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Li Y, Kang DH, Kim WM, Lee HG, Kim SH, You HE, Choi JI, Yoon MH. Systemically administered neurotensin receptor agonist produces antinociception through activation of spinally projecting serotonergic neurons in the rostral ventromedial medulla. Korean J Pain 2021; 34:58-65. [PMID: 33380568 PMCID: PMC7783846 DOI: 10.3344/kjp.2021.34.1.58] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/12/2020] [Accepted: 12/16/2020] [Indexed: 11/05/2022] Open
Abstract
Background Supraspinal delivery of neurotensin (NTS), which may contribute to the effect of a systemically administered agonist, has been reported to be either pronociceptive or antinociceptive. Here, we evaluated the effects of systemically administered NTSR1 agonist in a rat model of neuropathic pain and elucidated the underlying supraspinal mechanism. Methods Neuropathic pain was induced by L5 and L6 spinal nerve ligation in male Sprague-Dawley rats. The effects of intraperitoneally administered NTSR1 agonist PD 149163 was assessed using von Frey filaments. To examine the role of 5-HT neurotransmission, a serotonin (5-HT) receptor antagonist dihydroergocristine was pretreated intrathecally, and spinal microdialysis studies were performed to measure the change in extracellular level of 5-HT in response to PD 149163 administration. To investigate the supraspinal mechanism, NTSR1 antagonist 48692 was microinjected into the rostral ventromedial medulla (RVM) prior to systemic PD 149163. Additionally, the effect of intrathecal DHE on intra-RVM PD 149163 was assessed. Results Intraperitoneally administered PD 149163 exhibited a dose-dependent attenuation of mechanical allodynia. This effect was partially reversed by intrathecal pretreatment with dihydroergocristine and was accompanied by an increased extracellular level of 5-HT in the spinal cord. The PD 149163-produced antinociception was also blocked by intra-RVM SB 48692. Direct injection of PD 149163 into the RVM mimicked the maximum effect of the same drug delivered intraperitoneally, which was reversed by intrathecal dihydroergocristine. Conclusions These observations indicate that systemically administered NTSR1 agonist produces antinociception through the NTSR1 in the RVM, activating descending serotonergic projection to release 5-HT into the spinal dorsal horn.
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Affiliation(s)
- Yaqun Li
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Dong Ho Kang
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Woong Mo Kim
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.,Department of Anesthesiology and Pain Medicine, Chonnam National University Hwasun Hospital, Hwasun, Korea
| | - Hyung Gon Lee
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.,Center for Creative Biomedical Scientists, Chonnam National University Medical School, Gwangju, Korea
| | - Seung Hoon Kim
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Hyun Eung You
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hwasun Hospital, Hwasun, Korea
| | - Jeong Il Choi
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.,Center for Creative Biomedical Scientists, Chonnam National University Medical School, Gwangju, Korea
| | - Myung Ha Yoon
- Department of Anesthesiology and Pain Medicine, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.,Center for Creative Biomedical Scientists, Chonnam National University Medical School, Gwangju, Korea
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Abstract
Neurotensin (NT) can produce a profound analgesia or enhance pain responses, depending on the circumstances. Recent evidence suggests that this may be due to a dose-dependent recruitment of distinct populations of pain modulatory neurons. NT knockout mice display defects in both basal nociceptive responses and stress-induced analgesia. Stress-induced antinociception is absent in these mice and instead stress induces a hyperalgesic response, suggesting that NT plays a key role in the stress-induced suppression of pain. Cold water swim stress results in increased NT mRNA expression in hypothalamic regions known to project to periaqueductal gray, a key region involved in pain modulation. Thus, stress-induced increases in NT signaling in pain modulatory regions may be responsible for the transition from pain facilitation to analgesia. This review focuses on recent advances that have provided insights into the role of NT in pain modulation.
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Affiliation(s)
- Paul R Dobner
- Department of Molecular Genetics and Microbiology, Program in Neuroscience, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, MA 01655, USA.
