Pharmacological characterisation of α6β4⁎ nicotinic acetylcholine receptors assembled from three chimeric α6/α3 subunits in tsA201 cells

Jensen, Andreas Tue Ingemann; Hoestgaard-Jensen, Kirsten; Jensen, Anders A.

doi:10.1016/j.ejphar.2014.06.005

Cited by 4 publications

(4 citation statements)

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“…From then on, a-CtxMII and its variants have been used extensively to locate and study neuropharmacological functions of a6* AChRs in brain (see Section 2 and 3.1.1). Although a6b2* AChRs are more important and prevalent than a6b4* AChRs in vivo (see Section 3), a6b4* subtypes are easier to express in heterologous systems, thus better investigated in mammalian cell lines (Gerzanich et al, 1997;Fucile et al, 1998;Evans et al, 2003;Jensen et al, 2013Jensen et al, , 2014. We will discuss both a6b2* and a6b4* AChRs to investigate the barriers to expressing cloned a6* AChRs.…”

Section: Expression Of Cloned A6* Achrs In Xenopus Ooctyes and Cell Lmentioning

confidence: 99%

“…Another issue of expressing heteromeric AChRs in both oocytes and cells is the potential of forming multiple stoichiometries with distinct properties, such as (a4b2) 2 b2 and (a4b2) 2 a4 (Zwart and Vijverberg, 1998;Nelson et al, 2003;Kuryatov et al, 2005;Sallette et al, 2005;Harpsøe et al, 2011;Mazzaferro et al, 2011). These challenges are being overcome through the use of mutants, chimeras, and concatamers (Kuryatov et al, 2000(Kuryatov et al, , 2011Broadbent et al, 2006;Capelli et al, 2011;Jensen et al, 2013Jensen et al, , 2014Henderson et al, 2014;Ley et al, 2014). This review focuses primarily on the significance and expression of a6b2* AChRs, but compares them with what is known about a6b4* AChRs.…”

Section: Introductionmentioning

confidence: 99%

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Expression of cloned α6* nicotinic acetylcholine receptors

2015

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Section: Expression Of Cloned A6* Achrs In Xenopus Ooctyes and Cell Lmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Expression of cloned α6* nicotinic acetylcholine receptors

2015

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“…Ϫ/Ϫ mice, and NS9283 had no measurable effect when added on saz-A (n ϭ 3). saz-A has been shown to activate some ␤ 4 * receptors, but with an EC 50 in the 100 nM range (Campling et al, 2013;Jensen et al, 2014). The results thus suggest that, at concentrations of Ͻ50 nM, the effects of saz-A in WT mice involve ␤ 2 * nAChRs, some of which could associate ␤ 2 and ␤ 4 subunits.…”

Section: Ns9283 50 M Acts On Both the Nachrs And The Achementioning

confidence: 82%

“…The CNS EPSCs or EPSPs involving heteromeric nAChRs have time constants of decay varying from a few 10s of milliseconds (Nose et al, 1991;Bell et al, 2011;English et al, 2011;Leão et al, 2012;Sun et al, 2013;Unal et al, 2015) to hundreds of milliseconds (Hu et al, 1989;Nose et al, 1991;Bell et al, 2011;Ren et al, 2011;Arroyo et al, 2012;Bennett et al, 2012;Sun et al, 2013;Hay et al, 2016). The slow EPSCs were often assumed to be mediated by A2B3 nAChRs because A3B2 nAChRs were initially characterized as low affinity LS receptors.…”

