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de Paula Rodrigues BM, Coimbra NC. CB 1 receptor signalling mediates cannabidiol-induced panicolytic-like effects and defensive antinociception impairment in mice threatened by Bothrops jararaca lancehead pit vipers. J Psychopharmacol 2022; 36:1384-1396. [PMID: 35946605 DOI: 10.1177/02698811221115755] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Cannabis sativa-derived substances such as cannabidiol (CBD) have attracted increasing clinical interest and consist in a new perspective for treating some neurological and psychiatric diseases. AIMS The aim of this work was to investigate the effect of acute treatment with CBD on panic-like defensive responses displayed by mice threatened by the venomous snake Bothrops jararaca. METHODS Mice were habituated in the enriched polygonal arena for snake panic test. After recording the baseline responses of the tail-flick test, the prey were pretreated with intraperitoneal (i.p.) administrations of the endocannabinoid type 1 receptor (CB1) antagonist AM251 (selective cannabinoid 1 receptor antagonist with an IC50 of 8 nM) at different doses, which were followed after 10 min by i.p. treatment with CBD (3 mg/kg). Thirty minutes after treatment with CBD, mice were subjected to confrontations by B. jararaca for 5 min, and the following defensive responses were recorded: risk assessment, oriented escape behaviour, inhibitory avoidance and prey-versus-snake interactions. Immediately after the escape behaviour was exhibited, the tail-flick latencies were recorded every 5 min for 30 min. OUTCOMES Mice threatened by snakes displayed several anti-predatory defensive and innate fear-induced antinociception responses in comparison to the control. CBD significantly decreased the risk assessment and escape responses, with a consequent decrease in defensive antinociception. The CBD panicolytic effect was reversed by i.p. treatment with AM251. CONCLUSIONS These findings suggest that the anti-aversive effect of CBD depends at least in part on the recruitment of CB1 receptors.
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Affiliation(s)
- Bruno Mangili de Paula Rodrigues
- Laboratory of Neuroanatomy and Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
- NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
- Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Norberto Cysne Coimbra
- Laboratory of Neuroanatomy and Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
- NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
- Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
- Behavioural Neurosciences Institute (INeC), Ribeirão Preto, São Paulo, Brazil
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Calvo F, Lobão-Soares B, de Freitas RL, Paschoalin-Maurin T, Dos Anjos-Garcia T, Medeiros P, da Silva JA, Lovick TA, Coimbra NC. The endogenous opioid system modulates defensive behavior evoked by Crotalus durissus terrificus: Panicolytic-like effect of intracollicular non-selective opioid receptors blockade. J Psychopharmacol 2019; 33:51-61. [PMID: 30407114 DOI: 10.1177/0269881118806301] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND There is a controversy regarding the key role played by opioid peptide neurotransmission in the modulation of panic-attack-related responses. AIMS Using a prey versus rattlesnakes paradigm, the present work investigated the involvement of the endogenous opioid peptide-mediated system of the inferior colliculus in the modulation of panic attack-related responses. METHODS Wistar rats were pretreated with intracollicular administration of either physiological saline or naloxone at different concentrations and confronted with rattlesnakes ( Crotalus durissus terrificus). The prey versus rattlesnake confrontations were performed in a polygonal arena for snakes. The defensive behaviors displayed by prey (defensive attention, defensive immobility, escape response, flat back approach and startle) were recorded twice: firstly, over a period of 15 min the presence of the predator and a re-exposure was performed 24 h after the confrontation, when animals were exposed to the experimental enclosure without the rattlesnake. RESULTS The intramesencephalic non-specific blockade of opioid receptors with microinjections of naloxone at higher doses decreased both anxiety- (defensive attention and flat back approach) and panic attack-like (defensive immobility and escape) behaviors, evoked in the presence of rattlesnakes and increased non-defensive responses. During the exposure to the experimental context, there was a decrease in duration of defensive attention. CONCLUSIONS These findings suggest a panicolytic-like effect of endogenous opioid receptors antagonism in the inferior colliculus on innate (panic attack) and conditioned (anticipatory anxiety) fear in rats threatened by rattlesnakes.
