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Huneke NTM, Cross C, Fagan HA, Molteni L, Phillips N, Garner M, Baldwin DS. Placebo Effects Are Small on Average in the 7.5% CO2 Inhalational Model of Generalized Anxiety. Int J Neuropsychopharmacol 2024; 27:pyae019. [PMID: 38577951 PMCID: PMC11059817 DOI: 10.1093/ijnp/pyae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/10/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Anxiety disorders are highly prevalent and socio-economically costly. Novel pharmacological treatments for these disorders are needed because many patients do not respond to current agents or experience unwanted side effects. However, a barrier to treatment development is the variable and large placebo response rate seen in trials of novel anxiolytics. Despite this, the mechanisms that drive placebo responses in anxiety disorders have been little investigated, possibly due to low availability of convenient experimental paradigms. We aimed to develop and test a novel protocol for inducing placebo anxiolysis in the 7.5% CO2 inhalational model of generalized anxiety in healthy volunteers. METHODS Following a baseline 20-minute CO2 challenge, 32 healthy volunteers were administered a placebo intranasal spray labelled as either the anxiolytic "lorazepam" or "saline." Following this, participants surreptitiously underwent a 20-minute inhalation of normal air. Post-conditioning, a second dose of the placebo was administered, after which participants completed another CO2 challenge. RESULTS Participants administered sham "lorazepam" reported significant positive expectations of reduced anxiety (P = .001), but there was no group-level placebo effect on anxiety following CO2 challenge post-conditioning (Ps > .350). Surprisingly, we found many participants exhibited unexpected worsening of anxiety, despite positive expectations. CONCLUSIONS Contrary to our hypothesis, our novel paradigm did not induce a placebo response, on average. It is possible that effects of 7.5% CO2 inhalation on prefrontal cortex function or behavior in line with a Bayesian predictive coding framework attenuated the effect of expectations on subsequent placebo response. Future studies are needed to explore these possibilities.
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Affiliation(s)
- Nathan T M Huneke
- Southern Health National Health Service Foundation Trust, Southampton, UK
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, Southampton, UK
| | - Cosmina Cross
- Southern Health National Health Service Foundation Trust, Southampton, UK
| | - Harry A Fagan
- Southern Health National Health Service Foundation Trust, Southampton, UK
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, Southampton, UK
| | - Laura Molteni
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, Southampton, UK
| | | | - Matthew Garner
- Center for Innovation in Mental Health, School of Psychology, Faculty of Environmental and Life Sciences, University of Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, Southampton, UK
| | - David S Baldwin
- University Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
- Southern Health National Health Service Foundation Trust, Southampton, UK
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, UK
- University Department of Psychiatry, Academic Centre, College Keep, Southampton, UK
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Müller JC, Walter C, Leibold N, Wiedemann K, Kellner M, Demiralay C. Copeptin response to panic provocation with CO 2 in healthy adults. J Psychiatr Res 2023; 165:225-232. [PMID: 37517243 DOI: 10.1016/j.jpsychires.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/27/2023] [Accepted: 07/06/2023] [Indexed: 08/01/2023]
Abstract
Repeated panic attacks are the core symptom of panic disorder and severely stressful for patients. Additional to the psychological response, the physiological symptoms are an important aspect of the experienced panic. However, data on the extent of hypothalamic-pituitary-adrenal (HPA)-axis activation during panic attacks is inconsistent. Therefore, in the present study, we aimed at investigating the stress-axis activity in more detail by including Copeptin (CoP) as a stable surrogate parameter for the vasopressinergic hypothalamic activity during experimentally induced panic attacks in healthy adults (N = 21). During a placebo-controlled panic challenge with 35% CO2 compared to normal air inhalation, we measured CoP and the peripheral effector hormones Adrenocorticotropic Releasing Hormone (ACTH) and cortisol in plasma along with the psychological response to panic anxiety. We analyzed hormonal secretion patterns, their correlations and individual panic ratings over time and explored differences between female and male participants. We found a significant CO2-induced increase of CoP plasma levels and psychological panic symptoms after CO2-administration, while no positive correlations of CoP levels with the peripheral HPA-axis hormones and with panic symptoms were present. No differences between female and male participants concerning their psychological response nor their baseline CoP levels, the release of CoP or its increase during the experiment were found. CoP could be a sensitive indicator for an organism's physiologic acute hypothalamic response during stress and panic attacks.
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Affiliation(s)
- Jana Christina Müller
- Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Martini Straße 52, 20251, Hamburg, Germany.
