1
|
Effects of Intra-BLA Administration of PPAR Antagonists on Formalin-Evoked Nociceptive Behaviour, Fear-Conditioned Analgesia, and Conditioned Fear in the Presence or Absence of Nociceptive Tone in Rats. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27062021. [PMID: 35335382 PMCID: PMC8949000 DOI: 10.3390/molecules27062021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 11/16/2022]
Abstract
There is evidence for the involvement of peroxisome proliferator-activated receptors (PPARs) in pain, cognition, and anxiety. However, their role in pain–fear interactions is unknown. The amygdala plays a key role in pain, conditioned fear, and fear-conditioned analgesia (FCA). We investigated the effects of intra-basolateral amygdala (BLA) administration of PPARα, PPARβ/δ, and PPARγ antagonists on nociceptive behaviour, FCA, and conditioned fear in the presence or absence of nociceptive tone. Male Sprague-Dawley (SD) rats received footshock (FC) or no footshock (NFC) in a conditioning arena. Twenty-three and a half hours later, rats received an intraplantar injection of formalin or saline and, 15 min later, intra-BLA microinjections of vehicle, PPARα (GW6471) PPARβ/δ (GSK0660), or PPARγ (GW9662) antagonists before arena re-exposure. Pain and fear-related behaviour were assessed, and neurotransmitters/endocannabinoids measured post-mortem. Intra-BLA administration of PPARα or PPARγ antagonists potentiated freezing in the presence of nociceptive tone. Blockade of all PPAR subtypes in the BLA increased freezing and BLA dopamine levels in NFC rats in the absence of nociceptive tone. Administration of intra-BLA PPARα and PPARγ antagonists increased levels of dopamine in the BLA compared with the vehicle-treated counterparts. In conclusion, PPARα and PPARγ in the BLA play a role in the expression or extinction of conditioned fear in the presence or absence of nociceptive tone.
Collapse
|
2
|
de Almeida Silva M, de Toledo TS, de Figueiredo RM, Leite-Panissi CRA, Huston JP, Coimbra NC, Mattern C, de Carvalho MC. The activation of D2-like receptors by intranasal dopamine facilitates the extinction of contextual fear and prevents conditioned fear-induced antinociception. Behav Brain Res 2022; 417:113611. [PMID: 34592376 DOI: 10.1016/j.bbr.2021.113611] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 01/11/2023]
Abstract
Fear extinction (FExt) is used to treat patients with posttraumatic stress disorder (PTSD). However, fear related to traumatic events can be persistent and return even after successful extinction. The neurochemical control of extinction seems to be performed by several neurotransmitters, including dopamine (DA), through D1 and D2 receptors. Recently, we showed that intranasally applied DA (IN-DA) facilitated the FExt, but the mechanisms by which it promoted this effect are still unknown. This study focused on investigating whether these effects are mediated by the action of DA on D2-like receptors since these receptors seem to be related to neurochemical and molecular changes underlying extinction. Also, we investigated whether IN-DA treatment would affect conditioned fear-induced antinociception (Fear-IA). Rats treated with IN-DA (1 mg/kg) twenty-five minutes after sulpiride (SUL; 40 mg/kg, i.p., D2-antagonist) were subjected to the extinction of contextual fear. IN-DA applied before the extinction session induced the FExt and prevented Fear-IA. These effects were impaired by pre-treatment with SUL, suggesting that the IN-DA effects are mediated by DA on D2-like receptors. SUL per se also facilitated the FExt but did not affect Fear-IA. These data suggest IN-DA as a promising pharmacological tool to supplement the psychotherapy of patients suffering from PTSD.
Collapse
Affiliation(s)
- Marília de Almeida Silva
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Thaís Seghese de Toledo
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rebeca Machado de Figueiredo
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
| | - Christie Ramos Andrade Leite-Panissi
- Department of Psychology, Ribeirão Preto School of Philosophy, Science and Literature of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil; NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil; Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
| | - Joseph P Huston
- Center for Behavioral Neuroscience, Institute of Experimental Psychology, University of Düsseldorf, Düsseldorf, Germany
| | - Norberto Cysne Coimbra
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil; NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil; Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
| | - Claudia Mattern
- MetP Pharma AG, Emmetten, Switzerland, and Oceanographic Center, Nova Southeastern University, FL, USA
| | - Milene Cristina de Carvalho
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil.
| |
Collapse
|
3
|
Sexually Dimorphic Expression of Fear-conditioned Analgesia in Rats and Associated Alterations in the Endocannabinoid System in the Periaqueductal Grey. Neuroscience 2021; 480:117-130. [PMID: 34774710 DOI: 10.1016/j.neuroscience.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/16/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022]
Abstract
The endocannabinoid system within the periaqueductal grey (PAG) has been implicated in fear-conditioned analgesia (FCA), the profound suppression of pain upon re-exposure to a context previously paired with an aversive stimulus. Since the endocannabinoid and nociceptive systems exhibit sexual dimorphism, the aim of the present study was to assess possible sex differences in the expression of FCA, fear in the presence of nociceptive tone, and associated sex-dependent alterations in the endocannabinoid system within the PAG. Male and female Sprague-Dawley rats received footshock (10 × 1s; 0.4 mA; every 60 s) or no-footshock in a conditioning arena and 23.5 h later received intraplantar injection of formalin (2.5%) under brief isoflourane anaesthetic into the right hind paw. Nociceptive and fear-related behaviours were assessed 30 min later. Levels of endocannabinoids, N-acylethanolamines and neurotransmitters in the PAG were assessed by LC-MS/MS and expression of endocannabinoid system-related proteins by Western immunoblotting. Male, but not female, rats exhibited robust FCA and greater expression of fear-related behaviours than females. Fear-conditioned formalin-treated males, but not females, had higher levels of N-oleoylethanolamine (OEA) and γ-aminobutyric acid (GABA) in the PAG, compared with non-fear-conditioned controls. There was no effect of fear conditioning on the levels of FAAH or CB1 receptor expression (CB1R) in the PAG of male or female formalin-treated rats. Non-fear-conditioned females had higher levels of CB1R and PPARγ expression than non-fear-conditioned male counterparts. In summary, our results provide evidence of sexual dimorphism in the expression of FCA and fear-related behaviours, and associated alterations in components of the endocannabinoid system and GABA within the PAG.
Collapse
|
4
|
Presto P, Ji G, Junell R, Griffin Z, Neugebauer V. Fear Extinction-Based Inter-Individual and Sex Differences in Pain-Related Vocalizations and Anxiety-like Behaviors but Not Nocifensive Reflexes. Brain Sci 2021; 11:brainsci11101339. [PMID: 34679403 PMCID: PMC8533751 DOI: 10.3390/brainsci11101339] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 02/06/2023] Open
Abstract
Inter-individual and sex differences in pain responses are recognized but their mechanisms are not well understood. This study was intended to provide the behavioral framework for analyses of pain mechanisms using fear extinction learning as a predictor of phenotypic and sex differences in sensory (mechanical withdrawal thresholds) and emotional-affective aspects (open field tests for anxiety-like behaviors and audible and ultrasonic components of vocalizations) of acute and chronic pain. In acute arthritis and chronic neuropathic pain models, greater increases in vocalizations were found in females than males and in females with poor fear extinction abilities than females with strong fear extinction, particularly in the neuropathic pain model. Female rats showed higher anxiety-like behavior than males under baseline conditions but no inter-individual or sex differences were seen in the pain models. No inter-individual and sex differences in mechanosensitivity were observed. The data suggest that vocalizations are uniquely suited to detect inter-individual and sex differences in pain models, particularly in chronic neuropathic pain, whereas no such differences were found for mechanosensitivity, and baseline differences in anxiety-like behaviors disappeared in the pain models.
