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Wang F, Chen Y, Lin Y, Wang X, Li K, Han Y, Wu J, Shi X, Zhu Z, Long C, Hu X, Duan S, Gao Z. A parabrachial to hypothalamic pathway mediates defensive behavior. eLife 2023; 12:85450. [PMID: 36930206 PMCID: PMC10023160 DOI: 10.7554/elife.85450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/13/2023] [Indexed: 03/18/2023] Open
Abstract
Defensive behaviors are critical for animal's survival. Both the paraventricular nucleus of the hypothalamus (PVN) and the parabrachial nucleus (PBN) have been shown to be involved in defensive behaviors. However, whether there are direct connections between them to mediate defensive behaviors remains unclear. Here, by retrograde and anterograde tracing, we uncover that cholecystokinin (CCK)-expressing neurons in the lateral PBN (LPBCCK) directly project to the PVN. By in vivo fiber photometry recording, we find that LPBCCK neurons actively respond to various threat stimuli. Selective photoactivation of LPBCCK neurons promotes aversion and defensive behaviors. Conversely, photoinhibition of LPBCCK neurons attenuates rat or looming stimuli-induced flight responses. Optogenetic activation of LPBCCK axon terminals within the PVN or PVN glutamatergic neurons promotes defensive behaviors. Whereas chemogenetic and pharmacological inhibition of local PVN neurons prevent LPBCCK-PVN pathway activation-driven flight responses. These data suggest that LPBCCK neurons recruit downstream PVN neurons to actively engage in flight responses. Our study identifies a previously unrecognized role for the LPBCCK-PVN pathway in controlling defensive behaviors.
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Affiliation(s)
- Fan Wang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Yuge Chen
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Yuxin Lin
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Xuze Wang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Kaiyuan Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Yong Han
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Jintao Wu
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Xingyi Shi
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Zhenggang Zhu
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Chaoying Long
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
| | - Xiaojun Hu
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang UniversityHangzhouChina
| | - Shumin Duan
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang UniversityHangzhouChina
- Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Fudan UniversityShanghaiChina
- The Institute of Brain and Cognitive Sciences, Zhejiang University City CollegeHangzhouChina
- Chuanqi Research and Development Center of Zhejiang UniversityHangzhouChina
| | - Zhihua Gao
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
- Liangzhu Laboratory, Zhejiang University Medical Center, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Labotatory of Brain-machine intelligence, Zhejiang UniversityHangzhouChina
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang UniversityHangzhouChina
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Vázquez-León P, Miranda-Páez A, Chávez-Reyes J, Allende G, Barragán-Iglesias P, Marichal-Cancino BA. The Periaqueductal Gray and Its Extended Participation in Drug Addiction Phenomena. Neurosci Bull 2021; 37:1493-1509. [PMID: 34302618 DOI: 10.1007/s12264-021-00756-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 05/11/2021] [Indexed: 12/19/2022] Open
Abstract
The periaqueductal gray (PAG) is a complex mesencephalic structure involved in the integration and execution of active and passive self-protective behaviors against imminent threats, such as immobility or flight from a predator. PAG activity is also associated with the integration of responses against physical discomfort (e.g., anxiety, fear, pain, and disgust) which occurs prior an imminent attack, but also during withdrawal from drugs such as morphine and cocaine. The PAG sends and receives projections to and from other well-documented nuclei linked to the phenomenon of drug addiction including: (i) the ventral tegmental area; (ii) extended amygdala; (iii) medial prefrontal cortex; (iv) pontine nucleus; (v) bed nucleus of the stria terminalis; and (vi) hypothalamus. Preclinical models have suggested that the PAG contributes to the modulation of anxiety, fear, and nociception (all of which may produce physical discomfort) linked with chronic exposure to drugs of abuse. Withdrawal produced by the major pharmacological classes of drugs of abuse is mediated through actions that include participation of the PAG. In support of this, there is evidence of functional, pharmacological, molecular. And/or genetic alterations in the PAG during the impulsive/compulsive intake or withdrawal from a drug. Due to its small size, it is difficult to assess the anatomical participation of the PAG when using classical neuroimaging techniques, so its physiopathology in drug addiction has been underestimated and poorly documented. In this theoretical review, we discuss the involvement of the PAG in drug addiction mainly via its role as an integrator of responses to the physical discomfort associated with drug withdrawal.
