Synthesis and in Vitro Characterisation of Ifenprodil-Based Fluorescein Conjugates as GluN1/GluN2B N-Methyl-D-aspartate Receptor Antagonists
ChemBioChem. 2013-03-26; 14(6): 759-769
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1. Chembiochem. 2013 Apr 15;14(6):759-69. doi: 10.1002/cbic.201200675. Epub 2013 Mar
Synthesis and in vitro characterisation of ifenprodil-based fluorescein
conjugates as GluN1/GluN2B N-Methyl-D-aspartate receptor antagonists.
Dhilly M(1), Becerril-Ortega J, Colloc’h N, MacKenzie ET, Barré L, Buisson A,
Nicole O, Perrio C.
(1)CNRS, UMR 6301 ISTCT, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, BP5229,
14074 Caen Cedex, France.
GluN2B-containing NMDA receptors are involved in many important physiological
functions and play a pivotal role in mediating pain as well as in several
neurodegenerative disorders. We aimed to develop fluorescent probes to target the
GluN2B subunit selectively in order to allow better understanding of the
relationships between receptor localisation and physiological importance.
Ifenprodil, known as the GluNR2B antagonist of reference, was chosen as the
template for the elaboration of probes. We had previously reported a fluorescein
conjugate that was shown (by confocal microscopy imaging of DS-red-labelled
cortical neurons) to bind specifically to GluN2B. To elaborate this probe, we
explored the influence of both the nature and the attachment point of the spacer
between the fluorophore and the parent compound, ifenprodil. We performed
chemical modifications of ifenprodil at the benzylic position and on the phenol
ring by introducing secondary amine or amide functions and evaluated alkyl chains
from two to 20 bonds either including or not including secondary amide functions
as spacers. The previously developed probe was found to display the greatest
activity in the inhibition of NMDA-induced Ca(2+) influx by calcium imaging
experiments on HEK293 cells transfected with the cDNA encoding for GluN1-1A and
GluN2B. Further investigations revealed that this probe had a neuroprotective
effect equivalent to that of ifenprodil in a standard test for neurotoxicity.
Despite effects of lesser amplitude with these probes relative to ifenprodil, we
demonstrated that they displaced [(3) H]ifenprodil in mouse brain slices in a
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PMID: 23532918 [Indexed for MEDLINE]