Collapse
Affiliation(s)
- Peyton Presto
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Guangchen Ji
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
| | - Riley Junell
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Zach Griffin
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
- Correspondence: ; Tel.: +1-806-743-3880; Fax: +1-806-732-2744
| |
Collapse
|
5
|
Shao FB, Fang JF, Wang SS, Qiu MT, Xi DN, Jin XM, Liu JG, Shao XM, Shen Z, Liang Y, Fang JQ, Du JY. Anxiolytic effect of GABAergic neurons in the anterior cingulate cortex in a rat model of chronic inflammatory pain. Mol Brain 2021; 14:139. [PMID: 34507588 PMCID: PMC8431944 DOI: 10.1186/s13041-021-00849-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/31/2021] [Indexed: 01/08/2023] Open
Abstract
Chronic pain easily leads to concomitant mood disorders, and the excitability of anterior cingulate cortex (ACC) pyramidal neurons (PNs) is involved in chronic pain-related anxiety. However, the mechanism by which PNs regulate pain-related anxiety is still unknown. The GABAergic system plays an important role in modulating neuronal activity. In this paper, we aimed to study how the GABAergic system participates in regulating the excitability of ACC PNs, consequently affecting chronic inflammatory pain-related anxiety. A rat model of CFA-induced chronic inflammatory pain displayed anxiety-like behaviors, increased the excitability of ACC PNs, and reduced inhibitory presynaptic transmission; however, the number of GAD65/67 was not altered. Interestingly, intra-ACC injection of the GABAAR agonist muscimol relieved anxiety-like behaviors but had no effect on chronic inflammatory pain. Intra-ACC injection of the GABAAR antagonist picrotoxin induced anxiety-like behaviors but had no effect on pain in normal rats. Notably, chemogenetic activation of GABAergic neurons in the ACC alleviated chronic inflammatory pain and pain-induced anxiety-like behaviors, enhanced inhibitory presynaptic transmission, and reduced the excitability of ACC PNs. Chemogenetic inhibition of GABAergic neurons in the ACC led to pain-induced anxiety-like behaviors, reduced inhibitory presynaptic transmission, and enhanced the excitability of ACC PNs but had no effect on pain in normal rats. We demonstrate that the GABAergic system mediates a reduction in inhibitory presynaptic transmission in the ACC, which leads to enhanced excitability of pyramidal neurons in the ACC and is associated with chronic inflammatory pain-related anxiety.
Collapse
Affiliation(s)
- Fang-Bing Shao
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Jun-Fan Fang
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Si-Si Wang
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Meng-Ting Qiu
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Dan-Ning Xi
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Xiao-Ming Jin
- Department of Anatomy and Cell Biology, Stark Neurosciences Research Institute, Indiana University School of Medicine, NB Building, 320w 15th Street #141, Indianapolis, IN, 46202, USA
| | - Jing-Gen Liu
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China.,Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Xiao-Mei Shao
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Zui Shen
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Yi Liang
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China
| | - Jian-Qiao Fang
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China.
| | - Jun-Ying Du
- Department of Neurobiology and Acupuncture Research, the Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, 310053, China.
| |
Collapse
|
6
|
Ji G, Neugebauer V. Kappa opioid receptors in the central amygdala modulate spinal nociceptive processing through an action on amygdala CRF neurons. Mol Brain 2020; 13:128. [PMID: 32948219 PMCID: PMC7501648 DOI: 10.1186/s13041-020-00669-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022] Open
Abstract
The amygdala plays an important role in the emotional-affective aspects of behaviors and pain, but can also modulate sensory aspect of pain ("nociception"), likely through coupling to descending modulatory systems. Here we explored the functional coupling of the amygdala to spinal nociception. We found that pharmacological activation of neurons in the central nucleus of the amygdala (CeA) increased the activity of spinal dorsal horn neurons; and this effect was blocked by optogenetic silencing of corticotropin releasing factor (CRF) positive CeA neurons. A kappa opioid receptor (KOR) agonist (U-69,593) was administered into the CeA by microdialysis. KOR was targeted because of their role in averse-affective behaviors through actions in limbic brain regions. Extracellular single-unit recordings were made of CeA neurons or spinal dorsal horn neurons in anesthetized transgenic Crh-Cre rats. Neurons responded more strongly to noxious than innocuous stimuli. U-69,593 increased the responses of CeA and spinal neurons to innocuous and noxious mechanical stimulation of peripheral tissues. The facilitatory effect of the agonist was blocked by optical silencing of CRF-CeA neurons though light activation of halorhodopsin expressed in these neurons by viral-vector. The CRF system in the amygdala has been implicated in aversiveness and pain modulation. The results suggest that the amygdala can modulate spinal nociceptive processing in a positive direction through CRF-CeA neurons and that KOR activation in the amygdala (CeA) has pro-nociceptive effects.
Collapse
Affiliation(s)
- Guangchen Ji
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, 3601 4th St, Lubbock, TX, 79430-6592, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, 3601 4th St, Lubbock, TX, 79430-6592, USA.
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| |
Collapse
|
7
|
Corcoran L, Mattimoe D, Roche M, Finn DP. Attenuation of fear-conditioned analgesia in rats by monoacylglycerol lipase inhibition in the anterior cingulate cortex: Potential role for CB 2 receptors. Br J Pharmacol 2020; 177:2240-2255. [PMID: 31967664 PMCID: PMC7174879 DOI: 10.1111/bph.14976] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 12/01/2019] [Accepted: 12/19/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Improved understanding of brain mechanisms regulating endogenous analgesia is important from a fundamental physiological perspective and for identification of novel therapeutic strategies for pain. The endocannabinoid system plays a key role in stress-induced analgesia, including fear-conditioned analgesia (FCA), a potent form of endogenous analgesia. Here, we studied the role of the endocannabinoid 2-arachidonoyl glycerol (2-AG) within the anterior cingulate cortex (ACC; a brain region implicated in the affective component of pain) in FCA in rats. EXPERIMENTAL APPROACH FCA was modelled in male Lister-hooded rats by assessing formalin-evoked nociceptive behaviour in an arena previously paired with footshock. The effects of intra-ACC administration of MJN110 (inhibitor of monoacylglycerol lipase [MGL], the primary enzyme catabolizing 2-AG), AM630 (CB2 receptor antagonist), AM251 (CB1 receptor antagonist) or MJN110 + AM630 on FCA were assessed. KEY RESULTS MJN110 attenuated FCA when microinjected into the ACC, an effect associated with increased levels of 2-AG in the ACC. This effect of MJN110 on FCA was unaltered by co-administration of AM251 but was blocked by AM630, which alone reduced nociceptive behaviour in non-fear-conditioned rats. RT-qPCR confirmed that mRNA encoding CB1 and CB2 receptors was detectable in the ACC of formalin-injected rats and unchanged in those expressing FCA. CONCLUSION AND IMPLICATIONS These results suggest that an MGL substrate in the ACC, likely 2-AG, modulates FCA and that within the ACC, 2-AG-CB2 receptor signalling may suppress this form of endogenous analgesia. These results may facilitate increased understanding and improved treatment of pain- and fear-related disorders and their co-morbidity.