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Affiliation(s)
- Priscila Vázquez-León
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, 20131, Aguascalientes, Ags., Mexico
| | - Abraham Miranda-Páez
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Wilfrido Massieu esq. Manuel Stampa s/n Col. Nueva Industrial Vallejo, 07738, Gustavo A. Madero, Mexico City, Mexico
| | - Jesús Chávez-Reyes
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, 20131, Aguascalientes, Ags., Mexico
| | - Gonzalo Allende
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, 20131, Aguascalientes, Ags., Mexico
| | - Paulino Barragán-Iglesias
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, 20131, Aguascalientes, Ags., Mexico.
| | - Bruno A Marichal-Cancino
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, 20131, Aguascalientes, Ags., Mexico.
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He X, Jin C, Ma M, Zhou R, Wu S, Huang H, Li Y, Chen Q, Zhang M, Zhang H, Tian M. PET imaging on neurofunctional changes after optogenetic stimulation in a rat model of panic disorder. Front Med 2019; 13:602-609. [PMID: 31321611 DOI: 10.1007/s11684-019-0704-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/12/2019] [Indexed: 12/24/2022]
Abstract
Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology. The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD. However, the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo. In this study, optogenetic stimulation to the dPAG was performed to induce panic-like behaviors, and in vivo positron emission tomography (PET) imaging with 18F-flurodeoxyglucose (18F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation. Compared with the baseline, post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P < 0.001) in dPAG, the cuneiform nucleus, the cerebellar lobule, the cingulate cortex, the alveus of the hippocampus, the primary visual cortex, the septohypothalamic nucleus, and the retrosplenial granular cortex but significantly decreased (P < 0.001) in the basal ganglia, the frontal cortex, the forceps minor corpus callosum, the primary somatosensory cortex, the primary motor cortex, the secondary visual cortex, and the dorsal lateral geniculate nucleus. Taken together, these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.
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Affiliation(s)
- Xiao He
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Chentao Jin
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Mindi Ma
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Rui Zhou
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Shuang Wu
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Haoying Huang
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Yuting Li
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
| | - Qiaozhen Chen
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.,Department of Psychiatry, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Mingrong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Anagawa 4-9-1, Inage-ku, Chiba, 263-8555, Japan.
| | - Hong Zhang
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China. .,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China. .,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China.
| | - Mei Tian
- Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China. .,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China. .,Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China.
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Vázquez-León P, Campos-Rodríguez C, Gonzalez-Pliego C, Miranda-Páez A. Differential effects of cholecystokinin (CCK-8) microinjection into the ventrolateral and dorsolateral periaqueductal gray on anxiety models in Wistar rats. Horm Behav 2018; 106:105-111. [PMID: 30342011 DOI: 10.1016/j.yhbeh.2018.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 09/28/2018] [Accepted: 10/03/2018] [Indexed: 01/27/2023]
Abstract
Cholecystokinin (CCK) is one of the main neurohormone peptide systems in the brain, and a major anxiogenic mediator. The periaqueductal gray (PAG) is a key midbrain structure for defensive behaviors, which could include anxiety, fear, or even panic. The CCK system has wide distribution in the PAG, where the dorsolateral region (DL) participates in active defensive behavior and the ventrolateral region (VL) in passive defensive behavior. The aim of this study was to assess the effect of CCK-8 microinjection into DL-PAG or VL-PAG on anxiety-like behavior through two tests: elevated plus maze (EPM) and defensive burying behavior (DBB). CCK-8 (0.5 and 1.0 μg/0.5 μL) presently microinjected into the DL-PAG produced an anxiogenic-like effect on the EPM evidenced by decreasing the time spent/number of entries in open arms compared to vehicle group. Additionally, the latency to burying decreased and burying time increased on the DBB test. Contrarily, CCK-8 microinjected into the VL-PAG resulted in greater open-arm time and more open-arm entries compared to the vehicle-microinjected group. The results on the DBB test confirmed an anxiolytic-like response of CCK-8 into the VL-PAG. In conclusion, CCK-8 microinjected into DL-PAG produced anxiety-like behavior on EPM, and for first time reported on DBB. Contrarily, CCK-8 microinjected into the VL-PAG reduced anxiety-like behavior also for first time reported using both behavioral models EPM and DBB.