| | - Charlotte Walter
- Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Martini Straße 52, 20251, Hamburg, Germany
| | - Nicole Leibold
- Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616 (location Vijverdal), 6200, MD, Maastricht, Netherlands
| | - Klaus Wiedemann
- Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Martini Straße 52, 20251, Hamburg, Germany
| | - Michael Kellner
- Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Martini Straße 52, 20251, Hamburg, Germany; Department of Psychiatry and Psychotherapy, University Hospital rechts der Isar, Technical University Munich, Ismaninger Straße 22, 81675, München, Germany
| | - Cüneyt Demiralay
- Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Martini Straße 52, 20251, Hamburg, Germany; Oberberg Tagesklinik Hamburg, Hermannstraße, 20095, Hamburg, Germany
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Winter A, McMurray KMJ, Ahlbrand R, Allgire E, Shukla S, Jones J, Sah R. The subfornical organ regulates acidosis-evoked fear by engaging microglial acid-sensor TDAG8 and forebrain neurocircuits in male mice. J Neurosci Res 2022; 100:1732-1746. [PMID: 35553084 PMCID: PMC9812228 DOI: 10.1002/jnr.25059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 04/06/2022] [Accepted: 04/23/2022] [Indexed: 01/07/2023]
Abstract
An important role of pH homeostasis has been suggested in the physiology of panic disorder, with acidosis as an interoceptive trigger leading to fear and panic. Identification of novel mechanisms that can translate acidosis into fear will promote a better understanding of panic physiology. The current study explores a role of the subfornical organ (SFO), a blood-brain barrier compromised brain area, in translating acidosis to fear-relevant behaviors. We performed SFO-targeted acidification in male, wild-type mice and mice lacking microglial acid-sensing G protein-coupled receptor-T-cell death-associated gene 8 (TDAG8). Localized SFO acidification evoked significant freezing and reduced exploration that was dependent on the presence of acid-sensor TDAG8. Acidosis promoted the activation of SFO microglia and neurons that were absent in TDAG8-deficient mice. The assessment of regional neuronal activation in wild-type and TDAG8-deficient mice following SFO acidification revealed significant acidosis and genotype-dependent alterations in the hypothalamus, amygdala, prefrontal cortex, and periaqueductal gray nuclei. Furthermore, mapping of interregional co-activation patterns revealed that SFO acidosis promoted positive hypothalamic-cortex associations and desynchronized SFO-cortex and amygdala-cortex associations, suggesting an interplay of homeostatic and fear regulatory areas. Importantly, these alterations were not evident in TDAG8-deficient mice. Overall, our data support a regulatory role of subfornical organ microglial acid sensing in acidosis-evoked fear, highlighting a centralized role of blood-brain barrier compromised nodes in interoceptive sensing and behavioral regulation. Identification of pathways by which humoral information can modulate fear behavior is relevant to panic disorder, where aberrant interoceptive signaling has been reported.
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Affiliation(s)
- Andrew Winter
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio, USA
| | - Katherine M. J. McMurray
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
- VA Medical Center, Cincinnati, Ohio, USA
| | - Rebecca Ahlbrand
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
- VA Medical Center, Cincinnati, Ohio, USA
| | - Emily Allgire
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio, USA
| | - Sachi Shukla
- Neuroscience Undergraduate Program, University of Cincinnati, Cincinnati, Ohio, USA
| | - James Jones
- Neuroscience Undergraduate Program, University of Cincinnati, Cincinnati, Ohio, USA
| | - Renu Sah
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio, USA
- VA Medical Center, Cincinnati, Ohio, USA
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Tural U, Iosifescu DV. A systematic review and network meta-analysis of carbon dioxide provocation in psychiatric disorders. J Psychiatr Res 2021; 143:508-515. [PMID: 33250190 DOI: 10.1016/j.jpsychires.2020.11.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/09/2020] [Accepted: 11/15/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND False suffocation alarm hypothesis has been widely used to explain carbon dioxide hypersensitivity in panic disorder (PD). However, hypersensitivity to carbon dioxide has been observed in other psychiatric disorders. We explored the specificity of carbon dioxide inhalation as a panic provocation test among psychiatric disorders via network meta-analysis. METHODS A systematic literature search on PubMed, EMBASE, and PsycNET was performed to acquire the studies using the carbon dioxide provocation test in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and checklists. Odds ratios (OR) for a panic attack (PA) induced by the carbon dioxide inhalation tests were extracted from each of the original studies and were pooled using the random-effects model. RESULTS Network meta-analysis on a pool of 2181 participants from 41 studies was used to compare the efficacy of carbon dioxide provocation tests among psychiatric disorders. The network meta-analysis showed that the odds for PA in response to carbon dioxide inhalation are higher in patients with PD, premenstrual dysphoric syndrome (PMDD), and social anxiety disorder (SAD) than healthy controls (HC). The odds for PA were not significantly different among patients with generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), major depressive disorder (MDD), and healthy controls (HC). CONCLUSIONS The vulnerability to the carbon dioxide provocation test is not limited to PD. The specificity of the test for PD is questionable, as individuals suffering from PMDD and SAD are also significantly more responsive to carbon dioxide inhalation compared to HC, OCD, MDD, and GAD. There may be shared underpinning biological mechanisms between PD, PMDD, and SAD.
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Affiliation(s)
- Umit Tural
- Clinical Research Division, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
| | - Dan V Iosifescu
- Clinical Research Division, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Psychiatry Department, New York University School of Medicine, New York, NY 10016, USA
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5
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Leibold NK, van den Hove DLA, Weidner MT, Buchanan GF, Steinbusch HWM, Lesch KP, Schruers KRJ. Effect of serotonin transporter genotype on carbon dioxide-induced fear-related behavior in mice. J Psychopharmacol 2020; 34:1408-1417. [PMID: 33103571 PMCID: PMC7708670 DOI: 10.1177/0269881120959611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inhaling 35% carbon dioxide induces an emotional and symptomatic state in humans closely resembling naturally occurring panic attacks, the core symptom of panic disorder. Previous research has suggested a role of the serotonin system in the individual sensitivity to carbon dioxide. In line with this, we previously showed that a variant in the SLC6A4 gene, encoding the serotonin transporter, moderates the fear response to carbon dioxide in humans. To study the etiological basis of carbon dioxide-reactivity and panic attacks in more detail, we recently established a translational mouse model. AIM The purpose of this study was to investigate whether decreased expression of the serotonin transporter affects the sensitivity to carbon dioxide. METHODS Based on our previous work, wildtype and serotonin transporter deficient (+/-, -/-) mice were monitored while being exposed to carbon dioxide-enriched air. In wildtype and serotonin transporter +/- mice, also cardio-respiration was assessed. RESULTS For most behavioral measures under air exposure, wildtype and serotonin transporter +/- mice did not differ, while serotonin transporter -/- mice showed more fear-related behavior. Carbon dioxide exposure evoked a marked increase in fear-related behaviors, independent of genotype, with the exception of time serotonin transporter -/- mice spent in the center zone of the modified open field test and freezing in the two-chamber test. On the physiological level, when inhaling carbon dioxide, the respiratory system was strongly activated and heart rate decreased independent of genotype. CONCLUSION Carbon dioxide is a robust fear-inducing stimulus. It evokes inhibitory behavioral responses such as decreased exploration and is associated with a clear respiratory profile independent of serotonin transporter genotype.
