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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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2
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Fincham GW, Kartar A, Uthaug MV, Anderson B, Hall L, Nagai Y, Critchley H, Colasanti A. High ventilation breathwork practices: An overview of their effects, mechanisms, and considerations for clinical applications. Neurosci Biobehav Rev 2023; 155:105453. [PMID: 37923236 DOI: 10.1016/j.neubiorev.2023.105453] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
High Ventilation Breathwork (HVB) refers to practices employing specific volitional manipulation of breathing, with a long history of use to relieve various forms of psychological distress. This paper seeks to offer a consolidative insight into potential clinical application of HVB as a treatment of psychiatric disorders. We thus review the characteristic phenomenological and neurophysiological effects of these practices to inform their mechanism of therapeutic action, safety profiles and future clinical applications. Clinical observations and data from neurophysiological studies indicate that HVB is associated with extraordinary changes in subjective experience, as well as with profound effects on central and autonomic nervous systems functions through modulation of neurometabolic parameters and interoceptive sensory systems. This growing evidence base may guide how the phenomenological effects of HVB can be understood, and potentially harnessed in the context of such volitional perturbation of psychophysiological state. Reports of putative beneficial effects for trauma-related, affective, and somatic disorders invite further research to obtain detailed mechanistic knowledge, and rigorous clinical testing of these potential therapeutic uses.
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Affiliation(s)
- Guy W Fincham
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK; University of Sussex, School of Psychology, Brighton, UK.
| | - Amy Kartar
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK
| | - Malin V Uthaug
- The Centre for Psychedelic Research, Division of Psychiatry, Imperial College London, UK; Department of Neuropsychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, The Netherlands
| | - Brittany Anderson
- University of Wisconsin School of Medicine & Public Health, Department of Psychiatry, University of Wisconsin-Madison, USA
| | - Lottie Hall
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK
| | - Yoko Nagai
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK
| | - Hugo Critchley
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK
| | - Alessandro Colasanti
- Brighton & Sussex Medical School, Department of Neuroscience, University of Sussex, UK; Sussex Partnership NHS Foundation Trust.
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3
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Caddye E, Pineau J, Reyniers J, Ronen I, Colasanti A. Lactate: A Theranostic Biomarker for Metabolic Psychiatry? Antioxidants (Basel) 2023; 12:1656. [PMID: 37759960 PMCID: PMC10526106 DOI: 10.3390/antiox12091656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 09/29/2023] Open
Abstract
Alterations in neurometabolism and mitochondria are implicated in the pathophysiology of psychiatric conditions such as mood disorders and schizophrenia. Thus, developing objective biomarkers related to brain mitochondrial function is crucial for the development of interventions, such as central nervous system penetrating agents that target brain health. Lactate, a major circulatory fuel source that can be produced and utilized by the brain and body, is presented as a theranostic biomarker for neurometabolic dysfunction in psychiatric conditions. This concept is based on three key properties of lactate that make it an intriguing metabolic intermediate with implications for this field: Firstly, the lactate response to various stimuli, including physiological or psychological stress, represents a quantifiable and dynamic marker that reflects metabolic and mitochondrial health. Second, lactate concentration in the brain is tightly regulated according to the sleep-wake cycle, the dysregulation of which is implicated in both metabolic and mood disorders. Third, lactate universally integrates arousal behaviours, pH, cellular metabolism, redox states, oxidative stress, and inflammation, and can signal and encode this information via intra- and extracellular pathways in the brain. In this review, we expand on the above properties of lactate and discuss the methodological developments and rationale for the use of functional magnetic resonance spectroscopy for in vivo monitoring of brain lactate. We conclude that accurate and dynamic assessment of brain lactate responses might contribute to the development of novel and personalized therapies that improve mitochondrial health in psychiatric disorders and other conditions associated with neurometabolic dysfunction.