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d'Amore A, Chiarotti F, Renzi P. High-intensity nociceptive stimuli minimize behavioral effects induced by restraining stress during the tail-flick test. J Pharmacol Toxicol Methods 1992; 27:197-201. [PMID: 1421528 DOI: 10.1016/1056-8719(92)90041-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Analgesia following exposure to various stressors is a well-documented phenomenon. Restraint of an animal during the tail-flick test (TFT) represents a potent stressor that can induce both altered baseline latencies and enhanced response to opioids. The present study shows that the use of higher stimulus intensities during TFT minimizes the stress influences produced by restraint on the animal's response rendering the test more sensitive to the pharmacological action of analgesic drugs.
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Affiliation(s)
- A d'Amore
- Istituto Superiore di Sanita, Laboratori di Farmacologia e Fisiopatologia di Organo e di Sistema, Rome, Italy
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LaBella FS, Geiger JD, Glavin GB. Administered peptides inhibit the degradation of endogenous peptides. The dilemma of distinguishing direct from indirect effects. Peptides 1985; 6:645-60. [PMID: 2999731 DOI: 10.1016/0196-9781(85)90168-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Virtually all peptides are biologically active following central administration as a consequence of both direct and indirect cellular actions. Direct effects are mainly interactions with specific membrane receptors but may include unions with other components of the receptor/effector complex. Significant indirect biological effects of exogenous peptides, including apparent secretagogue effects on endogenous peptides largely overlooked in practice, result from extensive competition with endogenous peptides for degradative enzymes (peptidases). A consequence of this competition is enhancement of tonic or intermittent activity of endogenous peptides. The pharmacological profile of any peptide reflects or includes, therefore, the spectrum of endogenous peptides that is protected from peptidase action. It is likely that certain pharmacologically active peptides, including a large number of di-, tri- and oligo-peptides, elicit responses mainly or exclusively by competing for peptidases. Therefore, reliable estimates of the relative contributions of direct and indirect actions of exogenous peptides may be difficult, if not impossible, to obtain.
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Clark WG, Lipton JM. Changes in body temperature after administration of amino acids, peptides, dopamine, neuroleptics and related agents: II. Neurosci Biobehav Rev 1985; 9:299-371. [PMID: 2861591 DOI: 10.1016/0149-7634(85)90052-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This survey begins a second series of compilations of data regarding changes in body temperature induced by drugs and related agents. The information listed includes the species used, the route of administration and dose of drug, the environmental temperature at which experiments were performed, the number of tests, the direction and magnitude of change in body temperature and remarks on the presence of special conditions, such as age or brain lesions. Also indicated is the influence of other drugs, such as antagonists, on the response to the primary agent. Most of the papers were published since 1978, but data from many earlier papers are also tabulated.
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Bodnar RJ, Nilaver G, Wallace MM, Badillo-Martinez D, Zimmerman EA. Pain threshold changes in rats following central injection of beta-endorphin, met-enkephalin, vasopressin or oxytocin antisera. Int J Neurosci 1984; 24:149-60. [PMID: 6094376 DOI: 10.3109/00207458409089803] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Both opioid peptides such as beta-endorphin and met-enkephalin and nonopioid peptides such as vasopressin and oxytocin increase pain thresholds in rodents. Antisera raised against each of these peptides have been developed for use in immunocytochemical and radioimmunoassay procedures. The present study assessed whether central administration of antisera raised against beta-endorphin (ABE), met-enkephalin (AME), arginine, vasopressin (AAVP) or oxytocin (AOT) altered tail-flick latencies elicited by three different levels of radiant heat, jump thresholds, core body temperatures and locomotor activity. ABE induced a transient hyperalgesia on the tail-flick test at thermal levels at which beta-endorphin administration would elicit an analgesic effect. While met-enkephalin increases tail-flick latencies elicited by high thermal levels, AME failed to alter latencies at this level, but rather induced a short-acting hyperalgesia at a low thermal level. While vasopressin increased tail-flick latencies at high thermal levels, AAVP produced reciprocal decreases. Yet AAVP inexplicably induced analgesic effects at moderate and low thermal levels. Finally, while oxytocin increased latencies at high thermal levels, AOT failed to alter latencies. Rather, it decreased latencies at the moderate thermal level and increased latencies at the low thermal level. Neither jump thresholds nor core body temperatures were affected by any antiserum pretreatment. While activity levels were unaffected by either ABE, AME or AAVP pretreatment, AOT decreased activity in a fashion complementry to oxytocin-induced hyperactivity and seizures. There data are discussed in terms of tonic versus phasic influences of these peptides upon pain perception.
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