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Affiliation(s)
- Nicole K Leibold
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,Department of Neurology, Yale School of Medicine, New Haven, USA,Nicole K Leibold, Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616 (Vijverdal), 6200 MD Maastricht, The Netherlands.
| | - Daniel LA van den Hove
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Magdalena T Weidner
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany,Department of Psychiatry and Psychotherapy, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gordon F Buchanan
- Department of Neurology, Yale School of Medicine, New Haven, USA,Department of Neurology, University of Iowa, Iowa City, USA,University of Iowa Graduate College, Iowa City, USA
| | - Harry WM Steinbusch
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technoglogy (DGIST), Daegu, South Korea
| | - Klaus-Peter Lesch
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany,Laboratory of Psychiatric Neurobiology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Koen RJ Schruers
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Department of Psychology, University of Leuven, Leuven, Belgium
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6
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Tenorio-Lopes L, Fournier S, Henry MS, Bretzner F, Kinkead R. Disruption of estradiol regulation of orexin neurons: a novel mechanism in excessive ventilatory response to CO 2 inhalation in a female rat model of panic disorder. Transl Psychiatry 2020; 10:394. [PMID: 33173029 PMCID: PMC7656265 DOI: 10.1038/s41398-020-01076-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/01/2020] [Accepted: 10/20/2020] [Indexed: 12/27/2022] Open
Abstract
Panic disorder (PD) is ~2 times more frequent in women. An excessive ventilatory response to CO2 inhalation is more likely during the premenstrual phase. While ovarian hormones appear important in the pathophysiology of PD, their role remains poorly understood as female animals are rarely used in pre-clinical studies. Using neonatal maternal separation (NMS) to induce a "PD-like" respiratory phenotype, we tested the hypothesis that NMS disrupts hormonal regulation of the ventilatory response to CO2 in female rats. We then determined whether NMS attenuates the inhibitory actions of 17-β estradiol (E2) on orexin neurons (ORX). Pups were exposed to NMS (3 h/day; postnatal day 3-12). The ventilatory response to CO2-inhalation was tested before puberty, across the estrus cycle, and following ovariectomy. Plasma E2 and hypothalamic ORXA were measured. The effect of an ORX1 antagonist (SB334867; 15 mg/kg) on the CO2 response was tested. Excitatory postsynaptic currents (EPSCs) were recorded from ORX neurons using whole-cell patch-clamp. NMS-related increase in the CO2 response was observed only when ovaries were functional; the largest ventilation was observed during proestrus. SB334867 blocked this effect. NMS augmented levels of ORXA in hypothalamus extracts. EPSC frequency varied according to basal plasma E2 levels across the estrus cycle in controls but not NMS. NMS reproduces developmental and cyclic changes of respiratory manifestations of PD. NMS disrupts the inhibitory actions of E2 on the respiratory network. Impaired E2-related inhibition of ORX neurons during proestrus is a novel mechanism in respiratory manifestations of PD in females.
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Affiliation(s)
- Luana Tenorio-Lopes
- Hotchkiss Brain Institute; Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Stéphanie Fournier
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec. Département de Pédiatrie. Université Laval, Québec, QC, Canada
| | - Mathilde S Henry
- INRAE, Université de Bordeaux, Bordeaux INP, Nutrineuro, UMR 1286, F-33000, Bordeaux, France
| | - Frédéric Bretzner
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences. Département de Psychiatrie et de Neurosciences, Université Laval, Québec, QC, Canada
| | - Richard Kinkead
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec. Département de Pédiatrie. Université Laval, Québec, QC, Canada.
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Abstract
The aim of this review is to summarize evidence regarding rat emotional experiences during carbon dioxide (CO2) exposure. The studies reviewed show that CO2 exposure is aversive to rats, and that rats respond to CO2 exposure with active and passive defense behaviors. Plasma corticosterone and bradycardia increased in rats exposed to CO2. As with anxiogenic drugs, responses to CO2 are counteracted by the administration of anxiolytics, SRIs, and SSRI's. Human studies reviewed indicate that, when inhaling CO2, humans experience feelings of anxiety fear and panic, and that administration of benzodiazepines, serotonin precursors, and SSRIs ameliorate these feelings. In vivo and in vitro rat studies reviewed show that brain regions, ion channels, and neurotransmitters involved in negative emotional responses are activated by hypercapnia and acidosis associated with CO2 exposure. On the basis of the behavioral, physiological, and neurobiological evidence reviewed, we conclude that CO2 elicits negative emotions in rats.