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Affiliation(s)
- Edward Caddye
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
- Department of Clinical Neuroscience, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
| | - Julien Pineau
- Independent Researcher, Florianópolis 88062-300, Brazil
| | - Joshua Reyniers
- Department of Clinical Neuroscience, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
- School of Life Sciences, University of Sussex, Falmer BN1 9RR, UK
| | - Itamar Ronen
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
| | - Alessandro Colasanti
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
- Department of Clinical Neuroscience, Brighton and Sussex Medical School, University of Sussex, Falmer BN1 9RR, UK
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4
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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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5
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Caldirola D, Alciati A, Cuniberti F, Perna G. Experimental Drugs for Panic Disorder: An Updated Systematic Review. J Exp Pharmacol 2021; 13:441-459. [PMID: 33889031 PMCID: PMC8055642 DOI: 10.2147/jep.s261403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/25/2021] [Indexed: 01/02/2023] Open
Abstract
Several effective pharmacological therapies for panic disorder (PD) are available, but they have some drawbacks, and unsatisfactory outcomes can occur. Expanding the variety of anti-panic medications may allow for improving PD treatment. The authors performed an updated systematic review of preclinical and clinical (Phase I–III) pharmacological studies to look for advances made in the last six years concerning novel-mechanism-based anti-panic compounds or using medications approved for nonpsychiatric medical conditions to treat PD. The study included seven published articles presenting a series of preclinical studies, two Phase I clinical studies with orexin receptor (OXR) antagonists, and two clinical studies investigating the effects of D-cycloserine (DCS) and xenon gas in individuals with PD. The latest preclinical findings confirmed and expanded previous promising indications of OXR1 antagonists as novel-mechanism-based anti-panic compounds. Translating preclinical research into clinical applications remains in the early stages. However, limited clinical findings suggested the selective OXR1 antagonist JNJ-61393115 may exert anti-panic effects in humans. Overall, OXR1 antagonists displayed a favorable profile of short-term safety and tolerability. Very preliminary suggestions of possible anti-panic effects of xenon gas emerged but need confirmation with more rigorous methodology. DCS did not seem promising as an enhancer of cognitive-behavioral therapy in PD. Future studies, including objective panic-related physiological parameters, such as respiratory measures, and expanding the use of panic vulnerability biomarkers, such as hypersensitivity to CO2 panic provocation, may allow for more reliable conclusions about the anti-panic properties of new compounds.
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Affiliation(s)
- Daniela Caldirola
- Department of Biomedical Sciences, Humanitas University, Milan, 20090, Italy.,Department of Clinical Neurosciences, Villa San Benedetto Menni Hospital, Hermanas Hospitalarias, Como, 22032, Italy
| | - Alessandra Alciati
- Department of Biomedical Sciences, Humanitas University, Milan, 20090, Italy.,Department of Clinical Neurosciences, Villa San Benedetto Menni Hospital, Hermanas Hospitalarias, Como, 22032, Italy.,Humanitas Clinical and Research Center, IRCCS, Milan, Rozzano, 20089, Italy
| | - Francesco Cuniberti
- Department of Biomedical Sciences, Humanitas University, Milan, 20090, Italy.,Department of Clinical Neurosciences, Villa San Benedetto Menni Hospital, Hermanas Hospitalarias, Como, 22032, Italy
| | - Giampaolo Perna
- Department of Biomedical Sciences, Humanitas University, Milan, 20090, Italy.,Department of Clinical Neurosciences, Villa San Benedetto Menni Hospital, Hermanas Hospitalarias, Como, 22032, Italy
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Batista LA, Lopes JB, Brianis RC, Haibara AS, Moreira FA. Intravenous doxapram administration as a potential model of panic attacks in rats. Behav Pharmacol 2021; 32:182-193. [PMID: 33136614 DOI: 10.1097/fbp.0000000000000594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Panic disorder can be categorized into the nonrespiratory or the respiratory subtypes, the latter comprising dyspnea, shortness of breath, chest pain, feelings of suffocation, and paresthesias. Doxapram is an analeptic capable of inducing panic attacks with respiratory symptoms in individuals diagnosed with the disorder; however, its neuroanatomical targets and its effects on experimental animals remain uncharacterized. One of the brain regions proposed to trigger panic attacks is the midbrain periaqueductal gray (PAG). Therefore, in this study, we evaluated the effects of doxapram in Fos (c-Fos) protein expression in the PAG and characterized its cardiorespiratory and behavioral effects on the elevated T maze and in the conditioned place aversion (CPA) paradigms. Doxapram increased Fos expression in different columns of the PAG, increased respiratory frequency, decreased heart rate, and increased arterial pressure when injected via intravenous route. Alprazolam, a panicolytic benzodiazepine, injected via intraperitoneal route, decreased respiratory frequency, whereas URB597, an anandamide hydrolysis inhibitor injected via intraperitoneal route, was ineffective. Doxapram injected via intraperitoneal route induced an anxiogenic-like effect in the elevated T-maze model; however, it failed to induce CPA. This study suggests that the cardiorespiratory and behavioral effects of doxapram in rodents serve as an experimental model that can provide insights into the neurobiology of panic attacks.