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Affiliation(s)
- Fabrício Calvo
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,3 Department of Pharmacology, São Lucas College, Porto Velho (RO), Brazil.,4 Aparício Carvalho Integrative College, Porto Velho (RO), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Bruno Lobão-Soares
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,5 Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte (UFRN), Natal (RN), Brazil.,6 Instituto de Neurociências e Comportamento (INeC), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Renato Leonardo de Freitas
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,7 Laboratory of Neurobiology of Pain and Emotions and Multi-User Centre of Neuroelectrophysiology, Department of Surgery and Anatomy, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto (SP), Brazil.,10 Biomedical Sciences Institute, Federal University of Alfenas (UNIFAL-MG), Alfenas (MG), Brazil
| | - Tatiana Paschoalin-Maurin
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,6 Instituto de Neurociências e Comportamento (INeC), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Tayllon Dos Anjos-Garcia
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Priscila Medeiros
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Juliana Almeida da Silva
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
| | - Thelma Anderson Lovick
- 2 School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.,6 Instituto de Neurociências e Comportamento (INeC), Ribeirão Preto (SP), Brazil
| | - Norberto Cysne Coimbra
- 1 Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,6 Instituto de Neurociências e Comportamento (INeC), Ribeirão Preto (SP), Brazil.,7 Laboratory of Neurobiology of Pain and Emotions and Multi-User Centre of Neuroelectrophysiology, Department of Surgery and Anatomy, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto (SP), Brazil.,8 NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil.,9 Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), Brazil
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Ko J. Neuroanatomical Substrates of Rodent Social Behavior: The Medial Prefrontal Cortex and Its Projection Patterns. Front Neural Circuits 2017; 11:41. [PMID: 28659766 PMCID: PMC5468389 DOI: 10.3389/fncir.2017.00041] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 05/29/2017] [Indexed: 12/30/2022] Open
Abstract
Social behavior encompasses a number of distinctive and complex constructs that form the core elements of human imitative culture, mainly represented as either affiliative or antagonistic interactions with conspecifics. Traditionally considered in the realm of psychology, social behavior research has benefited from recent advancements in neuroscience that have accelerated identification of the neural systems, circuits, causative genes and molecular mechanisms that underlie distinct social cognitive traits. In this review article, I summarize recent findings regarding the neuroanatomical substrates of key social behaviors, focusing on results from experiments conducted in rodent models. In particular, I will review the role of the medial prefrontal cortex (mPFC) and downstream subcortical structures in controlling social behavior, and discuss pertinent future research perspectives.
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Affiliation(s)
- Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu, South Korea
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Siba IP, Bortolanza M, Frazão Vital MAB, Andreatini R, da Cunha JM, Del Bel EA, Zanoveli JM. Fish oil prevents rodent anxious states comorbid with diabetes: A putative involvement of nitric oxide modulation. Behav Brain Res 2017; 326:173-186. [DOI: 10.1016/j.bbr.2017.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 03/02/2017] [Accepted: 03/04/2017] [Indexed: 01/17/2023]
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Muthuraju S, Talbot T, Brandão ML. Dopamine D2 receptors regulate unconditioned fear in deep layers of the superior colliculus and dorsal periaqueductal gray. Behav Brain Res 2015; 297:116-23. [PMID: 26455877 DOI: 10.1016/j.bbr.2015.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 09/30/2015] [Accepted: 10/03/2015] [Indexed: 11/16/2022]
Abstract
RATIONALE Electrical and chemical stimulation of the dorsal periaqueductal gray (dPAG), deep layers of the superior colliculus (dlSC), and inferior colliculus (IC) causes freezing and escape behavior in rodents. Systemic injections of the selective dopamine D2 receptor antagonist sulpiride increased the number of switch-off responses (SORs) to light and auditory evoked potentials in response to loud sounds. Dopamine D2 receptor inhibition in the IC was shown to enhance unconditioned fear. Nevertheless, the role of dopamine receptors in the dlSC and dPAG in the mediation of unconditioned fear has not yet been demonstrated. OBJECTIVES The purpose of the present study was to characterize the effects of sulpiride injections (4 and 8 μg/0.2 μl) in the dlSC and dPAG in rats that were subjected to unconditioned fear paradigms. METHODS Switch-off responses to light and exploratory behavior in the elevated plus maze were used to evaluate unconditioned fear in rats. RESULTS Intra-dlSC microinjections of sulpiride increased the number of SORs to light. Intra-dlSC and intra-dPAG injections of sulpiride reduced the number of entries into and time spent on the open arms and decreased end-arm exploration and head dipping in the elevated plus maze. CONCLUSION These findings suggest that dopamine, through D2 receptors in the dlSC and dPAG, is involved in defense reactions that are organized in the midbrain tectum.
