Related Experiment Video
Updated: Aug 17, 2026

Affinity Labeling Detection of Endogenous Receptors from Zebrafish Embryos
Published on: August 31, 2016
[Search for an endogenous ligand for sigma receptors]
Abstract:
Whether there is an endogenous ligand for sigma receptors remains unknown. A total lipid fraction was isolated from the porcine liver, which was then subjected to chromatographic separation, yielding nine chromatographic fractions eluated at various chloroform/methanol ratios: each fraction was tested for its capacity of inhibiting the binding of (+)-[3H]SKF 10047 to hepatic sigma-receptors. The chromatographic fraction 7 + 7A (eluated at chloroform/methanol ratios of 60:40-10:90) which consisted mainly of phospholipids was found to have the highest activity. However, a complex analysis of this fraction revealed no relationship of its sigma-inhibiting activity to phospholipids. It is suggested that the non-competitive inhibition of (+)-[3H]SKF 10047 binding by the isolated active fraction is due to its presence of an endogenous ligand which, interacting with sigma-2 receptor, allosterically inhibits the binding of the labelled (+)-benzomorphan.
Related Concept Videos
G-protein Coupled Receptors
Internal Receptors
G Protein-coupled Receptors
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
GPCR Desensitization
Ligand-Gated Ion Channel Receptor: Gating Mechanism
The Two-State Receptor Model
The binding affinity of a drug determines its interaction with one...

