Biomaterial Database

Angiotensin-(1-7) binding at angiotensin II receptors in the rat brain. 1995

B P Rowe, and D L Saylor, and R C Speth, and D R Absher

Department of Physiology, East Tennessee State University, James H. Quillen College of Medicine, Johnson City 37614-0576, USA.

Angiotensin-(1-7) (Ang-(1-7)) is reported to be equipotent with angiotensin II (AII) in producing some central biological effects but the receptors responsible for these actions have not been defined. Three classes of receptor have been proposed: AT1, AT2, and a putative Ang-(1-7) selective receptor. This study specifically evaluates Ang-(1-7) competition at AII binding sites (AT1 and AT2) in the rat brain. 125I Sar1 Ile8 AII (269-312 pM) was used to conduct receptor autoradiographic binding assays in brain sections. Competition with Ile5 AII and Val5 AII was similar at nuclei in which either AT1 or AT2 receptor subtypes predominate (Ki = 11-18 nM). Ang-(1-7) competed 150-fold less effectively than native AII at AT1 predominant brain nuclei (Ki = 2.4 microM). At brain regions where AT2 receptors predominate, Ang-(1-7) showed a very low affinity (Ki = 104 microM) for the majority of the 125I Sar1 Ile8 AII binding sites (AT2). A small proportion of 125I Sar1 Ile8 AII binding sites showed an affinity of 2.0 microM, presumably AT1 receptors present in those brain regions. For biological responses where Ang-(1-7) is reported to be equipotent with AII, it is unlikely that these actions are mediated by the widely distributed AT1 or AT2 receptor subtypes which recognize 125I Sar1 Ile8 AII.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011945	Receptors, Angiotensin	Cell surface proteins that bind ANGIOTENSINS and trigger intracellular changes influencing the behavior of cells.	Angiotensin Receptor,Angiotensin Receptors,Angiotensin II Receptor,Angiotensin III Receptor,Receptor, Angiotensin II,Receptor, Angiotensin III,Receptor, Angiotensin
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D000803	Angiotensin I	A decapeptide that is cleaved from precursor angiotensinogen by RENIN. Angiotensin I has limited biological activity. It is converted to angiotensin II, a potent vasoconstrictor, after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME.
D000804	Angiotensin II	An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.	Angiotensin II, Ile(5)-,Angiotensin II, Val(5)-,5-L-Isoleucine Angiotensin II,ANG-(1-8)Octapeptide,Angiotensin II, Isoleucine(5)-,Angiotensin II, Valine(5)-,Angiotensin-(1-8) Octapeptide,Isoleucine(5)-Angiotensin,Isoleucyl(5)-Angiotensin II,Valyl(5)-Angiotensin II,5 L Isoleucine Angiotensin II,Angiotensin II, 5-L-Isoleucine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia