Tolerance and morphine-induced cross-tolerance are not shown to Tyr-W-MIF-1 analgesia

Richard L. Bell, Anthony L. Vaccarino, Richard D. Olson, Gayle A. Olson, William L. Nores, James G. Cambre, James E. Zadina, Abba J. Kastin

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Tolerance and cross-tolerance between Tyr-W-MIF-1, a mixed μ-agonist/antagonist, and morphine were examined. Opiate dependence also was examined. Rats were pretreated with Tyr-W-MIF-1, morphine, or saline for 4 days. On day 5, the animals were tested for Tyr-W-MIF-1 analgesia, morphine analgesia, or naloxone-precipitated withdrawal. Tyr-W-MIF-1- and morphine-pretreated animals showed similar levels of dependence. Animals pretreated with Tyr-W-MIF-1 failed to express tolerance to Tyr-W-MIF-1 analgesia but did display cross-tolerance to morphine analgesia. Animals pretreated with morphine displayed tolerance to morphine analgesia but did not express cross-tolerance to Tyr-W-MIF-1 analgesia. Therefore, tolerance and morphine-induced cross-tolerance were not expressed to Tyr-W-MIF-1 analgesia. Copyright (C) 1999 Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)971-978
Number of pages8
Issue number8
StatePublished - Sep 14 1999
Externally publishedYes


  • Nociception
  • Opioid
  • Pain
  • Peptide
  • Tyr-MIF-1

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience

Fingerprint Dive into the research topics of 'Tolerance and morphine-induced cross-tolerance are not shown to Tyr-W-MIF-1 analgesia'. Together they form a unique fingerprint.

Cite this