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Dai SP, Yang CC, Chin Y, Sun WH. T cell death-associated gene 8-mediated distinct signaling pathways modulate the early and late phases of neuropathic pain. iScience 2024; 27:110955. [PMID: 39381739 PMCID: PMC11460492 DOI: 10.1016/j.isci.2024.110955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 05/01/2024] [Accepted: 09/10/2024] [Indexed: 10/10/2024] Open
Abstract
Peripheral nerve injury alters the transduction of nociceptive signaling. The coordination of neurons, glia, and immune cells results in persistent pain and inflammation. T cell death-associated gene 8 (TDAG8), located at nociceptors and immune cells, is involved in inflammatory pain and arthritis-induced pain. Here, we employed TDAG8-deficient mice, pharmacological approaches, and calcium/sodium imaging to elucidate how TDAG8-mediated signaling modulates neuron activities in a mouse model of chronic constriction injury-induced neuropathic pain. We demonstrated that TDAG8 participated alone in mechanical allodynia induced by constriction injury. (1) TDAG8-Nav1.8 signaling in small-diameter isolectin B4-positive [IB4(+)] neurons initiates mechanical allodynia; it also modulated substance P release from IB4(-) neurons to facilitate the development of early mechanical allodynia. (2) TDAG8-mediated signaling increased medium-to large-diameter IB4(-) neuron activity to maintain late mechanical allodynia; it also modulated substance P release in soma to reduce satellite glial number and Nav1.7 expression, thus attenuating chronic mechanical allodynia.
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Affiliation(s)
- Shih-Ping Dai
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chun-Chieh Yang
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
| | - Yin Chin
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Wei-Hsin Sun
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
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McPherson KB, Ingram SL. Cellular and circuit diversity determines the impact of endogenous opioids in the descending pain modulatory pathway. Front Syst Neurosci 2022; 16:963812. [PMID: 36045708 PMCID: PMC9421147 DOI: 10.3389/fnsys.2022.963812] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/15/2022] [Indexed: 01/31/2023] Open
Abstract
The descending pain modulatory pathway exerts important bidirectional control of nociceptive inputs to dampen and/or facilitate the perception of pain. The ventrolateral periaqueductal gray (vlPAG) integrates inputs from many regions associated with the processing of nociceptive, cognitive, and affective components of pain perception, and is a key brain area for opioid action. Opioid receptors are expressed on a subset of vlPAG neurons, as well as on both GABAergic and glutamatergic presynaptic terminals that impinge on vlPAG neurons. Microinjection of opioids into the vlPAG produces analgesia and microinjection of the opioid receptor antagonist naloxone blocks stimulation-mediated analgesia, highlighting the role of endogenous opioid release within this region in the modulation of nociception. Endogenous opioid effects within the vlPAG are complex and likely dependent on specific neuronal circuits activated by acute and chronic pain stimuli. This review is focused on the cellular heterogeneity within vlPAG circuits and highlights gaps in our understanding of endogenous opioid regulation of the descending pain modulatory circuits.
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Affiliation(s)
- Kylie B. McPherson
- Division of Neuroscience and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy,Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, United States
| | - Susan L. Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, United States,*Correspondence: Susan L. Ingram
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Inhibition of angiotensin converting enzyme induces mechanical allodynia through increasing substance P expression in mice. Neurochem Int 2021; 146:105020. [PMID: 33744374 DOI: 10.1016/j.neuint.2021.105020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/25/2021] [Accepted: 03/10/2021] [Indexed: 11/20/2022]
Abstract
Although emerging evidence shows that angiotensin converting enzyme (ACE) is associated with pain, it is not clear whether inhibition of ACE could affect to nociceptive transmission and which mediators are involved in this process. Here we investigated whether administration of the ACE inhibitors, captopril and enalapril increases the expression of substance P (SP) and whether this increase contributes to the induction of mechanical allodynia in mice. ACE was expressed in the lumbar dorsal root ganglion (DRG) and the superficial dorsal horn (SDH) region of the spinal cord in mice. Either intraperitoneal or intrathecal administration of the ACE inhibitors, captopril and enalapril for 10 days significantly increased the paw withdrawal frequency to innocuous mechanical stimuli and the levels of SP in both the lumbar DRG and the SDH region of the spinal cord dorsal horn. In addition, intraperitoneal administration of the SP receptor (neurokinin-1 receptor) antagonist, L-733,060 suppressed mechanical allodynia that was induced by pretreatment of captopril and enalapril. Intraplantar administration of SP for 3 days induces mechanical allodynia, and this effect was reduced by exogenous ACE administration. These findings demonstrate that inhibition of ACE increases the levels of SP in both the lumbar DRG and spinal cord dorsal horn, ultimately contributing to the induction of mechanical allodynia in mice.
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Lee MT, Chiu YT, Chiu YC, Hor CC, Lee HJ, Guerrini R, Calo G, Chiou LC. Neuropeptide S-initiated sequential cascade mediated by OX 1, NK 1, mGlu 5 and CB 1 receptors: a pivotal role in stress-induced analgesia. J Biomed Sci 2020; 27:7. [PMID: 31915019 PMCID: PMC6950992 DOI: 10.1186/s12929-019-0590-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/18/2019] [Indexed: 02/03/2023] Open
Abstract
Background Stress-induced analgesia (SIA) is an evolutionarily conserved phenomenon during stress. Neuropeptide S (NPS), orexins, substance P, glutamate and endocannabinoids are known to be involved in stress and/or SIA, however their causal links remain unclear. Here, we reveal an unprecedented sequential cascade involving these mediators in the lateral hypothalamus (LH) and ventrolateral periaqueductal gray (vlPAG) using a restraint stress-induced SIA model. Methods Male C57BL/6 mice of 8–12 week-old were subjected to intra-cerebroventricular (i.c.v.) and/or intra-vlPAG (i.pag.) microinjection of NPS, orexin-A or substance P alone or in combination with selective antagonists of NPS receptors (NPSRs), OX1 receptors (OX1Rs), NK1 receptors (NK1Rs), mGlu5 receptors (mGlu5Rs) and CB1 receptors (CB1Rs), respectively. Antinociceptive effects of these mediators were evaluated via the hot-plate test. SIA in mice was induced by a 30-min restraint stress. NPS levels in the LH and substance P levels in vlPAG homogenates were compared in restrained and unrestrained mice. Results NPS (i.c.v., but not i.pag.) induced antinociception. This effect was prevented by i.c.v. blockade of NPSRs. Substance P (i.pag.) and orexin-A (i.pag.) also induced antinociception. Substance P (i.pag.)-induced antinociception was prevented by i.pag. Blockade of NK1Rs, mGlu5Rs or CB1Rs. Orexin-A (i.pag.)-induced antinociception has been shown previously to be prevented by i.pag. blockade of OX1Rs or CB1Rs, and here was prevented by NK1R or mGlu5R antagonist (i.pag.). NPS (i.c.v.)-induced antinociception was prevented by i.pag. blockade of OX1Rs, NK1Rs, mGlu5Rs or CB1Rs. SIA has been previously shown to be prevented by i.pag. blockade of OX1Rs or CB1Rs. Here, we found that SIA was also prevented by i.c.v. blockade of NPSRs or i.pag. blockade of NK1Rs or mGlu5Rs. Restrained mice had higher levels of NPS in the LH and substance P in the vlPAG than unrestrained mice. Conclusions These results suggest that, during stress, NPS is released and activates LH orexin neurons via NPSRs, releasing orexins in the vlPAG. Orexins then activate OX1Rs on substance P-containing neurons in the vlPAG to release substance P that subsequently. Activates NK1Rs on glutamatergic neurons to release glutamate. Glutamate then activates perisynaptic mGlu5Rs to initiate the endocannabinoid retrograde inhibition of GABAergic transmission in the vlPAG, leading to analgesia.
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Affiliation(s)
- Ming Tatt Lee
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.,Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.,Faculty of Pharmaceutical Sciences, UCSI University, 56000, Kuala Lumpur, Malaysia
| | - Yu-Ting Chiu
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Yu-Chun Chiu
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Chia Chun Hor
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Hsin-Jung Lee
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Remo Guerrini
- Department of Chemical and Pharmaceutical Sciences, Laboratorio per le Tecnologie delle Terapie Avanzate (LTTA), Ferrara, Italy
| | - Girolamo Calo
- Department of Medical Sciences and National Institute of Neurosciences, Section of Pharmacology, University of Ferrara, 44121, Ferrara, Italy
| | - Lih-Chu Chiou
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan. .,Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan. .,Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan. .,Graduate Institute of Acupuncture Science, China Medical University, Taichung, 40402, Taiwan.
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5
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Abstract
Hybrid compounds (also known as chimeras, designed multiple ligands, bivalent compounds) are chemical units where two active components, usually possessing affinity and selectivity for distinct molecular targets, are combined as a single chemical entity. The rationale for using a chimeric approach is well documented as such novel drugs are characterized by their enhanced enzymatic stability and biological activity. This allows their use at lower concentrations, increasing their safety profile, particularly when considering undesirable side effects. In the group of synthetic bivalent compounds, drugs combining pharmacophores having affinities toward opioid and neurokinin-1 receptors have been extensively studied as potential analgesic drugs. Indeed, substance P is known as a major endogenous modulator of nociception both in the peripheral and central nervous systems. Hence, synthetic peptide fragments showing either agonism or antagonism at neurokinin 1 receptor were both assigned with analgesic properties. However, even though preclinical studies designated neurokinin-1 receptor antagonists as promising analgesics, early clinical studies revealed a lack of efficacy in human. Nevertheless, their molecular combination with enkephalin/endomorphin fragments has been considered as a valuable approach to design putatively promising ligands for the treatment of pain. This paper is aimed at summarizing a 20-year journey to the development of potent analgesic hybrid compounds involving an opioid pharmacophore and devoid of unwanted side effects. Additionally, the legitimacy of considering neurokinin-1 receptor ligands in the design of chimeric drugs is discussed.
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Lénárd L, László K, Kertes E, Ollmann T, Péczely L, Kovács A, Kállai V, Zagorácz O, Gálosi R, Karádi Z. Substance P and neurotensin in the limbic system: Their roles in reinforcement and memory consolidation. Neurosci Biobehav Rev 2018; 85:1-20. [DOI: 10.1016/j.neubiorev.2017.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/24/2017] [Accepted: 09/02/2017] [Indexed: 12/18/2022]
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7
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Kim J, Zhang X, Muralidhar S, LeBlanc SA, Tonegawa S. Basolateral to Central Amygdala Neural Circuits for Appetitive Behaviors. Neuron 2017; 93:1464-1479.e5. [PMID: 28334609 DOI: 10.1016/j.neuron.2017.02.034] [Citation(s) in RCA: 284] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 01/30/2017] [Accepted: 02/15/2017] [Indexed: 01/07/2023]
Abstract
Basolateral amygdala (BLA) principal cells are capable of driving and antagonizing behaviors of opposing valence. BLA neurons project to the central amygdala (CeA), which also participates in negative and positive behaviors. However, the CeA has primarily been studied as the site for negative behaviors, and the causal role for CeA circuits underlying appetitive behaviors is poorly understood. Here, we identify several genetically distinct populations of CeA neurons that mediate appetitive behaviors and dissect the BLA-to-CeA circuit for appetitive behaviors. Protein phosphatase 1 regulatory subunit 1B+ BLA pyramidal neurons to dopamine receptor 1+ CeA neurons define a pathway for promoting appetitive behaviors, while R-spondin 2+ BLA pyramidal neurons to dopamine receptor 2+ CeA neurons define a pathway for suppressing appetitive behaviors. These data reveal genetically defined neural circuits in the amygdala that promote and suppress appetitive behaviors analogous to the direct and indirect pathways of the basal ganglia. VIDEO ABSTRACT.
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Affiliation(s)
- Joshua Kim
- RIKEN-MIT Center for Neural Circuit Genetics at The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Xiangyu Zhang
- RIKEN-MIT Center for Neural Circuit Genetics at The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Shruti Muralidhar
- RIKEN-MIT Center for Neural Circuit Genetics at The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sarah A LeBlanc
- RIKEN-MIT Center for Neural Circuit Genetics at The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Susumu Tonegawa
- RIKEN-MIT Center for Neural Circuit Genetics at The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Brain Science Institute, RIKEN, Saitama 351-0198, Japan.
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8
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Li Z, Yin P, Chen J, Jin S, Liu J, Luo F. CaMKIIα may modulate fentanyl-induced hyperalgesia via a CeLC-PAG-RVM-spinal cord descending facilitative pain pathway in rats. PLoS One 2017; 12:e0177412. [PMID: 28489932 PMCID: PMC5425219 DOI: 10.1371/journal.pone.0177412] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/26/2017] [Indexed: 11/30/2022] Open
Abstract
Each of the lateral capsular division of central nucleus of amygdala(CeLC), periaqueductal gray (PAG), rostral ventromedial medulla(RVM) and spinal cord has been proved to contribute to the development of opioid-induced hyperalgesia(OIH). Especially, Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) in CeLC and spinal cord seems to play a key role in OIH modulation. However, the pain pathway through which CaMKIIα modulates OIH is not clear. The pathway from CeLC to spinal cord for this modulation was explored in the present study. Mechanical and thermal hyperalgesia were tested by von Frey test or Hargreaves test, respectively. CaMKIIα activity (phospho-CaMKIIα, p-CaMKIIα) was evaluated by western blot analysis. CaMKIIα antagonist (KN93) was micro-infused into CeLC, spinal cord or PAG, respectively, to evaluate its effect on behavioral hyperalgesia and p-CaMKIIα expression in CeLC, PAG, RVM and spinal cord. Then the underlying synaptic mechanism was explored by recording miniature excitatory postsynaptic currents (mEPSCs) on PAG slices using whole-cell voltage-clamp methods. Results showed that inhibition of CeLC, PAG or spinal CaMKIIα activity respectively by KN93, reversed both mechanical and thermal hyperalgesia. Microinjection of KN93 into CeLC decreased p-CaMKIIα expression in CeLC, PAG, RVM and spinal cord; while intrathecal KN93 can only block spinal but not CeLC CaMKIIα activity. KN93 injected into PAG just decreased p-CaMKIIα expression in PAG, RVM and spinal cord, but not in the CeLC. Similarly, whole-cell voltage-clamp recording found the frequency and amplitude of mEPSCs in PAG cells were decreased by KN93 added in PAG slice or micro-infused into CeLC in vivo. These results together with previous findings suggest that CaMKIIα may modulate OIH via a CeLC-PAG-RVM-spinal cord descending facilitative pain pathway.
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Affiliation(s)
- Zhen Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pingping Yin
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian Chen
- The Laboratory of Membrane Ion Channels and Medicine, Key Laboratory of Cognitive Science, State Ethnic Affairs Commission, College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, China
| | - Shenglan Jin
- Department of Anesthesiology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jieqiong Liu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Luo
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Biological evaluation and molecular docking studies of AA3052, a compound containing a μ-selective opioid peptide agonist DALDA and d-Phe-Phe-d-Phe-Leu-Leu-NH2, a substance P analogue. Eur J Pharm Sci 2016; 93:11-20. [PMID: 27423260 DOI: 10.1016/j.ejps.2016.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/05/2016] [Accepted: 07/10/2016] [Indexed: 11/20/2022]
Abstract
The design of novel drugs for pain relief with improved analgesic properties and diminished side effect induction profile still remains a challenging pursuit. Tolerance is one of the most burdensome phenomena that may hamper ongoing opioid therapy, especially in chronic pain patients. Therefore, a promising strategy of hybridizing two pharmacophores that target distinct binding sites involved in pain modulation and transmission was established. Previous studies have led to the development of opioid agonist/NK1 agonist hybrids that produce sufficient analgesia and also suppress opioid-induced tolerance development. In our present investigation we assessed the antinociceptive potency of a new AA3052 chimera comprised of a potent MOR selective dermorphin derivative (DALDA) and an NK1 agonist, a stabilized substance P analogue. We have shown that AA3052 significantly prolonged responses to both mechanical and noxious thermal stimuli in rats after intracerebroventricular administration. Additionally, AA3052 did not trigger the development of tolerance in a 6-day daily injection paradigm nor did it produce any sedative effects, as assessed in the rotarod performance test. However, the antinociceptive effect of AA3052 was independent of opioid receptor stimulation by the DALDA pharmacophore as shown in the agonist-stimulated G-protein assay. Altogether the current results confirm the antinociceptive effectiveness of a novel opioid/SP hybrid agonist, AA3052, and more importantly its ability to inhibit the development of tolerance.
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10
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Abstract
Pain is more than merely nociception and response, but rather it encompasses emotional, behavioral and cognitive components that make up the pain experience. With the recent advances in imaging techniques, we now understand that nociceptive inputs can result in the activation of complex interactions among central sites, including cortical regions that are active in cognitive, emotional and reward functions. These sites can have a bimodal influence on the serotonergic and noradrenergic descending pain modulatory systems via communications among the periaqueductal gray, rostral ventromedial medulla and pontine noradrenergic nuclei, ultimately either facilitating or inhibiting further nociceptive inputs. Understanding these systems can help explain the emotional and cognitive influences on pain perception and placebo/nocebo effects, and can help guide development of better pain therapeutics.
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Affiliation(s)
- Milena De Felice
- The University of Sheffield, Academic Unit of Oral & Maxillofacial Medicine & Surgery, Sheffield, South Yorkshire, UK
| | - Michael H Ossipov
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, AZ 85724-5050, USA
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Hu SSJ, Ho YC, Chiou LC. No more pain upon Gq-protein-coupled receptor activation: role of endocannabinoids. Eur J Neurosci 2014; 39:467-84. [PMID: 24494686 DOI: 10.1111/ejn.12475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 01/24/2023]
Abstract
Marijuana has been used to relieve pain for centuries. The analgesic mechanism of its constituents, the cannabinoids, was only revealed after the discovery of cannabinoid receptors (CB1 and CB2) two decades ago. The subsequent identification of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), and their biosynthetic and degradation enzymes discloses the therapeutic potential of compounds targeting the endocannabinoid system for pain control. Inhibitors of the anandamide and 2-AG degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase, respectively, may be superior to direct cannabinoid receptor ligands as endocannabinoids are synthesized on demand and rapidly degraded, focusing action at generating sites. Recently, a promising strategy for pain relief was revealed in the periaqueductal gray (PAG). It is initiated by Gq-protein-coupled receptor (Gq PCR) activation of the phospholipase C-diacylglycerol lipase enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. Here, we introduce the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, particularly in the PAG. We also review recent studies disclosing the Gq PCR-phospholipase C-diacylglycerol lipase-2-AG retrograde disinhibition mechanism in the PAG, induced by activating several Gq PCRs, including metabotropic glutamatergic (type 5 metabotropic glutamate receptor), muscarinic acetylcholine (M1/M3), and orexin 1 receptors. Disinhibition mediated by type 5 metabotropic glutamate receptor can be initiated by glutamate transporter inhibitors or indirectly by substance P, neurotensin, cholecystokinin and capsaicin. Finally, the putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is discussed.
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Affiliation(s)
- Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
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12
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Nakamura Y, Izumi H, Fukushige R, Shimizu T, Watanabe K, Morioka N, Hama A, Takamatsu H, Nakata Y. Continuous infusion of substance P into rat striatum alleviates nociceptive behavior via phosphorylation of extracellular signal-regulated kinase 1/2. J Neurochem 2014; 131:755-66. [PMID: 25175638 DOI: 10.1111/jnc.12938] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/12/2014] [Accepted: 08/22/2014] [Indexed: 12/21/2022]
Abstract
Intraplantar injection of 0.4% formalin into the rat hind paw leads to a biphasic nociceptive response; an 'acute' phase (0-15 min) and 'tonic' phase (16-120 min), which is accompanied by significant phosphorylation of extracellular signal-regulated kinase (ERK)1/2 in the contralateral striatum at 120 min post-formalin injection. To uncover a possible relationship between the slow-onset substance P (SP) release and increased ERK1/2 phosphorylation in the striatum, continuous infusion of SP into the striatum by reverse microdialysis (0.4 μg/mL in microdialysis fiber, 1 μL/min) was performed to mimic volume neurotransmission of SP. Continuous infusion for 3 h of SP reduced the duration of 'tonic' phase nociception, and this SP effect was mediated by neurokinin 1 (NK1) receptors since pre-treatment with NK1 receptor antagonist CP96345 (10 μM) blocked the effect of SP infusion. However, formalin-induced 'tonic' phase nociception was significantly prolonged following acute injection of the MAP/ERK kinase 1/2 inhibitor PD0325901 (100 pmol) by microinjection. The coinfusion of SP and PD0325901 significantly increased the 'tonic' phase of nociception. These data demonstrate that volume transmission of striatal SP triggered by peripheral nociceptive stimulation does not lead to pain facilitation but a significant decrease of tonic nociception by the activation of the SP-NK1 receptor-ERK1/2 system. Noxious stimulation induces a slow-onset substance P (SP) release as a volume transmitter, activating extra-synaptic NK1 receptors, and evokes phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. The SP-NK1-ERK1/2 system in the striatum decreases tonic nociception.
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Affiliation(s)
- Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
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Chiou LC, Hu SSJ, Ho YC. Targeting the cannabinoid system for pain relief? ACTA ACUST UNITED AC 2013; 51:161-70. [PMID: 24529672 DOI: 10.1016/j.aat.2013.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/11/2013] [Indexed: 12/15/2022]
Abstract
Marijuana has been used to relieve pain for centuries, but its analgesic mechanism has only been understood during the past two decades. It is mainly mediated by its constituents, cannabinoids, through activating central cannabinoid 1 (CB1) receptors, as well as peripheral CB1 and CB2 receptors. CB2-selective agonists have the benefit of lacking CB1 receptor-mediated CNS side effects. Anandamide and 2-arachidonoylglycerol (2-AG) are two intensively studied endogenous lipid ligands of cannabinoid receptors, termed endocannabinoids, which are synthesized on demand and rapidly degraded. Thus, inhibitors of their degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase (MAGL), respectively, may be superior to direct cannabinoid receptor ligands as a promising strategy for pain relief. In addition to the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, we also review recent studies that revealed a novel analgesic mechanism, involving 2-AG in the periaqueductal gray (PAG), a midbrain region for initiating descending pain inhibition. It is initiated by Gq-protein-coupled receptor (GqPCR) activation of the phospholipase C (PLC)-diacylglycerol lipase (DAGL) enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. This GqPCR-PLC-DAGL-2-AG retrograde disinhibition mechanism in the PAG can be initiated by activating type 5 metabotropic glutamate receptor (mGluR5), muscarinic acetylcholine (M1/M3), and orexin (OX1) receptors. mGluR5-mediated disinhibition can be initiated by glutamate transporter inhibitors, or indirectly by substance P, neurotensin, cholecystokinin, capsaicin, and AM404, the bioactive metabolite of acetaminophen in the brain. The putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is also discussed.
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Affiliation(s)
- Lih-Chu Chiou
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.
| | - Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Cheng Ho
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Szajkowski S, Marcol W, Właszczuk A, Cieślar G, Pietrucha-Dutczak M, Sieroń A, Lewin-Kowalik J. The influence of spatial pulsed magnetic field application on neuropathic pain after tibial nerve transection in rat. Electromagn Biol Med 2013; 33:35-46. [PMID: 23781991 DOI: 10.3109/15368378.2013.783849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of the study was to examine the influence of the spatial variable magnetic field (induction: 150-300 µT, 80-150 µT, 20-80 µT; frequency 40 Hz) on neuropathic pain after tibial nerve transection. The experiments were carried out on 64 male Wistar C rats. The exposure of animals to magnetic field was performed 1 d/20 min., 5 d/week, for 28 d. Behavioural tests assessing the intensity of allodynia and sensitivity to mechanical and thermal stimuli were conducted 1 d prior to surgery and 3, 7, 14, 21 and 28 d after the surgery. The extent of autotomy was examined. Histological and immunohistochemical analysis was performed. The use of extremely low-frequency magnetic fields of minimal induction values (20-80 µT/40 Hz) decreased pain in rats after nerve transection. The nociceptive sensitivity of healthy rats was not changed following the exposition to the spatial magnetic field of the low frequency. The results of histological and immunohistochemical investigations confirm those findings. Our results indicate that extremely low-frequency magnetic field may be useful in the neuropathic pain therapy.
