Related Experiment Video
Updated: Aug 10, 2026

Receptor Autoradiography Protocol for the Localized Visualization of Angiotensin II Receptors
Published on: June 7, 2016
Characterization of angiotensin II binding sites in the human term placenta
Abstract:
Specific angiotensin II (AII) binding sites were identified and characterized in membranes from human term placenta. The binding of iodinated [125I](Sar1)AII was time-dependent and saturable; it could be totally reversed on addition of unlabelled (Sar1)AII and GTP + NaCl. Scatchard plot analysis of dose-dependent [125I](Sar1)AII binding indicated the presence of a single class of binding sites with an equilibrium dissociation constant of 0.27 +/- 0.06 nM and a maximum binding capacity of 38.4 +/- 4.3 fmol/mg protein. The affinity of five AII analogues for the placental receptor was determined in competitive binding assays; the order of inhibitory potency was: (Sar1)AII greater than (Sar1, Ile8)AII approximately (Sar1, Ala8)AII approximately AII greater than angiotensin I greater than (Des-Phe8)AII. (Sar1)AII did not cause any significant change in the basal or stimulated adenylate cyclase activity. In order to investigate the subunit molecular structure of the placenta AII receptor, membranes were covalently labelled with the photoaffinity ligand [125I](Sar1, (4N3Phe)8)AII. Sodium dodecylsulfate-polyacrylamide gel electrophoresis followed by autoradiography showed that the labelling was specifically incorporated into a protein of Mr 92,000 in the presence or absence of dithiothreitol. It therefore appears that the AII receptor from human placenta has the same binding and pharmacological properties as other well-known AII receptors; by contrast, it is characterized by a significantly higher molecular weight, pointing out that structural differences in AII receptors may exist between species.
More Related Videos
09:51Live Cell Imaging and 3D Analysis of Angiotensin Receptor Type 1a Trafficking in Transfected Human Embryonic Kidney Cells Using Confocal Microscopy
Published on: March 27, 2017
08:45Quantitating Iron Transport Across the Mouse Placenta In Vivo Using Nonradioactive Iron Isotopes
Published on: May 10, 2022
Related Concept Videos
Ligand Binding and Linkage
Transcytosis of IgG
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Transducer Mechanism: Enzyme-Linked Receptors
Major types that are helpful drug targets include:
Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Antihypertensive Drugs: Angiotensin-Converting Enzyme Inhibitors
Antihypertensive Drugs: Angiotensin II Receptor Blockers