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Affiliation(s)
| | | | | | - Andrea S Haibara
- Departament of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Fukushi I, Pokorski M, Okada Y. Mechanisms underlying the sensation of dyspnea. Respir Investig 2020; 59:66-80. [PMID: 33277231 DOI: 10.1016/j.resinv.2020.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/13/2020] [Accepted: 10/17/2020] [Indexed: 01/17/2023]
Abstract
Dyspnea is defined as a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity. It is a common symptom among patients with respiratory diseases that reduces daily activities, induces deconditioning, and is self-perpetuating. Although clinical interventions are needed to reduce dyspnea, its underlying mechanism is poorly understood depending on the intertwined peripheral and central neural mechanisms as well as emotional factors. Nonetheless, experimental and clinical observations suggest that dyspnea results from dissociation or a mismatch between the intended respiratory motor output set caused by the respiratory neuronal network in the lower brainstem and the ventilatory output accomplished. The brain regions responsible for detecting the mismatch between the two are not established. The mechanism underlying the transmission of neural signals for dyspnea to higher sensory brain centers is not known. Further, information from central and peripheral chemoreceptors that control the milieu of body fluids is summated at higher brain centers, which modify dyspneic sensations. The mental status also affects the sensitivity to and the threshold of dyspnea perception. The currently used methods for relieving dyspnea are not necessarily fully effective. The search for more effective therapy requires further insights into the pathophysiology of dyspnea.
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Affiliation(s)
- Isato Fukushi
- Faculty of Health Sciences, Uekusa Gakuen University, 1639-3 Ogura-cho, Wakaba-ku, Chiba, 264-0007, Japan; Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.
| | - Mieczyslaw Pokorski
- Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan; Faculty of Health Sciences, The Jan Dlugosz University in Czestochowa, 4/8 Jerzego Waszyngtona Street, 42-200, Czestochowa, Poland
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, 2-37-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
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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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McIntosh RC, Hoshi RA, Timpano KR. Take my breath away: Neural activation at breath-hold differentiates individuals with panic disorder from healthy controls. Respir Physiol Neurobiol 2020; 277:103427. [PMID: 32120012 DOI: 10.1016/j.resp.2020.103427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/12/2020] [Accepted: 02/24/2020] [Indexed: 01/04/2023]
Abstract
There is neuroanatomical evidence of an "extended fear network" of brain structures involved in the etiology of panic disorder (PD). Although ventilatory distrubance is a primary symptom of PD these sensations may also trigger onset of a panic attack (PA). Here, a voluntary breath-holding paradigm was used to mimic the hypercapnia state in order to compare blood oxygen level-dependent (BOLD) response, at the peak of a series of 18 s breath-holds, of 21 individuals with PD to 21 low anxiety matched controls. Compared to the rest condition, BOLD activity at the peak (12 - 18 s) of the breath-hold was greater for PD versus controls within a number of structures implicated in the extended fear network, including hippocampus, thalamus, and brainstem. Activation was also observed in cortical structures that are shown to be involved in interoceptive and self-referential processing, such as right insula, middle frontal gyrus, and precuneus/posterior cingulate. In lieu of amygdala activation, our findings show elevated activity throughout an extended network of cortical and subcortical structures involved in contextual, interoceptive and self-referential processing when individuals with PD engage in voluntary breath-holding.