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Xia RL, Fu CY, Zhang SF, Jin YT, Zhao FK. Study on the distribution sites and the molecular mechanism of analgesia after intracerebroventricular injection of rat/mouse hemokinin-1 in mice. Peptides 2013; 43:113-20. [PMID: 23470255 DOI: 10.1016/j.peptides.2013.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/24/2013] [Accepted: 02/25/2013] [Indexed: 11/22/2022]
Abstract
Hemokinin-1 is a peptide encoded by Pptc, which belongs to the family of mammalian tachykinins. Our previous results showed that rat/mouse hemokinin-1 (r/m HK-1) produced striking analgesia after intracerebroventricular (i.c.v.) injection in mice, and the analgesia could be blocked by the NK1 receptor antagonist and the opioid receptor antagonist, respectively. However, the precise distribution sites and the molecular mechanism involved in the analgesic effect after i.c.v. administration of r/m HK-1 are needed to be further investigated deeply. Using the fluorescence labeling method, our present results directly showed that r/m HK-1 peptides were mainly distributed at the ventricular walls and several juxta-ventricular structures for the first time. Our results showed that the mRNA expressions of NK1 receptor, PPT-A, PPT-C, KOR, PDYN, DOR and PENK were not changed markedly, as well as the protein expression of NK1 receptor was hardly changed. However, both the transcripts and proteins of MOR and POMC were up-regulated significantly, indicating that the analgesic effect induced by i.c.v. administration of r/m HK-1 is related to the activation of NK1 receptor first, then it is related to the release of endogenous proopiomelanocortin, as well as the increased expression level of μ opioid receptor. These results should facilitate further the analysis of the analgesia of r/m HK-1 in the central nerval system in acute pain and may open novel pharmacological interventions.
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Affiliation(s)
- Rui-Long Xia
- Lab of Proteomics & Molecular Enzymology, School of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China
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Nakamura Y, Izumi H, Shimizu T, Hisaoka-Nakashima K, Morioka N, Nakata Y. Volume Transmission of Substance P in Striatum Induced by Intraplantar Formalin Injection Attenuates Nociceptive Responses via Activation of the Neurokinin 1 Receptor. J Pharmacol Sci 2013; 121:257-71. [DOI: 10.1254/jphs.12218fp] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Parenti C, Aricò G, Ronsisvalle G, Scoto GM. Supraspinal injection of Substance P attenuates allodynia and hyperalgesia in a rat model of inflammatory pain. Peptides 2012; 34:412-8. [PMID: 22306475 DOI: 10.1016/j.peptides.2012.01.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/20/2012] [Accepted: 01/20/2012] [Indexed: 01/03/2023]
Abstract
The neuropeptide Substance P (SP), that has a high affinity for the neurokinin 1 (NK1) receptor, is involved in modulation of pain transmission. Although SP is thought to have excitatory actions and promote nociception in the spinal cord, the peptide induces analgesia at the supraspinal level. The aim of this study was to evaluate the role of supraspinal SP and the NK1 receptor in inflammatory pain induced by injection of carrageenan in the hind paw of the rat. There are two nociceptive behavioral responses associated with this pain state: mechanical allodynia and heat hyperalgesia. Because the NK1 receptor colocalizes with the MOP receptor in supraspinal sites involved in pain modulation, we also decided to study the possible involvement of the opioid system on SP-induced analgesia. We found that treatment with SP, at doses of 3.5, 5 and 7 μg/5 μl/rat i.c.v., clearly showed inhibition of allodynia and hyperalgesia. Pretreatment with the selective NK1 antagonist L-733,060 (10mg/kg i.p.) blocked the SP-induced analgesia, suggesting the involvement of the NK1 receptor. This SP-induced analgesia was significantly reduced by administration of the opioid antagonist naloxone (3mg/kg s.c.). This reduction occurred when SP was administered either before or after the carrageenan injection. These results suggest a significant antinociceptive role for SP and the NK1 receptor in inflammatory pain at the supraspinal level, possibly through the release of endogenous opioids.
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Affiliation(s)
- Carmela Parenti
- Department of Drug Sciences-Pharmacology and Toxicology Section, University of Catania, v.le A. Doria 6, 95125 Catania, Italy.
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Yao G, Man Y, Luo X, Yu T, Ji L. Rizatriptan benzoate influences the endogenous pain modulatory system in a rat model of migraine. Neural Regen Res 2012; 7:131-5. [PMID: 25767488 PMCID: PMC4354128 DOI: 10.3969/j.issn.1673-5374.2012.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/19/2011] [Indexed: 12/29/2022] Open
Abstract
The present study utilized a nitroglycerin-induced rat model of migraine to detect the effects of rizatriptan benzoate on proenkephalin and substance P gene expression in the midbrain using real-time quantitative polymerase chain reaction and investigate whether rizatriptan benzoate can regulate the endogenous pain modulatory system. The results showed that rizatriptan benzoate significantly reduced expression of the mRNAs for proenkephalin and substance P. Rizatriptan benzoate may inhibit the analgesic effect of the endogenous pain modulatory system.
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Affiliation(s)
- Gang Yao
- Department of Neurology, Second Hospital of Jilin University, Changchun 130041, Jilin Province, China ; Department of Neurology, First Hospital of Jilin University, Changchun 130021, Jilin Province, China
| | - Yuhong Man
- Department of Neurology, Second Hospital of Jilin University, Changchun 130041, Jilin Province, China
| | - Xiangdan Luo
- Department of Food Science, College of Quartermaster Technology, Jilin University, Changchun 130000, Jilin Province, China
| | - Tingmin Yu
- Department of Neurology, Second Hospital of Jilin University, Changchun 130041, Jilin Province, China
| | - Lin Ji
- Liaoyuan Vocational Technical and Medical College, Liaoyuan 136200, Jilin Province, China
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19
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Commons KG. Neuronal pathways linking substance P to drug addiction and stress. Brain Res 2009; 1314:175-82. [PMID: 19913520 DOI: 10.1016/j.brainres.2009.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 01/14/2023]
Abstract
Accumulating evidence suggests that the neuropeptide substance P (SP) and its principal receptor neurokinin 1 (NK1) play a specific role in the behavioral response to opioids and stress that may help to initiate and maintain addictive behavior. In animal models, the NK1 receptor is required for opioids to produce their rewarding and motivational effects. SP neurotransmission is also implicated in the behavioral response to stress and in the process of drug sensitization, potentially contributing to vulnerability to addiction or relapse. However, SP neurotransmission only plays a minor role in opioid-mediated antinociception and the development of opioid tolerance. Moreover, the effects of SP on addiction-related behavior are selective for opioids and evidence supporting a role in the response to cocaine or psychostimulants is less compelling. This review will summarize the effects of SP neurotransmission on opioid-dependent behaviors and correlate them with potential contributing neural pathways. Specifically, SP neurotransmission within components of the basal forebrain particularly the nucleus accumbens and ventral pallidum as well as actions within the ascending serotonin system will be emphasized. In addition, cellular- or network-level interactions between opioids and SP signaling that may underlie the specificity of their relationship will be reviewed.
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Affiliation(s)
- K G Commons
- Department of Anesthesiology, Perioperative, and Pain Medicine, Children's Hospital Boston, Department of Anaesthesia, Harvard Medical School, 300 Longwood Ave., Enders 1206, Boston, MA, USA.
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Hamity MV, White SR, Hammond DL. Effects of neurokinin-1 receptor agonism and antagonism in the rostral ventromedial medulla of rats with acute or persistent inflammatory nociception. Neuroscience 2009; 165:902-13. [PMID: 19892001 DOI: 10.1016/j.neuroscience.2009.10.064] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 10/27/2009] [Accepted: 10/29/2009] [Indexed: 12/21/2022]
Abstract
The rostral ventromedial medulla (RVM), a central relay in the bulbospinal pathways that modulate nociception, contains high concentrations of substance P (Sub P) and neurokinin-1 (NK1) receptors. However, the function of Sub P in the RVM is poorly understood. This study characterized the actions of Sub P in the RVM in the absence of injury and then used two NK1 receptor antagonists, L-733,060 and L-703, 606, to probe the role of endogenously released Sub P in the development and maintenance of persistent inflammatory nociception of immune or neurogenic origin. In uninjured rats, microinjection of Sub P in the RVM produced a transient thermal antinociception that was attenuated by pretreatment with L-733,060 or L-703,606. It did not alter threshold to withdrawal from tactile stimulation with von Frey filaments. Microinjection of the antagonists alone did not alter paw withdrawal latency (PWL) or threshold suggesting that Sub P is not tonically released in the RVM in the absence of injury. However, microinjection of either antagonist in the RVM was sufficient to reverse heat hyperalgesia 4 h, 4 days or 2 weeks after intraplantar (ipl) injection of complete Freund's adjuvant (CFA). Antagonism of NK1 receptors in the RVM did not prevent or reverse tactile hypersensitivity induced by CFA, but did attenuate that produced by capsaicin. NK1 receptor antagonism did not prevent the development of thermal hyperalgesia, tactile hypersensitivity or spontaneous pain behaviors induced by mustard oil (MO). The results suggest that Sub P has bimodal actions in the RVM and that following inflammatory injury, it can play a critical role as a pronociceptive agent in the development and maintenance of hyperalgesia and tactile hypersensitivity. However, its actions are highly dependent on the stimulus modality and the type of injury, and this may be an additional basis for the poor efficacy of NK1 receptor antagonists in clinical trials.
