Functional and structural interaction of (-)-Reboxetine with the human α4β2 nicotinic acetylcholine receptor

Authors
Arias, Hugo Rubén; Fedorov, Nikolai B.; Benson, Lisa C.; Lippiello, Patrick M.; Gatto, Greg J.; Feuerbach, Dominik; Ortells, Marcelo Oscar
Publication Year
2013
Language
English
Format
article
Status
Published version
Description
The interaction of the selective norepinephrine reuptake inhibitor (-)-reboxetine with the human α4β2 nicotinic acetylcholine receptor (nAChR) in different conformational states was studied by several functional and structural approaches. Patch-clamp and Ca(2+)-influx results indicate that (-)-reboxetine does not activate hα4β2 nAChRs via interaction with the orthosteric sites, but inhibits agonist-induced hα4β2 activation by a noncompetitive mechanism. Consistently, the results from the electrophysiology-based functional approach suggest that (-)-reboxetine may act via open channel block; therefore, it is capable of producing a use-dependent type of inhibition of the hα4β2 nAChR function. We tested whether (-)-reboxetine binds to the luminal [(3)H]imipramine site. The results indicate that, although (-)-reboxetine binds with low affinity to this site, it discriminates between the resting and desensitized hα4β2 nAChR ion channels. Patch-clamp results also indicate that (-)-reboxetine progressively inhibits the hα4β2 nAChR with two-fold higher potency at the end of one-second application of agonist, compared with the peak current. The molecular docking studies show that (-)-reboxetine blocks the ion channel at the level of the imipramine locus, between M2 rings 6´ and 14´. In addition, we found a (-)-reboxetine conformer that docks in the helix bundle of the α4 subunit, near the middle region. According to molecular dynamics simulations, (-)-reboxetine binding is stable for both sites, albeit less stable than imipramine. The interaction of these drugs with the helix bundle might alter allostericaly the functionality of the channel. In conclusion, the clinical action of (-)-reboxetine may be produced (at least partially) by its inhibitory action on hα4β2 nAChRs.
Fil: Arias, Hugo Rubén. California Northstate University. College of Medicine. Department of Medical Education; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Fedorov, Nikolai B.. Targacept, Inc.; Estados Unidos
Fil: Benson, Lisa C.. Targacept, Inc.; Estados Unidos
Fil: Lippiello, Patrick M.. Targacept, Inc.; Estados Unidos
Fil: Gatto, Greg J.. Targacept, Inc.; Estados Unidos
Fil: Feuerbach, Dominik. Novartis Institutes for Biomedical Research; Suiza. Universidad de Morón. Facultad de Medicina; Argentina
Fil: Ortells, Marcelo Oscar. Novartis Institutes for Biomedical Research; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Morón; Argentina
Subject
Nicotinic acetylcholine receptors
Ion channel
Reboxetine
Pharmacology
Antidepressant
Bioquímica y Biología Molecular
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Biofísica
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/21142