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8
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Francesetti G, Alcaro A, Settanni M. Panic disorder: attack of fear or acute attack of solitude? Convergences between affective neuroscience and phenomenological-Gestalt perspective. ACTA ACUST UNITED AC 2020; 23:421. [PMID: 32913822 PMCID: PMC7451360 DOI: 10.4081/ripppo.2020.421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 02/19/2020] [Indexed: 11/23/2022]
Abstract
There is consensus among scientists in considering Panic Attack (PA) as an exaggerated fear response triggered by intense activation of the amygdala and related Fear brain network. Current guidelines for treatment (e.g. National Institute for Clinical Excellence, NICE, 2011), that are based on this view, do not achieve satisfactory results: one-third of all treated patients report persistent PAs and other Panic Disorder (PD) symptoms, and several meta-analyses report the high likelihood of relapse. Here we review findings from Affective Neuroscience and clinical insights from a phenomenological-Gestalt perspective, putting into question the link between PD and activation of the Fear brain network. We propose an alternative hypothesis about PD etiology: PD is mainly connected to the Panic system, that is activated in situations of separation from affective support and overexposure to the environment. In our view, PA can be understood as an acute attack of solitude which is not adequately recognized by the patient due to the intervention of a dissociative component that makes it impossible to integrate all neuro-physiological responses activated by the Panic/Separation brain system within a coherent emotional feeling. This perspective can explain many evidences that otherwise remain isolated elements without a comprehensive frame: i.e., the association with agoraphobia, the onset of PD during adolescence and young adult life, the need to be accompanied, the connection with air hunger and other respiratory anomalies, the efficacy of antidepressants and the lack of activation of the Hypothalamic-Pituitary-Adrenal (HPA) axe. We discuss future steps to test this hypothesis and the consequences for psychotherapeutic treatment.
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Affiliation(s)
- Gianni Francesetti
- International Institute for Gestalt Therapy and Psychopathology - IPsiG.,Department of Psychology, University of Turin
| | - Antonio Alcaro
- Santa Lucia Foundation, European Centre for Brain Research, Italy
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Liu JJW, Ein N, Gervasio J, Vickers K. Subjective and physiological responses to the 35% carbon dioxide challenge in healthy and non-clinical control populations: a meta-analysis and systematic review. ANXIETY STRESS AND COPING 2020; 32:216-230. [PMID: 30696328 DOI: 10.1080/10615806.2019.1570803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND/RATIONALE The carbon dioxide (CO2) challenge has been reliably used in laboratory settings as a panicogen in clinical populations. However, the magnitude of these effects on healthy and non-clinical control populations are not clear. The aim of this meta-analysis and systematic review is to provide quantitative estimates of those effects. Specifically, the current paper will evaluate the relative efficacy of the CO2 challenge in eliciting both subjective and physiological arousal in healthy and non-clinical control populations. METHOD A total of 16 articles with 35 independent samples were included in the meta-analysis, while 37 studies with 74 independent samples were included in the systematic review. RESULTS Both the meta-analysis and systematic review found the CO2 challenge to elicit an increase in subjective distress via self-reported anxiety and fear. Physiological responses via blood pressure and heart rate were heterogeneous in studies sampled, with no significant changes observed across studies. Moderator analyses revealed the variations in findings may be attributed to participant screening and invasive sampling. DISCUSSION Findings highlight the CO2 challenge as a useful tool in the provocation of subjective distress. Implications for both the use of the CO2 challenge and its anticipated effects in healthy and non-clinical control populations are discussed.
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Affiliation(s)
- Jenny J W Liu
- a Department of Psychology , Ryerson University , Toronto , Canada.,b Institute for Stress and Wellbeing Research , Ryerson University , Toronto , Ontario , Canada
| | - Natalie Ein
- a Department of Psychology , Ryerson University , Toronto , Canada.,b Institute for Stress and Wellbeing Research , Ryerson University , Toronto , Ontario , Canada
| | - Julia Gervasio
- a Department of Psychology , Ryerson University , Toronto , Canada.,b Institute for Stress and Wellbeing Research , Ryerson University , Toronto , Ontario , Canada
| | - Kristin Vickers
- a Department of Psychology , Ryerson University , Toronto , Canada.,b Institute for Stress and Wellbeing Research , Ryerson University , Toronto , Ontario , Canada
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10
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Améndola L, Ratuski A, Weary DM. Variation in the onset of CO 2-induced anxiety in female Sprague Dawley rats. Sci Rep 2019; 9:19007. [PMID: 31831816 PMCID: PMC6908729 DOI: 10.1038/s41598-019-55493-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
Carbon dioxide (CO2) is commonly used to kill laboratory rats. Rats find CO2 aversive and aversion varies between individuals, indicating that rats vary in CO2 sensitivity. Healthy humans experience feelings of anxiety at concentrations similar to those avoided by rats, and these feelings are diminished by the administration of benzodiazepines. Our aim was to assess the effects of the benzodiazepine midazolam on individual thresholds of rat aversion to CO2. Six female Sprague Dawley rats were repeatedly exposed to CO2 gradual-fill in approach-avoidance testing. The first three exposures were to a control-treatment followed by three exposures to midazolam (0.375 mg/kg). Within each treatment aversion to CO2 was not affected by exposure number; however, tolerance increased from an average of 10.7% CO2 avoided during control sessions, to 15.5% CO2 avoided when treated with midazolam. These results indicate that rats experience anxiety when exposed to CO2, and that variation in rat CO2 sensitivity is driven by individual differences in the onset of these feelings of anxiety. No rat tolerated CO2 concentrations required to induce loss of consciousness.
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Affiliation(s)
- Lucía Améndola
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Anna Ratuski
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Daniel M Weary
- Animal Welfare Program, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada.