Collapse
Affiliation(s)
- Louise Corcoran
- Pharmacology and Therapeutics, School of MedicineNational University of Ireland GalwayGalwayIreland
- Galway Neuroscience Centre and Centre for Pain ResearchNational University of Ireland GalwayGalwayIreland
| | - Darragh Mattimoe
- Pharmacology and Therapeutics, School of MedicineNational University of Ireland GalwayGalwayIreland
- Galway Neuroscience Centre and Centre for Pain ResearchNational University of Ireland GalwayGalwayIreland
| | - Michelle Roche
- Physiology, School of MedicineNational University of Ireland GalwayGalwayIreland
- Galway Neuroscience Centre and Centre for Pain ResearchNational University of Ireland GalwayGalwayIreland
| | - David P. Finn
- Pharmacology and Therapeutics, School of MedicineNational University of Ireland GalwayGalwayIreland
- Galway Neuroscience Centre and Centre for Pain ResearchNational University of Ireland GalwayGalwayIreland
| |
Collapse
|
8
|
Gaspar JC, Okine BN, Llorente-Berzal A, Roche M, Finn DP. Pharmacological Blockade of PPAR Isoforms Increases Conditioned Fear Responding in the Presence of Nociceptive Tone. Molecules 2020; 25:molecules25041007. [PMID: 32102354 PMCID: PMC7070536 DOI: 10.3390/molecules25041007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/29/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors with three isoforms (PPARα, PPARβ/δ, PPARγ) and can regulate pain, anxiety, and cognition. However, their role in conditioned fear and pain-fear interactions has not yet been investigated. Here, we investigated the effects of systemically administered PPAR antagonists on formalin-evoked nociceptive behaviour, fear-conditioned analgesia (FCA), and conditioned fear in the presence of nociceptive tone in rats. Twenty-three and a half hours following fear conditioning to context, male Sprague-Dawley rats received an intraplantar injection of formalin and intraperitoneal administration of vehicle, PPARα (GW6471), PPARβ/δ (GSK0660) or PPARγ (GW9662) antagonists, and 30 min later were re-exposed to the conditioning arena for 15 min. The PPAR antagonists did not alter nociceptive behaviour or fear-conditioned analgesia. The PPARα and PPARβ/δ antagonists prolonged context-induced freezing in the presence of nociceptive tone without affecting its initial expression. The PPARγ antagonist potentiated freezing over the entire trial. In conclusion, pharmacological blockade of PPARα and PPARβ/δ in the presence of formalin-evoked nociceptive tone, impaired short-term, within-trial fear-extinction in rats without affecting pain response, while blockade of PPARγ potentiated conditioned fear responding. These results suggest that endogenous signalling through these three PPAR isoforms may reduce the expression of conditioned fear in the presence of nociceptive tone.
Collapse
Affiliation(s)
- Jessica C. Gaspar
- Pharmacology and Therapeutics Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland; (J.C.G.); (B.N.O.); (A.L.-B.)
- Galway Neuroscience Centre, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland;
- Centre for Pain Research, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
| | - Bright N. Okine
- Pharmacology and Therapeutics Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland; (J.C.G.); (B.N.O.); (A.L.-B.)
- Galway Neuroscience Centre, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland;
- Centre for Pain Research, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
| | - Alvaro Llorente-Berzal
- Pharmacology and Therapeutics Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland; (J.C.G.); (B.N.O.); (A.L.-B.)
- Galway Neuroscience Centre, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland;
- Centre for Pain Research, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
| | - Michelle Roche
- Galway Neuroscience Centre, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland;
- Centre for Pain Research, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
- Physiology Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
| | - David P. Finn
- Pharmacology and Therapeutics Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland; (J.C.G.); (B.N.O.); (A.L.-B.)
- Galway Neuroscience Centre, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland;
- Physiology Department, National University of Ireland Galway, University Road, H91 W5P7 Galway, Ireland
- Correspondence: ; Tel.: +353-(0)91-495-280; Fax: +353-(0)91-495-586
| |
Collapse
|
9
|
Della Valle R, Mohammadmirzaei N, Knox D. Single prolonged stress alters neural activation in the periacqueductal gray and midline thalamic nuclei during emotional learning and memory. Learn Mem 2019; 26:1-9. [PMID: 31527186 PMCID: PMC6749928 DOI: 10.1101/lm.050310.119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 07/20/2019] [Indexed: 12/25/2022]
Abstract
Clinical and preclinical studies that have examined the neurobiology of persistent fear memory in posttraumatic stress disorder (PTSD) have focused on the medial prefrontal cortex, hippocampus, and amygdala. Sensory systems, the periaqueductal gray (PAG), and midline thalamic nuclei have been implicated in fear and extinction memory, but whether neural activity in these substrates is sensitive to traumatic stress (at baseline or during emotional learning and memory) remains unexplored. To address this, we used the single prolonged stress (SPS) model of traumatic stress. SPS and control rats were either subjected to fear conditioning (CS-fear) or presented with CSs alone (CS-only) during fear conditioning. All rats were then subjected to extinction training and testing. A subset of rats were euthanized after each behavioral stage and c-Fos and c-Jun used to measure neural activation in all substrates. SPS lowered c-Jun levels in the dorsomedial and lateral PAG at baseline, but the elevated c-Jun expression in the PAG during emotional learning and memory. SPS also altered c-Fos expression during fear and extinction learning/memory in midline thalamic nuclei. These findings suggest changes in neural function in the PAG and midline thalamic nuclei could contribute to persistent fear memory induced by traumatic stress. Interestingly, SPS effects were also observed in animals that never learned fear or extinction (i.e., CS-only). This raises the possibility that traumatic stress could have broader effects on the psychological function that are dependent on the PAG and midline thalamic nuclei.
Collapse
Affiliation(s)
- Rebecca Della Valle
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware 19716, USA
| | - Negin Mohammadmirzaei
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware 19716, USA
| | - Dayan Knox
- Department of Psychological and Brain Sciences, University of Delaware, Newark, Delaware 19716, USA
| |
Collapse
|
10
|
Morena M, Aukema RJ, Leitl KD, Rashid AJ, Vecchiarelli HA, Josselyn SA, Hill MN. Upregulation of Anandamide Hydrolysis in the Basolateral Complex of Amygdala Reduces Fear Memory Expression and Indices of Stress and Anxiety. J Neurosci 2019; 39:1275-1292. [PMID: 30573646 PMCID: PMC6381235 DOI: 10.1523/jneurosci.2251-18.2018] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/09/2018] [Accepted: 12/14/2018] [Indexed: 11/21/2022] Open
Abstract
Increased anandamide (AEA) signaling through inhibition of its catabolic enzyme fatty acid amide hydrolase (FAAH) in the basolateral complex of amygdala (BLA) is thought to buffer against the effects of stress and reduces behavioral signs of anxiety and fear. However, examining the role of AEA signaling in stress, anxiety, and fear through pharmacological depletion has been challenging due to the redundant complexity of its biosynthesis and the lack of a pharmacological synthesis inhibitor. We developed a herpes simplex viral vector to rapidly yet transiently overexpress FAAH specifically within the BLA to assess the impact of suppressing AEA signaling on stress, fear, and anxiety in male rats. Surprisingly, FAAH overexpression in BLA dampened stress-induced corticosterone release, reduced anxiety-like behaviors, and decreased conditioned fear expression. Interestingly, depleting AEA signaling in the BLA did not prevent fear conditioning itself or fear reinstatement. These effects were specific to the overexpression of FAAH because they were reversed by intra-BLA administration of an FAAH inhibitor. Moreover, the fear-suppressive effects of FAAH overexpression were also mitigated by intra-BLA administration of a low dose of a GABAA receptor antagonist, but not an NMDA/AMPA/kainate receptor antagonist, suggesting that they were mediated by an increase in GABAergic neurotransmission. Our data suggest that a permissive AEA tone within the BLA might gate GABA release and that loss of this tone through elevated AEA hydrolysis increases inhibition in the BLA, which in turn reduces stress, anxiety, and fear. These data provide new insights on the mechanisms by which amygdalar endocannabinoid signaling regulates emotional behavior.SIGNIFICANCE STATEMENT Amygdala endocannabinoid signaling is involved in the regulation of stress, anxiety, and fear. Our data indicate that viral-mediated augmentation of anandamide hydrolysis within the basolateral amygdala reduces behavioral indices of stress, anxiety, and conditioned fear expression. These same effects have been previously documented with inhibition of anandamide hydrolysis in the same brain region. Our results indicate that the ability of anandamide signaling to regulate emotional behavior is nonlinear and may involve actions at distinct neuronal populations, which could be influenced by the basal level of anandamide. Modulation of anandamide signaling is a current clinical therapeutic target for stress-related psychiatric illnesses, so these data underscore the importance of fully understanding the mechanisms by which anandamide signaling regulates amygdala-dependent changes in emotionality.
Collapse
Affiliation(s)
- Maria Morena
- Hotchkiss Brain Institute,
- Mathison Centre for Mental Health Research
- Departments of Cell Biology and Anatomy and Psychiatry
| | - Robert J Aukema
- Hotchkiss Brain Institute
- Mathison Centre for Mental Health Research
- Neuroscicence Program, Cumming School of Medicine, University of Calgary, T2N 4N1 Calgary, Alberta, Canada, and
| | - Kira D Leitl
- Hotchkiss Brain Institute
- Mathison Centre for Mental Health Research
| | - Asim J Rashid
- Hospital for Sick Children and Departments of Psychology and Physiology, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Haley A Vecchiarelli
- Hotchkiss Brain Institute
- Mathison Centre for Mental Health Research
- Neuroscicence Program, Cumming School of Medicine, University of Calgary, T2N 4N1 Calgary, Alberta, Canada, and
| | - Sheena A Josselyn
- Hospital for Sick Children and Departments of Psychology and Physiology, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Matthew N Hill
- Hotchkiss Brain Institute,
- Mathison Centre for Mental Health Research
- Departments of Cell Biology and Anatomy and Psychiatry
| |
Collapse
|
11
|
Periaqueductal gray and emotions: the complexity of the problem and the light at the end of the tunnel, the magnetic resonance imaging. Endocr Regul 2018; 52:222-238. [DOI: 10.2478/enr-2018-0027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract
The periaqueductal gray (PAG) is less referred in relationship with emotions than other parts of the brain (e.g. cortex, thalamus, amygdala), most probably because of the difficulty to reach and manipulate this small and deeply lying structure. After defining how to evaluate emotions, we have reviewed the literature and summarized data of the PAG contribution to the feeling of emotions focusing on the behavioral and neurochemical considerations. In humans, emotions can be characterized by three main domains: the physiological changes, the communicative expressions, and the subjective experiences. In animals, the physiological changes can mainly be studied. Indeed, early studies have considered the PAG as an important center of the emotions-related autonomic and motoric processes. However, in vivo imaging have changed our view by highlighting the PAG as a significant player in emotions-related cognitive processes. The PAG lies on the crossroad of networks important in the regulation of emotions and therefore it should not be neglected. In vivo imaging represents a good tool for studying this structure in living organism and may reveal new information about its role beyond its importance in the neurovegetative regulation.
Collapse
|
12
|
Seno MDJ, Assis DV, Gouveia F, Antunes GF, Kuroki M, Oliveira CC, Santos LCT, Pagano RL, Martinez RCR. The critical role of amygdala subnuclei in nociceptive and depressive-like behaviors in peripheral neuropathy. Sci Rep 2018; 8:13608. [PMID: 30206257 PMCID: PMC6134132 DOI: 10.1038/s41598-018-31962-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/30/2018] [Indexed: 01/05/2023] Open
Abstract
The amygdala is an important component of the limbic system that participates in the control of the pain response and modulates the affective-motivational aspect of pain. Neuropathic pain is a serious public health problem and has a strong affective-motivational component that makes it difficult to treat. The central (CeA), basolateral (BLA) and lateral (LA) nuclei of the amygdala are involved in the processing and regulation of chronic pain. However, the roles of these nuclei in the maintenance of neuropathic pain, anxiety and depression remain unclear. Thus, the main objective of this study was to investigate the role of amygdala subnuclei in the modulation of neuropathic pain, including the affective-motivational axis, in an experimental model of peripheral neuropathy. The specific goals were as follows: (1) To evaluate the nociceptive responses and the patterns of activation of the CeA, BLA and LA in neuropathic rats; and (2) To evaluate the effect of inactivating the amygdala nuclei on the nociceptive response, anxiety and depressive behaviors, motor activity, and plasma stress hormones in animals with neuropathic pain. Thus, mechanical hyperalgesia and allodynia, and the pattern of c-Fos staining in the amygdala subnuclei were evaluated in rats with chronic constriction of the sciatic nerve, as well as sham-operated and naïve rats. Once the amygdala subnuclei involved in neuropathic pain response were defined, those subnuclei were pharmacological inactivated. The effect of muscimol inactivation on the nociceptive response (hyperalgesia and allodynia), anxiety (elevated plus-maze), depressive-like behavior (forced swim test), motor activity (open field), and plasma stress hormone levels (corticosterone and adrenocorticotropic hormone) were evaluated in sham-operated and neuropathic animals. The results showed that the anterior and posterior portions of the BLA and the central portion of the CeA are involved in controlling neuropathic pain. The inactivation of these nuclei reversed hyperalgesia, allodynia and depressive-like behavior in animals with peripheral neuropathy. Taken together, our findings improve our understanding of the neurocircuitry involved in persistent pain and the roles of specific amygdala subnuclei in the modulation of neuropathic pain, including the neurocircuitry that processes the affective-motivational component of pain.
Collapse
Affiliation(s)
- Midiã D J Seno
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | - Danielle V Assis
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | - Flávia Gouveia
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | - Geiza F Antunes
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | - Mayra Kuroki
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | | | - Lennon C T Santos
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | - Rosana L Pagano
- Laboratory of Neuroscience, Hospital Sirio-Libanes, Sao Paulo, SP, Brazil
| | | |
Collapse
|
13
|
Rea K, McGowan F, Corcoran L, Roche M, Finn DP. The prefrontal cortical endocannabinoid system modulates fear-pain interactions in a subregion-specific manner. Br J Pharmacol 2018; 176:1492-1505. [PMID: 29847859 DOI: 10.1111/bph.14376] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/11/2018] [Accepted: 05/15/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE The emotional processing and coordination of top-down responses to noxious and conditioned aversive stimuli involves the medial prefrontal cortex (mPFC). Evidence suggests that subregions of the mPFC [infralimbic (IfL), prelimbic (PrL) and anterior cingulate (ACC) cortices] differentially alter the expression of contextually induced fear and nociceptive behaviour. We investigated the role of the endocannabinoid system in the IfL, PrL and ACC in formalin-evoked nociceptive behaviour, fear-conditioned analgesia (FCA) and conditioned fear in the presence of nociceptive tone. EXPERIMENTAL APPROACH FCA was modelled in male Lister-hooded rats by assessing formalin-evoked nociceptive behaviour in an arena previously paired with footshock. The effects of intra-mPFC administration of AM251 [cannabinoid type 1 (CB1 ) receptor antagonist/inverse agonist], URB597 [fatty acid amide hydrolase (FAAH) inhibitor] or URB597 + AM251 on FCA and freezing behaviour were assessed. KEY RESULTS AM251 attenuated FCA when injected into the IfL or PrL and reduced contextually induced freezing behaviour when injected intra-IfL but not intra-PrL or intra-ACC. Intra-ACC administration of AM251 alone or in combination with URB597 had no effect on FCA or freezing. URB597 attenuated FCA and freezing behaviour when injected intra-IfL, prolonged the expression of FCA when injected intra-PrL and had no effect on these behaviours when injected intra-ACC. CONCLUSIONS AND IMPLICATIONS These results suggest important and differing roles for FAAH substrates or CB1 receptors in the PrL, IfL and ACC in the expression of FCA and conditioned fear in the presence of nociceptive tone. LINKED ARTICLES This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.