Section: Two Populations Of A3b2 Nachrs?mentioning

confidence: 99%

Stoichiometry of the Heteromeric Nicotinic Receptors of the Renshaw Cell

et al. 2018

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Neuronal nicotinic acetylcholine receptors (nAChRs) are pentamers built from a variety of subunits. Some are homomeric assemblies of α subunits, others heteromeric assemblies of α and β subunits which can adopt two stoichiometries (2α:3β or 3α:2β). There is evidence for the presence of heteromeric nAChRs with the two stoichiometries in the CNS, but it has not yet been possible to identify them at a given synapse. The 2α:3β receptors are highly sensitive to agonists, whereas the 3α:2β stoichiometric variants, initially described as low sensitivity receptors, are indeed activated by low and high concentrations of ACh. We have taken advantage of the discovery that two compounds (NS9283 and Zn) potentiate selectively the 3α:2β nAChRs to establish (in mice of either sex) the presence of these variants at the motoneuron-Renshaw cell (MN-RC) synapse. NS9283 prolonged the decay of the two-component EPSC mediated by heteromeric nAChRs. NS9283 and Zn also prolonged spontaneous EPSCs involving heteromeric nAChRs, and one could rule out prolongations resulting from AChE inhibition by NS9283. These results establish the presence of 3α:2β nAChRs at the MN-RC synapse. At the functional level, we had previously explained the duality of the EPSC by assuming that high ACh concentrations in the synaptic cleft account for the fast component and that spillover of ACh accounts for the slow component. The dual ACh sensitivity of 3α:2β nAChRs now allows to attribute to these receptors both components of the EPSC. Heteromeric nicotinic receptors assemble α and β subunits in pentameric structures, which can adopt two stoichiometries: 3α:2β or 2α:3β. Both stoichiometric variants are present in the CNS, but they have never been located and characterized functionally at the level of an identified synapse. Our data indicate that 3α:2β receptors are present at the spinal cord synapses between motoneurons and Renshaw cells, where their dual mode of activation (by high concentrations of ACh for synaptic receptors, by low concentrations of ACh for extrasynaptic receptors) likely accounts for the biphasic character of the synaptic current. More generally, 3α:2β nicotinic receptors appear unique by their capacity to operate both in the cleft of classical synapses and at extrasynaptic locations.

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Pharmacological and functional comparisons of α6/α3β2β3-nAChRs and α4β2-nAChRs heterologously expressed in the human epithelial SH-EP1 cell line

Chen

Gao

et al. 2018

Acta Pharmacol Sin

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Neuronal nicotinic acetylcholine receptors containing α6 subunits (α6-nAChRs) show highly restricted distribution in midbrain neurons associated with pleasure, reward, and mood control, suggesting an important impact of α6-nAChRs in modulating mesolimbic functions. However, the function and pharmacology of α6-nAChRs remain poorly understood because of the lack of selective agonists for α6-nAChRs and the challenging heterologous expression of functional α6-nAChRs in mammalian cell lines. In particular, the α6 subunit is commonly co-expressed with α4-nAChRs in the midbrain, which masks α6-nAChR (without α4) function and pharmacology. In this study, we systematically profiled the pharmacology and function of α6-nAChRs and compared these properties with those of α4β2 nAChRs expressed in the same cell line. Heterologously expressed human α6/α3 chimeric subunits (α6 N-terminal domain joined with α3 trans-membrane domains and intracellular loops) with β2 and β3 subunits in the human SH-EP1 cell line (α6-nAChRs) were used. Patch-clamp whole-cell recordings were performed to measure these receptor-mediated currents. Functionally, the heterologously expressed α6-nAChRs exhibited excellent function and showed distinct nicotine-induced current responses, such as kinetics, inward rectification and recovery from desensitization, compared with α4β2-nAChRs. Pharmacologically, α6-nAChR was highly sensitive to the α6 subunit-selective antagonist α-conotoxin MII but had lower sensitivity to mecamylamine and dihydro-β-erythroidine. Nicotine and acetylcholine were found to be full agonists for α6-nAChRs, whereas epibatidine and cytisine were determined to be partial agonists. Heterologously expressed α6-nAChRs exhibited pharmacology and function distinct from those of α4β2-nAChRs, suggesting that α6-nAChRs may mediate different cholinergic signals. Our α6-nAChR expression system can be used as an excellent cell model for future investigations of α6-nAChR function and pharmacology.

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Pharmacological characterisation of α6β4⁎ nicotinic acetylcholine receptors assembled from three chimeric α6/α3 subunits in tsA201 cells

Cited by 4 publications

References 40 publications

Expression of cloned α6* nicotinic acetylcholine receptors

Expression of cloned α6* nicotinic acetylcholine receptors

Stoichiometry of the Heteromeric Nicotinic Receptors of the Renshaw Cell

Pharmacological and functional comparisons of α6/α3β2β3-nAChRs and α4β2-nAChRs heterologously expressed in the human epithelial SH-EP1 cell line

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