement in the pathophysiology of the organ.

Authors+Show Affiliations

Department of Pharmacology, Faculty of Medicine, National University of Singapore, 119260 Singapore. phcsimmk@nus.edu.sgNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15927708

Citation

Sim, Meng-Kwoon, and Le Min. "Des-aspartate-angiotensin I and Angiotensin AT1 Receptors in Rat Cardiac Ventricles." Regulatory Peptides, vol. 129, no. 1-3, 2005, pp. 133-7.
Sim MK, Min L. Des-aspartate-angiotensin I and angiotensin AT1 receptors in rat cardiac ventricles. Regul Pept. 2005;129(1-3):133-7.
Sim, M. K., & Min, L. (2005). Des-aspartate-angiotensin I and angiotensin AT1 receptors in rat cardiac ventricles. Regulatory Peptides, 129(1-3), 133-7.
Sim MK, Min L. Des-aspartate-angiotensin I and Angiotensin AT1 Receptors in Rat Cardiac Ventricles. Regul Pept. 2005 Jul 15;129(1-3):133-7. PubMed PMID: 15927708.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Des-aspartate-angiotensin I and angiotensin AT1 receptors in rat cardiac ventricles. AU - Sim,Meng-Kwoon, AU - Min,Le, PY - 2004/09/16/received PY - 2005/02/04/accepted PY - 2005/6/2/pubmed PY - 2005/9/15/medline PY - 2005/6/2/entrez SP - 133 EP - 7 JF - Regulatory peptides JO - Regul Pept VL - 129 IS - 1-3 N2 - The binding of 125I-[Sar1,Ile8]angiotensin II and 125I-angiotensin II to ventricular membranes of rat heart was studied. Displacement of bound 125I-[Sar1,Ile8]angiotensin II by its cold equivalents, angiotensin I, angiotensin II, angiotensin III, des-aspartate-angiotensin I, losartan, PD123319 and CGP42112B supports the presence of the AT1 and the near absence of the AT2 angiotensin receptor in adult rat ventricle. The presence of binding sites for des-aspartate-angiotensin I could account for its reported cardioprotective actions. Binding of 125I-angiotensin II but not that of 125I-[Sar1,Ile8]angiotensin II was partially displaced by GppNHp suggesting that a portion of the receptor population was in the active state with dissociated G-protein. Saturation experiments carried out in the absence and presence of 1 mM GppNHp showed similar magnitude of decrease in the number of receptors (Bmax from 26.2+/-1.3 to 15.7+/-1.1 fmol/mg protein) in [125I]-angiotensin II binding. However, the guanine nucleotide had no effect on the binding of 125I-[Sar1,Ile8]angiotensin II as has also been reported elsewhere, and may suggest that Sar1-Ile8-angiotensin II, being a partial agonist, binds to both the G-protein coupled and uncoupled states of the angiotensin receptors. The present study demonstrates that des-aspartate-angiotensin I binds to angiotensin receptors in the heart, and provides further evidence for its involvement in the pathophysiology of the organ. SN - 0167-0115 UR - https://www.unboundmedicine.com/medline/citation/15927708/Des_aspartate_angiotensin_I_and_angiotensin_AT1_receptors_in_rat_cardiac_ventricles_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0167-0115(05)00065-0 DB - PRIME DP - Unbound Medicine ER -