Identification and characterization of a novel angiotensin binding site in cultured vascular smooth muscle cells that is specific for the hexapeptide (3–8) fragment of angiotensin II, angiotensin IV
| Autor: | Amy E. Ball, Howard L. Hosick, Keith L. Hall, Jodie M. Hanesworth, Joseph W. Harding, Grant P Felgenhauer |
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| Rok vydání: | 1993 |
| Předmět: |
medicine.medical_specialty
Angiotensin receptor Vascular smooth muscle GTP' Pyridines Physiology Molecular Sequence Data Clinical Biochemistry Tetrazoles Biology Binding Competitive Biochemistry Losartan Muscle Smooth Vascular Angiotensin Receptor Antagonists Radioligand Assay Cellular and Molecular Neuroscience Endocrinology Internal medicine Renin–angiotensin system medicine Animals Amino Acid Sequence Binding site Aorta Cells Cultured Receptors Angiotensin Angiotensin II Biphenyl Compounds Imidazoles Angiotensin III In vitro medicine.anatomical_structure Guanosine 5'-O-(3-Thiotriphosphate) Cattle Blood vessel |
| Zdroj: | Regulatory Peptides. 44:225-232 |
| ISSN: | 0167-0115 |
| DOI: | 10.1016/0167-0115(93)90246-5 |
| Popis: | This study demonstrates the existence of a previously unrecognized class of angiotensin binding sites on vascular smooth muscle that exhibit high affinity and specificity for the hexapeptide (3–8) fragment of angiotensin II (AngIV). Binding of [ 125 I]AngIV is saturable, reversible and describes a pharmacologic profile that is distinct and separate from the classic AT 1 or AT 2 angiotensin receptors. Saturation binding studies utilizing cultured vascular smooth muscle cells obtained from bovine aorta (BVSM) revealed that [ 125 I]AngIV bound to a single high affinity site with an associated Hill coefficient of 0.99 ± 0.003, exhibiting a K D = 1.85 ± 0.45 nM and a corresponding B max = 960 ± 100 fmol mg −1 protein. Competition binding curves in BVSM demonstrated the following rank order effectiveness: AngIV > AngII(3–7) ⪢ AngIII > Sar 1 ,Ile 8 AngII > AngII > AngII(1–7) > AngII(4–8), DuP 753, PD123177. The presence of the non-hydrolyzable GTP analog GTPγS, had no effect on [ 125 I]AngIV binding affinity in BVSM. The presence of this novel angiotensin binding site on smooth muscle in high concentration suggests the possibility that this system may play an important, yet unrecognized role in vascular control. |
| Databáze: | OpenAIRE |
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