title: The muscarinic acetylcholine receptor agonist BuTAC mediates antipsychotic-like effects via the M4 subtype.
abstract: The generation of muscarinic acetylcholine receptor (mAChR) subtype-selective compounds has been challenging, requiring use of nonpharmacological approaches, such as genetically engineered animals, to deepen our understanding of the potential that members of the muscarinic receptor subtype family hold as therapeutic drug targets. The muscarinic receptor agonist 'BuTAC' was previously shown to exhibit efficacy in animal models of psychosis, although the particular receptor subtype(s) responsible for such activity was unclear. Here, we evaluate the in vitro functional agonist and antagonist activity of BuTAC using an assay that provides a direct measure of G protein activation. In addition, we employ the conditioned avoidance response paradigm, an in vivo model predictive of antipsychotic activity, and mouse genetic deletion models to investigate which presynaptic mAChR subtype mediates the antipsychotic-like effects of BuTAC. Our results show that, in vitro, BuTAC acts as a full agonist at the M2AChR and a partial agonist at the M1 and M4 receptors, with full antagonist activity at M3- and M5AChRs. In the mouse conditioned avoidance response (CAR) assay, BuTAC exhibits an atypical antipsychotic-like profile by selectively decreasing avoidance responses at doses that do not induce escape failures. CAR results using M2(-/-), M4(-/-), and M2/M4 (M2/M4(-/-)) mice found that the effects of BuTAC were near completely lost in M2/M4(-/-) double-knockout mice and potency of BuTAC was right-shifted in M4(-/-) as compared with wild-type and M2(-/-) mice. The M2/M4(-/-) mice showed no altered sensitivity to the antipsychotic effects of either haloperidol or clozapine, suggesting that these compounds mediate their actions in CAR via a non-mAChR-mediated mechanism. These data support a role for the M4AChR subtype in mediating the antipsychotic-like activity of BuTAC and implicate M4AChR agonism as a potential novel therapeutic mechanism for ameliorating symptoms associated with schizophrenia.
authors.affiliation: Lilly Research Laboratories, Eli Lilly, Lilly Corporate Center, Indianapolis, IN, USA.
authors.forename: Marla L
authors.initials: ML
authors.lastname: Watt
authors.forename: Linda
authors.initials: L
authors.lastname: Rorick-Kehn
authors.forename: David B
authors.initials: DB
authors.lastname: Shaw
authors.forename: Karen M
authors.initials: KM
authors.lastname: Knitowski
authors.forename: Anne T
authors.initials: AT
authors.lastname: Quets
authors.forename: Amy K
authors.initials: AK
authors.lastname: Chesterfield
authors.forename: David L
authors.initials: DL
authors.lastname: McKinzie
authors.forename: Christian C
authors.initials: CC
authors.lastname: Felder
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D016466:CHO Cells; D003216:Conditioning, Operant / Q000187:drug effects* / Q000502:physiology; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000493:pharmacokinetics; D006220:Haloperidol / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding / Q000187:drug effects; D043585:Receptor, Muscarinic M2 / Q000235:genetics / Q000378:metabolism; D043588:Receptor, Muscarinic M4 / Q000172:deficiency / Q000378:metabolism*; D014326:Tropanes / Q000494:pharmacology*
chemical_list: C466794:6-(4-butylthio-1,2,5-thiadiazol-3-yl)-1-azabicyclo(3.2.1)octane; D014150:Antipsychotic Agents; D043585:Receptor, Muscarinic M2; D043588:Receptor, Muscarinic M4; D014326:Tropanes; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006220:Haloperidol
references.citation: Schizophr Res. 2000 May 5;42(3):249-59
references.pmid: 10785583
references.citation: Biol Psychiatry. 2001 Apr 15;49(8):716-25
references.pmid: 11313039
references.citation: Psychopharmacology (Berl). 2012 Nov;224(2):277-87
