title: CB1 receptors modulate affective behaviour induced by neuropathic pain.
abstract: Patients suffering from chronic pain are often diagnosed with a psychiatric condition, in particular generalized anxiety and major depression. The underlying pathomechanisms contributing to this comorbidity, however, are not entirely clear. In this manuscript we have focussed on the potential role of the cannabinoid receptor CB1, because it is known to modulate neuronal circuits contributing to chronic pain states and affective behaviours. For this purpose we analysed the consequences of a partial sciatic nerve ligation on anxiety- and depression-related behaviours in mice lacking CB1 receptors. Our results show that the development of mechanical hypersensitivity was similar in CB1 deficient mice and wild type controls. However, CB1 knockouts showed much more pronounced behavioural manifestations of anxiety-related behaviours in the light-dark and zero-maze tests, sucrose anhedonia, and disturbed home-cage activity. These results indicate that the endocannabinoid system affects chronic pain-induced mood changes through CB1 receptors.
authors: Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany. Electronic address: iracz@uni-bonn.de.
authors: Ildikó
authors: I
authors: Rácz
authors: Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.
authors: Elisa
authors: E
authors: Nent
authors: Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.
authors: Edda
authors: E
authors: Erxlebe
authors: Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany. Electronic address: a.zimmer@uni-bonn.de.
authors: Andreas
authors: A
authors: Zimmer
mesh_terms: D059445:Anhedonia / Q000502:physiology*; D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D059350:Chronic Pain / Q000503:physiopathology / Q000523:psychology; D003863:Depression / Q000503:physiopathology*; D019422:Dietary Sucrose / Q000008:administration & dosage; D004195:Disease Models, Animal; D006799:Housing, Animal; D006930:Hyperalgesia / Q000503:physiopathology / Q000523:psychology; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009437:Neuralgia / Q000503:physiopathology* / Q000523:psychology; D010641:Phenotype; D011581:Psychological Tests; D011597:Psychomotor Performance / Q000502:physiology*; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics / Q000378:metabolism*; D020426:Sciatic Neuropathy; D014110:Touch
chemical_list: C578453:CNR1 protein, mouse; D019422:Dietary Sucrose; D043884:Receptor, Cannabinoid, CB1
keywords: Anxiety; CB1 receptor; Depression; Endocannabinoid system; Neuropathic pain; Partial sciatic nerve ligation