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Study · Measured the body's own peptide · 1994

3 results

Opioids influence neurohypophysial but not central oxytocin release following direct hyperosmotic stimulation of the supraoptic nucleus in urethane-anaesthetised rats.

Munro G, Ludwig M, Landgraf R, Russell JA

Neuropeptides1 Aug 1994Cited by 4 (Europe PMC)

PMID7991066 (opens in a new tab)DOI10.1016/0143-4179(94)90052-3 (opens in a new tab)PepBankPUB-07991066
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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

No result from this study comes from a test of the peptide.

Natural levels measured3

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

  1. 01AnimalEndogenous levelAnimal study (in vivo)Other

    In anaesthetised rats, central oxytocin release during hyperosmotic stimulation of the supraoptic nucleus did not differ between vehicle, morphine and naloxone groups.

    In plain wordsIn rats, the body's own oxytocin release in the brain did not differ between vehicle, morphine and naloxone groups.

    Peptide
    Oxytocin
    Outcome
    No significant changeCentral oxytocin release during hyperosmotic stimulation with morphine or naloxone
    Study

    ratn: not reported in source

    urethane-anaesthetised rats with hyperosmotic stimulation of the supraoptic nuclei
    Comparator
    Vehicle
    Outcome group
    Sex hormones and fertility · Endocrine and hormones

    Source sentences

    Summary
    There were no differences in central peptide release during direct hyperosmotic stimulation between groups of rats given either vehicle, morphine (5 mg/kg) or naloxone (5 mg/kg) intravenously.
    1 context sentence
    Summary · context
    Microdialysis was used to apply an osmotic stimulus (0.5 M NaCl-aCSF) into both supraoptic nuclei (SON) to investigate the role of endogenous opioid peptides in the control of both central and peripheral oxytocin release in response to this stimulus.

    This result measures the body's own Oxytocin. Nobody was given the peptide. It is not evidence about taking it.

  2. 02AnimalEndogenous levelAnimal study (in vivo)Other

    In anaesthetised rats, naloxone potentiated oxytocin release into blood during hyperosmotic stimulation.

    In plain wordsIn rats, naloxone increased the body's own oxytocin release into blood.

    Peptide
    Oxytocin
    Outcome
    IncreaseOxytocin release into blood with naloxone
    Study

    ratn: not reported in source

    urethane-anaesthetised rats with hyperosmotic stimulation of the supraoptic nuclei
    Outcome group
    Sex hormones and fertility · Endocrine and hormones

    Source sentences

    Summary
    Naloxone potentiated oxytocin release into blood; this suggests that endogenous opioid peptides at the level of the neurohypophysis, but not in the SON are important modulators of oxytocin release to this stimulus.
    1 context sentence
    Summary · context
    Microdialysis was used to apply an osmotic stimulus (0.5 M NaCl-aCSF) into both supraoptic nuclei (SON) to investigate the role of endogenous opioid peptides in the control of both central and peripheral oxytocin release in response to this stimulus.

    This result measures the body's own Oxytocin. Nobody was given the peptide. It is not evidence about taking it.

  3. 03AnimalEndogenous levelAnimal study (in vivo)Other

    In anaesthetised rats, morphine blocked oxytocin release into blood during hyperosmotic stimulation.

    In plain wordsIn rats, morphine blocked the body's own oxytocin release into blood.

    Peptide
    Oxytocin
    Outcome
    DecreaseOxytocin release into blood with morphine
    Study

    ratn: not reported in source

    urethane-anaesthetised rats with hyperosmotic stimulation of the supraoptic nuclei
    Outcome group
    Sex hormones and fertility · Endocrine and hormones

    Source sentences

    Summary
    However morphine blocked oxytocin release into blood indicative of a central inhibitory action on the firing rate of oxytocin neurones, contrasted with insensitivity to morphine of oxytocin secretion from the dendrites stimulated directly by hyperosmolarity.
    1 context sentence
    Summary · context
    Microdialysis was used to apply an osmotic stimulus (0.5 M NaCl-aCSF) into both supraoptic nuclei (SON) to investigate the role of endogenous opioid peptides in the control of both central and peripheral oxytocin release in response to this stimulus.

    This result measures the body's own Oxytocin. Nobody was given the peptide. It is not evidence about taking it.

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

    11 Oct 2026, 20:03 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 02:51 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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