title: Chronic restraint stress exacerbates nociception and inflammatory response induced by bee venom in rats: the role of the P2X7 receptors.
abstract: OBJECTIVE
  Chronic restraint stress exacerbates pain and inflammation. The present study was designed to evaluate the effect of chronic restraint stress on inflammatory pain induced by subcutaneous injection of bee venom (BV).
  
  
  METHODS
  First, we investigated: (1) the effect of two-week restraint stress with daily 2 or 8 h on the baseline paw withdrawal mechanical threshold (PWMT), paw withdrawal thermal latency (PWTL) and paw circumference (PC); (2) the effect of chronic stress on the spontaneous paw-flinching reflex (SPFR), decrease in PWM, PWTL and increase in PC of the injected paw induced by BV.
  
  
  RESULTS
  The results showed that (1) chronic restraint decreased significantly the PWMT and inhibited significantly the increase in PC, but had no effect on PWTL, compared with control group; (2) chronic restraint enhanced significantly BV-induced SPFR and inflammatory swelling of the injected paw. In a second series of experiments, the role of P2X7 receptor (P2X7R) in the enhancement of BV-induced inflammatory pain produced by chronic restraint stress was determined. Systemic pretreatment with P2X7R antagonist completely reversed the decrease in PWMT produced by chronic restraint, inhibited significantly the enhancement of BV-induced inflammatory pain produced by chronic restraint stress.
  
  
  CONCLUSIONS
  Taken together, our data indicate that chronic restraint stress-enhanced nociception and inflammation in the BV pain model, possibly involving the P2X7R.
authors.affiliation: a Department of Neurology , General Hospital of Shen-Yang Military Area Command , Shen Yang , China.
authors.forename: Xiao-Qiu
authors.initials: XQ
authors.lastname: Li
authors.affiliation: a Department of Neurology , General Hospital of Shen-Yang Military Area Command , Shen Yang , China.
authors.forename: Man
authors.initials: M
authors.lastname: Li
authors.affiliation: a Department of Neurology , General Hospital of Shen-Yang Military Area Command , Shen Yang , China.
authors.forename: Zhong-He
authors.initials: ZH
authors.lastname: Zhou
authors.affiliation: b Department of Medical Administration , General Hospital of Shen-Yang Military Area Command , Shen Yang , China.
authors.forename: Bao-Jun
authors.initials: BJ
authors.lastname: Liu
authors.affiliation: a Department of Neurology , General Hospital of Shen-Yang Military Area Command , Shen Yang , China.
authors.forename: Hui-Sheng
authors.initials: HS
authors.lastname: Chen
mesh_terms: D000818:Animals; D001514:Bee Venoms / Q000633:toxicity*; D001557:Benzenesulfonates / Q000627:therapeutic use; D001835:Body Weight / Q000187:drug effects; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000188:drug therapy; D007249:Inflammation / Q000139:chemically induced* / Q000188:drug therapy; D008297:Male; D059225:Nociception / Q000187:drug effects*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation; D058919:Purinergic P2 Receptor Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D012149:Restraint, Physical / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D001514:Bee Venoms; D001557:Benzenesulfonates; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; C408879:purinergic P2X8 receptor; C006796:brilliant blue
keywords: Bee venom; Chronic restraint stress; Hyperalgesia; Inflammation; P2X7 receptor; Spontaneous pain