title: Differences in morphine-induced antinociception in male and female offspring born of morphine exposed mothers.
abstract: OBJECTIVE
  Antinociceptive effect of morphine in offspring born of mothers that received saline or morphine during the gestation period was investigated.
  
  
  METHODS
  Wistar rats (200-250 g) received saline, morphine 0.5 mg/kg or 5 mg/kg during gestation days 14-16. All pups after weaning were isolated treatment/sex dependently and were allowed to fully mature. The antinociceptive effect of morphine was assessed in formalin test. Morphine (0.5-7.5 mg/kg) or saline (1 ml/kg) was injected intraperitoneally 10 min before formalin (50 μl of 2.5% solution in right hind-paw).
  
  
  RESULTS
  Male offspring born of saline-treated mothers were less morphine-sensitive than females. On the contrary, male offspring exposed prenatally to morphine (5 mg/kg) were more sensitive to morphine-induced antinociceptive response in formalin test. However, no difference in antinociceptive effect was observed amongst offspring of either sex born of mothers treated with morphine 0.5 mg/kg, identifying a lower dose effect of the opioid.
  
  
  CONCLUSIONS
  The exposure to morphine during the developmental period may result in altered development of tolerance to morphine and thus involved in drug abuse.
authors.affiliation: Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
authors.forename: Masoomeh
authors.initials: M
authors.lastname: Biglarnia
authors.forename: Manizheh
authors.initials: M
authors.lastname: Karami
authors.forename: Zahra Khodabakhshi
authors.initials: ZK
authors.lastname: Hafshejani
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D005557:Formaldehyde; D008297:Male; D008431:Maternal-Fetal Exchange; D009020:Morphine / Q000008:administration & dosage*; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors
chemical_list: D000701:Analgesics, Opioid; D005557:Formaldehyde; D009020:Morphine
keywords: Formalin test; gestation; morphine; offspring; pain