Characterization of nicotinic acetylcholine receptors from the insectsAphis craccivora,Myzus persicae, andLocusta migratoria by radioligand binding assays: Relation to thiamethoxam action

We report the discovery and functional characterization of αM-Conotoxin MIIIJ, a peptide from the venom of the fish-hunting cone snail Conus magus. Injections of αM-MIIIJ induced paralysis in goldfish (Carassius auratus) but not mice. Intracellular recording from skeletal muscles of fish (C. auratus) and frog (Xenopus laevis) revealed that αM-MIIIJ inhibited postsynaptic nicotinic acetylcholine receptors (nAChRs) with an IC50 of ~0.1 μM. With comparable potency, αM-MIIIJ reversibly blocked ACh-gated currents (IACh) of voltage-clamped X. laevis oocytes exogenously expressing nAChRs cloned from zebrafish (Danio rerio) muscle. αM-MIIIJ also protected against slowly-reversible block of IACh by α-bungarotoxin (α-BgTX, a snake neurotoxin) and α-conotoxin EI (α-EI, from Conus ermineus another fish hunter) that competitively block nAChRs at the ACh binding site. Furthermore, assessment by fluorescence microscopy showed that αM-MIIIJ inhibited the binding of fluorescently-tagged α-BgTX at neuromuscular junctions of X. laevis, C. auratus, and D. rerio. (Note, we observed that αM-MIIIJ can block adult mouse and human muscle nAChRs exogenously expressed in X. laevis oocytes, but with IC50s ~100-times higher than those of zebrafish nAChRs.) Taken together, these results indicate that αM-MIIIJ inhibits muscle nAChRs and furthermore apparently does so by interfering with the binding of ACh to its receptor. Comparative alignments with homologous sequences identified in other fish hunters revealed that αM-MIIIJ defines a new class of muscle nAChR inhibitors from cone snails.

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Synthesis of Novel Nicotinic Ligands with Multimodal Action: Targeting Acetylcholine α4β2, Dopamine and Serotonin Transporters

Molecules ◽

10.3390/molecules24203808 ◽

2019 ◽

Vol 24 (20) ◽

pp. 3808

Author(s):

Juan Pablo González-Gutiérrez ◽

Hernán Armando Pessoa-Mahana ◽

Patricio Ernesto Iturriaga-Vásquez ◽

Miguel Iván Reyes-Parada ◽

Nicolas Esteban Guerra-Díaz ◽

...

Keyword(s):

Binding Site ◽

Nicotinic Acetylcholine Receptors ◽

Acetylcholine Receptors ◽

Radioligand Binding ◽

Docking Studies ◽

Binding Assays ◽

Serotonin Transporters ◽

Paroxetine Binding ◽

Compound 21 ◽

Binding Percentage

Nicotinic acetylcholine receptors (nAChRs), serotonin transporters (SERT) and dopamine transporters (DAT) represent targets for the development of novel nicotinic derivatives acting as multiligands associated with different health conditions, such as depressive, anxiety and addiction disorders. In the present work, a series of functionalized esters structurally related to acetylcholine and nicotine were synthesized and pharmacologically assayed with respect to these targets. The synthesized compounds were studied in radioligand binding assays at α4β2 nAChR, h-SERT and h-DAT. SERT experiments showed not radioligand [3H]-paroxetine displacement, but rather an increase in the radioligand binding percentage at the central binding site was observed. Compound 20 showed Ki values of 1.008 ± 0.230 μM for h-DAT and 0.031 ± 0.006 μM for α4β2 nAChR, and [3H]-paroxetine binding of 191.50% in h-SERT displacement studies, being the only compound displaying triple affinity. Compound 21 displayed Ki values of 0.113 ± 0.037 μM for α4β2 nAChR and 0.075 ± 0.009 μM for h-DAT acting as a dual ligand. Molecular docking studies on homology models of α4β2 nAChR, h-DAT and h-SERT suggested potential interactions among the compounds and agonist binding site at the α4/β2 subunit interfaces of α4β2 nAChR, central binding site of h-DAT and allosteric modulator effect in h-SERT.

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Characterization of AN317, a novel selective agonist of α6β2-containing nicotinic acetylcholine receptors

Biochemical Pharmacology ◽

10.1016/j.bcp.2019.113786 ◽

2020 ◽

Vol 174 ◽

pp. 113786 ◽

Cited By ~ 1

Author(s):

Karin Sandager-Nielsen ◽

Philip K. Ahring ◽

Jessica Klein ◽

Marloes van Hout ◽

Siganya Thaneshwaran ◽

...

Keyword(s):

Nicotinic Acetylcholine Receptors ◽

Acetylcholine Receptors ◽

Nicotinic Acetylcholine ◽

Selective Agonist

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Molecular cloning and characterization of a novel human variant of RIC-3, a putative chaperone of nicotinic acetylcholine receptors

Bioscience Reports ◽

10.1042/bsr20080055 ◽

2008 ◽

Vol 28 (6) ◽

pp. 299-306 ◽

Cited By ~ 6

Author(s):

Tamara Seredenina ◽

Teresa Ferraro ◽

Georg C. Terstappen ◽

Andrea Caricasole ◽

Renza Roncarati

Keyword(s):

Nicotinic Acetylcholine Receptors ◽

Acetylcholine Receptors ◽

Coiled Coil ◽

Surface Expression ◽

Protein Product ◽

Nicotinic Acetylcholine ◽

Α7 Nachr ◽

New Variant ◽

Novel Variant

Recent reports demonstrate that the RIC-3 (resistant to inhibitors of cholinesterase-3) protein is important for the maturation of nAChRs (nicotinic acetylcholine receptors). In the present study RIC-3e, a novel variant of RIC-3, is described. This variant contains a deletion of exons 4 and 5 of RIC-3, resulting in a protein product lacking a conserved coiled-coil domain. Like RIC-3, the new variant is predominantly, but not exclusively, expressed in the brain. The analysis of expression of variant RIC-3 mRNA and of α7-nAChR mRNA in a set of human tissues shows a similar profile. The RIC-3e protein is functionally active and enables surface expression of mature α7-nAChRs in cell lines not otherwise permissive for the expression of this receptor.

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