title: Activation of cannabinoid receptors by the pentacyclic triterpene α,β-amyrin inhibits inflammatory and neuropathic persistent pain in mice.
abstract: In this study, we report that α,β-amyrin, a plant-derived pentacyclic triterpene, reduced persistent inflammatory and neuropathic hyperalgesia in mice by a direct activation of the CB(1) and CB(2) cannabinoid receptors (CB(1)R and CB(2)R). The oral treatment with α,β-amyrin (30 mg/kg) significantly reduced mechanical and thermal hyperalgesia and inflammation induced by complete Freund's adjuvant (CFA) and by partial sciatic nerve ligation (PSNL). The pretreatment with either CB(1)R or CB(2)R antagonists and the knockdown gene of the receptors significantly reverted the antinociceptive effect of α,β-amyrin. Of note, binding studies showed that α,β-amyrin directly bound with very high affinity to CB(1)R (K(i)=0.133 nM) and with a lower affinity to CB(2)R (K(i)=1989 nM). Interestingly, α,β-amyrin, ACEA (CB(1)R agonist), or JWH-133 (CB(2)R agonist), at doses that caused antinociception, failed to provoke any behavioral disturbance, as measured in the tetrad assay. In addition, α,β-amyrin largely decreased interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), keratinocyte-derived chemokine (KC) and interleukin 6 (IL-6) levels, and myeloperoxidase activity. Likewise, α,β-amyrin prevented the activation of the transcriptional factors: nuclear factor κB (NF-κB) and cyclic adenosine monophosphate response element binding (CREB) and the expression of cyclooxygenase 2 in mice footpads and spinal cords. The present results demonstrated that α,β-amyrin exhibits long-lasting antinociceptive and anti-inflammatory properties in 2 models of persistent nociception via activation of cannabinoid receptors and by inhibiting the production of cytokines and expression of NF-κB, CREB and cyclooxygenase 2.
authors.affiliation: Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário Trindade, Bloco D, CCB, Caixa Postal 476, CEP 88049-900, Florianópolis, Santa Catarina, Brazil.
authors.forename: Kathryn A B
authors.initials: KAB
authors.lastname: Simão da Silva
authors.forename: Ana F
authors.initials: AF
authors.lastname: Paszcuk
authors.forename: Giselle F
authors.initials: GF
authors.lastname: Passos
authors.forename: Eduardo S
authors.initials: ES
authors.lastname: Silva
authors.forename: Allisson Freire
authors.initials: AF
authors.lastname: Bento
authors.forename: Flavia C
authors.initials: FC
authors.lastname: Meotti
authors.forename: João B
authors.initials: JB
authors.lastname: Calixto
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000627:therapeutic use*; D019540:Area Under Curve; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D003511:Cyclohexanols / Q000493:pharmacokinetics; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004487:Edema / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D007249:Inflammation / Q000188:drug therapy* / Q000503:physiopathology; D008124:Locomotion / Q000187:drug effects; D008297:Male; D051379:Mice; D009437:Neuralgia / Q000188:drug therapy* / Q000503:physiopathology; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000627:therapeutic use; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D017288:Pain Threshold / Q000187:drug effects; D053978:Pentacyclic Triterpenes / Q000737:chemistry / Q000627:therapeutic use*; D009195:Peroxidase / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D043882:Receptors, Cannabinoid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014316:Tritium / Q000493:pharmacokinetics
chemical_list: D000893:Anti-Inflammatory Agents; D003511:Cyclohexanols; D016207:Cytokines; D020319:Oligodeoxyribonucleotides, Antisense; D053978:Pentacyclic Triterpenes; D043882:Receptors, Cannabinoid; D014316:Tritium; D009828:Oleanolic Acid; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; D009195:Peroxidase; C036380:beta-amyrin