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11
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Van Diest I. Interoception, conditioning, and fear: The panic threesome. Psychophysiology 2019; 56:e13421. [DOI: 10.1111/psyp.13421] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/11/2019] [Accepted: 05/16/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Ilse Van Diest
- Health, Behavior & Psychopathology, Faculty of Psychology & Educational Sciences; University of Leuven; Leuven Belgium
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12
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Améndola L, Weary DM. Evidence for consistent individual differences in rat sensitivity to carbon dioxide. PLoS One 2019; 14:e0215808. [PMID: 31017958 PMCID: PMC6481838 DOI: 10.1371/journal.pone.0215808] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 04/09/2019] [Indexed: 12/24/2022] Open
Abstract
Carbon dioxide (CO2) gradual-fill is commonly used to kill laboratory rats, but this use remains controversial due to a lack of agreement between studies. Inconsistencies may arise from differences in behaviors measured (e.g. active versus passive behaviors), in how rats cope with threats, or in rat sensitivity to CO2. The aims of the current study were to 1) describe active and passive responses during CO2 forced exposure, 2) determine if these responses are consistent within individuals and across aversive stimuli, 3) assess individual differences in aversion to CO2 in aversion-avoidance and approach-avoidance tests and 4) determine how responses in aversion tests relate to individual differences in behavior during forced exposure. Twelve Sprague Dawley female rats were exposed twice to three treatments: CO2, oxygen (O2), and fox scent, and were exposed to CO2 twice in each aversion test. The change in behavior from baseline was higher for rearing and locomotion when rats were exposed to CO2 than when exposed to O2 and fox scent. Responses varied among rats but were consistent across multiple tests within rats. For example, rearing was consistent within individuals between two exposures to CO2. Similarly, the strength of aversion was consistent within individuals across multiple exposures to CO2 in aversion-avoidance and approach-avoidance testing. Latency to avoid CO2 in aversion-avoidance tests was negatively correlated with rearing during CO2 forced exposure. Collectively, these results indicate that rat responses to CO2 vary between (but are consistent within) individuals, suggesting that rats vary in CO2 sensitivity. However, even the less responsive rats avoided CO2 concentrations far below those necessary to achieve unconsciousness, indicating that all rats likely experience negative states when euthanized with CO2.
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Affiliation(s)
- Lucía Améndola
- Animal Welfare Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel M. Weary
- Animal Welfare Program, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Leibold NK, Schruers KR. Assessing Panic: Bridging the Gap Between Fundamental Mechanisms and Daily Life Experience. Front Neurosci 2018; 12:785. [PMID: 30459546 PMCID: PMC6232935 DOI: 10.3389/fnins.2018.00785] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/10/2018] [Indexed: 12/16/2022] Open
Abstract
Panic disorder (PD) is one of the most common psychiatric disorders. Recurrent, unexpected panic attacks (PAs) are the primary symptom and strongly impact patients’ quality of life. Clinical manifestations are very heterogeneous between patients, emphasizing the need for a dimensional classification integrating various aspects of neurobiological and psychological circuits in line with the Research Domain Criteria (RDoC) proposed by the US National Institute of Mental Health. To go beyond data that can be collected in the daily clinical situation, experimental panic provocation is widely used, which has led to important insights into involved brain regions and systems. Genetic variants can determine the sensitivity to experimental models such as carbon dioxide (CO2) exposure and can increase the risk to develop PD. Recent developments now allow to better assess the dynamic course of PAs outside the laboratory in patients’ natural environment. This can provide novel insights into the underlying mechanisms and the influence of environmental factors that can alter gene regulation by changing DNA methylation. In this mini review, we discuss assessment of PAs in the clinic, in the laboratory using CO2 exposure, genetic associations, and the benefits of real-life assessment and epigenetic research.
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Affiliation(s)
- Nicole K Leibold
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, European Graduate School of Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Koen R Schruers
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, European Graduate School of Neuroscience, Maastricht University, Maastricht, Netherlands.,Faculty of Psychology, Center for Experimental and Learning Psychology, University of Leuven, Leuven, Belgium
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Dynamics of Defensive Response Mobilization to Approaching External Versus Interoceptive Threat. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 3:525-538. [DOI: 10.1016/j.bpsc.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/06/2017] [Accepted: 12/07/2017] [Indexed: 11/18/2022]
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Leibold NK, van den Hove DLA, Viechtbauer W, Kenis G, Goossens L, Lange I, Knuts I, Smeets HJ, Myin-Germeys I, Steinbusch HW, Schruers KR. Amiloride-sensitive cation channel 2 genotype affects the response to a carbon dioxide panic challenge. J Psychopharmacol 2017; 31:1294-1301. [PMID: 28121219 DOI: 10.1177/0269881116686880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Until recently, genetic research into panic disorder (PD) has had only limited success. Inspired by rodent research, demonstrating that the acid-sensing ion channel 1a (ASIC1a) is critically involved in the behavioral fear response to carbon dioxide (CO2) exposure, variants in the human homologue gene amiloride-sensitive cation channel 2 (ACCN2) were shown to be associated with PD. However, the relationship between changes in brain pH and ACCN2, as done in rodents by CO2 exposure, has not been investigated yet in humans. Here, we examined this link between the ACCN2 gene and the response to CO2 exposure in two studies: in healthy volunteers as well as PD patients and using both behavioral and physiological outcome measures. More specifically, 107 healthy volunteers and 183 PD patients underwent a 35% CO2 inhalation. Negative affect was assessed using visual analogue scales and the panic symptom list (PSL), and, in healthy volunteers, cardiovascular measurements. The single nucleotide polymorphism rs10875995 was significantly associated with a higher emotional response in PD patients and with an increase in systolic as well as diastolic blood pressure in healthy subjects. In all measurements, subjects homozygous for the T-allele showed a heightened reactivity to CO2. Furthermore, a trend towards an rs685012 genotype effect on the emotional response was found in PD patients. We provide the first evidence that genetic variants in the ACCN2 are associated with differential sensitivity to CO2 in PD patients as well as healthy volunteers, further supporting ACCN2 as a promising candidate for future research to improve current treatment options.