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Affiliation(s)
- Sangu Muthuraju
- Laboratory of Neuropsychopharmacology, FFCLRP, Universidade de São Paulo, Campus USP, Ribeirão Preto, SP 14049-901, Brazil; Instituto de Neurociencias e Comportamento, Avenida do Café, 2450, Ribeirão Preto, São Paulo, 14050-000, Brazil
| | - Teddy Talbot
- Instituto de Neurociencias e Comportamento, Avenida do Café, 2450, Ribeirão Preto, São Paulo, 14050-000, Brazil; Department of Neurosciences and Behavior, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirao Preto, São Paulo, Brazil
| | - Marcus Lira Brandão
- Laboratory of Neuropsychopharmacology, FFCLRP, Universidade de São Paulo, Campus USP, Ribeirão Preto, SP 14049-901, Brazil; Instituto de Neurociencias e Comportamento, Avenida do Café, 2450, Ribeirão Preto, São Paulo, 14050-000, Brazil.
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Sergio TDO, Spiacci A, Zangrossi H. Effects of dorsal periaqueductal gray CRF1- and CRF2-receptor stimulation in animal models of panic. Psychoneuroendocrinology 2014; 49:321-30. [PMID: 25146701 DOI: 10.1016/j.psyneuen.2014.07.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 10/24/2022]
Abstract
An increasing amount of evidence suggests that dysregulation of corticotrophin-releasing factor (CRF) signaling may contribute to the etiology of anxiety disorders such as post-traumatic stress disorder and panic. The dorsal periaqueductal gray matter (dPAG) in the midbrain has been considered a key region involved in the physiopathology of anxiety and panic. Administration of CRF in this structure enhances the expression of anxiety-related defensive behaviors in different animal models. Controversial results have been obtained regarding the involvement of CRF1 and CRF2 receptors in the regulation of panic-related responses. We report here that CRF (0.0625-1 μg) in the dPAG facilitates escape expression in two animal models that associate this behavior with panic, the elevated T-maze and the electrical stimulation of the dPAG. This effect, equally observed after CRF injection in the dorsomedial and dorsolateral columns of the PAG, is due to the activation of CRF1 receptors as revealed by its blockade by the CRF1 receptor antagonist antalarmin. In the elevated T-maze, CRF also facilitates inhibitory avoidance acquisition, suggesting an anxiogenic effect. Local administration of urocortin 2 (0.01-0.1 μg), a preferential CRF2 receptor agonist, failed to change escape expression, but impaired avoidance learning, indicating an anxiolytic effect. The results indicate that CRF1 receptors in the dPAG play a pervasive role in the regulation of defensive responses associated with both generalized anxiety and panic. Recruitment of CRF2 receptors only impacts upon the former type of behaviors, leading to an effect opposed to that caused by CRF1 receptor activation.
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Affiliation(s)
- Thatiane de Oliveira Sergio
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Ailton Spiacci
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Hélio Zangrossi
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, São Paulo, Brazil.
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Periaqueductal gray matter modulates the hypercapnic ventilatory response. Pflugers Arch 2012; 464:155-66. [PMID: 22665049 DOI: 10.1007/s00424-012-1119-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/16/2012] [Accepted: 05/22/2012] [Indexed: 01/15/2023]
Abstract
The periaqueductal gray (PAG) is a midbrain structure directly involved in the modulation of defensive behaviors. It has direct projections to several central nuclei that are involved in cardiorespiratory control. Although PAG stimulation is known to elicit respiratory responses, the role of the PAG in the CO(2)-drive to breathe is still unknown. The present study assessed the effect of chemical lesion of the dorsolateral and dorsomedial and ventrolateral/lateral PAG (dlPAG, dmPAG, and vPAG, respectively) on cardiorespiratory and thermal responses to hypercapnia. Ibotenic acid (IBO) or vehicle (PBS, Sham group) was injected into the dlPAG, dmPAG, or vPAG of male Wistar rats. Rats with lesions outside the dlPAG, dmPAG, or vPAG were considered as negative controls (NC). Pulmonary ventilation (VE: ), mean arterial pressure (MAP), heart rate (HR), and body temperature (Tb) were measured in unanesthetized rats during normocapnia and hypercapnic exposure (5, 15, 30 min, 7 % CO(2)). IBO lesioning of the dlPAG/dmPAG caused 31 % and 26.5 % reductions of the respiratory response to CO(2) (1,094.3 ± 115 mL/kg/min) compared with Sham (1,589.5 ± 88.1 mL/kg/min) and NC groups (1,488.2 ± 47.7 mL/kg/min), respectively. IBO lesioning of the vPAG caused 26.6 % and 21 % reductions of CO(2) hyperpnea (1,215.3 ± 108.6 mL/kg/min) compared with Sham (1,657.3 ± 173.9 mL/kg/min) and NC groups (1,537.6 ± 59.3). Basal VE: , MAP, HR, and Tb were not affected by dlPAG, dmPAG, or vPAG lesioning. The results suggest that dlPAG, dmPAG, and vPAG modulate hypercapnic ventilatory responses in rats but do not affect MAP, HR, or Tb regulation in resting conditions or during hypercapnia.
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Serotonin-2A receptor regulation of panic-like behavior in the rat dorsal periaqueductal gray matter: the role of GABA. Psychopharmacology (Berl) 2011; 218:725-32. [PMID: 21660445 DOI: 10.1007/s00213-011-2369-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 05/20/2011] [Indexed: 12/28/2022]
Abstract
RATIONALE Electrical stimulation of the dorsal periaqueductal gray (dPAG) evokes escape, a defensive response associated with panic attacks. Stimulation of 5-HT1A or 5-HT2A receptors in this midbrain area equally inhibits escape performance, even though at the molecular level these receptors cause opposite effects, i.e., activation of the former hyperpolarizes the cell membrane, while the latter excites it. A proposal has been made that 5-HT2A receptor agonists exert their inhibitory effect on escape by activating GABAergic interneurons located in the dPAG. OBJECTIVES In the present study, we evaluated this hypothesis by investigating whether previous intra-dPAG administration of the GABAA receptor antagonist bicuculline blocks the anti-escape effect caused by the local injection of different 5-HT2A/2C receptor agonists. RESULTS Intra-dPAG administration of 5-HT, the preferential 5-HT2A receptor agonist DOI, the nonselective 5-HT2C receptor agonist mCPP or the 5-HT2C receptor agonist RO 60-0175 significantly inhibited the escape reaction induced by electrical stimulation of the same brain area. In all cases, this panicolytic-like effect was blocked by previous microinjection of bicuculline. This GABAA antagonist, however, failed to antagonize the anti-escape effect caused by the 5-HT1A receptor agonist 8-OH-DPAT. The inhibitory effect caused by DOI, RO 60-0175, and mCPP was also blocked by previous intra-dPAG injection of the preferential 5-HT2A receptor antagonist ketanserin. Pre-administration of the 5-HT2C receptor antagonist SB-242084 in the dPAG did not block the anti-escape effect of RO 60-0175. CONCLUSIONS Stimulation of 5-HT2A but not 5-HT2C receptors in the dPAG causes a panicolytic-like effect that is mediated by facilitation of GABAergic neurotransmission.
