Methadone induced physical dependence in the rat

Geoffrey S.F. Ling, Nancy S. Tappe, Charles E. Inturrisi

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Although the morphine withdrawal syndrome has been well described in the rat, a syndrome having similar characteristics has not been demonstrated following chronic methadone treatment. In this study we describe the behavioral effects produced by naloxone (4 mg/kg sc) following 72 hours of continuous iv infusion of methadone, (12.2 ug/kg/min), morphine (12.2 to 97.9 ug/kg/min) or saline. The cessation of methadone or morphine but not saline treatment followed by naloxone resulted in graded signs including wet dog shakes, escape attempts, self-stimulation and body weight loss and quantal signs including diarrhea, ear blanching, exophthalmos, ptosis, tachypnea and teeth chattering. These results indicate that this mode of methadone administration produces physical dependence characterized by a morphine-like withdrawal syndrome in the rat.

Original languageEnglish (US)
Pages (from-to)683-690
Number of pages8
JournalLife Sciences
Issue number7
StatePublished - Feb 13 1984

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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