Volume 14, Issue 6 p. 759-769
Full Paper

Synthesis and in Vitro Characterisation of Ifenprodil-Based Fluorescein Conjugates as GluN1/GluN2B N-Methyl-D-aspartate Receptor Antagonists

Martine Dhilly

Martine Dhilly

CNRS, UMR 6301 ISTCT, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, BP5229, 14074 Caen Cedex (France)

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

CEA, DSV/I2BM, LDM-TEP, GIP Cyceron, 14074 Caen Cedex (France)

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Javier Becerril-Ortega

Javier Becerril-Ortega

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

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Dr. Nathalie Colloc'h

Dr. Nathalie Colloc'h

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

CNRS, UMR 6301 ISTCT, CERVOxy, GIP Cyceron, 14074 Caen Cedex (France)

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Dr. Eric T. MacKenzie

Dr. Eric T. MacKenzie

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

CNRS, UMR 6301 ISTCT, CERVOxy, GIP Cyceron, 14074 Caen Cedex (France)

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Dr. Louisa Barré

Dr. Louisa Barré

CNRS, UMR 6301 ISTCT, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, BP5229, 14074 Caen Cedex (France)

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

CEA, DSV/I2BM, LDM-TEP, GIP Cyceron, 14074 Caen Cedex (France)

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Prof. Alain Buisson

Prof. Alain Buisson

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

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Dr. Olivier Nicole

Dr. Olivier Nicole

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

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Dr. Cécile Perrio

Corresponding Author

Dr. Cécile Perrio

CNRS, UMR 6301 ISTCT, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, BP5229, 14074 Caen Cedex (France)

Université de Caen Basse-Normandie, GIP Cyceron, 14074 Caen Cedex (France)

CEA, DSV/I2BM, LDM-TEP, GIP Cyceron, 14074 Caen Cedex (France)

CNRS, UMR 6301 ISTCT, LDM-TEP, GIP Cyceron, Boulevard Henri Becquerel, BP5229, 14074 Caen Cedex (France)Search for more papers by this author
First published: 26 March 2013
Citations: 6

Graphical Abstract

GluN2B/NMDA receptor probes: A selection of ifenprodil analogues with modifications either at the benzylic position or in the phenol ring, were synthesised, conjugated to fluorescein and characterised. Benzylamine-based derivatives substituted with an amino or amidoalkyl chain were found to display potent inhibitory and selectivity properties toward GluN2B-containing NMDARs.

Abstract

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 Ca2+ 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 [3H]ifenprodil in mouse brain slices in a similar manner.