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Affiliation(s)
- M V Hamity
- Department of Anesthesia, The University of Iowa, 200 Hawkins Drive 6 JCP, Iowa City, IA 52242, USA
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21
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Takeda K, Muramatsu M, Chikuma T, Kato T. Effect of memantine on the levels of neuropeptides and microglial cells in the brain regions of rats with neuropathic pain. J Mol Neurosci 2009; 39:380-90. [PMID: 19653132 DOI: 10.1007/s12031-009-9224-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Accepted: 07/15/2009] [Indexed: 12/25/2022]
Abstract
Neuropathic pain induced by sciatic nerve injury not only causes peripheral dysfunctions but also affects the cortical and subcortical regions of the brain. It is still unknown whether neuropathic pain could relate to behavioral and neurochemical alterations in the central nervous system. This paper deals with the effect of peripheral neuropathic pain on mechanical allodynia, neuropeptide levels, neuropeptide-degrading enzyme activities, and microglial cells in the brain regions of rats by applying chronic constriction injury, a partial sciatic nerve injury. We examined the possible protection effect on the allodynia and changes in levels of neuropeptides and microglial activation in chronic constriction injury of the rat brain by memantine. On 4 days after chronic constriction injury, the induction of mechanical allodynia was suppressed by memantine treatment. Reductions in the substance P in the hypothalamus and somatostatin in the periaqueductal gray of chronic constriction injury rat brain were reversed by memantine. This suggests the role of these neuropeptides in pain information processing in the brain. Immunohistochemical experiments revealed that the expression of CD11b, a marker protein of microglia, was increased in the hypothalamus and periaqueductal gray in the chronic constriction injury rat brain as compared with the controls, and memantine treatment could suppress the activation of microglia, suggesting the involvement of microglia in pain mechanism. The present behavioral, biochemical, and immunohistochemical studies demonstrated that peripheral neuropathic pain affects the neuropeptide levels and microglial activation in the brain regions, and these events described above may play an important role in neuropathic pain pathogenesis.
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Affiliation(s)
- Katsumichi Takeda
- Department of Research and Development, Abbott Diagnostic Division, Minato, Tokyo 106-8535, Japan
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22
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Substance P drives endocannabinoid-mediated disinhibition in a midbrain descending analgesic pathway. J Neurosci 2009; 29:7220-9. [PMID: 19494144 DOI: 10.1523/jneurosci.4362-08.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Substance P is thought to play an essential role in several forms of supraspinally mediated analgesia. The actions of substance P on synaptic transmission within descending analgesic pathways, however, are largely unknown. Here, we used whole-cell recordings from rat midbrain slices to examine the effects of substance P on GABAergic and glutamatergic transmission within the periaqueductal gray (PAG), a key component of a descending analgesic pathway that projects via the rostral ventromedial medulla (RVM) to the spinal cord dorsal horn. We found that substance P reversibly decreased the amplitude and increased the paired-pulse ratio of evoked IPSCs recorded from identified PAG-RVM projection neurons and from unidentified PAG neurons. Substance P had no effect on miniature IPSCs, implying an indirect mode of action. The effects of substance P were abolished by metabotropic glutamate type 5 and cannabinoid CB1 receptor antagonists, but unaltered by NMDA, GABA(B), mu,delta-opioid, adenosine A(1), and 5HT(1A) receptor antagonists. Consistent with a role for endogenous glutamate in this process, substance P increased the frequency of action potential-dependent spontaneous EPSCs. Moreover, the effect of substance P on evoked IPSCs was mimicked and occluded by a glutamate transport inhibitor. Finally, these effects were dependent on postsynaptic G-protein activation and diacylglycerol lipase activity, suggesting the requirement for retrograde signaling by the endocannabinoid 2-arachidonoylglycerol. Thus, substance P may facilitate descending analgesia in part by enhancing glutamate-mediated excitation and endocannabinoid-mediated disinhibition of PAG-RVM projection neurons.
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Bassi GS, Broiz AC, Gomes MZ, Brandão ML. Evidence for mediation of nociception by injection of the NK-3 receptor agonist, senktide, into the dorsal periaqueductal gray of rats. Psychopharmacology (Berl) 2009; 204:13-24. [PMID: 19093101 DOI: 10.1007/s00213-008-1434-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/01/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE Ultrasound vocalizations (USVs) at approximately 22 kHz are usual components of the defensive response of rats. However, depending on the neural substrate that is activated, such as the dorsal periaqueductal gray (dPAG), USV emissions may be reduced. Activation of neurokinin-1 (NK-1)-mediated mechanisms of the dPAG causes analgesia, reduced 22 kHz USVs, and anxiogenic-like effects in rats exposed to the elevated plus maze (EPM). Involvement of other types of neurokinin receptors in this activation has not yet been evaluated. OBJECTIVES The present study examined whether local injections of the selective NK-3 agonist senktide (1-100 pmol/0.2 microL) into the dPAG can (1) cause anxiogenic effects in the EPM, (2) influence novelty-induced 22 kHz USVs, or (3) change nociceptive reactivity in the tail-flick test. RESULTS Senktide elicited a significant increase in exploratory behavior, an effect accompanied by hyperalgesia and an increase in the number of 22 kHz USVs. The nociceptive effects, increased locomotor activity, and USV emissions elicited by local injections of senktide (50 pmol/0.2 microL) were reduced by prior injections of the selective NK-3 receptor antagonist SB222200 (50 pmol/0.2 microL) into the dPAG. CONCLUSIONS These findings show that NK-3 receptors in the dPAG mediate nociceptive responses in this area, contrasting with the known fear-related processes mediated by NK-1 receptors in the dPAG. Both hyperalgesia and fear-related processes are accompanied by emissions of 22 kHz USVs.
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Affiliation(s)
- Gabriel S Bassi
- Instituto de Neurociências & Comportamento-INeC, Ribeirão Preto, SP, Brasil
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24
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Holden JE, Pizzi JA, Jeong Y. An NK1 receptor antagonist microinjected into the periaqueductal gray blocks lateral hypothalamic-induced antinociception in rats. Neurosci Lett 2009; 453:115-9. [PMID: 19356605 PMCID: PMC3463133 DOI: 10.1016/j.neulet.2009.01.083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 01/23/2009] [Accepted: 01/31/2009] [Indexed: 12/22/2022]
Abstract
Substantial data are accumulating that implicate the lateral hypothalamus (LH) as part of the descending pain modulatory system. The LH modifies nociception in the spinal cord dorsal horn partly through connections with the periaqueductal gray (PAG), an area known to play a central role in brainstem modulation of nociception. Early work demonstrated a putative substance P connection between the LH and the PAG, but the connection is not fully defined. To determine whether LH-induced antinociception mediated by the PAG is neurokinin1 (NK1) receptor-dependent, we conducted behavioral experiments in which the cholinergic agonist carbachol (125 nmol) was microinjected into the LH of lightly anesthetized female Sprague-Dawley rats (250-350 g) and antinociception was obtained on the tail flick or foot withdrawal tests. Cobalt chloride (100 nM), which reversibly blocks synaptic activation, blocked LH-induced antinociception. In another set of experiments, the specific NK1 receptor antagonist L-703,606 (5 microg) was microinjected in the PAG following LH stimulation with carbachol abolished LH-induced antinociception as well. Microinjection of cobalt chloride or L-703,606 in the absence of LH stimulation had no effect. These behavioral experiments coupled with earlier work provide converging evidence to support the hypothesis that antinociception produced by activating neurons in the LH is mediated in part by the subsequent activation of neurons in the PAG by NK1 receptors.
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Affiliation(s)
- Janean E Holden
- Division of Acute, Critical and Long-Term Care Programs, School of Nursing, The University of Michigan, Ann Arbor, MI 48109-5482, USA.
