Related Experiment Video
Updated: Aug 13, 2026

Quantifying Agonist Activity at G Protein-coupled Receptors
Published on: December 26, 2011
Design, synthesis, and biological activity of methoctramine-related polyamines as putative G(i) protein activators
C Melchiorre1, M L Bolognesi, R Budriesi
1Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy. camelch@kaiser.alma.unibo.it
Abstract:
The universal template approach provided a prospect of modifying methoctramine (2) structure. Thus, polyamines 3-7 were designed in which the flexibility of the diaminohexane spacer of 2 was replaced by a bipiperidinyl moiety. In electrically stimulated guinea pig left atria, these novel polyamines, unlike prototype 2, displayed a potent intrinsic activity, which was in contrast with the muscarinic antagonism shown in binding studies by some of them (3 and 4) and was inhibited by benzalkonium chloride, an inhibitor of G(i) proteins.
Related Concept Videos
G-protein Coupled 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...
Activation and Inactivation of G Proteins
GPCRs Regulate Adenylyl Cylase Activity
Two...
Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Structure-Activity Relationships and Drug Design
SAR studies the intricate relationship between a drug's chemical structure and biological activity. It focuses on understanding how modifications to a drug's structure can influence its...

