title: Significant determinants of mouse pain behaviour.
abstract: Transgenic mouse behavioural analysis has furthered our understanding of the molecular and cellular mechanisms underlying damage sensing and pain. However, it is not unusual for conflicting data on the pain phenotypes of knockout mice to be generated by reputable groups. Here we focus on some technical aspects of measuring mouse pain behaviour that are often overlooked, which may help explain discrepancies in the pain literature. We examined touch perception using von Frey hairs and mechanical pain thresholds using the Randall-Selitto test. Thermal pain thresholds were measured using the Hargreaves apparatus and a thermal place preference test. Sodium channel Nav1.7 knockout mice show a mechanical deficit in the hairy skin, but not the paw, whilst shaving the abdominal hair abolished this phenotype. Nav1.7, Nav1.8 and Nav1.9 knockout mice show deficits in noxious mechanosensation in the tail, but not the paw. TRPA1 knockout mice, however, have a loss of noxious mechanosensation in the paw but not the tail. Studies of heat and cold sensitivity also show variability depending on the intensity of the stimulus. Deleting Nav1.7, Nav1.8 or Nav1.9 in Nav1.8-positive sensory neurons attenuates responses to slow noxious heat ramps, whilst responses to fast noxious heat ramps are only reduced when Nav1.7 is lost in large diameter sensory neurons. Deleting Nav1.7 from all sensory neurons attenuates responses to noxious cooling but not extreme cold. Finally, circadian rhythms dramatically influence behavioural outcome measures such as von Frey responses, which change by 80% over the day. These observations demonstrate that fully characterising the phenotype of a transgenic mouse strain requires a range of behavioural pain models. Failure to conduct behavioural tests at different anatomical locations, stimulus intensities, and at different points in the circadian cycle may lead to a pain behavioural phenotype being misinterpreted, or missed altogether.
authors.affiliation: Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Minett
authors.affiliation: Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom; Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Niels
authors.initials: N
authors.lastname: Eijkelkamp
authors.affiliation: Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom.
authors.forename: John N
authors.initials: JN
authors.lastname: Wood
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D017353:Gene Deletion; D051379:Mice; D018345:Mice, Knockout; D010146:Pain / Q000235:genetics / Q000503:physiopathology; D011984:Sensory Receptor Cells / Q000378:metabolism* / Q000473:pathology; D015222:Sodium Channels / Q000235:genetics*; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000235:genetics*
chemical_list: D015222:Sodium Channels; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse
references.citation: Curr Protoc Mouse Biol. 2011 Sep 01;1(3):383-412
references.pmid: 26068997
references.citation: Nature. 2007 Jul 12;448(7150):204-8
references.pmid: 17538622
references.citation: Pain. 2012 Oct;153(10):2017-2030
references.pmid: 22703890
references.citation: Proc Natl Acad Sci U S A. 1988 Jul;85(14):5166-70
references.pmid: 2839833
references.citation: Nat Neurosci. 1999 Jun;2(6):541-8
references.pmid: 10448219
references.citation: Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12706-11
references.pmid: 15314237
references.citation: Pain. 1988 Jan;32(1):77-88
references.pmid: 3340425
references.citation: Science. 2008 Aug 1;321(5889):702-5
references.pmid: 18669863
references.citation: J Physiol. 2008 Feb 15;586(4):1077-87
references.pmid: 18096591
references.citation: Neuron. 2013 Aug 21;79(4):618-39
references.pmid: 23972592
references.citation: Cell. 2006 Mar 24;124(6):1269-82
references.pmid: 16564016
references.citation: Cell. 2002 Mar 8;108(5):705-15
references.pmid: 11893340
references.citation: Pain. 1990 Nov;43(2):205-218
references.pmid: 1982347
references.citation: Nat Neurosci. 2002 Nov;5(11):1101-2
references.pmid: 12403996
references.citation: PLoS One. 2012;7(10):e46917
references.pmid: 23071662
references.citation: Neurosci Lett. 2012 Jun 29;520(2):131-9
references.pmid: 22445887
references.citation: Cell Rep. 2014 Jan 30;6(2):301-12
references.pmid: 24440715
references.citation: Pain. 1999 Mar;80(1-2):83-93
references.pmid: 10204720
references.citation: Anesthesiology. 2004 Feb;100(2):413-27
references.pmid: 14739819
references.citation: J Neurosci Methods. 1994 Jul;53(1):55-63
references.pmid: 7990513
references.citation: Pain. 2010 Oct;151(1):12-17
references.pmid: 20696526
references.citation: Mol Pain. 2007 Dec 17;3:40
references.pmid: 18086313
references.citation: Neuron. 2006 Apr 20;50(2):277-89
references.pmid: 16630838
references.citation: J Comp Neurol. 2011 Oct 15;519(15):3085-101
references.pmid: 21618224
references.citation: Mol Cell Biol. 1987 Jun;7(6):2087-96
references.pmid: 3037344
references.citation: Mol Pain. 2006 Oct 19;2:33
references.pmid: 17052333
references.citation: EMBO J. 2011 Feb 2;30(3):582-93
references.pmid: 21139565
references.citation: Arch Int Pharmacodyn Ther. 1957 Sep 1;111(4):409-19
references.pmid: 13471093
references.citation: Nat Commun. 2012 Apr 24;3:791
references.pmid: 22531176
references.citation: Pain. 2005 Jan;113(1-2):27-36
references.pmid: 15621361
references.citation: J Pain. 2008 Feb;9(2):174-84
references.pmid: 18088557
references.citation: J Pharmacol Exp Ther. 1953 Mar;107(3):385-93
references.pmid: 13035677
references.citation: Curr Biol. 1998 Dec 3;8(24):1323-6
references.pmid: 9843687
references.citation: Pain. 1999 Mar;80(1-2):67-82
references.pmid: 10204719
references.citation: Neuron. 2007 May 3;54(3):371-8
references.pmid: 17481391
references.citation: Mol Pain. 2010 Nov 26;6:83
references.pmid: 21108841
references.citation: Science. 1977 Nov 18;198(4318):756-8
references.pmid: 561998
references.citation: Proc Natl Acad Sci U S A. 2010 May 18;107(20):9424-9
references.pmid: 20439739
references.citation: Cell. 2011 Dec 23;147(7):1615-27
references.pmid: 22196735