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25
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Chen YL, Li AH, Yeh TH, Chou AH, Wang HL. Nocistatin and nociceptin exert opposite effects on the excitability of central amygdala nucleus-periaqueductal gray projection neurons. Mol Cell Neurosci 2009; 40:76-88. [PMID: 18930828 DOI: 10.1016/j.mcn.2008.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 09/08/2008] [Accepted: 09/10/2008] [Indexed: 11/29/2022] Open
Abstract
Central amygdala nucleus (CeA)-periaqueductal gray (PAG) pathway is the component of descending antinociceptive circuitry. Nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) produce supraspinal pronociceptive and antinociceptive effects, respectively. We hypothesized that opposite effects of N/OFQ and NST on supraspinal pain modulation result from their opposing effects on the excitability of CeA-PAG projection neurons. This hypothesis was tested by investigating electrophysiological effects of N/OFQ and NST on medial CeA neurons that project to PAG (CeA(M)-PAG). N/OFQ hyperpolarized CeA(M)-PAG projection neurons by enhancing inwardly rectifying potassium conductance. In contrast, NST depolarized CeA(M)-PAG neurons by causing the opening of TRPC cation channels via G(alphaq/11)-PLC-PKC pathway. CeA(M)-PAG neurons hyperpolarized by N/OFQ express CRF or neurotensin mRNA. NST-responsive CeA(M)-PAG neurons contain CRF or substance P mRNA. Our study provides the evidence that the molecular and cellular basis for opposite effects of N/OFQ and NST on supraspinal pain regulation is their opposing effects on the excitability of peptidergic CeA(M)-PAG neurons.
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Affiliation(s)
- Ying-Ling Chen
- Department of Physiology, Chang Gung University School of Medicine, Kwei-San, Tao-Yuan, Taiwan, ROC
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26
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Pinto M, Sousa M, Lima D, Tavares I. Participation of mu-opioid, GABA(B), and NK1 receptors of major pain control medullary areas in pathways targeting the rat spinal cord: implications for descending modulation of nociceptive transmission. J Comp Neurol 2008; 510:175-87. [PMID: 18615498 DOI: 10.1002/cne.21793] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Several brain areas modulate pain transmission through direct projections to the spinal cord. The descending modulation is exerted by neurotransmitters acting both at spinally projecting neurons and at interneurons that target the projection neurons. We analyzed the expression of mu-opioid (MOR), gamma-aminobutyric acid GABA(B), and NK1 receptors in spinally projecting neurons of major medullary pain control areas of the rat: rostroventromedial medulla (RVM), dorsal reticular nucleus (DRt), nucleus of the solitary tract, ventral reticular nucleus, and lateralmost part of the caudal ventrolateral medulla. The retrograde tracer cholera toxin subunit B (CTb) was injected into the spinal dorsal horn, and medullary sections were processed by double immunocytochemistry for CTb and each receptor. The RVM contained the majority of double-labeled neurons followed by the DRt. In general, high percentages of MOR- and NK1-expressing neurons were retrogradely labeled, whereas GABA(B) receptors were mainly expressed in neurons that were not labeled from the cord. The results suggest that MOR and NK1 receptors play an important role in direct and indirect control of descending modulation. The co-localization of MOR and GABA(B) in DRt neurons also demonstrated by the present study suggests that the pronociceptive effects of this nucleus may be controlled by local opoidergic and GABAergic inhibition of the pronociception increased during chronic pain.
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Affiliation(s)
- Marta Pinto
- Institute of Histology and Embryology, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
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27
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de Lange RPJ, Wiegant VM, Stam R. Altered neuropeptide Y and neurokinin messenger RNA expression and receptor binding in stress-sensitised rats. Brain Res 2008; 1212:35-47. [PMID: 18440496 DOI: 10.1016/j.brainres.2008.03.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 03/07/2008] [Accepted: 03/10/2008] [Indexed: 10/22/2022]
Abstract
A single session of footshocks in rats causes long-lasting sensitisation of behavioural, hormonal and autonomic responses to subsequent novel stressful challenges as well as altered pain sensitivity. These changes mimic aspects of post-traumatic stress disorder in humans. Our aim was to identify neuropeptide substrates in the central nervous system involved in stress sensitisation. Male Wistar rats were exposed to ten footshocks in 15 min (preshocked) or placed in the same cage without shocks (control). Two weeks later, rats were placed in a novel cage, subjected to 5 min of 85 dB noise, and returned to their home cage. Rats were killed either before or 1 h after noise and their brains processed for in situ hybridization for neuropeptide Y (NPY) and beta-preprotachykinin-I (PPT) mRNA. Additional groups of rats were killed under basal conditions and brains processed for NPY and neurokinin receptor binding with radiolabelled ligands. Two weeks after footshock treatment NPY mRNA expression was increased in the basolateral amygdala and showed preshockxnoise interaction in the locus coeruleus (down after noise in controls, lower basal and unchanged after noise in preshocked). PPT expression in the lateral parabrachial nucleus also showed preshockxnoise interaction (up after noise in controls, higher basal and down after noise in preshocked), and was increased after noise in the periaquaeductal grey. NK1 receptor binding in the agranular insular cortex and arcuate nucleus of the hypothalamus and NK2 receptor binding in the amygdala was lower in preshocked rats than in controls. Altered expression of NPY in the basolateral amygdala and locus coeruleus could contribute to or compensate for behavioural and autonomic sensitisation in preshocked rats. Altered PPT expression in the parabrachial nucleus may be involved in the altered pain processing seen in this model. Lower NK1 and NK2 receptor numbers in cortex, hypothalamus and amygdala may reflect secondary adaptations to altered neuropeptide release. These long-term changes in brain neuropeptide systems could offer novel leads for pharmacological modulation of long-term stress-induced sensitisation.
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Affiliation(s)
- Robert P J de Lange
- Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, P.O. box 80040, 3508 TA Utrecht, The Netherlands
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28
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Lin Q, Li D, Xu X, Zou X, Fang L. Roles of TRPV1 and neuropeptidergic receptors in dorsal root reflex-mediated neurogenic inflammation induced by intradermal injection of capsaicin. Mol Pain 2007; 3:30. [PMID: 17961222 PMCID: PMC2174436 DOI: 10.1186/1744-8069-3-30] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Accepted: 10/25/2007] [Indexed: 05/25/2023] Open
Abstract
Background Acute cutaneous neurogenic inflammation initiated by activation of transient receptor potential vanilloid-1 (TRPV1) receptors following intradermal injection of capsaicin is mediated mainly by dorsal root reflexes (DRRs). Inflammatory neuropeptides are suggested to be released from primary afferent nociceptors participating in inflammation. However, no direct evidence demonstrates that the release of inflammatory substances is due to the triggering of DRRs and how activation of TRPV1 receptors initiates neurogenic inflammation via triggering DRRs. Results Here we used pharmacological manipulations to analyze the roles of TRPV1 and neuropeptidergic receptors in the DRR-mediated neurogenic inflammation induced by intradermal injection of capsaicin. The degree of cutaneous inflammation in the hindpaw that followed capsaicin injection was assessed by measurements of local blood flow (vasodilation) and paw-thickness (edema) of the foot skin in anesthetized rats. Local injection of capsaicin, calcitonin gene-related peptide (CGRP) or substance P (SP) resulted in cutaneous vasodilation and edema. Removal of DRRs by either spinal dorsal rhizotomy or intrathecal administration of the GABAA receptor antagonist, bicuculline, reduced dramatically the capsaicin-induced vasodilation and edema. In contrast, CGRP- or SP-induced inflammation was not significantly affected after DRR removal. Dose-response analysis of the antagonistic effect of the TRPV1 receptor antagonist, capsazepine administered peripherally, shows that the capsaicin-evoked inflammation was inhibited in a dose-dependent manner, and nearly completely abolished by capsazepine at doses between 30–150 μg. In contrast, pretreatment of the periphery with different doses of CGRP8–37 (a CGRP receptor antagonist) or spantide I (a neurokinin 1 receptor antagonist) only reduced the inflammation. If both CGRP and NK1 receptors were blocked by co-administration of CGRP8–37 and spantide I, a stronger reduction in the capsaicin-initiated inflammation was produced. Conclusion Our data suggest that 1) the generation of DRRs is critical for driving the release of neuropeptides antidromically from primary afferent nociceptors; 2) activation of TRPV1 receptors in primary afferent nociceptors following intradermal capsaicin injection initiates this process; 3) the released CGRP and SP participate in neurogenic inflammation.
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Affiliation(s)
- Qing Lin
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-1069, USA.
