Analgesic activity and release of [Met5]enkephalin-Arg6-Gly7-Leu8 from rat spinal cord in vivo

doi:10.1016/0014-2999(86)90390-0

European Journal of Pharmacology

Volume 121, Issue 1, 11 February 1986, Pages 39-48

https://doi.org/10.1016/0014-2999(86)90390-0 Get rights and content

Abstract

Rat spinal cord contains the opioid peptide including [Met⁵]enkephalin-Arg⁶-Gly⁷-Leu⁸ (YGGFMRGL) and a higher molecular weight (HMW) immunoreactive peptide which is an N-terminal extended molecular form of YGGFMRGL. Since a high proportion of tissue immunoreactivity resides in the HMW component we have determined whether this form is released during perfusion of the spinal cord subarachnoid space in vivo while (1) electrically stimulating the sciatic nerves bilaterally or (2) superfusing with substance P. We have found that YGGFMRGL and the HMW immunoreactivity are released by both types of stimuli. The HMW material appeared to be the more stable of the two species of immunoreactivity; its presence in the superfusate was more consistently observed than that of YGGFMRGL itself. Injection of YGGFMRGL into the spinal subarachnoid space in chronically catheterized rats produced a suppression of the tail-flick response. This effect of YGGFMRGL was reversed by naloxone suggesting an action mediated by spinal opiate receptors. These data suggest that YGGFMRGL plays an integral role in the neurotransmission process between spinal neurons storing enkephalin and other neurons. The possibility that enkephalin-mediated neurotransmission includes multiple chemical signals can be entertained.

References (25)

Y. Audigier et al.
Met-enkephalin Arg⁶-Phe⁷ interacts with the κ-receptors on guinea-pig ileum
European J. Pharmacol.
(1980)
M. Benuck et al.
Rat brain and kidney metalloendopeptidase: enkephalin heptapeptide conversion to a cardioactive neuropeptide Phe-Met-Arg-Pheamide
Biochem. Biophys. Res. Commun.
(1981)
T.D. Hexum et al.
Secretion of enkephalin-like peptides from canine adrenal gland following splanchnic nerve stimulation
Neuropeptides
(1980)
T.D. Hexum et al.
Biochemical characterization of enkephalin-like immunoreactive peptides of adrenal glands
Life Sci.
(1980)
V. Höllt et al.
Opioid peptides derived from proenkephalin A but not that derived from proenkephalin B are substantial analgesics after administration into brain of mice
European J. Pharmacol.
(1982)
M. Iadarola et al.
The opioid octapeptide Met⁵-enkephalin-Arg⁶-Gly⁷-Leu⁸: Characterization and distribution in rat spinal cord
Brain Res.
(1985)
I. Lindberg et al.
Release of high molecular weight forms of Met⁵-enkephalin-Arg⁶-Gly⁷-Leu⁸ from rat brain
Neuropeptides
(1985)
A. Ljungdahl et al.
Distribution of substance P-like immunoreactivity in the central nervous system of the rat. 1. Cell bodies and nerve terminals
Neuroscience
(1978)
J.A. Norman et al.
Proteolytic conversion of Met-enkephalin-Arg⁶-Gly⁶-Leu⁸ by brain synaptic membranes
J. Biol. Chem.
(1985)
S.M. Stine et al.
Release of enkephalin-like immunoreactivity from isolated bovine chromaffin cells
Neuropharmacology
(1980)

T.L. Yaksh et al.

Studies on the release by somatic stimulation from rat and cat spinal cord of active materials which displace dihydromorphine in an opiate-binding assay

Brain Res.

(1983)

H.-Y.T. Yang et al.

