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Long‐term effect of morphine administration in young rats on the analgesic opioid response in adult life
Author(s) -
Rozisky Joanna Ripoll,
Dantas Giovana,
Adachi Lauren Spezia,
Alves Viviane Soares,
Ferreira Maria Beatriz Cardoso,
Sarkis João José Freitas,
Torres Iraci Lucena Da Silva
Publication year - 2008
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/j.ijdevneu.2008.05.005
Subject(s) - morphine , medicine , opioid , analgesic , anesthesia , pharmacology , receptor
Neonates, infants and children are often exposed to pain from invasive procedures during intensive care and during the post‐operative period. Opioid anesthesia and post‐operative opioid analgesia have been used in infants and result in clinical benefits. The objectives of this study were to verify the effect of repeated 5 μg morphine administration (subcutaneous), once a day for 7 days in 8‐day‐old rats, at P8 until P14. To verify the long‐term effect of morphine, the animals were submitted to a second exposure of 5 mg/kg (intraperitoneal) of morphine at P80 until P86. Animals that received morphine for 7 days, at P14 did not develop tolerance, however at P80, rats demonstrated greater morphine analgesia. At P86, after 7 days of morphine administration, animals showed classical tolerance. These findings may have important implications for the human neonate, suggesting a possible explanation for the differences in the requirements of morphine observed in the youngest patients.