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Study · Animal study (in vivo) · mouse · 1984

18 results

Dose-dependent effects of prolyl-leucyl-glycinamide on morphine-induced analgesia, tolerance and dependence.

Contreras PC, Takemori AE

European journal of pharmacology1 Jun 1984Cited by 11 (Europe PMC)

PMID6148243 (opens in a new tab)DOI10.1016/0014-2999(84)90332-7 (opens in a new tab)PepBankPUB-06148243
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 study18

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

  1. 01AnimalAnimal study (in vivo)Efficacy outcome

    In mice, low-dose PLG did not affect morphine analgesia.

    In plain wordsIn mice, low-dose PLG did not change pain relief from morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeMorphine analgesia at low PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Pain · Nervous system and cognition
    Studied dose
    10 ng/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    Prolyl-leucyl-glycinamide (PLG) at a low dose (10 ng/mouse) administered intracerebroventricularly (i.c.v.) did not affect morphine analgesia, but produced a greater increase in the ED50 of morphine-pretreated (100 mg/kg of morphine sulfate) mice as compared to control mice.
  2. 02AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intermediate-dose PLG antagonized morphine analgesia.

    In plain wordsIn mice, intermediate-dose PLG reduced pain relief from morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseMorphine analgesia at intermediate PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Pain · Nervous system and cognition
    Studied dose
    10 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG at doses of 10 and 100 micrograms/mouse antagonized morphine analgesia.
  3. 03AnimalAnimal study (in vivo)Efficacy outcome

    In mice, high-dose PLG antagonized morphine analgesia.

    In plain wordsIn mice, high-dose PLG reduced pain relief from morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseMorphine analgesia at high PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Pain · Nervous system and cognition
    Studied dose
    100 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG at doses of 10 and 100 micrograms/mouse antagonized morphine analgesia.
  4. 04AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intermediate-dose PLG did not affect development of morphine tolerance.

    In plain wordsIn mice, intermediate-dose PLG did not change development of tolerance to morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeMorphine tolerance at intermediate PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    10 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    Development of morphine tolerance was unaffected by 10 micrograms/mouse but antagonized by 100 micrograms/mouse of PLG.
  5. 05AnimalAnimal study (in vivo)Efficacy outcome

    In mice, high-dose PLG antagonized development of morphine tolerance.

    In plain wordsIn mice, high-dose PLG reduced development of tolerance to morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseMorphine tolerance at high PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    100 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    Development of morphine tolerance was unaffected by 10 micrograms/mouse but antagonized by 100 micrograms/mouse of PLG.
  6. 06AnimalAnimal study (in vivo)Efficacy outcome

    In mice, low-dose PLG potentiated development of morphine dependence.

    In plain wordsIn mice, low-dose PLG increased development of dependence on morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreaseMorphine dependence at low PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    10 ng/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG (10 ng/mouse) potentiated, 10 micrograms/mouse had no effect and 100 micrograms/mouse antagonized development of morphine dependence.
    1 context sentence
    Summary · context
    Development of morphine dependence was assessed by changes in body weight and temperature during naloxone-induced withdrawal.
  7. 07AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intermediate-dose PLG did not affect development of morphine dependence.

    In plain wordsIn mice, intermediate-dose PLG did not change development of dependence on morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeMorphine dependence at intermediate PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    10 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG (10 ng/mouse) potentiated, 10 micrograms/mouse had no effect and 100 micrograms/mouse antagonized development of morphine dependence.
    1 context sentence
    Summary · context
    Development of morphine dependence was assessed by changes in body weight and temperature during naloxone-induced withdrawal.
  8. 08AnimalAnimal study (in vivo)Efficacy outcome

    In mice, high-dose PLG antagonized development of morphine dependence.

    In plain wordsIn mice, high-dose PLG reduced development of dependence on morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    DecreaseMorphine dependence at high PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    100 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG (10 ng/mouse) potentiated, 10 micrograms/mouse had no effect and 100 micrograms/mouse antagonized development of morphine dependence.
    1 context sentence
    Summary · context
    Development of morphine dependence was assessed by changes in body weight and temperature during naloxone-induced withdrawal.
  9. 09AnimalAnimal study (in vivo)Safety outcome

    In morphine-dependent mice, intermediate-dose PLG precipitated withdrawal.

    In plain wordsIn mice dependent on morphine, intermediate-dose PLG triggered withdrawal.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreasePrecipitated morphine withdrawal at intermediate PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    10 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG at doses of 10 and 100 micrograms/mouse precipitated withdrawal in morphine-dependent mice.
  10. 10AnimalAnimal study (in vivo)Safety outcome

    In morphine-dependent mice, high-dose PLG precipitated withdrawal.

    In plain wordsIn mice dependent on morphine, high-dose PLG triggered withdrawal.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreasePrecipitated morphine withdrawal at high PLG dose
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    100 micrograms/mouse · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    PLG at doses of 10 and 100 micrograms/mouse precipitated withdrawal in morphine-dependent mice.
  11. 11AnimalAnimal study (in vivo)Pharmacokinetics

    In mice, none of the tested PLG doses altered whole-brain morphine levels.

    In plain wordsIn mice, PLG did not change whole-brain morphine levels at any tested dose.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeWhole-brain morphine levels
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Pharmacokinetics · Nervous system and cognition
    Studied dose
    Dose not stated · intracerebroventricularAs given in this study (mouse).