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Lim LW, Blokland A, Tan S, Vlamings R, Sesia T, Aziz-Mohammadi M, Visser-Vandewalle V, Steinbusch HW, Schruers K, Temel Y. Attenuation of fear-like response by escitalopram treatment after electrical stimulation of the midbrain dorsolateral periaqueductal gray. Exp Neurol 2010; 226:293-300. [DOI: 10.1016/j.expneurol.2010.08.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/26/2010] [Accepted: 08/30/2010] [Indexed: 11/26/2022]
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Panicolytic-like effect of BDNF in the rat dorsal periaqueductal grey matter: the role of 5-HT and GABA. Int J Neuropsychopharmacol 2010; 13:573-82. [PMID: 20047714 DOI: 10.1017/s146114570999112x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A wealth of evidence suggests a role for brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase B (TrkB) in the aetiology of depression and in the mode of action of antidepressant drugs. Less clear is the involvement of this neurotrophin in other stress-related pathologies such as anxiety disorders. The dorsal periaqueductal grey matter (DPAG), a midbrain area rich in BDNF and TrkB receptor mRNAs and proteins, has been considered a key structure in the pathophysiology of panic disorder. In this study we investigated the effect of intra-DPAG injection of BDNF in a proposed animal model of panic: the escape response evoked by the electrical stimulation of the same midbrain area. To this end, the intensity of electrical current that needed to be applied to DPAG to evoke escape behaviour was measured before and after microinjection of BDNF. We also assessed whether 5-HT- or GABA-related mechanisms may account for the putative behavioural/autonomic effects of the neurotrophin. BDNF (0.05, 0.1, 0.2 ng) dose-dependently inhibited escape performance, suggesting a panicolytic-like effect. Local microinjection of K252a, an antagonist of TrkB receptors, or bicuculline, a GABAA receptor antagonist, blocked this effect. Intra-DPAG administration of WAY-100635 or ketanserin, respectively 5-HT1A and 5-HT2A/2C receptor antagonists, did not alter BDNF's effects on escape. Bicuculline also blocked the inhibitory effect of BDNF on mean arterial pressure increase caused by electrical stimulation of DPAG. Therefore, in the DPAG, BDNF-TrkB signalling interacts with the GABAergic system to cause a panicolytic-like effect.
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Vizi ES, Fekete A, Karoly R, Mike A. Non-synaptic receptors and transporters involved in brain functions and targets of drug treatment. Br J Pharmacol 2010; 160:785-809. [PMID: 20136842 DOI: 10.1111/j.1476-5381.2009.00624.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Beyond direct synaptic communication, neurons are able to talk to each other without making synapses. They are able to send chemical messages by means of diffusion to target cells via the extracellular space, provided that the target neurons are equipped with high-affinity receptors. While synaptic transmission is responsible for the 'what' of brain function, the 'how' of brain function (mood, attention, level of arousal, general excitability, etc.) is mainly controlled non-synaptically using the extracellular space as communication channel. It is principally the 'how' that can be modulated by medicine. In this paper, we discuss different forms of non-synaptic transmission, localized spillover of synaptic transmitters, local presynaptic modulation and tonic influence of ambient transmitter levels on the activity of vast neuronal populations. We consider different aspects of non-synaptic transmission, such as synaptic-extrasynaptic receptor trafficking, neuron-glia communication and retrograde signalling. We review structural and functional aspects of non-synaptic transmission, including (i) anatomical arrangement of non-synaptic release sites, receptors and transporters, (ii) intravesicular, intra- and extracellular concentrations of neurotransmitters, as well as the spatiotemporal pattern of transmitter diffusion. We propose that an effective general strategy for efficient pharmacological intervention could include the identification of specific non-synaptic targets and the subsequent development of selective pharmacological tools to influence them.
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Affiliation(s)
- E S Vizi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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Descarries L, Riad M, Parent M. Ultrastructure of the Serotonin Innervation in the Mammalian Central Nervous System. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70072-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Implication of the 5-HT2A and 5-HT2C (but not 5HT1A) receptors located within the periaqueductal gray in the elevated plus-maze test-retest paradigm in mice. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:1261-9. [PMID: 19625008 DOI: 10.1016/j.pnpbp.2009.07.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 07/03/2009] [Accepted: 07/10/2009] [Indexed: 11/21/2022]
