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Study · Animal study (in vivo) · mouse · 1982

3 results

Hypothalamic peptide hormone, prolyl-leucyl-glycinamide and analog, inhibit tolerance to the analgesic and locomotor depressant but not to the locomotor stimulant effects of morphine in the mouse.

Bhargava HN

Neuropharmacology1 Mar 1982Cited by 4 (Europe PMC)

PMID6122186 (opens in a new tab)DOI10.1016/0028-3908(82)90192-7 (opens in a new tab)PepBankPUB-06122186
Publisher pagePubMedAsk about this study
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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study3

3 results from studies that gave the peptide. No result from this study comes from people.

  1. 01AnimalAnimal study (in vivo)Efficacy outcome

    In morphine-tolerant mice, MIF inhibited analgesic tolerance compared with vehicle treatment.

    In plain wordsIn mice, MIF reduced tolerance to morphine pain relief compared with vehicle.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseTolerance to morphine analgesia
    Study

    mousen: not reported in source

    Morphine tolerance
    Comparator
    Vehicle-treated morphine-tolerant mice
    Outcome group
    Drug tolerance · Nervous system and cognition
    Studied dose
    2 mg/kg/day · 3 daysAs given in this study (mouse).

    Source sentences

    Summary
    Both MIF and cyclo(Leu-Gly) inhibited the development of tolerance to the analgesic response to a challenge dose of morphine in peptide-treated as compared to vehicle-treated morphine-tolerant mice.
    3 context sentences
    Summary · context
    Administration of MIF or cyclo(Leu-Gly) during induction of tolerance in doses (2 mg/kg/day for 3 days) that inhibited the development of tolerance to morphine-induced analgesia and locomotor depressant activity, did not alter the development of tolerance to the locomotor stimulant effect.
    Summary · context
    The effects of prolyl-leucyl-glycinamide (melanotropin release inhibiting factor, MIF) and cyclo(Leu-Gly) on development of tolerance to the analgesic, locomotor stimulant and depressant effects of morphine were investigated in the mouse.
    Summary · context
    Mice were made tolerant to morphine by subcutaneous implantation of pellet (each pellet contained 75 mg of morphine free base) for three days.
  2. 02AnimalAnimal study (in vivo)Efficacy outcome

    In mice, MIF inhibited tolerance to morphine-induced locomotor depression compared with vehicle treatment.

    In plain wordsIn mice, MIF reduced tolerance to morphine-induced movement suppression compared with vehicle.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseTolerance to locomotor depression
    Study

    mousen: not reported in source

    Morphine tolerance
    Comparator
    Vehicle-treated morphine-tolerant mice
    Outcome group
    Drug tolerance · Nervous system and cognition
    Studied dose
    2 mg/kg/day · 3 daysAs given in this study (mouse).

    Source sentences

    Summary
    Administration of MIF or cyclo(Leu-Gly) during induction of tolerance in doses (2 mg/kg/day for 3 days) that inhibited the development of tolerance to morphine-induced analgesia and locomotor depressant activity, did not alter the development of tolerance to the locomotor stimulant effect.
    2 context sentences
    Summary · context
    The effects of prolyl-leucyl-glycinamide (melanotropin release inhibiting factor, MIF) and cyclo(Leu-Gly) on development of tolerance to the analgesic, locomotor stimulant and depressant effects of morphine were investigated in the mouse.
    Summary · context
    Mice were made tolerant to morphine by subcutaneous implantation of pellet (each pellet contained 75 mg of morphine free base) for three days.
  3. 03AnimalAnimal study (in vivo)Efficacy outcome

    In mice, MIF did not alter tolerance to morphine-induced locomotor stimulation.

    In plain wordsIn mice, MIF did not change tolerance to morphine-induced movement stimulation compared with vehicle treatment.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeTolerance to locomotor stimulation
    Study

    mousen: not reported in source

    Morphine tolerance
    Comparator
    Vehicle-treated morphine-tolerant mice
    Outcome group
    Drug tolerance · Nervous system and cognition
    Studied dose
    2 mg/kg/day · 3 daysAs given in this study (mouse).

    Source sentences

    Summary
    Administration of MIF or cyclo(Leu-Gly) during induction of tolerance in doses (2 mg/kg/day for 3 days) that inhibited the development of tolerance to morphine-induced analgesia and locomotor depressant activity, did not alter the development of tolerance to the locomotor stimulant effect.
    2 context sentences
    Summary · context
    The effects of prolyl-leucyl-glycinamide (melanotropin release inhibiting factor, MIF) and cyclo(Leu-Gly) on development of tolerance to the analgesic, locomotor stimulant and depressant effects of morphine were investigated in the mouse.
    Summary · context
    Mice were made tolerant to morphine by subcutaneous implantation of pellet (each pellet contained 75 mg of morphine free base) for three days.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    22 Oct 2026, 02:26 UTC

    Study results updated

  2. Version 1

    21 Oct 2026, 18:59 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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