Collapse
Affiliation(s)
- Kieran Rea
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland.,Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| | - Fiona McGowan
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland.,Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| | - Louise Corcoran
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland.,Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| | - Michelle Roche
- Physiology, School of Medicine, National University of Ireland Galway, Galway, Ireland.,Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland.,Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| |
Collapse
|
14
|
Ji G, Yakhnitsa V, Kiritoshi T, Presto P, Neugebauer V. Fear extinction learning ability predicts neuropathic pain behaviors and amygdala activity in male rats. Mol Pain 2018; 14:1744806918804441. [PMID: 30209982 PMCID: PMC6172937 DOI: 10.1177/1744806918804441] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/15/2018] [Accepted: 09/02/2018] [Indexed: 12/14/2022] Open
Abstract
Background The amygdala plays a key role in fear learning and extinction and has emerged as an important node of emotional-affective aspects of pain and pain modulation. Impaired fear extinction learning, which involves prefrontal cortical control of amygdala processing, has been linked to neuropsychiatric disorders. Here, we tested the hypothesis that fear extinction learning ability can predict the magnitude of neuropathic pain. Results We correlated fear extinction learning in naive adult male rats with sensory and affective behavioral outcome measures (mechanical thresholds, vocalizations, and anxiety- and depression-like behaviors) before and after the induction of the spinal nerve ligation model of neuropathic pain compared to sham controls. Auditory fear conditioning, extinction learning, and extinction retention tests were conducted after baseline testing. All rats showed increased freezing responses after fear conditioning. During extinction training, the majority (75%) of rats showed a decline in freezing level to 50% in 5 min (fear extinction+), whereas 25% of the rats maintained a high freezing level (>50%, fear extinction-). Fear extinction- rats showed decreased open-arm preference in the elevated plus maze, reflecting anxiety-like behavior, but there were no significant differences in sensory thresholds, vocalizations, or depression-like behavior (forced swim test) between fear extinction+ and fear extinction- types. In the neuropathic pain model (four weeks after spinal nerve ligation), fear extinction- rats showed a greater increase in vocalizations and anxiety-like behavior than fear extinction+ rats. Fear extinction- rats, but not fear extinction+ rats, also developed depression-like behavior. Extracellular single unit recordings of amygdala (central nucleus) neurons in behaviorally tested rats (anesthetized with isoflurane) found greater increases in background activity, bursting, and evoked activity in fear extinction- rats than fear extinction+ rats in the spinal nerve ligation model compared to sham controls. Conclusion The data may suggest that fear extinction learning ability predicts the magnitude of neuropathic pain-related affective rather than sensory behaviors, which correlates with differences in amygdala activity changes.
Collapse
Affiliation(s)
- Guangchen Ji
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Vadim Yakhnitsa
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA
| | - Takaki Kiritoshi
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA
| | - Peyton Presto
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| |
Collapse
|
15
|
Zeitler A, Kamoun N, Goyon S, Wahis J, Charlet A, Poisbeau P, Darbon P. Favouring inhibitory synaptic drive mediated by GABA(A) receptors in the basolateral nucleus of the amygdala efficiently reduces pain symptoms in neuropathic mice. Eur J Neurosci 2016; 43:1082-8. [PMID: 26913957 DOI: 10.1111/ejn.13217] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 01/06/2023]
Abstract
Pain is an emotion and neuropathic pain symptoms are modulated by supraspinal structures such as the amygdala. The central nucleus of the amygdala is often called the 'nociceptive amygdala', but little is known about the role of the basolateral amygdala. Here, we monitored the mechanical nociceptive thresholds in a mouse model of neuropathic pain and infused modulators of the glutamate/GABAergic transmission in the basolateral nucleus of the amygdala (BLA) via chronically-implanted cannulas. We found that an N-methyl-D-aspartate-type glutamate receptor antagonist (MK-801) exerted a potent antiallodynic effect, whereas a transient allodynia was induced after perfusion of bicuculline, a GABA(A) receptor antagonist. Potentiating GABA(A) receptor function using diazepam or etifoxine (a non-benzodiazepine anxiolytic) fully but transiently alleviated mechanical allodynia. Interestingly, the antiallodynic effect of etifoxine disappeared in animals that were incapable of producing 3α-steroids. Diazepam had a similar effect but of shorter duration. As indicated by patch-clamp recordings of BLA neurons, these effects were mediated by a potentiation of GABA(A) receptor-mediated synaptic transmission. Together with a presynaptic elevation of miniature inhibitory postsynaptic current frequency, the duration and amplitude of GABA(A) miniature inhibitory postsynaptic currents were also increased (postsynaptic effect). The analgesic contribution of endogenous neurosteroid seemed to be exclusively postsynaptic. This study highlights the importance of the BLA and the local inhibitory/excitatory neuronal network activity while setting the mechanical nociceptive threshold. Furthermore, it appears that promoting inhibition in this specific nucleus could fully alleviate pain symptoms. Therefore, the BLA could be a novel interesting target for the development of pharmacological or non-pharmacological therapies.
Collapse
Affiliation(s)
- Alexandre Zeitler
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| | - Nisrine Kamoun
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| | - Stéphanie Goyon
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| | - Jérôme Wahis
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| | - Alexandre Charlet
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France.,University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
| | - Pierrick Poisbeau
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| | - Pascal Darbon
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212 CNRS, Centre National de la Recherche Scientifique and University of Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg Cedex, France
| |
Collapse
|
16
|
Morland RH, Novejarque A, Huang W, Wodarski R, Denk F, Dawes JD, Pheby T, McMahon SB, Rice AS. Short-term effect of acute and repeated urinary bladder inflammation on thigmotactic behaviour in the laboratory rat. F1000Res 2015; 4:109. [PMID: 27158443 PMCID: PMC4850861 DOI: 10.12688/f1000research.6255.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/28/2015] [Indexed: 12/13/2022] Open
Abstract
Understanding the non-sensory components of the pain experience is crucial to developing effective treatments for pain conditions. Chronic pain is associated with increased incidence of anxio-depressive disorders, and patients often report feelings of vulnerability which can decrease quality of life. In animal models of pain, observation of behaviours such as thigmotaxis can be used to detect such affective disturbances by exploiting the influence of nociceptive stimuli on the innate behavioural conflict between exploration of a novel space and predator avoidance behaviour. This study investigates whether acute and repeated bladder inflammation in adult female Wistar rats increases thigmotactic behaviour in the open field paradigm, and aims to determine whether this correlates with activation in the central amygdala, as measured by c-Fos immunoreactivity. Additionally, up-regulation of inflammatory mediators in the urinary bladder was measured using RT-qPCR array featuring 92 transcripts to examine how local mediators change under experimental conditions. We found acute but not repeated turpentine inflammation of the bladder increased thigmotactic behaviour (decreased frequency of entry to the inner zone) in the open field paradigm, a result that was also observed in the catheter-only instrumentation group. Decreases in locomotor activity were also observed in both models in turpentine and instrumentation groups. No differences were observed in c-Fos activation, although a general increased in activation along the rostro-caudal axis was seen. Inflammatory mediator up-regulation was greatest following acute inflammation, with CCL12, CCL7, and IL-1β significantly up-regulated in both conditions when compared to naïve tissue. These results suggest that acute catheterisation, with or without turpentine inflammation, induces affective alterations detectable in the open field paradigm accompanied by up-regulation of multiple inflammatory mediators.