Abstract
A single exposure to the elevated plus-maze test (EPM) increases open arms avoidance and reduces or abolishes the anxiolytic-like effect of benzodiazepines assessed during a second trial, a phenomenon defined as "one-trial tolerance" (OTT). It has been emphasized that the dorsal portion of the midbrain periaqueductal gray (dPAG) plays a role on this enhanced aversion phenomenon in maze-experienced rodents. Given that intra-dPAG injections of a wide range of serotonergic 5-HT(1A), 5-HT(2A) and 5-HT(2C) receptor agonists produce anxiolytic-like effects in maze-naïve rodents, the present study examined the effects of the 5-HT(1A) receptor agonist 8-OH-DPAT (5.6 and 10.0nmol in 0.15microl) the preferential 5-HT(2A) receptor agonist DOI (2.0 and 8.0nmol in 0.1microl) and the preferential 5-HT(2C) receptor agonist MK-212 (21.2 and 63.6nmol in 0.1microl) microinjected into the dPAG prior to Trial 1 and Trial 2 on the behaviour of mice in the EPM. Test sessions were recorded and subsequently scored for anxiety-like behaviour (percentage of open arms entries and time) as well as general locomotor activity (closed arm entries). The results showed a lack of 8-OH-DPAT (5.6 and 10.0nmol) effect on the behaviour of maze-naïve and maze-experienced mice, while intra-dPAG microinfusions of DOI (8nmol) reduced anxiety-like behaviour only in maze-experienced mice that had received a similar treatment prior to Trial 1. Furthermore, intra-dPAG MK-212 (63.6nmol) showed an anxiolytic-like effect on both Trial 1 and Trial 2. Importantly, these effects were observed in the absence of any significant change in closed arm entries, the parameter considered to be a valid index of locomotor activity in the plus-maze. These results support the dPAG as a crucial structure involved in the neurobiology of the OTT phenomenon as well as accounting the role of the 5-HT(2A) and 5-HT(2C) receptors located within this midbrain structure on the emotional state induced by EPM test and retest paradigm mice.
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Influence of dorsal periaqueductal gray activation on respiratory occlusion reflexes in rats. Auton Neurosci 2009; 150:62-9. [DOI: 10.1016/j.autneu.2009.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 03/10/2009] [Accepted: 04/29/2009] [Indexed: 01/10/2023]
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Carvalho-Netto EF, Gomes KS, Amaral VCS, Nunes-de-Souza RL. Role of glutamate NMDA receptors and nitric oxide located within the periaqueductal gray on defensive behaviors in mice confronted by predator. Psychopharmacology (Berl) 2009; 204:617-25. [PMID: 19241059 DOI: 10.1007/s00213-009-1492-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 02/08/2009] [Indexed: 12/01/2022]
Abstract
RATIONALE The midbrain periaqueductal gray (PAG) is part of the brain system involved in active defense reactions to threatening stimuli. Glutamate N-methyl-D: -aspartate (NMDA) receptor activation within the dorsal column of the PAG (dPAG) leads to autonomic and behavioral responses characterized as the fear reaction. Nitric oxide (NO) has been proposed to be a mediator of the aversive action of glutamate, since the activation of NMDA receptors in the brain increases NO synthesis. OBJECTIVES We investigated the effects of intra-dPAG infusions of NMDA on defensive behaviors in mice pretreated with a neuronal nitric oxide synthase (nNOS) inhibitor [Nomega-propyl-L: -arginine (NPLA)], in the same midbrain site, during a confrontation with a predator in the rat exposure test (RET). MATERIALS AND METHODS Male Swiss mice received intra-dPAG injections of NPLA (0.1 or 0.4 nmol/0.1 microl), and 10 min later, they were infused with NMDA (0.04 nmol/0.1 microl) into the dPAG. After 10 min, each mouse was placed in the RET. RESULTS NMDA treatment enhanced avoidance behavior from the predator and markedly increased freezing behavior. These proaversive effects of NMDA were prevented by prior injection of NPLA. Furthermore, defensive behaviors (e.g., avoidance, risk assessment, freezing) were consistently reduced by the highest dose of NPLA alone, suggesting an intrinsic effect of nitric oxide on defensive behavior in mice exposed to the RET. CONCLUSIONS These findings suggest a potential role of glutamate NMDA receptors and NO in the dPAG in the regulation of defensive behaviors in mice during a confrontation with a predator in the RET.