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Affiliation(s)
- Nicole K Leibold
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Daniel LA van den Hove
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands.,2 Department of Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Wolfgang Viechtbauer
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Gunter Kenis
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Liesbet Goossens
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Iris Lange
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Inge Knuts
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Hubert J Smeets
- 3 Genome Center Maastricht, Maastricht University, Maastricht, the Netherlands
| | - Inez Myin-Germeys
- 3 Genome Center Maastricht, Maastricht University, Maastricht, the Netherlands
| | - Harry Wm Steinbusch
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
| | - Koen Rj Schruers
- 1 Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands
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16
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Differential behavioral sensitivity to carbon dioxide (CO 2) inhalation in rats. Neuroscience 2017; 346:423-433. [PMID: 28087339 DOI: 10.1016/j.neuroscience.2017.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/14/2016] [Accepted: 01/03/2017] [Indexed: 01/21/2023]
Abstract
Inhalation of carbon dioxide (CO2) is frequently employed as a biological challenge to evoke intense fear and anxiety. In individuals with panic disorder, CO2 reliably evokes panic attacks. Sensitivity to CO2 is highly heterogeneous among individuals, and although a genetic component is implicated, underlying mechanisms are not clear. Preclinical models that can simulate differential responsivity to CO2 are therefore relevant. In the current study we investigated CO2-evoked behavioral responses in four different rat strains: Sprague-Dawley (SD), Wistar (W), Long Evans (LE) and Wistar-Kyoto, (WK) rats. We also assessed tryptophan hydroxylase 2 (TPH-2)-positive serotonergic neurons in anxiety/panic regulatory subdivisions of the dorsal raphe nucleus (DR), as well as dopamine β hydroxylase (DβH)-positive noradrenergic neurons in the locus coeruleus, implicated in central CO2-chemosensitivity. Behavioral responsivity to CO2 inhalation varied between strains. CO2-evoked immobility was significantly higher in LE and WK rats as compared with W and SD cohorts. Differences were also observed in CO2-evoked rearing and grooming behaviors. Exposure to CO2 did not produce conditioned behavioral responses upon re-exposure to CO2 context in any strain. Reduced TPH-2-positive cell counts were observed specifically in the panic-regulatory dorsal raphe ventrolateral (DRVL)-ventrolateral periaqueductal gray (VLPAG) subdivision in CO2-sensitive strains. Conversely, DβH-positive cell counts within the LC were significantly higher in CO2-sensitive strains. Collectively, our data provide evidence for strain dependent, differential CO2-sensitivity and potential differences in monoaminergic systems regulating panic and anxiety. Comparative studies between CO2-vulnerable and resistant strains may facilitate the mechanistic understanding of differential CO2-sensitivity in the development of panic and anxiety disorders.
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Vollmer LL, Ghosal S, McGuire JL, Ahlbrand RL, Li KY, Santin JM, Ratliff-Rang CA, Patrone LGA, Rush J, Lewkowich IP, Herman JP, Putnam RW, Sah R. Microglial Acid Sensing Regulates Carbon Dioxide-Evoked Fear. Biol Psychiatry 2016; 80:541-51. [PMID: 27422366 PMCID: PMC5014599 DOI: 10.1016/j.biopsych.2016.04.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 04/08/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND Carbon dioxide (CO2) inhalation, a biological challenge and pathologic marker in panic disorder, evokes intense fear and panic attacks in susceptible individuals. The molecular identity and anatomic location of CO2-sensing systems that translate CO2-evoked fear remain unclear. We investigated contributions of microglial acid sensor T cell death-associated gene-8 (TDAG8) and microglial proinflammatory responses in CO2-evoked behavioral and physiological responses. METHODS CO2-evoked freezing, autonomic, and respiratory responses were assessed in TDAG8-deficient ((-/-)) and wild-type ((+/+)) mice. Involvement of TDAG8-dependent microglial activation and proinflammatory cytokine interleukin (IL)-1β with CO2-evoked responses was investigated using microglial blocker, minocycline, and IL-1β antagonist IL-1RA. CO2-chemosensitive firing responses using single-cell patch clamping were measured in TDAG8(-/-) and TDAG8(+/+) mice to gain functional insights. RESULTS TDAG8 expression was localized in microglia enriched within the sensory circumventricular organs. TDAG8(-/-) mice displayed attenuated CO2-evoked freezing and sympathetic responses. TDAG8 deficiency was associated with reduced microglial activation and proinflammatory cytokine IL-1β within the subfornical organ. Central infusion of microglial activation blocker minocycline and IL-1β antagonist IL-1RA attenuated CO2-evoked freezing. Finally, CO2-evoked neuronal firing in patch-clamped subfornical organ neurons was dependent on acid sensor TDAG8 and IL-1β. CONCLUSIONS Our data identify TDAG8-dependent microglial acid sensing as a unique chemosensor for detecting and translating hypercapnia to fear-associated behavioral and physiological responses, providing a novel mechanism for homeostatic threat detection of relevance to psychiatric conditions such as panic disorder.