references.pmid: 22648127
references.citation: Proc Natl Acad Sci U S A. 2008 Aug 5;105(31):10978-83
references.pmid: 18678919
references.citation: Curr Drug Targets CNS Neurol Disord. 2002 Apr;1(2):163-81
references.pmid: 12769625
references.citation: J Neurosci. 2002 Jan 1;22(1):RC190
references.pmid: 11756520
references.citation: Psychopharmacology (Berl). 2010 Jan;207(4):547-58
references.pmid: 19820917
references.citation: Psychopharmacology (Berl). 2010 Feb;208(3):401-16
references.pmid: 20013114
references.citation: Pharmacol Ther. 2004 Jul;103(1):21-80
references.pmid: 15251227
references.citation: J Neurosci. 2011 Apr 20;31(16):5905-8
references.pmid: 21508215
references.citation: Biol Psychiatry. 2007 May 15;61(10):1161-70
references.pmid: 17239354
references.citation: J Pharmacol Exp Ther. 1992 Feb;260(2):576-80
references.pmid: 1346637
references.citation: J Pharmacol Exp Ther. 2001 Nov;299(2):782-92
references.pmid: 11602695
references.citation: J Neurosci. 1992 Sep;12(9):3591-600
references.pmid: 1527598
references.citation: Eur J Pharmacol. 1998 Sep 4;356(2-3):109-19
references.pmid: 9774240
references.citation: Synapse. 1997 Dec;27(4):357-66
references.pmid: 9372558
references.citation: Pharmacol Biochem Behav. 2004 Oct;79(2):359-65
references.pmid: 15501313
references.citation: Neuropsychopharmacology. 1999 Mar;20(3):263-70
references.pmid: 10063486
references.citation: Eur J Pharmacol. 2011 Apr 10;656(1-3):39-44
references.pmid: 21269601
references.citation: Psychopharmacology (Berl). 2008 Aug;199(3):331-88
references.pmid: 18568339
references.citation: Neuroscience. 2001;103(4):1017-24
references.pmid: 11301208
references.citation: Proc Natl Acad Sci U S A. 2003 Nov 11;100(23):13674-9
references.pmid: 14595031
references.citation: Eur J Pharmacol. 1997 Mar 5;321(3):349-54
references.pmid: 9085047
references.citation: Proc Natl Acad Sci U S A. 1999 Feb 16;96(4):1692-7
references.pmid: 9990086
references.citation: Eur J Neurosci. 2003 Apr;17(7):1403-10
references.pmid: 12713643
references.citation: Proc Natl Acad Sci U S A. 1990 Sep;87(18):7050-4
references.pmid: 2402490
references.citation: Prog Neurobiol. 1991;37(6):475-524
references.pmid: 1763188
references.citation: J Neurosci. 2002 Aug 1;22(15):6347-52
references.pmid: 12151512
references.citation: Life Sci. 2001 Apr 27;68(22-23):2457-66
references.pmid: 11392613
references.citation: J Neurosci. 1994 May;14(5 Pt 2):3351-63
references.pmid: 8182478
references.citation: Schizophr Res. 2001 Apr 15;49(1-2):193-201
references.pmid: 11343877
references.citation: Proc Natl Acad Sci U S A. 1999 Aug 31;96(18):10483-8
references.pmid: 10468635
references.citation: J Med Chem. 1998 Oct 22;41(22):4378-84
references.pmid: 9784113
references.citation: Biochem Biophys Res Commun. 2008 Sep 12;374(1):128-33
references.pmid: 18601900
references.citation: J Pharmacol Exp Ther. 1999 May;289(2):946-55
references.pmid: 10215674
references.citation: J Med Chem. 2000 Nov 16;43(23):4333-53
references.pmid: 11087557
references.citation: Am J Psychiatry. 2008 Aug;165(8):1033-9
references.pmid: 18593778
references.citation: J Pharmacol Exp Ther. 2005 Mar;312(3):1055-63
references.pmid: 15574685
references.citation: Neurochem Res. 2003 Apr;28(3-4):437-42
references.pmid: 12675128
references.citation: Eur J Pharmacol. 1999 Jul 2;376(1-2):119-25
references.pmid: 10440097
references.citation: J Pharmacol Exp Ther. 2000 Apr;293(1):121-7
references.pmid: 10734161
references.citation: Neuropsychopharmacology. 2001 Nov;25(5):633-41
references.pmid: 11682246
references.citation: PLoS One. 2011;6(11):e27538
references.pmid: 22102904
references.citation: Biol Psychiatry. 2011 Jun 15;69(12):e89-99
references.pmid: 21489408
references.citation: Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):15312-7
references.pmid: 11752469