Enkephalin in bovine adrenal gland: Multiple molecular weight forms of Met⁵-enkephalin immunoreactive peptides

Neuropharmacology

(1980)

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Dynorphin and Enkephalin Opioid Peptides and Transcripts in Spinal Cord and Dorsal Root Ganglion During Peripheral Inflammatory Hyperalgesia and Allodynia
2020, Journal of Pain
Citation Excerpt :
Release of enkephalin peptides has been shown in the spinal cord after painful mechanical and thermal stimulation.10,44 Intrathecal injection of MERGL exerts an analgesic action in the spinal cord, and MERGL is released in response to activation of spinal neurokinin 1 receptors that bind substance P, which is present at high levels in primary afferent nociceptors.36,45 Expression analysis and co-localization with Vglut2 revealed several populations of enkephalinergic neurons, including a large population of neurons that co-produce enkephalin peptides and glutamate, as well as inhibitory enkephalinergic interneurons.66
Understanding molecular alterations associated with peripheral inflammation is a critical factor in selectively controlling acute and persistent pain. The present report employs in situ hybridization of the 2 opioid precursor mRNAs coupled with quantitative measurements of 2 peptides derived from the prodynorphin and proenkephalin precursor proteins: dynorphin A 1-8 and [Met⁵]-enkephalin-Arg⁶-Gly⁷-Leu⁸. In dorsal spinal cord ipsilateral to the inflammation, dynorphin A 1-8 was elevated after inflammation, and persisted as long as the inflammation was sustained. Qualitative identification by high performance liquid chromatography and gel permeation chromatography revealed the major immunoreactive species in control and inflamed extracts to be dynorphin A 1-8. In situ hybridization in spinal cord after administration of the inflammatory agent, carrageenan, showed increased expression of prodynorphin (Pdyn) mRNA somatotopically in medial superficial dorsal horn neurons. The fold increase in preproenkephalin mRNA (Penk) was comparatively lower, although the basal expression is substantially higher than Pdyn. While Pdyn is not expressed in the dorsal root ganglion (DRG) in basal conditions, it can be induced by nerve injury, but not by inflammation alone. A bioinformatic meta-analysis of multiple nerve injury datasets confirmed Pdyn upregulation in DRG across different nerve injury models. These data support the idea that activation of endogenous opioids, notably dynorphin, is a dynamic indicator of persistent pain states in spinal cord and of nerve injury in DRG.
This is a systematic, quantitative assessment of dynorphin and enkephalin peptides and mRNA in dorsal spinal cord and DRG neurons in response to peripheral inflammation and axotomy. These studies form the foundational framework for understanding how endogenous spinal opioid peptides are involved in nociceptive circuit modulation.
Bioinformatic and biochemical studies on the phylogenetic variability of proenkephalin-derived octapeptides
2010, Neuroscience
Leu- and Met-enkephalins are proenkephalin-derived endogenous pentapeptides with opioid (morphine) activity. Among the seven enkephalin units found in the human proenkephalin (PENK), the fourth copy being an octapeptide: Tyr-Gly-Gly-Phe-Met-Arg-Gly-Leu (_HsYGGFMRGL). Bioinformatic analysis of the available PENK sequences revealed the presence of other octapeptide orthologues in these precursor polypeptides. Four types of the elongated Met-enkephalins we identified by searching protein databases, _XlYGGFMRGY (three frog species and platypus), _GgYGGFMRSV (chicken and one fish species), _HpYGGFMNGF (shark) and _MmYGGFMRSL (mouse and two lungfish species) were chemically synthesized and studied in receptor binding and G-protein activation assays performed on rat brain membranes. All peptides have also been prepared containing oxidized methionine (M_(O)). The overall binding and signalling profile of the novel octapeptides revealed moderate opioid agonist activities and a rank order of potencies for the mu∼delta≫kappa receptor binding sites. Peptides with the oxidized M_(O) residue were found to be less potent in both receptor binding and G-protein stimulation studies. Phylogenetic neuropeptide libraries, defined here as a collection of mutationally different species variants of orthologous and paralogous peptide sequences, represent the natural molecular diversity of the neuropeptides. Such libraries can provide a wide range of structural information establishing comparative functional analyses. Since DNA sequencing data are rapidly increasing, more development in the natural peptide library approach is expected.