Collapse
Affiliation(s)
- Rosemary H Morland
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| | - Amparo Novejarque
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| | - Wenlong Huang
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| | - Rachel Wodarski
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| | - Franziska Denk
- Wolfson Centre for Age Related Disease, King's College London, London, UK
| | - John D Dawes
- The Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, UK
| | - Tim Pheby
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| | - Stephen B McMahon
- Wolfson Centre for Age Related Disease, King's College London, London, UK
| | - Andrew Sc Rice
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College , London, UK
| |
Collapse
|
17
|
Bree D, Moriarty O, O'Mahony CM, Morris B, Bannerton K, Broom DC, Kelly JP, Roche M, Finn DP. Development and characterization of a novel, anatomically relevant rat model of acute postoperative pain. THE JOURNAL OF PAIN 2015; 16:421-35.e1-6. [PMID: 25640291 DOI: 10.1016/j.jpain.2015.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
Abstract
UNLABELLED Acute postoperative pain remains a significant health care issue. Development of anatomically relevant animal models of postoperative pain, with improved predictive validity, would advance understanding of postoperative pain mechanisms and improve treatment outcomes. This study aimed to develop, characterize, and validate a rat model of acute postoperative pain associated with inguinal hernia repair based on the Lichtenstein inguinal hernia repair procedure (without hernia induction). We hypothesized that the surgery would result in reduced spontaneous locomotor activity, which would represent a pain-related phenotype. Postsurgical characterization involved extensive monitoring of home cage and open field locomotor activity, as well as mechanical hypersensitivity and assessment of c-Fos expression in the dorsal horn of the spinal cord. In pharmacologic validation studies, rats received morphine, carprofen, or paracetamol 1 hour before, and/or immediately after, surgery. Rats that underwent hernia repair surgery exhibited significantly lower horizontal and vertical activities in the home cage and open field in the early postsurgical period, compared with sham rats or rats that underwent skin incision only. Morphine, carprofen, and paracetamol attenuated the surgery-induced reductions in locomotor activity, to varying degrees. Surgery was associated with significantly increased c-Fos expression in the ipsilateral dorsal horn of the spinal cord, an effect attenuated by carprofen treatment. These results support the development and characterization of a novel, anatomically relevant animal model of acute postoperative pain that may facilitate development of improved treatment regimens. PERSPECTIVE Acute pain following inguinal hernia repair can be difficult to treat. Here we report, for the first time, the development of a novel, anatomically relevant rat model to facilitate improved understanding and treatment of acute postoperative pain following inguinal hernia repair.
Collapse
Affiliation(s)
- Dara Bree
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Discipline of Physiology, School of Medicine, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | - Orla Moriarty
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Discipline of Physiology, School of Medicine, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Research and Development, Covidien, North Haven, Connecticut
| | - Cliona M O'Mahony
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Discipline of Physiology, School of Medicine, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Research and Development, Covidien, North Haven, Connecticut
| | - Bradley Morris
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Discipline of Physiology, School of Medicine, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | - Karen Bannerton
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | - Daniel C Broom
- Research and Development, Covidien, North Haven, Connecticut
| | - John P Kelly
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | - Michelle Roche
- Discipline of Physiology, School of Medicine, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | - David P Finn
- Discipline of Pharmacology and Therapeutics, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland.
| |
Collapse
|
18
|
Okine BN, Rea K, Olango WM, Price J, Herdman S, Madasu MK, Roche M, Finn DP. A role for PPARα in the medial prefrontal cortex in formalin-evoked nociceptive responding in rats. Br J Pharmacol 2014; 171:1462-71. [PMID: 24303983 DOI: 10.1111/bph.12540] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 10/02/2013] [Accepted: 10/27/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE The nuclear hormone receptor, PPARα, and its endogenous ligands, are involved in pain modulation. PPARα is expressed in the medial prefrontal cortex (mPFC), a key brain region involved in both the cognitive-affective component of pain and in descending modulation of pain. However, the role of PPARα in the mPFC in pain responding has not been investigated. Here, we investigated the effects of pharmacological modulation of PPARα in the rat mPFC on formalin-evoked nociceptive behaviour and the impact of formalin-induced nociception on components of PPARα signalling in the mPFC. EXPERIMENTAL APPROACH The effects of intra-mPFC microinjection of a PPARα agonist (GW7647) or a PPARα antagonist (GW6471) on formalin-evoked nociceptive behaviour in rats were studied. Quantitative real-time PCR and LC-MS/MS were used to study the effects of intraplantar injection of formalin on PPARα mRNA expression and levels of endogenous ligands, respectively, in the mPFC. KEY RESULTS Intra-mPFC administration of GW6471, but not GW7647, resulted in delayed onset of the early second phase of formalin-evoked nociceptive behaviour. Furthermore, formalin-evoked nociceptive behaviour was associated with significant reductions in mPFC levels of endogenous PPARα ligands (N-palmitoylethanolamide and N-oleoylethanolamide) and a 70% reduction in PPARα mRNA but not protein expression. CONCLUSIONS AND IMPLICATIONS These data suggest that endogenous ligands may act at PPARα in the mPFC to play a facilitatory/permissive role in second phase formalin-evoked nociceptive behaviour in rats. LINKED ARTICLES This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.
Collapse
Affiliation(s)
- B N Okine
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, Galway, Ireland
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Rea K, Ford GK, Olango WM, Harhen B, Roche M, Finn DP. Microinjection of 2-arachidonoyl glycerol into the rat ventral hippocampus differentially modulates contextually induced fear, depending on a persistent pain state. Eur J Neurosci 2014; 39:435-43. [PMID: 24494683 DOI: 10.1111/ejn.12452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/09/2013] [Accepted: 11/11/2013] [Indexed: 12/19/2022]
Abstract
The endogenous cannabinoid (endocannabinoid) system plays a key role in the modulation of aversive and nociceptive behaviour. The components of the endocannabinoid system are expressed throughout the hippocampus, a brain region implicated in both conditioned fear and pain. In light of evidence that pain can impact on the expression of fear-related behaviour, and vice versa, we hypothesised that exogenous administration of the endocannabinoid 2-arachidonoyl glycerol (2-AG) into the ventral hippocampus (vHip) would differentially regulate fear responding in the absence vs. the presence of formalin-evoked nociceptive tone. Fear-conditioned rats showed significantly increased freezing and a reduction in formalin-evoked nociceptive behaviour upon re-exposure to a context previously paired with footshock. Bilateral microinjection of 2-AG into the vHip significantly reduced contextually induced freezing in non-formalin-treated rats, and reduced formalin-evoked nociceptive behaviour in non-fear-conditioned rats. In contrast, 2-AG microinjection had no effect on fear responding in formalin-treated rats, and no effect on nociceptive behaviour in fear-conditioned rats. The inhibitory effect of 2-AG on fear-related behaviour, but not pain-related behaviour, was blocked by co-administration of the cannabinoid receptor 1 (CB1) antagonist/inverse agonist rimonabant. Tissue levels of the endocannabinoids N-arachidonoylethanolamide (anandamide, AEA) and 2-AG were similar in the vHip of fear-conditioned rats receiving formalin injection and the vHip of fear-conditioned rats receiving saline injection. However, the levels of AEA and 2-AG were significantly lower in the contralateral ventrolateral periaqueductal grey of formalin-treated fear-conditioned rats than in that of their saline-treated counterparts. These data suggest that 2-AG-CB1 receptor signalling in the vHip has an anti-aversive effect, and that this effect is abolished in the presence of a persistent pain state.
