Show simple item record

dc.contributor.authorOlango, WM
dc.contributor.authorRoche, M
dc.contributor.authorFord, GK
dc.contributor.authorHarhen, B
dc.contributor.authorFinn, David P.
dc.date.accessioned2018-09-20T16:20:41Z
dc.date.available2018-09-20T16:20:41Z
dc.date.issued2012-03-23
dc.identifier.citationOlango, WM; Roche, M; Ford, GK; Harhen, B; Finn, DP (2012). The endocannabinoid system in the rat dorsolateral periaqueductal grey mediates fear-conditioned analgesia and controls fear expression in the presence of nociceptive tone. British Journal of Pharmacology 165 (8), 2549-2560
dc.identifier.issn0007-1188
dc.identifier.urihttp://hdl.handle.net/10379/13342
dc.description.abstractBACKGROUND AND PURPOSE Endocannabinoids in the midbrain periaqueductal grey (PAG) modulate nociception and unconditioned stress-induced analgesia; however, their role in fear-conditioned analgesia (FCA) has not been examined. The present study examined the role of the endocannabinoid system in the dorsolateral (dl) PAG in formalin-evoked nociceptive behaviour, conditioned fear and FCA in rats. EXPERIMENTAL APPROACH Rats received intra-dlPAG administration of the CB1 receptor antagonist/inverse agonist rimonabant, or vehicle, before re-exposure to a context paired 24 h previously with foot shock. Formalin-evoked nociceptive behaviour and fear-related behaviours (freezing and 22 kHz ultrasonic vocalization) were assessed. In a separate cohort, levels of endocannabinoids [2-arachidonoyl glycerol (2-AG) and N-arachidonoyl ethanolamide (anandamide; AEA)] and the related N-acylethanolamines (NAEs) [N-palmitoyl ethanolamide (PEA) and N-oleoyl ethanolamide (OEA)] were measured in dlPAG tissue following re-exposure to conditioned context in the presence or absence of formalin-evoked nociceptive tone. KEY RESULTS Re-exposure of rats to the context previously associated with foot shock resulted in FCA. Intra-dlPAG administration of rimonabant significantly attenuated FCA and fear-related behaviours expressed in the presence of nociceptive tone. Conditioned fear without formalin-evoked nociceptive tone was associated with increased levels of 2-AG, AEA, PEA and OEA in the dlPAG. FCA was specifically associated with an increase in AEA levels in the dlPAG. CONCLUSIONS AND IMPLICATIONS Conditioned fear to context mobilises endocannabinoids and NAEs in the dlPAG. These data support a role for endocannabinoids in the dlPAG in mediating the potent suppression of pain responding which occurs during exposure to conditioned aversive contexts.
dc.publisherWiley-Blackwell
dc.relation.ispartofBritish Journal of Pharmacology
dc.subjectpain
dc.subjectfear
dc.subjectcannabinoid type 1 (cb1) receptor
dc.subjectendocannabinoids
dc.subjectn-acylethanolamines
dc.subjectperiaqueductal grey
dc.subjectrats
dc.subjectstress-induced analgesia
dc.subjectrostral ventromedial medulla
dc.subjectacid amide hydrolase
dc.subjectendogenous cannabinoid system
dc.subjectfos-like immunoreactivity
dc.subjectdefensive behavior
dc.subjectcb1 receptors
dc.subjectelectrical-stimulation
dc.subjectbasolateral amygdala
dc.subjectspinal nociception
dc.titleThe endocannabinoid system in the rat dorsolateral periaqueductal grey mediates fear-conditioned analgesia and controls fear expression in the presence of nociceptive tone
dc.typeArticle
dc.identifier.doi10.1111/j.1476-5381.2011.01478.x
dc.local.publishedsourcehttp://onlinelibrary.wiley.com/doi/10.1111/j.1476-5381.2011.01478.x/pdf
nui.item.downloads0


Files in this item

This item appears in the following Collection(s)

Show simple item record