1
|
Milanesi LH, Rossato DR, Dias VT, Kronbauer M, D’avila LF, Somacal S, Duarte T, Duarte MMF, Emanuelli T, Burger ME. Mediterranean X Western based diets: Opposite influences on opioid reinstatement. Toxicol Lett 2019; 308:7-16. [DOI: 10.1016/j.toxlet.2019.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/11/2019] [Accepted: 03/17/2019] [Indexed: 01/06/2023]
|
2
|
Individual differences in initial morphine sensitivity as a predictor for the development of opiate addiction in rats. Behav Brain Res 2016; 313:315-323. [DOI: 10.1016/j.bbr.2016.07.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/09/2016] [Accepted: 07/21/2016] [Indexed: 12/14/2022]
|
3
|
Essential role of mu opioid receptor in the regulation of delta opioid receptor-mediated antihyperalgesia. Neuroscience 2007; 150:807-17. [PMID: 17997230 DOI: 10.1016/j.neuroscience.2007.09.060] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 09/27/2007] [Accepted: 10/04/2007] [Indexed: 11/21/2022]
Abstract
Analgesic effects of delta opioid receptor (DOR) -selective agonists are enhanced during persistent inflammation and arthritis. Although the underlying mechanisms are still unknown, membrane density of DOR was shown to be increased 72 h after induction of inflammation, an effect abolished in mu opioid receptor (MOR) -knockout (KO) mice [Morinville A, Cahill CM, Kieffer B, Collier B, Beaudet A (2004b) Mu-opioid receptor knockout prevents changes in delta-opioid receptor trafficking induced by chronic inflammatory pain. Pain 109:266-273]. In this study, we demonstrated a crucial role of MOR in DOR-mediated antihyperalgesia. Intrathecal administration of the DOR selective agonist deltorphin II failed to induce antihyperalgesic effects in MOR-KO mice, whereas it dose-dependently reversed thermal hyperalgesia in wild-type mice. The antihyperalgesic effects of deltorphin II were blocked by naltrindole but not d-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) (CTOP) suggesting that this agonist was mainly acting through DOR. SNC80-induced antihyperalgesic effects in MOR-KO mice were also attenuated as compared with littermate controls. In contrast, kappa opioid receptor knockout did not affect deltorphin II-induced antihyperalgesia. As evaluated using mice lacking endogenous opioid peptides, the regulation of DOR's effects was also independent of beta-endorphin, enkephalins, or dynorphin opioids known to be released during persistent inflammation. We therefore conclude that DOR-mediated antihyperalgesia is dependent on MOR expression but that activation of MOR by endogenous opioids is probably not required.
Collapse
|
4
|
Holdridge SV, Armstrong SA, Taylor AMW, Cahill CM. Behavioural and morphological evidence for the involvement of glial cell activation in delta opioid receptor function: implications for the development of opioid tolerance. Mol Pain 2007; 3:7. [PMID: 17352824 PMCID: PMC1828713 DOI: 10.1186/1744-8069-3-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 03/12/2007] [Indexed: 11/12/2022] Open
Abstract
Previous studies have demonstrated that prolonged morphine treatment in vivo induces the translocation of delta opioid receptors (δORs) from intracellular compartments to neuronal plasma membranes and this trafficking event is correlated with an increased functional competence of the receptor. The mechanism underlying this phenomenon is unknown; however chronic morphine treatment has been shown to involve the activation and hypertrophy of spinal glial cells. In the present study we have examined whether activated glia may be associated with the enhanced δOR-mediated antinociception observed following prolonged morphine treatment. Accordingly, animals were treated with morphine with or without concomitant administration of propentofylline, an inhibitor of glial activation that was previously shown to block the development of morphine antinociceptive tolerance. The morphine regimen previously demonstrated to initiate δOR trafficking induced the activation of both astrocytes and microglia in the dorsal spinal cord as indicated by a significant increase in cell volume and cell surface area. Consistent with previous data, morphine-treated rats displayed a significant augmentation in δOR-mediated antinociception. Concomitant spinal administration of propentofylline with morphine significantly attenuated the spinal immune response as well as the morphine-induced enhancement of δOR-mediated effects. These results complement previous reports that glial activation contributes to a state of opioid analgesic tolerance, and also suggest that neuro-glial communication is likely responsible in part for the altered functional competence in δOR-mediated effects following morphine treatment.