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Moraes CL, Bertoglio LJ, Carobrez AP. Interplay between glutamate and serotonin within the dorsal periaqueductal gray modulates anxiety-related behavior of rats exposed to the elevated plus-maze. Behav Brain Res 2008; 194:181-6. [DOI: 10.1016/j.bbr.2008.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 07/07/2008] [Accepted: 07/09/2008] [Indexed: 11/26/2022]
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Buspirone induced acute and chronic changes of neural activation in the periaqueductal gray of rats. Neuroscience 2008; 155:164-73. [PMID: 18588948 DOI: 10.1016/j.neuroscience.2008.05.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 05/27/2008] [Accepted: 05/30/2008] [Indexed: 11/28/2022]
Abstract
5-HT(1A) modulation within the midbrain periaqueductal gray (PAG) is closely associated with anxiety- or panic-like behavior. Several findings have demonstrated that the properties of buspirone (a 5-HT(1A) partial agonist) would function as either anxiolytic or panicolytic in both clinical and laboratory animal research. In this study, we have investigated the neuronal activity occurring within the different regions of the PAG induced by buspirone treatment. Twenty-eight albino Wistar rats (350-400 g) were injected with either acute or chronic saline/buspirone (each, n=7), respectively. Our results show that buspirone treatment reduced locomotor activity, body weight and fecal boli, particularly in the chronic buspirone group. Two-way ANOVA revealed a significant decrease of c-Fos-immunoreactive (ir) cells expression in all regions of the rostral PAG after both acute and chronic buspirone (acute buspirone (AB) and chronic buspirone (CB), respectively) treatment. However, no effects on c-Fos-ir were detected in the caudal lateral periaqueductal gray (lPAG) and ventrolateral periaqueductal gray (vlPAG) in both the AB and CB groups, and in the dorsolateral periaqueductal gray (dlPAG) of the CB group. Interestingly, c-Fos-ir cells in the dorsomedial periaqueductal gray (dmPAG) column were reduced consistently in both the rostral and caudal PAG in both AB and CB groups. Besides, in all regions the number of c-Fos-ir cells was higher in the AB than in the CB group with exception of the rostral lPAG. In conclusion, the main anxiolytic effect of buspirone was specifically localized in all regions of the rostral PAG and in the caudal dmPAG. However, the caudal dlPAG, lPAG and vlPAG were found to be ineffective to buspirone treatment, probably due to their distinctive function in mediating higher level of anxiety in defensive behavior. This indicates that the longitudinal anatomical structure of the PAG possesses a different level of receptor sensitivity of 5-HT(1A) in the pathophysiology of anxiety and panic disorder.
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Regulation of conditioned and unconditioned fear in rats by 5-HT1A receptors in the dorsal periaqueductal gray. Pharmacol Biochem Behav 2008; 89:76-84. [DOI: 10.1016/j.pbb.2007.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 10/23/2007] [Accepted: 11/14/2007] [Indexed: 11/21/2022]
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Descarries L, Mechawar N. Ultrastructural evidence for diffuse transmission by monoamine and acetylcholine neurons of the central nervous system. PROGRESS IN BRAIN RESEARCH 2001; 125:27-47. [PMID: 11098652 DOI: 10.1016/s0079-6123(00)25005-x] [Citation(s) in RCA: 165] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- L Descarries
- Département de pathologie, Centre de recherche en sciences neurologiques, Faculté de médecine, Université de Montréal, Canada.
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Abstract
OBJECTIVE The purposes of this article are (1) to review current knowledge of and recent concepts pertaining to the causes of chronic pain and/or dysfunction following whiplash-type injuries and (2) to acquaint those who treat these types of injuries with possible mechanisms of continued pain and or dysfunction following whiplash. DATA COLLECTION A review of the literature on mechanisms of injury and neurologic considerations was undertaken. A hand search of relevant medical, neuroscience, chiropractic, and online Index Medicus sources and other sources involving mechanisms of nociception, neurotransmitters, and receptors that might evolve from whiplash-type soft tissue injuries was conducted. RESULTS Pain is a complex phenomenon that has great variability. Chronic pain appears to involve a deficient descending inhibitory process and/or ongoing excitatory input. CONCLUSIONS There is a wide variety of reactions by individuals to any given type of stimulus. Injury may lead to increases in neuronal activity and prolonged changes in the nervous system. Chronic pain may be seen as part of a central disturbance accompanied by disinhibition or sensitization of central pain modulation, mirrored in the immune and endocrine systems. Patients with chronic whiplash syndrome may have a generalized central hyperexcitability from a loss of tonic inhibitory input (disinhibition) and/or ongoing excitatory input contributing to dorsal horn hyperexcitability. Dysfunction of the motor system may also occur, with or without pain. The purpose of treatment should be not only to relieve pain but also to allow for proper proprioception.
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