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Affiliation(s)
- Priscila Vázquez-León
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico
| | - Carolina Campos-Rodríguez
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico
| | - Carlos Gonzalez-Pliego
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico
| | - Abraham Miranda-Páez
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico.
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Galanin subtype 1 and subtype 2 receptors mediate opposite anxiety-like effects in the rat dorsal raphe nucleus. Behav Brain Res 2016; 314:125-33. [DOI: 10.1016/j.bbr.2016.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/01/2016] [Accepted: 08/03/2016] [Indexed: 01/09/2023]
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Translational approach to studying panic disorder in rats: hits and misses. Neurosci Biobehav Rev 2015; 46 Pt 3:472-96. [PMID: 25316571 DOI: 10.1016/j.neubiorev.2014.10.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/26/2014] [Accepted: 10/01/2014] [Indexed: 12/30/2022]
Abstract
Panic disorder (PD) patients are specifically sensitive to 5–7% carbon dioxide. Another startling feature of clinical panic is the counterintuitive lack of increments in ‘stress hormones’. PD is also more frequent in women and highly comorbid with childhood separation anxiety (CSA). On the other hand, increasing evidence suggests that panic is mediated at dorsal periaqueductal grey matter (DPAG). In line with prior studies showing that DPAG-evoked panic-like behaviours are attenuated by clinically-effective treatments with panicolytics, we show here that (i) the DPAG harbors a hypoxia-sensitive alarm system, which is activated by hypoxia and potentiated by hypercapnia, (ii) the DPAG suffocation alarm system is inhibited by clinically-effective treatments with panicolytics, (iii) DPAG stimulations do not increase stress hormones in the absence of physical exertion, (iv) DPAG-evoked panic-like behaviours are facilitated in neonatally-isolated adult rats, a model of CSA, and (v) DPAG-evoked responses are enhanced in the late diestrus of female rats. Data are consistent with the DPAG mediation of both respiratory and non-respiratory types of panic attacks.
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Schimitel F, de Almeida G, Pitol D, Armini R, Tufik S, Schenberg L. Evidence of a suffocation alarm system within the periaqueductal gray matter of the rat. Neuroscience 2012; 200:59-73. [DOI: 10.1016/j.neuroscience.2011.10.032] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 10/14/2011] [Accepted: 10/17/2011] [Indexed: 10/15/2022]
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Efficacy of chronic antidepressant treatments in a new model of extreme anxiety in rats. DEPRESSION RESEARCH AND TREATMENT 2011; 2011:531435. [PMID: 21808731 PMCID: PMC3144710 DOI: 10.1155/2011/531435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 05/31/2011] [Accepted: 06/03/2011] [Indexed: 11/23/2022]
Abstract
Animal models of anxious disorders found in humans, such as panic disorder and posttraumatic stress disorder, usually include spontaneous and conditioned fear that triggers escape and avoidance behaviors. The development of a panic disorder model with a learned component should increase knowledge of mechanisms involved in anxiety disorders. In our ethological model of extreme anxiety in the rat, forced apnea was combined with cold water vaporization in an inescapable situation. Based on the reactions of vehicle controls, behaviors involved in paroxysmic fear were passive (freezing) and active (jumping) reactions. Our results show that subchronic fluoxetine (5 mg/kg, IP, 21 days) and imipramine (10 mg/kg, IP, 14 days) administration alleviated freezing and jumping behaviors, whereas acute fluoxetine (1 mg/kg, IP) provoked opposite effects. Acute low dose of diazepam (1 mg/kg, IP) was not effective, whereas the higher dose of 3 mg/kg, IP, and clonazepam (1 mg/kg, IP) only had an effect on jumping. Paroxysmic fear generated in this experimental condition may therefore mimic the symptomatology observed in patients with anxiety disorders.