Collapse
Affiliation(s)
- Kieran Rea
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, University Road, Galway, Ireland; Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland, Galway, Ireland
| | | | | | | | | | | |
Collapse
|
20
|
Rea K, Olango WM, Okine BN, Madasu MK, McGuire IC, Coyle K, Harhen B, Roche M, Finn DP. Impaired endocannabinoid signalling in the rostral ventromedial medulla underpins genotype-dependent hyper-responsivity to noxious stimuli. Pain 2014; 155:69-79. [DOI: 10.1016/j.pain.2013.09.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 08/18/2013] [Accepted: 09/09/2013] [Indexed: 12/20/2022]
|
21
|
Qi WJ, Wang W, Wang N, Wang JY, Luo F. Depressive-like history alters persistent pain behavior in rats: Opposite contribution of frontal cortex and amygdala implied. Psych J 2013; 2:133-145. [PMID: 26229589 PMCID: PMC4517677 DOI: 10.1002/pchj.27] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 02/25/2013] [Indexed: 12/18/2022]
Abstract
Numerous studies have shown that pain perception is strongly influenced by depression. However, very few studies have examined whether pain perception is altered in the remission period of depression, and what role the fronto-limbic circuits may play in the behavioral changes associated with remission. Using an unpredictable chronic mild stress (UCMS) animal model of depression, the present study investigated pain-related behaviors in rats with prior exposure to a UCMS stimulus. The γ-aminobutyric acid (GABA)A receptor agonist muscimol was microinjected bilaterally into the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) to examine the modulation of pain by these brain regions in the recovery state. Rats with a depression-like history displayed increased ongoing pain behavior in the formalin test, although their thermal pain thresholds were unchanged. Intra-BLA muscimol during the recovery phase dramatically decreased formalin-induced pain behavior and also significantly increased rats' sucrose preference. By contrast, in the mPFC, muscimol produced the opposite effect, suggesting different, perhaps opposing, roles of the BLA and mPFC in mediating the influence of prior UCMS exposure on pain perception. Taken together, these results demonstrated that a depressive experience may cause long-term alterations in limbic circuit excitability and thus lead to long-lasting changes in pain perception.
Collapse
Affiliation(s)
- Wei-Jing Qi
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Wei Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Ning Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Jin-Yan Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Fei Luo
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
22
|
Veinante P, Yalcin I, Barrot M. The amygdala between sensation and affect: a role in pain. J Mol Psychiatry 2013; 1:9. [PMID: 25408902 PMCID: PMC4223879 DOI: 10.1186/2049-9256-1-9] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/11/2013] [Indexed: 01/15/2023] Open
Abstract
The amygdala is a structure of the temporal lobe thought to be involved in assigning emotional significance to environmental information and triggering adapted physiological, behavioral and affective responses. A large body of literature in animals and human implicates the amygdala in fear. Pain having a strong affective and emotional dimension, the amygdala, especially its central nucleus (CeA), has also emerged in the last twenty years as key element of the pain matrix. The CeA receives multiple nociceptive information from the brainstem, as well as highly processed polymodal information from the thalamus and the cerebral cortex. It also possesses the connections that allow influencing most of the descending pain control systems as well as higher centers involved in emotional, affective and cognitive functions. Preclinical studies indicate that the integration of nociceptive inputs in the CeA only marginally contributes to sensory-discriminative components of pain, but rather contributes to associated behavior and affective responses. The CeA doesn’t have a major influence on responses to acute nociception in basal condition, but it induces hypoalgesia during aversive situation, such as stress or fear. On the contrary, during persistent pain states (inflammatory, visceral, neuropathic), a long-lasting functional plasticity of CeA activity contributes to an enhancement of the pain experience, including hyperalgesia, aversive behavioral reactions and affective anxiety-like states.
Collapse
Affiliation(s)
- Pierre Veinante
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212, Centre National de la Recherche Scientifique, 21 Rue René Descartes, 67084 Strasbourg Cedex, France ; Université de Strasbourg, 21 Rue René Descartes, 67084 Strasbourg Cedex, France
| | - Ipek Yalcin
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212, Centre National de la Recherche Scientifique, 21 Rue René Descartes, 67084 Strasbourg Cedex, France ; Université de Strasbourg, 21 Rue René Descartes, 67084 Strasbourg Cedex, France
| | - Michel Barrot
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212, Centre National de la Recherche Scientifique, 21 Rue René Descartes, 67084 Strasbourg Cedex, France ; Université de Strasbourg, 21 Rue René Descartes, 67084 Strasbourg Cedex, France
| |
Collapse
|
23
|
Borelli KG, Albrechet-Souza L, Fedoce AG, Fabri DS, Resstel LB, Brandão ML. Conditioned fear is modulated by CRF mechanisms in the periaqueductal gray columns. Horm Behav 2013; 63:791-9. [PMID: 23603480 DOI: 10.1016/j.yhbeh.2013.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 04/05/2013] [Accepted: 04/10/2013] [Indexed: 12/27/2022]
Abstract
The periaqueductal gray (PAG) columns have been implicated in controlling stress responses through corticotropin-releasing factor (CRF), which is a neuropeptide with a prominent role in the etiology of fear- and anxiety-related psychopathologies. Several studies have investigated the involvement of dorsal PAG (dPAG) CRF mechanisms in models of unconditioned fear. However, less is known about the role of this neurotransmission in the expression of conditioned fear memories in the dPAG and ventrolateral PAG (vlPAG) columns. We assessed the effects of ovine CRF (oCRF 0.25 and 1.0 μg/0.2 μL) locally administered into the dPAG and vlPAG on behavioral (fear-potentiated startle and freezing) and autonomic (arterial pressure and heart rate) responses in rats subjected to contextual fear conditioning. The lower dose injected into the columns promoted proaversive effects, enhanced contextual freezing, increased the blood pressure and heart rate and decreased tail temperature. The lower dose of oCRF into the vlPAG, but not into the dPAG, produced a pronounced enhancement of the fear-potentiated startle response. The results imply that the PAG is a heterogeneous structure that is involved in the coordination of distinct behaviors and autonomic control, suggest PAG involvement in the expression of contextual fear memory as well as implicate the CRF as an important modulator of the neural substrates of fear in the PAG.
