Stress-induced parallel changes in central opioid levels and pain responsiveness in the rat

  title={Stress-induced parallel changes in central opioid levels and pain responsiveness in the rat},
  author={John Madden and Huda Akil and Robert L. Patrick and Jack D. Barchas},
THE isolation and identification of endogenous opiate-like peptides from mammalian brain1,2, and from pituitary3–5 has led to an active investigation of their pharmacological properties. These peptides—the enkephalins and endorphins—have been shown to produce naloxone-reversible analgesia6,7, tolerance, and withdrawal7. While these effects seem consonant with those of morphine and other exogenous narcotics, little is yet known about the intrinsic, physiological functions of the opioid peptides… 

Regulation of prolactin release by endogenous opiates

Using naltrexone as a tool to block opiate receptor function, it is explored whether endorphins are tonically involved as a putative neurotransmitter in the regulation of prolactin release and demonstrates a new instance where an opiate antagonist modifies normal function.

Stress-induced analgesia: Neural and hormonal determinants

The Many Possible Roles of Opioids and Related Peptides in Stress‐Induced Analgesia a

The role of opioids in pain regulation in general and in stress-induced analgesia in particular are discussed, and the importance of understanding the cell biology and its regulatory dynamics in attempting to link these mechanisms is conveyed.

Analgesia, catatonia and changes in core temperature induced by opiates and endorphins: a comparison

The purpose of the present study was to compare the effects of a repre­sentative series of opioid peptides and opiate alkaloids on nociception, general motor behavior and body temperature.

Opioid and Catecholaminergic Mechanisms of Different Types of Analgesia

  • E. Bragin
  • Biology
    Annals of the New York Academy of Sciences
  • 1986
The aim of this work was to study the selective and differential support of various types of analgesia and pain excitation by a complex of neurochemical mechanisms possessing specific neurochemical and morphological structures.

Psychobiology of opioids.

Part VIII. Psychopharmacological and Biological Effects Of Opioid Peptides In Animals: THE ROLE OF ENDORPHINS IN STRESS‐INDUCED ANALGESIA

  • D. Kelly
  • Biology
    Annals of the New York Academy of Sciences
  • 1982
Not all stressors induce analgesia; among those that do not are some that produce maximal elevations in plasma beta-endorphin, ACTH, and adrenal corticosteroids, and Hypophysectomy produces a similarly uneven profile of effects across different stressors.



Analgesia induced in vivo by central administration of enkephalin in rat

It is found that methionine–enkephalin and leucine–eniophalin, when administered through permanently indwelling cannulae in the lateral ventricles of rats, induce a profound analgesia in vivo that is fully reversible by naloxone.

Stimulation-produced analgesia: development of tolerance and cross-tolerance to morphine.

It is suggested that morphine and electrical stimulation produce analgesia by common mechanisms and the fact that tolerance occurs to the analgesic effect of electrical stimulation indicates that tolerance may be an alteration of an endogenous neuronal process.

Morphine-like peptides in mammalian brain: isolation, structure elucidation, and interactions with the opiate receptor.

  • R. SimantovS. Snyder
  • Biology, Chemistry
    Proceedings of the National Academy of Sciences of the United States of America
  • 1976
Sodium and manganese effects on opiate receptor interactions show that both peptides are agonists, whereas leucine enkephalin may be a "purer" agonist than methionine enkphalin.

Antagonism of stimulation-produced analgesia by naloxone, a narcotic antagonist

Analgesia produced by focal electrical stimulation of the brain is partially reversed by the narcotic antagonist naloxone and it is suggested that stimulation-produced analgesia may result, at least in part, from release of an endogenous, narcotic-like substance.

Opiate Receptor: Demonstration in Nervous Tissue

Tritiated naloxone, a powerful opiate antagonist, specifically binds to an opiate receptor of mammalian brain and guinea pig intestine that closely parallels their pharmacological potency.

Identification of two related pentapeptides from the brain with potent opiate agonist activity

The evidence is based on the determination of the amino acid sequence of natural enkephalin by the dansyl–Edman procedure and by mass spectrometry followed by synthesis and comparison of the natural and synthetic peptides.


A simple, rapid method for determining the pain threshold in the rat was applied to the determination of analgesic properties of several substances, including cobra venom, where no analgesic property in the latter could be demonstrated.

Isolation and structure of an untriakontapeptide with opiate activity from camel pituitary glands.

  • C. LiD. Chung
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1976
The structure has been determined and shown to be identical to the sequence of carboxyl-terminal 31 amino acids of ovine beta-lipotropin, and the peptide possesses very low lipotropic activity but significant opiate activity.