Acute and chronic morphine alters formalin pain in neonatal rats.
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.
Zissen
Maurice H
MH
Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Zhang
Guohua
G
Kendig
Joan J
JJ
Sweitzer
Sarah M
SM
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
D005557:Formaldehyde; D009020:Morphine