title: JN403, in vitro characterization of a novel nicotinic acetylcholine receptor alpha7 selective agonist.
abstract: This report describes the in vitro features of a novel selective nicotinic acetylcholine receptor (nAChR) alpha7 agonist, JN403, (S)-(1-Aza-bicyclo[2.2.2]oct-3-yl)-carbamic acid (S)-1-(2-fluoro-phenyl)-ethyl ester. JN403 was evaluated in a number of in vitro systems of different species, at recombinant receptors using radioligand binding, signal transduction and electrophysiological studies. When using [(125)I] alpha-bungarotoxin (alpha-BTX) as a radioligand, JN403 has high affinity for human recombinant nAChR alpha7 (pK(D)=6.7). Functionally, JN403 is a partial and potent agonist at human nAChR alpha7. The compound stimulates calcium influx in GH3 cells recombinantly expressing the human nAChR with an pEC(50) of 7.0 and an E(max) of 85% (compared to the full agonist epibatidine). In Xenopus oocytes expressing human nAChR alpha7 JN403 induces inward currents with an pEC(50) of 5.7 and an E(max) of 55%. In both recombinant systems JN403 is a partial agonist and the agonistic effects are blocked after pre-administration of methyllycaconitine (MLA, 100nM), a nAChR alpha7 antagonist. In functional calcium influx assays, JN403 displays a significantly lower potency for other subtypes of human nAChRs like alpha4beta2, alpha3beta4, alpha1beta1gammadelta as well as 5HT(3) receptors when tested functionally as an antagonist (pIC(50)<4.8) and is devoid of agonistic activity (pEC(50)<4). Similarly, JN403 shows low binding activity at a wide panel of neurotransmitter receptors. Thus, JN403 is a potent and selective nAChR alpha7 agonist and will be a useful tool for the characterization of nAChR alpha7 mediated effects both in vitro and in vivo.
authors.affiliation: Neuroscience Research, Novartis Institutes for BioMedical Research, Basel, Switzerland. dominik.feuerbach@novartis.com
authors.forename: Dominik
authors.initials: D
authors.lastname: Feuerbach
authors.forename: Joachim
authors.initials: J
authors.lastname: Nozulak
authors.forename: Kurt
authors.initials: K
authors.lastname: Lingenhoehl
authors.forename: Kevin
authors.initials: K
authors.lastname: McAllister
authors.forename: Daniel
authors.initials: D
authors.lastname: Hoyer
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002219:Carbamates / Q000138:chemical synthesis / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008564:Membrane Potentials / Q000187:drug effects; D018722:Nicotinic Agonists / Q000138:chemical synthesis / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D011812:Quinuclidines / Q000138:chemical synthesis / Q000494:pharmacology*; D011869:Radioligand Assay; D011978:Receptors, Nicotinic / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014981:Xenopus; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: C520400:(S)-(1-azabicyclo(2.2.2)oct-3-yl)carbamic acid (S)-1-(2-fluorophenyl) ethyl ester; D002038:Bungarotoxins; D002219:Carbamates; C579167:Chrna7 protein, human; D007457:Iodine Radioisotopes; D018722:Nicotinic Agonists; D011812:Quinuclidines; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins; D064569:alpha7 Nicotinic Acetylcholine Receptor; D002118:Calcium