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Wager TD, Scott DJ, Zubieta JK. Placebo effects on human mu-opioid activity during pain. Proc Natl Acad Sci U S A 2007; 104:11056-61. [PMID: 17578917 PMCID: PMC1894566 DOI: 10.1073/pnas.0702413104] [Citation(s) in RCA: 406] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Placebo-induced expectancies have been shown to decrease pain in a manner reversible by opioid antagonists, but little is known about the central brain mechanisms of opioid release during placebo treatment. This study examined placebo effects in pain by using positron-emission tomography with [(11)C]carfentanil, which measures regional mu-opioid receptor availability in vivo. Noxious thermal stimulation was applied at the same temperature for placebo and control conditions. Placebo treatment affected endogenous opioid activity in a number of predicted mu-opioid receptor-rich regions that play central roles in pain and affect, including periaqueductal gray and nearby dorsal raphe and nucleus cuneiformis, amygdala, orbitofrontal cortex, insula, rostral anterior cingulate, and lateral prefrontal cortex. These regions appeared to be subdivided into two sets, one showing placebo-induced opioid activation specific to noxious heat and the other showing placebo-induced opioid reduction during warm stimulation in anticipation of pain. These findings suggest that a mechanism of placebo analgesia is the potentiation of endogenous opioid responses to noxious stimuli. Opioid activity in many of these regions was correlated with placebo effects in reported pain. Connectivity analyses on individual differences in endogenous opioid system activity revealed that placebo treatment increased functional connectivity between the periaqueductal gray and rostral anterior cingulate, as hypothesized a priori, and also increased connectivity among a number of limbic and prefrontal regions, suggesting increased functional integration of opioid responses. Overall, the results suggest that endogenous opioid release in core affective brain regions is an integral part of the mechanism whereby expectancies regulate affective and nociceptive circuits.
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Affiliation(s)
- Tor D. Wager
- *Department of Psychology, Columbia University, 1190 Amsterdam Avenue, New York, NY 10027; and
- To whom correspondence should be addressed. E-mail:
| | - David J. Scott
- Psychiatry and Molecular and Behavioral Neuroscience Institute, University of Michigan, 205 Zina Pitcher Place, Ann Arbor, MI 48109-0720
| | - Jon-Kar Zubieta
- Departments of Radiology and
- Psychiatry and Molecular and Behavioral Neuroscience Institute, University of Michigan, 205 Zina Pitcher Place, Ann Arbor, MI 48109-0720
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Nishii H, Nomura M, Aono H, Fujimoto N, Matsumoto T. Up-regulation of galanin and corticotropin-releasing hormone mRNAs in the key hypothalamic and amygdaloid nuclei in a mouse model of visceral pain. ACTA ACUST UNITED AC 2007; 141:105-12. [PMID: 17335920 DOI: 10.1016/j.regpep.2006.12.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 12/15/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
Cyclophosphamide (CP)-induced cystitis is often used as an animal model of visceral pain. Various neuropeptides in the hypothalamic and amygdaloid nuclei are implicated in pain-induced responses. However, little information is available regarding the regulation of the neuropeptides in response to visceral pain. In the present study, we examined the effects of CP-induced cystitis on the levels of mRNAs encoding galanin, corticotropin-releasing hormone (CRH), substance P, and enkephalins in the hypothalamic and limbic nuclei using in situ hybridization histochemistry in mouse. Galanin mRNA levels in CP-treated group increased significantly in the arcuate nucleus and the paraventricular nucleus (PVN) but not in the medial preoptic area after the intraperitoneal administration of CP (200 mg/kg body weight) in comparison to those in saline-treated group. CRH mRNA levels in CP-treated group also increased significantly in the central amygdala as well as the PVN after the CP administration. In contrast, CP-induced cystitis failed to upregulate the preprotachykinin-A and preproenkephalin genes which encode substance P and enkephalins, respectively in the hypothalamic and limbic nuclei at any of the time points examined. These results suggest that visceral nociception may upregulate both galanin and CRH gene expression in the hypothalamic and limbic nuclei.
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Affiliation(s)
- Hisae Nishii
- Department of Urology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
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31
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Bao X, Shi Y, Huo X, Song T. A possible involvement of β-endorphin, substance P, and serotonin in rat analgesia induced by extremely low frequency magnetic field. Bioelectromagnetics 2006; 27:467-72. [PMID: 16622860 DOI: 10.1002/bem.20232] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Most of the research concerning magnetic antinociception was focused on brief exposure less than 1 h. The main purpose of the present study was to determine the effect of extremely low frequency (ELF) magnetic field (MF) repeated exposures on rats in inducing antinociception and to find the effective analgesic "time window." Meanwhile this investigation was to examine the role of central beta-endorphin, substance P, and 5-HT in magnetic analgesia. We found tail flick latencies (TFLs) increased significantly after the rats were exposed to 55.6 Hz, 8.1 mT magnetic field for 4 days, 6 h each day. The analgesic effects seemed to decrease gradually when the rats were exposed daily for another 10 days. Their levels of TFLs decreased within 1 day when the rats were removed after a 4-day exposure. The concentrations of hypothalamus beta-endorphin, substance P, and brainstem serotonin (5-HT) were increased significantly on Day 4. However, no differences were found when rats were exposed for another 10 days, and there were no significant increases when rats were removed after the fourth day of exposure and tested for nociception on Days 5 and 7 with no changes in the biochemical markers at 7 days. These results suggest that the ELF magnetic field has analgesic effect, but only on Days 3 and 4. The effect may be associated with increases in endogenous beta-endorphin, substance P, and 5-HT stimulated by the 55.6 Hz, 8.1 mT magnetic field.
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Affiliation(s)
- Xiuqi Bao
- Bioelectromagnetic Lab, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
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Mensah-Brown EPK, Garey LJ. The superior colliculus of the camel: a neuronal-specific nuclear protein (NeuN) and neuropeptide study. J Anat 2006; 208:239-50. [PMID: 16441568 PMCID: PMC2100190 DOI: 10.1111/j.1469-7580.2006.00517.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In this study we examined the superior colliculus of the midbrain of the one-humped (dromedary) camel, Camelus dromedarius, using Nissl staining and anti-neuronal-specific nuclear protein (NeuN) immunohistochemistry for total neuronal population as well as for the enkephalins, somatostatin (SOM) and substance P (SP). It was found that, unlike in most mammals, the superior colliculus is much larger than the inferior colliculus. The superior colliculus is concerned with visual reflexes and the co-ordination of head, neck and eye movements, which are certainly of importance to this animal with large eyes, head and neck, and apparently good vision. The basic neuronal architecture and lamination of the superior colliculus are similar to that in other mammals. However, we describe for the first time an unusually large content of neurons in the superior colliculus with strong immunoreactivity for met-enkephalin, an endogenous opioid. We classified the majority of these neurons as small (perimeters of 40-50 microm), and localized diffusely throughout the superficial grey and stratum opticum. In addition, large pyramidal-like neurons with perimeters of 100 microm and above were present in the intermediate grey layer. Large unipolar cells were located immediately dorsal to the deep grey layer. By contrast, small neurons (perimeters of 40-50 microm) immunopositive to SOM and SP were located exclusively in the superficial grey layer. We propose that this system may be associated with a pain-inhibiting pathway that has been described from the periaqueductal grey matter, juxtaposing the deep layers of the superior colliculus, to the lower brainstem and spinal cord. Such pain inhibition could be important in relation to the camel's life in the harsh environment of its native deserts, often living in very high temperatures with no shade and a diet consisting largely of thorny branches.
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Affiliation(s)
- E P K Mensah-Brown
- Department of Anatomy, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates.
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Ebner K, Singewald N. The role of substance P in stress and anxiety responses. Amino Acids 2006; 31:251-72. [PMID: 16820980 DOI: 10.1007/s00726-006-0335-9] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 02/21/2006] [Indexed: 12/18/2022]
Abstract
Substance P (SP) is one of the most abundant peptides in the central nervous system and has been implicated in a variety of physiological and pathophysiological processes including stress regulation, as well as affective and anxiety-related behaviour. Consistent with these functions, SP and its preferred neurokinin 1 (NK1) receptor has been found within brain areas known to be involved in the regulation of stress and anxiety responses. Aversive and stressful stimuli have been shown repeatedly to change SP brain tissue content, as well as NK1 receptor binding. More recently it has been demonstrated that emotional stressors increase SP efflux in specific limbic structures such as amygdala and septum and that the magnitude of this effect depends on the severity of the stressor. Depending on the brain area, an increase in intracerebral SP concentration (mimicked by SP microinjection) produces mainly anxiogenic-like responses in various behavioural tasks. Based on findings that SP transmission is stimulated under stressful or anxiety-provoking situations it was hypothesised that blockade of NK1 receptors may attenuate stress responses and exert anxiolytic-like effects. Preclinical and clinical studies have found evidence in favour of such an assumption. The status of this research is reviewed here.
