title: Neonatal bee venom exposure induces sensory modality-specific enhancement of nociceptive response in adult rats.
abstract: OBJECTIVE
  Previous studies have shown that inflammatory pain at the neonatal stage can produce long-term structural and functional changes in nociceptive pathways, resulting in altered pain perception in adulthood. However, the exact pattern of altered nociceptive response and associated neurochemical changes in the spinal cord in this process is unclear.
  
  
  METHODS
  In this study, we used an experimental paradigm in which each rat first received intraplantar bee venom (BV) or saline injection on postnatal day 1, 4, 7, 14, 21, or 28. This was followed 2 months later by a second intraplantar bee venom injection in the same rats to examine the difference in nociceptive responses.
  
  
  RESULTS
  We found that neonatal inflammatory pain induced by the first BV injection significantly reduced baseline paw withdrawal mechanical threshold, but not baseline paw withdrawal thermal latency, when rats were examined 2 months from the first BV injection. Neonatal inflammatory pain also exacerbated mechanical, but not thermal, hyperalgesia in response to the second BV injection in these same rats. Rats exposed to neonatal inflammation also showed up-regulation of spinal NGF, TrkA receptor, BDNF, TrkB receptor, IL-1β, and COX-2 expression following the second BV injection, especially with prior BV exposure on postnatal day 21 or 28.
  
  
  CONCLUSIONS
  These results indicate that neonatal inflammation produces sensory modality-specific changes in nociceptive behavior and alters neurochemistry in the spinal cord of adult rats. These results also suggest that a prior history of inflammatory pain during the developmental period might have an impact on clinical pain in highly susceptible adult patients.
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Chinese PLA General Hospital, Beijing, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Li
authors.forename: Huisheng
authors.initials: H
authors.lastname: Chen
authors.forename: Jiaguang
authors.initials: J
authors.lastname: Tang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001514:Bee Venoms / Q000008:administration & dosage*; D006358:Hot Temperature / Q000009:adverse effects; D010146:Pain / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods*; D010812:Physical Stimulation / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001514:Bee Venoms
keywords: Bee Venom; Inflammation; Long-Term Consequences; Neonatal; Pain