Collapse
Affiliation(s)
- Sarah V Holdridge
- Department of Pharmacology & Toxicology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Stacey A Armstrong
- Department of Pharmacology & Toxicology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Anna MW Taylor
- Department of Pharmacology & Toxicology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Catherine M Cahill
- Department of Pharmacology & Toxicology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
- Department of Anesthesiology, Kingston General Hospital, Queen's University, Kingston, Ontario, K7L 2V7, Canada
| |
Collapse
|
5
|
Pradhan AAA, Siau C, Constantin A, Clarke PBS. Chronic morphine administration results in tolerance to delta opioid receptor-mediated antinociception. Neuroscience 2006; 141:947-954. [PMID: 16716526 DOI: 10.1016/j.neuroscience.2006.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 04/05/2006] [Accepted: 04/16/2006] [Indexed: 10/24/2022]
Abstract
Delta opioid receptor agonists produce only a moderate degree of antinociception, possibly reflecting the predominantly intracellular location of delta opioid receptor. However, recent studies suggest that short term morphine pretreatment can increase delta opioid receptor-mediated antinociception by promoting the translocation of delta opioid receptor to the cell surface. Even more striking sensitization has been reported after long term morphine pretreatment and withdrawal in locomotor tests. In the present study we therefore examined the effects of longer term morphine pretreatment and withdrawal on delta opioid receptor-mediated antinociception in the formalin test. Male adult rats were pretreated daily with morphine (10 mg/kg s.c.) or saline for 10 days, and were tested acutely with the delta opioid receptor agonist [D-Ala2,Glu4]-deltorphin (intrathecal) at 0, 7 and 14 days of withdrawal. Unexpectedly, chronic morphine pre-exposure resulted in tolerance to [D-Ala2,Glu4]-deltorphin-induced antinociception, and this occurred at 0 and 7 but not 14 days of morphine withdrawal. Morphine challenge at withdrawal day 7 confirmed the presence of tolerance to the antinociceptive effects of this drug. Chronic morphine pretreatment also resulted in tolerance to the locomotor stimulant effect of [D-Ala2,Glu4]-deltorphin (given i.c.v.), contrary to a previous report of sensitization. However, consistent with previous reports, short term (2 day) pretreatment with morphine did result in sensitization to [D-Ala2,Glu4]-deltorphin. Subsequent in vitro analysis, using [125I][D-Ala2,Glu4]-deltorphin or guanosine 5'(gamma-35S-thio) triphosphate autoradiography, did not reveal any changes in delta opioid receptor binding or function resulting from chronic morphine pretreatment. In conclusion, chronic morphine pretreatment caused tolerance to delta opioid receptor-mediated behavioral effects with no clear change at the receptor level.
Collapse
Affiliation(s)
- A A A Pradhan
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Room 1325, Montreal, QC H3G 1Y6 Canada
| | - C Siau
- Department of Anesthesia, McGill University, Montreal, QC H3G 1Y6 Canada
| | - A Constantin
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Room 1325, Montreal, QC H3G 1Y6 Canada
| | - P B S Clarke
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Room 1325, Montreal, QC H3G 1Y6 Canada.
| |
Collapse
|
6
|
Hack SP, Bagley EE, Chieng BCH, Christie MJ. Induction of delta-opioid receptor function in the midbrain after chronic morphine treatment. J Neurosci 2006; 25:3192-8. [PMID: 15788776 PMCID: PMC6725095 DOI: 10.1523/jneurosci.4585-04.2005] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Delta-opioid receptor (DOPr) activation fails to produce cellular physiological responses in many brain regions, including the periaqueductal gray (PAG), despite neural expression of high densities of the receptor. Previous histochemical studies have demonstrated that a variety of stimuli, including chronic morphine treatment, induce the translocation of DOPr from intracellular pools to the surface membrane of CNS neurons. PAG neurons in slices taken from untreated mice exhibited mu-opioid receptor (MOPr) but not DOPr-mediated presynaptic inhibition of GABAergic synaptic currents. In contrast, after 5-6 d of chronic morphine treatment, DOPr stimulation inhibited synaptic GABA release onto most neurons. Shorter exposure to morphine in vitro (upto 4 h) or in vivo (18 h) did not induce functional DOPr responses. DOPr-mediated presynaptic inhibition could not be induced in slices from untreated animals by increasing synaptic activity in vitro using high extracellular potassium concentrations or activation of protein kinase A. Induction of functional DOPr signaling by chronic morphine required MOPr expression, because no DOPr receptor responses were observed in MOPr knock-out mice. DOPr agonists also had no effect on miniature IPSCs in beta-arrestin-2 knock-out mice after chronic morphine. These results suggest that induction of DOPr-mediated actions in PAG by chronic morphine requires prolonged MOPr stimulation and expression of beta-arrestin-2.
