Structural Analysis, Molecular Modelling and Preliminary Competition Binding Studies of AM-DAN as a NMDA Receptor PCP-Site Fluorescent Ligand

Abstract

Excitotoxicity related to the dysfunction of the N-methyl-d-aspartate receptor (NMDAR) has been indicated to play an integral role in the pathophysiology of multiple disease states, including neurodegenerative disorders such as Parkinson’s disease. There is a notable gap in the market for novel NMDAR antagonists, however current methods to analyse potential antagonists rely on indirect measurements of calcium flux and hazardous radioligand binding assays. Recently, a fluorescent NMDAR ligand, N-adamantan-1-yl-dimethylamino-1-naphthalenesulfonic acid, known as AM-DAN was developed by our group. Additional studies on this ligand is necessary to evaluate its potential as a biological tool in NMDAR research. Therefore, this study was aimed at conducting structural analyses, fluorescence experiments, high-accuracy NMDAR molecular modelling and NMDAR phencyclidine (PCP) site competition binding studies using AM-DAN. Results revealed that AM-DAN has appropriate structural properties, significant fluorescent ability in various solvents and is able to bind selectively and compete for the PCP-binding site of the NMDAR. Therefore, AM-DAN holds promise as a novel fluorescent ligand to measure the affinity of prospective drugs binding at the NMDAR PCP-site and may circumvent the use of radioligands.

Synthesis of Fluorescent Dansyl Derivatives of Methoxyamine and Diphenylhydrazine as Free Radical Precursors

“…Dansyl-chloride (5-(dimethylamino)naphthalene-1-sulfonyl chloride) is a highly reactive nonfluorescent reagent that easily reacts with amines, yielding fluorescent derivatives; the reaction is widely used for amino-acids derivatization and many other detection techniques [9][10][11][12].…”

The Structural Characteristics of Compounds Interacting with the Amantadine-Sensitive Drug Transport System at the Inner Blood–Retinal Barrier

“…A previous study reported that amantadine and memantine (compound 8 ) bind to the phencyclidine (PCP) binding site of the NMDA receptor and exert pharmacological effects [ 29 , 30 , 31 ]. In addition, pharmacophore and quantitative structure–affinity relationship analyses showed the structural requirement for binding to the PCP binding site: an amine moiety with an aromatic ring or aliphatic hydrocarbon structure, such as an adamantane and cycloalkane skeleton [ 25 , 32 , 33 ]. These structural features are similar to those of the test compounds, which exhibited strong inhibitory effects on the amantadine transport system in this study ( Figure 1 and Table 2 ).…”

Illuminating the Path to Enhanced Bioimaging by Phosphole‐based Fluorophores

“…Coelenterazine H, E and 400a were used as luciferase substrates and added to a final concentration of 4.2 μM in BRET buffer. The BRET signal was measured at room temperature after different time points (5,15,30,45, 60 min) with a Tecan Spark plate reader (Tecan). The luminescence signal was observed within the range of 430 to 470 nm for coelenterazine H and coelenterazine E, while the TAMRA fluorescence signal was detected in the 550 to 700 nm range.…”