Effects of Endokinin A/B and Endokinin C/D on the modulation of pain in mice
2010, Peptides
Endokinins are novel tachykinins encoded on the human TAC4 and consist of Endokinin A (EKA), B (EKB), C (EKC) and D (EKD). To date, the function of Endokinins in pain processing was not fully understood. Therefore the aim of this study was to investigate the effects of Endokinin A/B (EKA/B, the common C-terminal decapeptide in EKA and EKB) and Endokinin C/D (EKC/D, the common C-terminal duodecapeptide in EKC and EKD) on pain modulation at supraspinal level in mice. Intracerebroventricular (i.c.v.) administration of EKA/B (1, 3, 12, 20 nmol/mouse) dose dependently induced potent analgesic effect. This effect could be fully antagonized by SR140333B but not SR48968C or SR142801. Naloxone could also block the analgesic effect, suggesting that this analgesic effect is related to opioid receptors. However, i.c.v. administration of EKA/B (10, 30, 100 pmol/mouse) caused hyperalgesic effect significantly, with a “U” shape curve. Interestingly, the hyperalgesic effect induced by EKA/B could be attenuated by SR140333B, SR142801 but not SR48968C. I.c.v. administration of EKC/D (1, 3, 12, 20 nmol/mouse) also dose dependently induced analgesic effect, which could not be blocked by SR48968C or SR142801 or naloxone. But to our astonishment, it could be significantly enhanced by SR140333B. More interestingly, the hyperalgesic effect induced by EKA/B could be significantly attenuated by EKC/D. In addition, the analgesic effect induced by co-administration of EKA/B and EKC/D was much less stronger than the effect of either EKA/B or EKC/D.
In vivo characterization of the effects of human hemokinin-1 and human hemokinin-1(4-11), mammalian tachykinin peptides, on the modulation of pain in mice
2008, Brain, Behavior, and Immunity
Citation Excerpt :
Previous studies have demonstrated that i.c.v. administration of SP produces antinociception in mice (Stewart et al., 1976), with the antinociceptive effect blocked by naloxone (Frederickson et al., 1978), indicating an involvement of SP in opioid antinociception in the brain. A close interaction between opioids and SP is supported by studies showing that SP stimulates the release of endogenous opioids (Tang et al., 1983; Iadarola et al., 1986; Naranjo et al., 1986). Our present results also show that the classical opioid receptor antagonist naloxone can reverse the analgesic effect of h HK-1 (i.c.v.), suggesting that descending opioid modulatory systems may be involved in the analgesic effect induced by h HK-1.
Human hemokinin-1 (h HK-1) and its truncated form h HK-1(4-11) are mammalian tachykinin peptides encoded by the recently identified TAC4 gene in human, and the biological functions of these peptides have not been well investigated. In the present study, an attempt has been made to investigate the effects and mechanisms of action of h HK-1 and h HK-1(4-11) in pain modulation at the supraspinal level in mice using the tail immersion test. Intracerebroventricular (i.c.v.) administration of h HK-1 (0.3, 1, 3 and 6 nmol/mouse) produced a dose- and time-related antinociceptive effect. This effect was significantly antagonized by the NK₁ receptor antagonist SR140333, but not by the NK₂ receptor antagonist SR48968, indicating that the analgesic effect induced by i.c.v. h HK-1 is mediated through the activation of NK₁ receptors. Interestingly, naloxone, β-funaltrexamine and naloxonazine, but not naltrindole and nor-binaltorphimine, could also block the analgesic effect markedly, suggesting that this effect is related to descending μ opioidergic neurons (primary μ₁ subtype). Human HK-1(4-11) could also induce a dose- and time-dependent analgesic effect after i.c.v. administration, however, the potency of analgesia was less than h HK-1. Surprisingly, SR140333 could not modify this analgesic effect, suggesting that this effect is not mediated through the NK₁ receptors like h HK-1. SR48968 could modestly enhance the analgesic effect induced by h HK-1(4-11), indicating that a small amount of h HK-1(4-11) may bind to NK₂ receptors. Furthermore, none of the opioid receptor (OR) antagonists could markedly block the analgesia of h HK-1(4-11), suggesting that the analgesic effect is not mediated through the descending opioidergic neurons. Blocking of δ ORs significantly enhanced the analgesia, indicating that δ OR is a negatively modulatory factor in the analgesic effect of h HK-1(4-11). It is striking that bicuculline (a competitive antagonist at GABA_A receptors) effectively blocked the analgesia induced by h HK-1(4-11), suggesting that this analgesic effect is mediated through the descending inhibitory GABAergic neurons. The novel mechanism involved in the analgesic effect of h HK-1(4-11), which is different from that of h HK-1, may pave the way for a new strategy for the investigation and control of pain.