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Affiliation(s)
- K Ebner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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Chappa AK, Audus KL, Lunte SM. Characteristics of substance P transport across the blood-brain barrier. Pharm Res 2006; 23:1201-8. [PMID: 16729222 DOI: 10.1007/s11095-006-0068-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 01/25/2006] [Indexed: 11/27/2022]
Abstract
PURPOSE Substance P (SP; NH3(+)-Arg(+)-Pro-Lys(+)-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2) belongs to a group of neurokinins that are widely distributed in the central nervous system and peripheral nervous system. The biological effects mediated by SP in the central nervous system include regulation of affective behavior, emesis, and nociception. Many of these actions are believed to be the result of the binding of SP to the neurokinin-1 (NK-1) receptor and subsequent transport across the blood-brain barrier (BBB). The objective of the study was to investigate the involvement of the NK-1 receptor in the permeation of SP across the BBB. METHODS Transport of 3H SP (1-13 nM) was investigated using BBMEC monolayers grown on polycarbonate membranes mounted on a Side-bi-Side diffusion apparatus. 3H SP samples were analyzed by scintillation spectrometry. Liquid chromatography-tandem mass spectrometry was used to monitor the transport at higher concentrations (micromolar). RESULTS SP transport across BBMEC monolayers was found to be saturable (Km = 8.57 +/- 1.59 nM, Vmax = 0.017 +/- 0.005 pmol min(-1) mg(-1) protein) in the concentration range of 0-13 nM. Significant (p < 0.05) decline in 3H SP permeation was observed in the presence of unlabeled SP and at 4 degrees C, indicating that the transport process is carrier-mediated. High-performance liquid chromatography analysis showed no significant metabolism of 3H SP in either the donor or receiver chambers. 3H SP transport was inhibited by 2-11 SP (p < 0.05) but not by any other fragments, indicating that both the C- and N-terminal regions are essential for molecular recognition by the receptor. Endocytic inhibitors (chloroquine, phenylarsine oxide, monensin, and brefeldin) did not inhibit SP transport, suggesting the involvement of a nonendocytic mechanism in SP permeation. Pro(9) SP, a high-affinity substrate for the NK-1 major subtype receptor, significantly (p < 0.05) inhibited the transport of SP. However, Sar(9)Met(O2)(11) SP, a high-affinity substrate for the NK-1 minor subtype receptor, septide, and neurokinin A, inhibitors of NK-1 and neurokinin-2 (NK-2) receptors, respectively, did not produce any inhibition of SP transport. Western blot analysis confirmed the presence of the NK-1 receptor in BBMEC monolayers. CONCLUSIONS The above results provide functional and molecular evidence for the existence of a carrier-mediated mechanism in the transport of SP across the BBB. The effects of specific inhibitors and the results of Western blot analyses demonstrate the involvement of the NK-1 receptor in the transport of SP across the BBB.
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Affiliation(s)
- Arvind K Chappa
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047, USA
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Fu CY, Yang Q, Wang KR, Kong ZQ, Chen Q, Wang R. Rat/mouse hemokinin-1, a mammalian tachykinin peptide, markedly potentiates the antinociceptive effects of morphine administered at the peripheral and supraspinal level. Behav Brain Res 2006; 170:293-301. [PMID: 16621052 DOI: 10.1016/j.bbr.2006.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 02/24/2006] [Accepted: 03/07/2006] [Indexed: 11/26/2022]
Abstract
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.
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Affiliation(s)
- Cai-Yun Fu
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, People's Republic of China
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Abstract
This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, USA.
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Janecka A, Poels J, Fichna J, Studzian K, Vanden Broeck J. Comparison of antagonist activity of spantide family at human neurokinin receptors measured by aequorin luminescence-based functional calcium assay. ACTA ACUST UNITED AC 2005; 131:23-8. [PMID: 15990182 DOI: 10.1016/j.regpep.2005.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 05/23/2005] [Indexed: 10/25/2022]
Abstract
Neurokinin receptors (NK1, NK2, NK3) are G-protein-coupled receptors, which upon activation by a peptide agonist induce a transient increase in the concentration of intracellular calcium. The functional assay based on aequorin-derived luminescence triggered by receptor-mediated changes in Ca2+ levels was used to compare the effect of spantides I-III on SP-, NKA- and NKB-stimulated NK1, NK2 and NK3 receptors, respectively. Recombinant cell lines expressing neurokinin receptors and apoaequorin were used in the study. The obtained results indicate that all three spantides acted as competitive antagonists at the NK1 and NK2 receptors and inhibited agonist-induced calcium responses. The rank order of antagonism at the NK1 receptor was spantide II>spantide III>spantide I and at the NK2 receptor was spantide III>spantide II>spantide I. All three spantides failed to antagonize NKB-induced calcium responses at the NK3 receptor.
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Affiliation(s)
- Anna Janecka
- Department of Medicinal Chemistry, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland.
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Drew GM, Mitchell VA, Vaughan CW. Postsynaptic actions of substance P on rat periaqueductal grey neurons in vitro. Neuropharmacology 2005; 49:587-95. [PMID: 15921708 DOI: 10.1016/j.neuropharm.2005.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Revised: 03/18/2005] [Accepted: 04/14/2005] [Indexed: 11/20/2022]
Abstract
The postsynaptic actions of substance P on rat midbrain periaqueductal grey (PAG) neurons were examined using whole-cell patch-clamp recordings in brain slices. Substance P produced an inward current in a subpopulation (60%) of PAG neurons. The substance P induced current was concentration dependent (EC50=27 nM) and was reduced by the NK1, NK2 and NK3 antagonists L-732,138 (20 microM), GR 159897 (3 microM) and SB 218795 (3 microM). The selective NK1, NK2 and NK3 agonists [Sar9,Met(O2)11]-Substance P (100 nM), GR 64349 (300-500 nM) and senktide (300 nM) also produced inward currents in subpopulations of neurons. A greater proportion of substance P-sensitive neurons (70%) than substance P-insensitive neurons (31%) responded to the mu/delta opioid agonist met-enkephalin (10 microM). Substance P reduced the outward current produced by met-enkephalin. The reversal potential of the substance P induced current varied from -5 mV to below -140 mV in the absence of met-enkephalin, and was -105 mV in the presence of met-enkephalin. These results indicate that substance P acts via NK1, NK2 and NK3 receptors to excite subpopulations of opioid-sensitive and insensitive PAG neurons by increasing a non-selective cation conductance and by reducing a K+ current. In addition, substance P has anti-opioid actions that are largely mediated by a reduction in the opioid induced K+ current.
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Affiliation(s)
- Geoffrey M Drew
- Pain Management Research Institute, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, E25, Sydney, NSW 2006, Australia.
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Hallberg M, Kindlundh AMS, Nyberg F. The impact of chronic nandrolone decanoate administration on the NK1 receptor density in rat brain as determined by autoradiography. Peptides 2005; 26:1228-34. [PMID: 15949641 DOI: 10.1016/j.peptides.2005.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 01/31/2005] [Accepted: 02/01/2005] [Indexed: 11/17/2022]
Abstract
Adult male Sprague-Dawley rats were treated with the anabolic androgenic steroid nandrolone decanoate (15 mg/kg day) or oil vehicle (sterile arachidis oleum) during 14 days. The effect on the densities of the neurokinin NK1 receptor in brain was examined with autoradiography. An overall tendency of attenuation of NK1 receptor density was observed after completed treatment with nandrolone decanoate. The density of the NK1 receptor was found to be significantly lower compared to control animals in the nucleus accumbens core (37% density reduction), in dentate gyrus (26%), in basolateral amygdaloid nucleus (23%), in ventromedial hypothalamic nucleus (36%), in dorsomedial hypothalamic nucleus (43%) and finally in the periaqueductal gray (PAG) (24%). In the cortex region, no structures exhibited any significant reduction of NK1 receptor density. This result provides additional support to the hypothesis that substance P and the NK1 receptor may be involved as important components that participate in mediating physiological responses including the adverse behaviors often associated with chronically administrated anabolic androgenic steroids in human.
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Affiliation(s)
- Mathias Hallberg
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Biomedical Center, Box 591, 75124 Uppsala, Sweden.
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