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Affiliation(s)
- Lauren Larke Vollmer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati; Neuroscience Graduate Program, University of Cincinnati, Cincinnati
| | - Sriparna Ghosal
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati; Neuroscience Graduate Program, University of Cincinnati, Cincinnati
| | - Jennifer L McGuire
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati
| | - Rebecca L Ahlbrand
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati
| | - Ke-Yong Li
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton
| | - Joseph M Santin
- Department of Biological Sciences, Wright State University, Dayton
| | | | - Luis G A Patrone
- Department of Animal Morphology and Physiology, São Paulo State University, FCAV, Jaboticabal, São Paulo, Brazil
| | - Jennifer Rush
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati
| | - Ian P Lewkowich
- Division of Immunobiology, Children's Hospital Medical Center, Cincinnati
| | - James P Herman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati; Neuroscience Graduate Program, University of Cincinnati, Cincinnati
| | - Robert W Putnam
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton
| | - Renu Sah
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati; Neuroscience Graduate Program, University of Cincinnati, Cincinnati; Veterans Affairs (VA) Medical Center, Cincinnati, Ohio.
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18
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CO2 exposure as translational cross-species experimental model for panic. Transl Psychiatry 2016; 6:e885. [PMID: 27598969 PMCID: PMC5048202 DOI: 10.1038/tp.2016.162] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 07/10/2016] [Accepted: 07/22/2016] [Indexed: 12/13/2022] Open
Abstract
The current diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders are being challenged by the heterogeneity and the symptom overlap of psychiatric disorders. Therefore, a framework toward a more etiology-based classification has been initiated by the US National Institute of Mental Health, the research domain criteria project. The basic neurobiology of human psychiatric disorders is often studied in rodent models. However, the differences in outcome measurements hamper the translation of knowledge. Here, we aimed to present a translational panic model by using the same stimulus and by quantitatively comparing the same outcome measurements in rodents, healthy human subjects and panic disorder patients within one large project. We measured the behavioral-emotional and bodily response to CO2 exposure in all three samples, allowing for a reliable cross-species comparison. We show that CO2 exposure causes a robust fear response in terms of behavior in mice and panic symptom ratings in healthy volunteers and panic disorder patients. To improve comparability, we next assessed the respiratory and cardiovascular response to CO2, demonstrating corresponding respiratory and cardiovascular effects across both species. This project bridges the gap between basic and human research to improve the translation of knowledge between these disciplines. This will allow significant progress in unraveling the etiological basis of panic disorder and will be highly beneficial for refining the diagnostic categories as well as treatment strategies.
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19
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Liu G, Liu X, Qin Z, Gu Z, Wang G, Shi W, Wen D, Yu L, Luo Y, Xiao H. Cardiovascular System Response to Carbon Dioxide and Exercise in Oxygen-Enriched Environment at 3800 m. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:11781-96. [PMID: 26393634 PMCID: PMC4586707 DOI: 10.3390/ijerph120911781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 11/22/2022]
Abstract
Background: This study explores the responses of the cardiovascular system as humans exercise in an oxygen-enriched room at high altitude under various concentrations of CO2. Methods: The study utilized a hypobaric chamber set to the following specifications: 3800 m altitude with 25% O2 and different CO2 concentrations of 0.5% (C1), 3.0% (C2) and 5.0% (C3). Subjects exercised for 3 min three times, separated by 30 min resting periods in the above-mentioned conditions, at sea level (SL) and at 3800 m altitude (HA). The changes of heart rate variability, heart rate and blood pressure were analyzed. Results: Total power (TP) and high frequency power (HF) decreased notably during post-exercise at HA. HF increased prominently earlier the post-exercise period at 3800 m altitude with 25% O2 and 5.0% CO2 (C3), while low frequency power (LF) changed barely in all tests. The ratios of LF/HF were significantly higher during post-exercise in HA, and lower after high intensity exercise in C3. Heart rate and systolic blood pressure increased significantly in HA and C3. Conclusions: Parasympathetic activity dominated in cardiac autonomic modulation, and heart rate and blood pressure increased significantly after high intensity exercise in C3.
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Affiliation(s)
- Guohui Liu
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China.
| | - Xiaopeng Liu
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Zhifeng Qin
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Zhao Gu
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Guiyou Wang
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Weiru Shi
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Dongqing Wen
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Lihua Yu
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Yongchang Luo
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
| | - Huajun Xiao
- High Altitude Physiology Laboratory, Institute of Aviation Medicine, Air Force, Beijing 100142, China.
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20
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The brain acid–base homeostasis and serotonin: A perspective on the use of carbon dioxide as human and rodent experimental model of panic. Prog Neurobiol 2015; 129:58-78. [DOI: 10.1016/j.pneurobio.2015.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 12/14/2022]
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Vollmer LL, Strawn JR, Sah R. Acid-base dysregulation and chemosensory mechanisms in panic disorder: a translational update. Transl Psychiatry 2015; 5:e572. [PMID: 26080089 PMCID: PMC4471296 DOI: 10.1038/tp.2015.67] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 02/19/2015] [Accepted: 04/06/2015] [Indexed: 12/13/2022] Open
Abstract
Panic disorder (PD), a complex anxiety disorder characterized by recurrent panic attacks, represents a poorly understood psychiatric condition which is associated with significant morbidity and an increased risk of suicide attempts and completed suicide. Recently however, neuroimaging and panic provocation challenge studies have provided insights into the pathoetiology of panic phenomena and have begun to elucidate potential neural mechanisms that may underlie panic attacks. In this regard, accumulating evidence suggests that acidosis may be a contributing factor in induction of panic. Challenge studies in patients with PD reveal that panic attacks may be reliably provoked by agents that lead to acid-base dysbalance such as CO2 inhalation and sodium lactate infusion. Chemosensory mechanisms that translate pH into panic-relevant fear, autonomic, and respiratory responses are therefore of high relevance to the understanding of panic pathophysiology. Herein, we provide a current update on clinical and preclinical studies supporting how acid-base imbalance and diverse chemosensory mechanisms may be associated with PD and discuss future implications of these findings.
