title: Acute and chronic morphine alters formalin pain in neonatal rats.
abstract: The present study tested the hypothesis that morphine exposure during the human developmental equivalent of the third trimester would alter inflammatory pain. This study examined whether acute or continuous opioid exposure in the neonatal rat alters formalin-induced nociception after 4 days of abstinence. Rats were exposed to a single acute administration of morphine on postnatal day 7 or 72 h of opioid infusion from postnatal days 5-7 via osmotic pump. When challenged with intraplantar formalin on postnatal day 11, rats exposed to acute or chronic morphine had increased phase II pain-associated behaviors. These findings suggest that neonatal morphine exposure may have unintended consequences on inflammatory pain.
authors.affiliation: Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Maurice H
authors.initials: MH
authors.lastname: Zissen
authors.forename: Guohua
authors.initials: G
authors.lastname: Zhang
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Kendig
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Sweitzer
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005557:Formaldehyde; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D005557:Formaldehyde; D009020:Morphine