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Siqueira CC, Rossoni RR, Tiengo ANCP, Tufik S, Schenberg LC. Methimazole-induced hypothyroidism inhibits the panic-like behaviors produced by electrical stimulation of dorsal periaqueductal gray matter of rats. Psychoneuroendocrinology 2010; 35:706-16. [PMID: 19931985 DOI: 10.1016/j.psyneuen.2009.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Revised: 10/07/2009] [Accepted: 10/22/2009] [Indexed: 11/16/2022]
Abstract
Conflicting clinical data on the relationship of panic disorder and thyroid diseases illustrate the need for a simpler approach using animal models. Defensive behaviors evoked by electrical or chemical stimulation of dorsal periaqueductal gray matter (DPAG) have been proposed as a model of panic attack. Therefore, the present study examined the effects of the anti-thyroid agent methimazole (MTZ) either on the panic-like behaviors induced by electrical stimulation of DPAG or the anxiety-like behaviors of rats exposed to the elevated plus-maze (EPM). Male Wistar rats bearing electrodes in the DPAG were stimulated with stepwise increased currents. Rats which displayed galloping at intensities below 60muA were retested following 5- and 10-day treatments with MTZ (0.6mg/kg/day, i.p.) or 10- and 15-day washout periods. MTZ effects on EPM performance were assessed in separate groups. MTZ-treated groups were compared to saline-treated controls. In other experiments, rats were similarly treated with MTZ and the blood was collected for hormone assays. The 10-day treatment with MTZ produced marked increases in the thresholds of exophthalmus (65%), immobility (75%), trotting (63%), galloping (56%), jumping (47%), defecation (114%) and micturition (85%). Effects outlasted the drug discontinuation. In contrast, MTZ had variable effects in the EPM, significantly increasing the open-arm exploration in 5-day treated and 10-day washout groups. Biochemical data revealed a small but significant decrease (13%) in free thyroxine in MTZ-treated groups. Although not significant, thyrotrophin levels showed a 111% increase following the 10-day treatment with MTZ. Selective attenuation by MTZ of DPAG-evoked defensive behaviors supports attenuation of panic attacks in hypothyroidism.
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Affiliation(s)
- Carla Coelho Siqueira
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
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Siqueira CC, Rossoni RR, Schenberg LC. Dorsal periaqueductal gray matter-evoked panic-like behaviors are markedly inhibited by a low peripheral dose of thyrotropin releasing hormone. Psychoneuroendocrinology 2010; 35:262-71. [PMID: 19631472 DOI: 10.1016/j.psyneuen.2009.06.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 05/08/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
Abstract
Stimulation of the dorsal periaqueductal gray matter (DPAG) produces defensive behaviors which are reminiscent of panic attacks. Recent evidence from our laboratory showed that DPAG-evoked defensive behaviors are markedly attenuated in short-term methimazole-induced hypothyroidism. It is not clear, however, whether these effects were due to an increase in thyrotropin releasing hormone (TRH), a decrease in thyroid hormones or to the overall effects of hypothyroidism. Accordingly, here we examined whether the peripheral injection of TRH has any effect either on the panic-like behaviors induced by electrical stimulation of DPAG or anxiety-like behaviors of rats exposed to the elevated plus-maze (EPM). Rats whose stimulation of DPAG produced flight responses (galloping or jumping) with intensities below 60 microA were injected with 1 microg/kg TRH (i.p.) and stimulated 10min after that. The day after, rats were treated with saline and subjected to the same stimulation procedure. Threshold curves were fitted through the logistic model and compared by likelihood-ratio chi(2) tests. TRH and saline effects on EPM performance were appraised in separate groups. Compared to saline-sessions, TRH-injected rats presented thresholds significantly higher for immobility (40%), trotting (33%), galloping (34%), jumping (39%) and exophthalmus (43%). In contrast, TRH had no effects on EPM arm exploration. TRH selective inhibition of DPAG-evoked defensive behaviors adds new evidence that panic attacks may be attenuated by increased levels of this hormone in hypothyroidism.
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Affiliation(s)
- Carla Coelho Siqueira
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória-ES, Brazil
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Panic disorder: is the PAG involved? Neural Plast 2009; 2009:108135. [PMID: 19283082 PMCID: PMC2654309 DOI: 10.1155/2009/108135] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/25/2008] [Accepted: 12/17/2008] [Indexed: 12/01/2022] Open
Abstract
Data from studies with humans have suggested that abnormalities of midbrain structures, including the periaqueductal gray matter (PAG), could be involved in the neurobiology of panic disorder (PD). The electrical stimulation of the PAG in neurosurgical patients induces panic-like symptoms and the effect of drugs that are effective in the treatment of PD in the simulation of public speaking model of anxiety is in agreement with data from animal models of PD. Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients. There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients. Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.
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Chapter 5.3 Experimental models: Panic and fear. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1569-7339(07)00019-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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