Collapse
MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Animals
- Arrestins/deficiency
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Interactions
- Electric Stimulation/methods
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, Leucine/analogs & derivatives
- Enkephalin, Leucine/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- G Protein-Coupled Inwardly-Rectifying Potassium Channels/physiology
- Glycine Agents/pharmacology
- In Vitro Techniques
- Isoquinolines/pharmacology
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Membrane Potentials/radiation effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Morphine/administration & dosage
- Narcotic Antagonists/pharmacology
- Narcotics/administration & dosage
- Neurons/drug effects
- Oligopeptides/pharmacology
- Patch-Clamp Techniques/methods
- Periaqueductal Gray/cytology
- Periaqueductal Gray/drug effects
- Protein Kinase Inhibitors/pharmacology
- Receptors, Opioid, delta/physiology
- Receptors, Opioid, mu/deficiency
- Strychnine/pharmacology
- Sulfonamides/pharmacology
- Synaptic Transmission/drug effects
- Time Factors
- Xanthines/pharmacology
- beta-Arrestin 2
- beta-Arrestins
- gamma-Aminobutyric Acid/metabolism
Collapse
Affiliation(s)
- Stephen P Hack
- Pain Management Research Institute, University of Sydney, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia
| | | | | | | |
Collapse
|
7
|
Yamaguchi M, Suzuki T, Seki T, Namba T, Liu J, Arai H, Hori T, Shiga T. Decreased cell proliferation in the dentate gyrus of rats after repeated administration of cocaine. Synapse 2006; 58:63-71. [PMID: 16088949 DOI: 10.1002/syn.20182] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cell proliferation in the dentate gyrus of hippocampus was assessed using in vivo labeling with 5-bromo-2'-deoxyuridine (BrdU) in adult rats that were administered cocaine (20 mg/kg) for 14 consecutive days. Rats showed increased stereotypy at a challenge dose of cocaine after 1 week of withdrawal, suggesting the acquisition of behavioral sensitization. Twenty-four hours after final injection of repetitive cocaine administration, a 26% decrease in BrdU-positive cells was observed, compared with control rats. However, this returned to control level within 1 week. No differences were observed in rats that received a single injection of cocaine. Differentiation of newly formed cells was not influenced. These data imply that the regulation of hippocampal cell proliferation by cocaine may be involved in the development of certain symptoms of addiction, such as cognitive impairment and acquisition of behavioral sensitization.
Collapse
Affiliation(s)
- Mika Yamaguchi
- Department of Psychiatry, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
When agonists to alpha(2)adrenergic receptor (AR) and delta opioid receptor (DOR) are co-administered, they act synergistically to inhibit nociceptive elicited behavior. Some previous studies of synergism have used the DOR-selective agonist [D-Pen(2),D-Pen(5)]-enkehphalin (DPDPE), however, DPDPE has been shown to be less potent in mu opioid receptor-knockout (MOR-KO) mice. It is possible, therefore, that MOR contributes to the synergism of DPDPE with the alpha(2)AR agonists. We compared the interactions of spinally administered DPDPE with an alpha(2)AR-adrenergic agonist in MOR-KO and MOR-wildtype (WT) mice. In these mice, morphine is ineffective and the potency of spinally administered DOR agonists, deltorphin II (DELT II) and DPDPE decreased 16- and 250-fold, respectively. Antagonism studies using the MOR-selective antagonist, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH(2) (CTOP) and the DOR-selective antagonist, naltrindole HCl (naltrindole) demonstrated that while DOR mediates DPDPE-induced antinociception in MOR-KO, both MOR and DOR participate in DPDPE antinociception in WT mice, suggesting that DPDPE is less selective for DOR than previously observed in binding studies when given in vivo. The potency of the alpha(2)AR agonist UK14,304 was equivalent in WT and MOR-KO, demonstrating that the loss of opioid-mediated antinociception in the MOR-KO was not due to generalized impairment of antinociceptive processing. Interestingly, isobolographic analysis showed that, despite substantial loss of DPDPE potency in MOR-KO, DPDPE-UK14,304 synergism is fully retained. Collectively, these experiments demonstrate that although MOR participates in DELT II- and DPDPE-mediated spinal antinociception, DOR independently participates in synergistic antinociception with alpha(2)AR. Resolution of the roles of the opioid receptor subtypes in opioid agonist-induced effects may require comparison of the effects of multiple selective agonists in knockout animals.