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Affiliation(s)
- L L Vollmer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA
| | - J R Strawn
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA,Cincinnati Children's Hospital Medical Center, Department of Psychiatry, Cincinnati, OH, USA
| | - R Sah
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, USA,Veterens' Affairs Medical Center, Cincinnati, OH, USA,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, 2170 East Galbraith Road, Cincinnati, OH 45237, USA. E-mail:
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Perna G, Schruers K, Alciati A, Caldirola D. Novel investigational therapeutics for panic disorder. Expert Opin Investig Drugs 2014; 24:491-505. [DOI: 10.1517/13543784.2014.996286] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Giampaolo Perna
- 1Hermanas Hospitalarias - Villa San Benedetto Menni Hospital, Department of Clinical Neurosciences, FoRiPsi, via Roma 16, 22032, Albese con Cassano, Como, Italy ;
- 2University of Maastricht, Medicine and Life Sciences, Department of Psychiatry and Neuropsychology, Faculty of Health, Maastricht, The Netherlands
- 3University of Miami, Leonard Miller School of Medicine, Department of Psychiatry and Behavioral Sciences, Miami, FL, USA
| | - Koen Schruers
- 2University of Maastricht, Medicine and Life Sciences, Department of Psychiatry and Neuropsychology, Faculty of Health, Maastricht, The Netherlands
- 4Faculty of Psychology, University of Leuven, Center for Learning and Experimental Psychology, Loeven, Belgium
| | - Alessandra Alciati
- 1Hermanas Hospitalarias - Villa San Benedetto Menni Hospital, Department of Clinical Neurosciences, FoRiPsi, via Roma 16, 22032, Albese con Cassano, Como, Italy ;
| | - Daniela Caldirola
- 1Hermanas Hospitalarias - Villa San Benedetto Menni Hospital, Department of Clinical Neurosciences, FoRiPsi, via Roma 16, 22032, Albese con Cassano, Como, Italy ;
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Lovick TA. Sex determinants of experimental panic attacks. Neurosci Biobehav Rev 2014; 46 Pt 3:465-71. [DOI: 10.1016/j.neubiorev.2014.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 01/15/2014] [Accepted: 03/01/2014] [Indexed: 12/16/2022]
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Bevins RA, Besheer J. Interoception and learning: import to understanding and treating diseases and psychopathologies. ACS Chem Neurosci 2014; 5:624-31. [PMID: 25010473 PMCID: PMC4140586 DOI: 10.1021/cn5001028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/09/2014] [Indexed: 12/23/2022] Open
Abstract
Chemotherapeutic agents nauseate cancer patients. Some individuals with schizophrenia hear voices. Chronic pain can be reduced by analgesics. Nausea, voices, and pain are examples of internal (interoceptive) stimuli closely linked with a disease and/or its treatment. There is evidence that the perception and, hence, role of these internal stimuli can be modified by one's learning history. There is also increased awareness by researchers and practitioners of the potential import of learning involving internal states to some diseases and psychopathologies. Unfortunately, the science, theory, and practice appear to be trailing behind awareness. In this mini-review, we describe two examples: smoking and panic disorder. While doing so, we discuss the need to develop translationally relevant animal models that will allow investigators to better understand the behavioral and neural mechanisms underlying interoception and learning.
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Affiliation(s)
- Rick A Bevins
- Behavioral Neuropharmacology Lab, Department of Psychology, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0308, United States
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Preter M, Klein DF. Lifelong opioidergic vulnerability through early life separation: a recent extension of the false suffocation alarm theory of panic disorder. Neurosci Biobehav Rev 2014; 46 Pt 3:345-51. [PMID: 24726574 DOI: 10.1016/j.neubiorev.2014.03.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 03/03/2014] [Accepted: 03/14/2014] [Indexed: 12/11/2022]
Abstract
The present paper is the edited version of our presentations at the "First World Symposium On Translational Models Of Panic Disorder", in Vitoria, E.S., Brazil, on November 16-18, 2012. We also review relevant work that appeared after the conference. Suffocation-False Alarm Theory (Klein, 1993) postulates the existence of an evolved physiologic suffocation alarm system that monitors information about potential suffocation. Panic attacks maladaptively occur when the alarm is erroneously triggered. The expanded Suffocation-False Alarm Theory (Preter and Klein, 2008) hypothesizes that endogenous opioidergic dysregulation may underlie the respiratory pathophysiology and suffocation sensitivity in panic disorder. Opioidergic dysregulation increases sensitivity to CO2, separation distress and panic attacks. That sudden loss, bereavement and childhood separation anxiety are also antecedents of "spontaneous" panic requires an integrative explanation. Our work unveiling the lifelong endogenous opioid system impairing effects of childhood parental loss (CPL) and parental separation in non-ill, normal adults opens a new experimental, investigatory area.
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Affiliation(s)
- Maurice Preter
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
| | - Donald F Klein
- Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience, Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, 550 1st Ave, New York, NY 10016, USA.
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