title: Co-application of lidocaine and QX-572 induces divergent pain behaviours in mice.
abstract: OBJECTIVE
  We investigated the analgesic effects of lidocaine (LDC) and lidocane derivative, QX-572, co-application on the evoked pain behaviour (complete Freund's Adjuvant (CFA)-induced) and spontaneous pain behaviour (formalin-induced) in mice.
  
  
  METHODS
  The experiments were performed using adult male Kunming mice. Formalin-induced acute pain model and CFA-induced chronic pain model was established by injecting formalin and CFA, respectively. Separate injections of LDC and QX-572, or co-injection of LDC and QX-572, were performed to observe the differences in neurobehavioural responses, paw withdrawal latency (PWL) and mechanical withdrawal threshold (MWT).
  
  
  RESULTS
  QX-572 injection alone did not influence PWL and MWT, but injection of LDC alone led to a substantial, but short-lived, elevation in PWL and MWT (45 min). Co-injection of LDC and QX-572, however, resulted in a significant increase in PWL and MWT (120 min) compared with the LDC group. Injection of LDC and QX-572 combination in the adjacent sciatic nerve also produced a long-lasting sensory-specific nerve block. Additionally, intraplantar co-injection of LDC and QX-572 combination inhibited spontaneous pain in formalin-treated mice, but did not detectably attenuated hyperalgesia and allodynia in CFA-treated mice.
  
  
  CONCLUSIONS
  Our results provide evidence that QX-572 induced sensory-selective blockade and co-injection of QX-572 and LDC enhance pain blockade, as evident from formalin-treated mice.
authors.affiliation: Department of Pain, The Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong, China.
authors.forename: Cui-Jie
authors.initials: CJ
authors.lastname: Shao
authors.affiliation: Department of Pain, The Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Gao
authors.affiliation: The People's Hospital of Binzhou, Binzhou, Shandong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Pain, The Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Jin
authors.affiliation: Department of Pain, The Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Pain, The Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong, China.
authors.forename: De-Qiang
authors.initials: DQ
authors.lastname: Wang
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D005620:Freund's Adjuvant / Q000494:pharmacology; D007267:Injections / Q000379:methods; D008012:Lidocaine / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D008297:Male; D051379:Mice; D009407:Nerve Block / Q000379:methods; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement / Q000187:drug effects; D012584:Sciatic Nerve / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D005620:Freund's Adjuvant; D008012:Lidocaine; C006110:carcainium chloride
keywords: QX-572; evoked pain behaviour; formalin; lidocaine; spontaneous pain behaviour