Collapse
MESH Headings
- Animals
- Brimonidine Tartrate
- Dose-Response Relationship, Drug
- Drug Synergism
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Pain Measurement/drug effects
- Pain Measurement/methods
- Quinoxalines/pharmacology
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/deficiency
- Receptors, Opioid, mu/genetics
- Spinal Cord/drug effects
- Spinal Cord/physiology
Collapse
Affiliation(s)
- Xiao-hong Guo
- Department of Pharmacology, University of Minnesota, 6-120 Jackson Hall, 321 Church St. SE, Minneapolis, MN 55455, USA
| | | | | | | |
Collapse
|
9
|
Abstract
Chronic opioid receptor (OR) activation by morphine causes distinct cellular adaptations responsible for the development of tolerance. The present study examines the effect of chronic morphine exposure on the ability of high-efficacy agonists to mediate delta-OR (DOR) and mu-OR (MOR) uncoupling and internalization, two regulatory mechanisms contributing to rapid desensitization of OR function. Chronic morphine treatment (1 microm; 72 hr) of DOR carrying neuroblastoma x glioma (NG108-15) hybrid cells, a prototypical model system frequently used to study cellular aspects of opioid tolerance, completely blocked the capacity of [d-Ala2, d-Leu5]enkephalin (DADLE) and etorphine to desensitize opioid-stimulated [35S]GTPgammaS binding and to mediate DOR internalization. Similar findings were obtained on stably DOR- and MOR-transfected human embryonic kidney (HEK) 293 cells. Chronic morphine treatment also heterologously impaired agonist regulation of non-opioid G-protein-coupled receptors, such as the m(4)-muscarinic acetylcholine receptor and the brain-type cannabinoid receptor. As a possible underlying mechanism, we found that chronic morphine treatment completely blocked agonist-induced redistribution of beta-arrestin1 in both NG108-15 and stably MOR-transfected HEK293 cells. Moreover, attenuation of beta-arrestin1 function appears to depend on persistent stimulation of MAP kinase activity during the course of chronic morphine treatment, because coincubation of the cells together with the MAP kinase blocker PD98059 fully restored beta-arrestin1 translocation and receptor internalization. These results demonstrate that chronic morphine treatment produces adaptational changes at the beta-arrestin1 level, which in turn attenuates agonist-mediated desensitization and internalization of G-protein-coupled receptors.
Collapse
|
10
|
Eisinger DA, Ammer H, Schulz R. Chronic morphine treatment inhibits opioid receptor desensitization and internalization. J Neurosci 2002; 22:10192-200. [PMID: 12451120 PMCID: PMC6758738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Chronic opioid receptor (OR) activation by morphine causes distinct cellular adaptations responsible for the development of tolerance. The present study examines the effect of chronic morphine exposure on the ability of high-efficacy agonists to mediate delta-OR (DOR) and mu-OR (MOR) uncoupling and internalization, two regulatory mechanisms contributing to rapid desensitization of OR function. Chronic morphine treatment (1 microm; 72 hr) of DOR carrying neuroblastoma x glioma (NG108-15) hybrid cells, a prototypical model system frequently used to study cellular aspects of opioid tolerance, completely blocked the capacity of [d-Ala2, d-Leu5]enkephalin (DADLE) and etorphine to desensitize opioid-stimulated [35S]GTPgammaS binding and to mediate DOR internalization. Similar findings were obtained on stably DOR- and MOR-transfected human embryonic kidney (HEK) 293 cells. Chronic morphine treatment also heterologously impaired agonist regulation of non-opioid G-protein-coupled receptors, such as the m(4)-muscarinic acetylcholine receptor and the brain-type cannabinoid receptor. As a possible underlying mechanism, we found that chronic morphine treatment completely blocked agonist-induced redistribution of beta-arrestin1 in both NG108-15 and stably MOR-transfected HEK293 cells. Moreover, attenuation of beta-arrestin1 function appears to depend on persistent stimulation of MAP kinase activity during the course of chronic morphine treatment, because coincubation of the cells together with the MAP kinase blocker PD98059 fully restored beta-arrestin1 translocation and receptor internalization. These results demonstrate that chronic morphine treatment produces adaptational changes at the beta-arrestin1 level, which in turn attenuates agonist-mediated desensitization and internalization of G-protein-coupled receptors.