    Source sentences

    Summary
    None of the doses of PLG altered whole brain levels of morphine.
  12. 12LabIn vitro (cell-free)Mechanism

    In receptor binding tests, PLG did not alter opioid receptor affinity for etorphine.

    In plain wordsIn lab tests, PLG did not change opioid receptor affinity for etorphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeOpioid receptor affinity for etorphine
    Study

    n: not reported in source

    Opioid receptor binding assay
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated

    Source sentences

    Summary
    PLG did not alter the affinity of opioid receptors for etorphine or the maximal number of binding sites but PLG did exhibit a very weak affinity for opioid receptors.
  13. 13LabIn vitro (cell-free)Mechanism

    In receptor binding tests, PLG did not alter the maximal number of opioid receptor binding sites.

    In plain wordsIn lab tests, PLG did not change the maximum number of opioid receptor binding sites.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeMaximal opioid receptor binding-site number
    Study

    n: not reported in source

    Opioid receptor binding assay
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated

    Source sentences

    Summary
    PLG did not alter the affinity of opioid receptors for etorphine or the maximal number of binding sites but PLG did exhibit a very weak affinity for opioid receptors.
  14. 14LabIn vitro (cell-free)Activity measurement

    In receptor binding tests, PLG exhibited very weak affinity for opioid receptors.

    In plain wordsIn lab tests, PLG bound very weakly to opioid receptors.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    Not applicablePLG affinity for opioid receptors
    Study

    n: not reported in source

    Opioid receptor binding assay
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated

    Source sentences

    Summary
    PLG did not alter the affinity of opioid receptors for etorphine or the maximal number of binding sites but PLG did exhibit a very weak affinity for opioid receptors.

Studies that did not test the peptide alone4

In this study, MIF-1 (Pro-Leu-Gly-NH2) was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking MIF-1 (Pro-Leu-Gly-NH2).

  1. 15AnimalNot a test of MIF-1 (Pro-Leu-Gly-NH2) aloneAnimal study (in vivo)Efficacy outcome

    In morphine-pretreated mice, low-dose PLG produced a greater morphine ED50 increase than in controls.

    In plain wordsIn mice, low-dose PLG increased morphine ED50 more after morphine pretreatment than in controls.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreaseMorphine ED50 increase in morphine-pretreated mice
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Comparator
    Control mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition

    Source sentences

    Summary
    Prolyl-leucyl-glycinamide (PLG) at a low dose (10 ng/mouse) administered intracerebroventricularly (i.c.v.) did not affect morphine analgesia, but produced a greater increase in the ED50 of morphine-pretreated (100 mg/kg of morphine sulfate) mice as compared to control mice.

    In this study, MIF-1 (Pro-Leu-Gly-NH2) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking MIF-1 (Pro-Leu-Gly-NH2).

  2. 16AnimalNot a test of MIF-1 (Pro-Leu-Gly-NH2) aloneAnimal study (in vivo)Efficacy outcome

    In naloxone-pretreated mice, all tested PLG doses had no effect on morphine analgesia.

    In plain wordsIn mice given naloxone first, all tested PLG doses did not change pain relief from morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    No significant changeMorphine analgesia after naloxone pretreatment
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Pain · Nervous system and cognition

    Source sentences

    Summary
    When mice were pretreated with 1.0 mg/kg naloxone i.p. 15 min before PLG, all doses of PLG had no effect on morphine analgesia, but potentiated the development of morphine tolerance and dependence.

    In this study, MIF-1 (Pro-Leu-Gly-NH2) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking MIF-1 (Pro-Leu-Gly-NH2).

  3. 17AnimalNot a test of MIF-1 (Pro-Leu-Gly-NH2) aloneAnimal study (in vivo)Efficacy outcome

    In naloxone-pretreated mice, all tested PLG doses potentiated development of morphine tolerance.

    In plain wordsIn mice given naloxone first, all tested PLG doses increased development of tolerance to morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreaseMorphine tolerance after naloxone pretreatment
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition

    Source sentences

    Summary
    When mice were pretreated with 1.0 mg/kg naloxone i.p. 15 min before PLG, all doses of PLG had no effect on morphine analgesia, but potentiated the development of morphine tolerance and dependence.

    In this study, MIF-1 (Pro-Leu-Gly-NH2) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking MIF-1 (Pro-Leu-Gly-NH2).

  4. 18AnimalNot a test of MIF-1 (Pro-Leu-Gly-NH2) aloneAnimal study (in vivo)Efficacy outcome

    In naloxone-pretreated mice, all tested PLG doses potentiated development of morphine dependence.

    In plain wordsIn mice given naloxone first, all tested PLG doses increased development of dependence on morphine.

    Peptide
    MIF-1 (Pro-Leu-Gly-NH2)
    Outcome
    IncreaseMorphine dependence after naloxone pretreatment
    Study

    mousen: not reported in source

    Morphine-exposed mice
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition

    Source sentences

    Summary
    When mice were pretreated with 1.0 mg/kg naloxone i.p. 15 min before PLG, all doses of PLG had no effect on morphine analgesia, but potentiated the development of morphine tolerance and dependence.

    In this study, MIF-1 (Pro-Leu-Gly-NH2) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking MIF-1 (Pro-Leu-Gly-NH2).

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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