Rat/mouse hemokinin-1, a mammalian tachykinin peptide, markedly potentiates the antinociceptive effects of morphine administered at the peripheral and supraspinal level
2006, Behavioural Brain Research
Rat/mouse hemokinin 1 (r/m HK-1) is a mammalian tachykinin peptide whose biological functions are not fully understood. Our recent report showed that i.c.v. administration of r/m HK-1 could produce dose- and time-related antinociceptive effect at nanomole concentration, and naloxone significantly antagonized this effect. Thus, we provide indirect evidence favoring a role of NK₁ supraspinal receptors in the inhibitory control of descending pain pathways, a role that seems to partially involve the activation of the endogenous opioid systems. Based on this report, the present study was conducted to further investigate the direct functional interaction between supraspinal tachykinin (r/m HK-1) and opioid systems. The results demonstrate that i.c.v. administration of r/m HK-1 (5 nmol/kg) could significantly potentiate the antinociceptive effects of morphine which was injected at peripheral and supraspinal level. These antinociceptive effects were blocked by prior treatment with the classical opioid receptors antagonist naloxone, indicating that the potentiated analgesic response is mediated by opioid-responsive neurons. Consistent with previous biochemical data, a likely mechanism underlying the peptide-mediated enhancement of opioid analgesia may center on the ability of r/m HK-1 to release endogenous opioid peptides. We suggest that there may be a cascade amplification mechanism in pain modulation when the two agents were co-administrated. The synergistic analgesic relationship of morphine and r/m HK-1 established here supports the hypothesis that supraspinal tachykinin and peripheral and central opioid systems have a direct functional interaction in the modulation of local nociceptive responses.
Substance P microinjected into the periaqueductal gray matter induces antinociception and is released following morphine administration
2004, Brain Research
Citation Excerpt :
It is also possible that the N-terminal SP fragments may induce antinociception by downregulating nitric oxide synthesis in the nociceptive pathways [21]. That there is a close interaction between opioids and SP is supported by studies showing that SP stimulates the release of endogenous opioids [12,18,47]. It has also been reported that mμ receptors co-localize with NK-1 receptors on the same neuron.
The aims of the present study were to investigate, in rats, the behavioral effects of substance P (SP) microinjected into the ventrolateral periaqueductal gray (PAG) and the effects of the neurokinin 1 (NK-1) receptor antagonist [d-Arg1, d-Trp7, 9, Leu11]-substance P (Spantide). The effect of morphine administration on the release of SP in the ventrolateral PAG was also investigated using microdialysis in awake rats.
SP microinjected into the ventrolateral part of the PAG induced significant increases in the hindpaw withdrawal latencies (HWLs) to thermal and mechanical stimulation as an antinociceptive response. The NK-1 receptor antagonist blocked these effects but exhibited no antinociceptive effect alone. Subcutaneous administration of morphine increased basal SP-like immunoreactivity (SP-LI) release in the microdialysate obtained from the ventrolateral PAG of freely moving rats.
Our results demonstrate that SP injected into the ventrolateral PAG induces an antinociceptive effect via activation of NK-1 receptors. Morphine administered systemically induces the release of SP in the ventrolateral PAG. We suggest that an increased release of SP in the PAG may contribute to opioid antinociception.

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Analgesic activity and release of [Met5]enkephalin-Arg6-Gly7-Leu8 from rat spinal cord in vivo

Abstract

European J. Pharmacol.

Biochem. Biophys. Res. Commun.

Neuropeptides

Life Sci.

European J. Pharmacol.

Brain Res.

Neuropeptides

Neuroscience

J. Biol. Chem.

Neuropharmacology

Brain Res.

Neuropharmacology

Analgesic activity and release of [Met⁵]enkephalin-Arg⁶-Gly⁷-Leu⁸ from rat spinal cord in vivo