Collapse
MESH Headings
- Animals
- Arrestins/genetics
- Arrestins/metabolism
- Cell Line
- Enkephalin, Leucine-2-Alanine/pharmacology
- Enzyme Activation/drug effects
- Enzyme Inhibitors/pharmacology
- GTP-Binding Proteins/metabolism
- Humans
- Hybrid Cells/cytology
- Hybrid Cells/drug effects
- Hybrid Cells/metabolism
- Ionophores/pharmacology
- Kidney/cytology
- Kidney/drug effects
- Kidney/metabolism
- Mice
- Mitogen-Activated Protein Kinases/drug effects
- Mitogen-Activated Protein Kinases/metabolism
- Morphine/pharmacology
- Narcotics/pharmacology
- Protein Transport/drug effects
- Receptor, Muscarinic M4
- Receptors, Cannabinoid
- Receptors, Cell Surface/drug effects
- Receptors, Cell Surface/metabolism
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, Muscarinic/drug effects
- Receptors, Muscarinic/metabolism
- Receptors, Opioid/drug effects
- Receptors, Opioid/genetics
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Time Factors
- Transfection
- beta-Arrestins
Collapse
Affiliation(s)
- Daniela A Eisinger
- Institute of Pharmacology, Toxicology and Pharmacy, University of Munich, D-80539 Munich, Germany.
| | | | | |
Collapse
|
11
|
Abstract
In 1980 the skin of certain frogs belonging to the genus Phyllomedusinae was found to contain two new peptides that proved to be selective mu-opioid agonists, and named dermorphins. Since 1987 deltorphins, a family of highly selective delta-opioid peptides were identified either by cloning of the cDNA from frog skins or isolation of the peptides. The distinctive feature of opioid peptides is the presence of a naturally occurring D-enantiomer at the second position in their common N-terminal sequence, Tyr-D-Xaa-Phe. The discovery of the amphibian opiate peptides, provided new insights into the functional role of the mu- and delta-opiate systems. It also provided models for novel analgesics with enhanced therapeutic benefits and reduced toxicity.
Collapse
Affiliation(s)
- L Negri
- Department of Human Physiology and Pharmacology, University "La Sapienza," P.le Aldo Moro, 5, I-00185, Rome, Italy.
| | | | | |
Collapse
|
12
|
Szumlinski KK, Maisonneuve IM, Glick SD. The potential anti-addictive agent, 18-methoxycoronaridine, blocks the sensitized locomotor and dopamine responses produced by repeated morphine treatment. Brain Res 2000; 864:13-23. [PMID: 10793182 DOI: 10.1016/s0006-8993(00)02069-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
18-Methoxycoronaridine (18-MC), a novel synthetic iboga congener, attenuates the reinforcing efficacy of morphine, disrupts some signs of morphine withdrawal in physically dependent rats and attenuates the dopamine response in the nucleus accumbens to acute morphine. The present study further investigated the interactions between 18-MC and morphine by examining the effects of 18-MC (40 mg/kg, i.p., 19 h earlier) on the expression of dopamine sensitization in the nucleus accumbens in response to morphine (20 mg/kg, i.p.) and on the dose-effect curves for morphine-induced locomotion (0-30 mg/kg, i.p.) in rats treated either acutely or repeatedly (five, once daily, injections of 20 mg/kg, i.p.) with morphine. Compared to vehicle pretreated controls, 18-MC increased the potency of morphine, shifting the dose-response curve to the left, in acute morphine treated rats; however, 18-MC did not alter the potency of morphine in rats treated repeatedly with morphine. Repeated morphine administration induced locomotor sensitization in approximately 50% of the rats tested; in vehicle pretreated rats, the morphine dose-response curve was shifted to the left in sensitized as compared to non-sensitized rats. In 18-MC pretreated rats, sensitized and non-sensitized rats responded similarly to morphine, revealing a blockade of sensitization by 18-MC. Consistent with this behavioural finding, 18-MC pretreatment completely abolished the sensitized dopamine response in the nucleus accumbens expressed by rats repeatedly treated with morphine. It is suggested that the potential anti-addictive efficacy of 18-MC might be related to an ability to restore normal functioning to a hypersensitive mesolimbic dopamine system produced by previous repeated morphine administration.