Collapse
Affiliation(s)
- Karina G Borelli
- Instituto de Neurociências e Comportamento, Ribeirão Preto, SP, Brazil.
| | | | | | | | | | | |
Collapse
|
24
|
Evidence for a role of GABAergic and glutamatergic signalling in the basolateral amygdala in endocannabinoid-mediated fear-conditioned analgesia in rats. Pain 2013; 154:576-585. [DOI: 10.1016/j.pain.2012.12.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/25/2012] [Accepted: 12/20/2012] [Indexed: 12/17/2022]
|
25
|
Watabe AM, Ochiai T, Nagase M, Takahashi Y, Sato M, Kato F. Synaptic potentiation in the nociceptive amygdala following fear learning in mice. Mol Brain 2013; 6:11. [PMID: 23452928 PMCID: PMC3606120 DOI: 10.1186/1756-6606-6-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 02/26/2013] [Indexed: 12/23/2022] Open
Abstract
Background Pavlovian fear conditioning is a classical form of associative learning, which depends on associative synaptic plasticity in the amygdala. Recent findings suggest that the central amygdala (CeA) plays an active role in the acquisition of fear learning. However, little is known about the synaptic properties of the CeA in fear learning. The capsular part of the central amygdala (CeC) receives direct nociceptive information from the external part of the lateral parabrachial nucleus (lPB), as well as highly processed polymodal signals from the basolateral nucleus of the amygdala (BLA). Therefore, we focused on CeC as a convergence point for polymodal BLA signals and nociceptive lPB signals, and explored the synaptic regulation of these pathways in fear conditioning. Results In this study, we show that fear conditioning results in synaptic potentiation in both lPB-CeC and BLA-CeC synapses. This potentiation is dependent on associative fear learning, rather than on nociceptive or sensory experience, or fear memory retrieval. The synaptic weight of the lPB-CeC and BLA-CeC pathways is correlated in fear-conditioned mice, suggesting that fear learning may induce activity-dependent heterosynaptic interactions between lPB-CeC and BLA-CeC pathways. This synaptic potentiation is associated with both postsynaptic and presynaptic changes in the lPB-CeC and BLA-CeC synapses. Conclusions These results indicate that the CeC may provide an important locus of Pavlovian association, integrating direct nociceptive signals with polymodal sensory signals. In addition to the well-established plasticity of the lateral amygdala, the multi-step nature of this association system contributes to the highly orchestrated tuning of fear learning.
Collapse
Affiliation(s)
- Ayako M Watabe
- Department of Neuroscience, Jikei University School of Medicine, Tokyo 105-8461, Japan.
| | | | | | | | | | | |
Collapse
|
26
|
Comparison between low doses of TMT and cat odor exposure in anxiety- and fear-related behaviors in mice. Behav Brain Res 2012; 238:227-31. [PMID: 23089645 DOI: 10.1016/j.bbr.2012.10.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 09/17/2012] [Accepted: 10/11/2012] [Indexed: 11/23/2022]
Abstract
Few comparisons were made between cat odor and synthetic fox odor (TMT) to study fear and anxiety in rodents. TMT is frequently used are at high concentration while the stimulus should be as possible closer to natural conditions. The aim of this work was to compare behavioral responses of mice exposed to cat odor and low doses of TMT (i.e. 10 μl of a solution containing 1%, 0.1% or 0.01% TMT). Behavioral parameters were recorded in elevated plus-maze and in open field. Results showed that 1% TMT and 0.1% TMT induced similar responses to cat odor, contrary to water and 0.01% TMT which failed to elicit fear or anxiety-related behaviors. Additionally, behavioral changes were more marked in EPM - e.g. time spent in open arms - than in open field - e.g. freezing. These findings are discussed in terms of a possible continuum of mild anxiety-like behaviors to strong fear-like behaviors linked to predator odor intensity.
Collapse
|
27
|
Tulogdi A, Sörös P, Tóth M, Nagy R, Biró L, Aliczki M, Klausz B, Mikics E, Haller J. Temporal changes in c-Fos activation patterns induced by conditioned fear. Brain Res Bull 2012; 88:359-70. [PMID: 22516520 DOI: 10.1016/j.brainresbull.2012.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 03/30/2012] [Accepted: 04/03/2012] [Indexed: 01/27/2023]
Abstract
Mechanisms underlying shock-induced conditioned fear - a paradigm frequently used to model posttraumatic stress disorder, PTSD - are usually studied shortly after shocks. Some of the brain regions relevant to conditioned fear were activated in all the c-Fos studies published so far, but the overlap between the activated regions was small across studies. We hypothesized that discrepant findings were due to dynamic neural changes that followed shocks, and a more consistent picture would emerge if consequences were studied after a longer interval. Therefore, we exposed rats to a single session of footshocks and studied their behavioral and neural responses one and 28 days later. The neuronal activation marker c-Fos was studied in 24 brain regions relevant for conditioned fear, e.g. in subdivisions of the prefrontal cortex, hippocampus, amygdala, hypothalamic defensive system, brainstem monoaminergic nuclei and periaqueductal gray. The intensity of conditioned fear (as shown by the duration of contextual freezing) was similar at the two time-points, but the associated neuronal changes were qualitatively different. Surprisingly, however, Multiple Regression Analyses suggested that conditioned fear-induced changes in neuronal activation patterns predicted the duration of freezing with high accuracy at both time points. We suggest that exposure to electric shocks is followed by a period of plasticity where the mechanisms that sustain conditioned fear undergo qualitative changes. Neuronal changes observed 28 days but not 1 day after shocks were consistent with those observed in human studies performed in PTSD patients.
Collapse
Affiliation(s)
- Aron Tulogdi
- Department of Behavioral Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Butler RK, Nilsson-Todd L, Cleren C, Léna I, Garcia R, Finn DP. Molecular and electrophysiological changes in the prefrontal cortex-amygdala-dorsal periaqueductal grey pathway during persistent pain state and fear-conditioned analgesia. Physiol Behav 2011; 104:1075-81. [PMID: 21683728 DOI: 10.1016/j.physbeh.2011.05.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 04/08/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
Abstract
Fear-conditioned analgesia (FCA) is the reduction in pain responding which is expressed upon re-exposure to a context previously paired with an aversive stimulus. Projections along the prefrontal cortex (PFC)-amygdala-dorsal periaqueductal grey (dPAG) pathway may mediate FCA. However, there is a paucity of studies measuring both molecular and electrophysiological changes in this pathway in rats expressing persistent pain-related behaviour or FCA. Male Lister-hooded rats, with stimulating and recording electrodes implanted in the amygdala and dPAG, respectively, either received or did not receive footshock (0.4 mA) paired with context, followed 23.5 h later by an intraplantar injection of saline or formalin (50 μL, 2.5%) into the right hindpaw. Thirty minutes post-formalin/saline, rats were re-exposed to the context for 15 min, during which pain-related behaviours were assessed in addition to evoked field potential recordings in the amygdala-dPAG pathway. Immediately after the 15-minute trial, PFC tissue was isolated for measurement of total and phosphorylated extracellular-signal regulated kinase (ERK) by western blotting. Formalin-evoked nociceptive behaviour in non-fear-conditioned rats was associated with increased field potential amplitude in the dPAG and increased relative expression of phospho-ERK in the PFC. These effects were abolished in rats expressing FCA. Fear conditioning in non-formalin treated rats was associated with increased phospho-ERK in the PFC but no change in field potential amplitude in the dPAG. Together, these data suggest differential, state-dependent alterations in electrophysiological activity and ERK phosphorylation along the PFC-amygdala-dPAG pathway during pain, conditioned fear, and FCA.
Collapse
Affiliation(s)
- Ryan K Butler
- Pharmacology and Therapeutics, NCBES Neuroscience Cluster and Centre for Pain Research, School of Medicine, National University of Ireland, Galway, Ireland
| | | | | | | | | | | |
Collapse
|