title: Evaluation of alpha7 nicotinic acetylcholine receptor agonists and positive allosteric modulators using the parallel oocyte electrophysiology test station.
abstract: Neuronal acetylcholine receptors (nAChRs) of the alpha7 subtype are ligand-gated ion channels that are widely distributed throughout the central nervous system and considered as attractive targets for the treatment of various neuropsychiatric and neurodegenerative diseases. Both agonists and positive allosteric modulators (PAMs) are being developed as means to enhance the function of alpha7 nAChRs. The in vitro characterization of alpha7 ligands, including agonists and PAMs, relies on multiple technologies, but only electrophysiological measurements assess the channel activity directly. Traditional electrophysiological approaches utilizing two-electrode voltage clamp or patch clamp in isolated cells have very low throughput to significantly impact drug discovery. Abbott (Abbott Park, IL) has developed a two-electrode voltage clamp-based system, the Parallel Oocyte Electrophysiology Test Station (POETs()), that allows for the investigation of ligand-gated ion channels such as alpha7 nAChRs in a higher-throughput manner. We describe the utility of this technology in the discovery of selective alpha7 agonists and PAMs. With alpha7 agonists, POETs experiments involved both single- and multiple-point concentration-response testing revealing diverse activation profiles (zero efficacy desensitizing, partial, and full agonists). In the characterization of alpha7 PAMs, POETs testing has served as a reliable primary or secondary screen identifying compounds that fall into distinct functional types depending on the manner in which current potentiation occurred. Type I PAMs (eg, genistein, NS1738, and 5-hydroxyindole) increase predominantly the peak amplitude response, type II PAMs affect the peak current and current decay (eg, PNU-120,596 and 4-(naphthalen-1-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide), and anothertype slowing the current decay kinetics in the absence of increases in the peak current. In summary, POETs technology allows for significant impact on higher throughput in the testing of alpha7 agonists and PAMs and for identification of compounds with unique profiles that could prove valuable in identifying an optimum in vitro profile in the development of therapeutics for which the alpha7 subtype is considered.
authors.affiliation: Neuroscience Research, Global Pharmaceutical Research and Development, Abbott, Abbott Park, Illinois 60064-6125, USA. john.malysz@abbott.com
authors.forename: John
authors.initials: J
authors.lastname: Malysz
authors.forename: Jens H
authors.initials: JH
authors.lastname: Grønlien
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Timmermann
authors.forename: Monika
authors.initials: M
authors.lastname: Håkerud
authors.forename: Kirsten
authors.initials: K
authors.lastname: Thorin-Hagene
authors.forename: Hilde
authors.initials: H
authors.lastname: Ween
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Trumbull
authors.forename: Yongli
authors.initials: Y
authors.lastname: Xiong
authors.forename: Clark A
authors.initials: CA
authors.lastname: Briggs
authors.forename: Philip K
authors.initials: PK
authors.lastname: Ahring
authors.forename: Tino
authors.initials: T
authors.lastname: Dyhring
authors.forename: Murali
authors.initials: M
authors.lastname: Gopalakrishnan
mesh_terms: D000818:Animals; D001597:Benzylidene Compounds / Q000494:pharmacology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007555:Isoxazoles / Q000494:pharmacology; D009447:Neuroblastoma / Q000473:pathology; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010671:Phenylurea Compounds / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000187:drug effects*; D014982:Xenopus laevis; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: C508388:1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-methylisoxazol-3-yl)urea; D001597:Benzylidene Compounds; C579167:Chrna7 protein, human; D007555:Isoxazoles; D018722:Nicotinic Agonists; D010671:Phenylurea Compounds; D011725:Pyridines; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; C088936:3-(2,4-dimethoxybenzylidene)anabaseine