Collapse
Affiliation(s)
- K K Szumlinski
- Department of Pharmacology and Neuroscience (MC-136), Albany Medical College, 47 New Scotland Avenue, Albany, NY, USA.
| | | | | |
Collapse
|
13
|
Abstract
The deltorphins are a class of highly selective delta-opioid heptapeptides from the skin of the Amazonian frogs Phyllomedusa sauvagei and P. bicolor. The first of these fascinating peptides came to light in 1987 by cloning of the cDNA of from frog skins, while the other members of this family were identified either by cDNA or isolation of the peptides. The distinctive feature of deltorphins is the presence of a naturally occurring D-enantiomer at the second position in their common N-terminal sequence, Tyr-D-Xaa-Phe, comparable to dermorphin, which is the prototype of a group of mu-selective opioids from the same source. The D-amino acid and the anionic residues, either Glu or Asp, as well as their unique amino acid compositions are responsible for the remarkable biostability, high delta-receptor affinity, bioactivity and peptide conformation. This review summarizes a decade of research from many laboratories that defined which residues and substituents in the deltorphins interact with the delta-receptor and characterized pharmacological and physiological activities in vitro and in vivo. It begins with a historical description of the topic and presents general schema for the synthesis of peptide analogues of deltorphins A, B and C as a means to document the methods employed in producing a myriad of analogues. Structure activity studies of the peptides and their pharmacological activities in vitro are detailed in abundantly tabulated data. A brief compendium of the current level of knowledge of the delta-receptor assists the reader to appreciate the rationale for the design of these analogues. Discussion of the conformation of these peptides addresses how structure leads to further hypotheses regarding ligand receptor interaction. The review ends with a broad discussion of the potential applications of these peptides in clinical and therapeutic settings.
Collapse
Affiliation(s)
- L H Lazarus
- Peptide Neurochemistry, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | | | | | | |
Collapse
|
14
|
Negri L, Improta G, Lattanzi R, Potenza RL, Luchetti F, Melchiorri P. Interaction between the mu-agonist dermorphin and the delta-agonist [D-Ala2, Glu4]deltorphin in supraspinal antinociception and delta-opioid receptor binding. Br J Pharmacol 1995; 116:2931-8. [PMID: 8680727 PMCID: PMC1909203 DOI: 10.1111/j.1476-5381.1995.tb15947.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. In rats, the interaction between the mu-opioid agonist dermorphin and the delta-opioid agonist [D-Ala2, Glu4]deltorphin was studied in binding experiments to delta-opioid receptors and in the antinociceptive test to radiant heat. 2. When injected i.c.v., doses of [D-Ala2, Glu4]deltorphin higher than 20 nmol produced antinociception in the rat tail-flick test to radiant heat. Lower doses were inactive. None of the doses tested elicited the maximum achievable response. This partial antinociception was accomplished with an in vivo occupancy of more than 97% of brain delta-opioid receptors and of 17% of mu-opioid receptors. Naloxone (0.1 mg kg-1, s.c.), and naloxonazine (10 mg kg-1, i.v., 24 h before), but not the selective delta-opioid antagonist naltrindole, antagonized the antinociception. 3. In vitro competitive inhibition studies in rat brain membranes showed that [D-Ala2, Glu4]deltorphin displaced [3H]-naltrindole from two delta-binding sites of high and low affinity. The addition of 100 microM Gpp[NH]p produced a three fold increase in the [D-Ala2, Glu4]deltorphin Ki value for both binding sites. The addition of 10 nM dermorphin increased the Ki value of the delta-agonist for the high affinity site five times. When Gpp[NH]p was added to the incubation medium together with 10 nM dermorphin, the high affinity Ki of the delta-agonist increased 15 times. 4. Co-administration into the rat brain ventricles of subanalgesic doses of dermorphin and [D-Ala2, Glu4]deltorphin resulted in synergistic antinociceptive responses. 5. Pretreatment with naloxone or with the non-equilibrium mu-antagonists naloxonazine and beta-funaltrexamine completely abolished the antinociceptive response of the mu-delta agonist combinations. 6. Pretreatment with the delta-opioid antagonists naltrindole and DALCE reduced the antinociceptive response of the dermorphin-[D-Ala2, Glu4]deltorphin combinations to a value near that observed after the mu-agonist alone. At the dosage used, naltrindole occupied more than 98% of brain delta-opioid receptors without affecting mu-opioid-receptors. 7. These data suggest that in the rat tail-flick test to radiant heat, mu- and delta-opioid agonists co-operate positively in evoking an antinociceptive response. Although interactions between different opioid pathways cannot be excluded, in vitro binding results indicate that this co-operative antinociception is probably mediated by co-activation of the delta-opioid receptors at the cellular level by the mu- and delta-agonist.
Collapse
MESH Headings
- Amino Acid Sequence
- Analgesics, Opioid/antagonists & inhibitors
- Analgesics, Opioid/pharmacology
- Analysis of Variance
- Animals
- Dose-Response Relationship, Drug
- Drug Interactions
- Injections, Intraventricular
- Male
- Molecular Sequence Data
- Oligopeptides/antagonists & inhibitors
- Oligopeptides/pharmacology
- Opioid Peptides
- Pain Measurement
- Rats
- Rats, Wistar
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
Collapse
Affiliation(s)
- L Negri
- Institute of Medical Pharmacology, University La Sapienza, Roma, Italy
| | | | | | | | | | | |
Collapse
|
15
|
Negri L, Lattanzi R, Melchiorri P. Production of antinociception by peripheral administration of [Lys7]dermorphin, a naturally occurring peptide with high affinity for mu-opioid receptors. Br J Pharmacol 1995; 114:57-66. [PMID: 7712029 PMCID: PMC1510172 DOI: 10.1111/j.1476-5381.1995.tb14905.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The opioid activity of the amphibian peptide, [Lys7]dermorphin, was studied in rats and mice. When administered intracerebroventricularly (i.c.v.), intravenously (i.v.) or subcutaneously (s.c.) it produced a long lasting analgesia. Its antinociceptive potency exceeded that of morphine 290 times by i.c.v. injection, and 25-30 times by peripheral administration. 2. The dose-response curves of [Lys7]dermorphin antinociception were shifted to the right by the pretreatment with naloxone (0.1 mg kg-1, s.c.) or with the mu 1-selective antagonist, naloxonazine (10 mg kg-1, i.v. 24 h before peptide injection). 3. The peptide also displayed potent antinociceptive effects in a chronic inflammatory pain model (rat Freund's adjuvant arthritis). In this pain model, systemic administration of the peptide raised the nociceptive threshold more in inflamed than in healthy paw. 4. High central and peripheral doses of [Lys7]dermorphin in rats produced catalepsy. The cataleptic response was antagonized by naloxone but left unchanged by naloxonazine pretreatment. 5. In rats and mice, central or peripheral administration of [Lys7]dermorphin induced a significantly slower development of tolerance to the antinociceptive effect than did morphine. 6. Upon naloxone precipitation of the withdrawal syndrome, [Lys7]dermorphin-dependent mice made fewer jumps and lost less weight than the morphine-dependent animals. Withdrawal hyperalgesia did not develop in [Lys7]dermorphin-dependent mice. 7. In conclusion, [Lys7]dermorphin seems to be a unique opioid peptide having a high penetration into the blood-brain barrier despite its low lipid solubility. This peptide causes fewer side-effects than other opioids and appears less likely than morphine to cause physical dependence in rats and mice.
Collapse
Affiliation(s)
- L Negri
- Institute of Medical Pharmacology, University La Sapienza, Roma, Italy
| | | | | |
Collapse
|