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Affiliation(s)
- R C McIntosh
- Department of Psychology, University of Miami, 1120 NW 14th Street, Miami, FL, 33136, United States.
| | - R A Hoshi
- Clinical and Epidemiological Research Center, Sao Paulo University. 2565 Professor Lineu Prestes Ave, Sao Paulo, 05508-000, Brazil
| | - K R Timpano
- Department of Psychology, University of Miami, 1120 NW 14th Street, Miami, FL, 33136, United States
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Kim M, Kujawa A, Battiston M, Demetriou E, Schneider T, Collorone S, Tur C, Evans V, Okuchi S, Atkinson D, Gandini Wheeler-Kingshott CAM, Golay X. Translating pH-sensitive PROgressive saturation for QUantifying Exchange rates using Saturation Times (PRO-QUEST) MRI to a 3T clinical scanner. Magn Reson Med 2020; 84:1734-1746. [PMID: 32112451 DOI: 10.1002/mrm.28229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/16/2020] [Accepted: 02/04/2020] [Indexed: 11/07/2022]
Abstract
PURPOSE To translate the recently developed PRO-QUEST (Progressive saturation for quantifying exchange rates using saturation times) sequence from preclinical 9.4T to 3T clinical magnetic field strength. METHODS Numerical simulations were performed to define the optimal saturation flip angles for PRO-QUEST saturation pulses at 3T and demonstrate the effect of a ∆T2 error on the exchange rate (kex ) estimation at various field strengths. Exchange-dependent relaxation rate (Rex ) was measured for glutamate solutions in various pH, healthy volunteers and patients with multiple sclerosis (MS). Additionally, concentration-independent ratiometric Rex maps were produced to evaluate regional signal variations across the brain of human volunteers. RESULTS The calculated Rex significantly correlates with pH in glutamate samples, however, kex values are underestimated as compared to those previously obtained at 9.4T. In the ratiometric Rex map of healthy volunteers, no significant differences are found between grey matter, white matter, and basal ganglia. In patients with MS, white matter lesions are visible in single saturation power Rex maps whereas only a periventricular lesion is apparent in the ratiometric Rex map. CONCLUSION We demonstrate that quantification of pH sensitive indices using PRO-QUEST is feasible at 3T within clinically acceptable acquisition times. Our initial findings in patients with MS show that pH sensitive indices varied with the type of lesion examined whereas no significant difference was found in healthy volunteers between tissue types, suggesting that it would be worthwhile to apply PRO-QUEST in a larger cohort of patients to better understand its distinct imaging features relative to conventional techniques.
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Affiliation(s)
- Mina Kim
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Aaron Kujawa
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Marco Battiston
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Eleni Demetriou
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | | | - Sara Collorone
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Carmen Tur
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Vincent Evans
- UCL Centre for Medical Imaging, University College London, London, UK
| | - Sachi Okuchi
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - David Atkinson
- UCL Centre for Medical Imaging, University College London, London, UK
| | - Claudia A M Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK.,Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.,Brain MRI 3T Research Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Xavier Golay
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
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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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12
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Schwarzmeier H, Kleint NI, Wittchen HU, Ströhle A, Hamm AO, Lueken U. Characterizing the nature of emotional-associative learning deficits in panic disorder: An fMRI study on fear conditioning, extinction training and recall. Eur Neuropsychopharmacol 2019; 29:306-318. [PMID: 30497840 DOI: 10.1016/j.euroneuro.2018.11.1108] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 12/22/2022]
Abstract
Emotional-associative learning represents a translational model for the development, maintenance and treatment of anxiety disorders such as panic disorder (PD). The exact nature of the underlying fear learning and extinction deficits however, remains under debate. Using a three-day paradigm to separate the distinct learning and consolidation processes, we aimed to gain insights into the neurofunctional substrates of altered fear conditioning, extinction training and recall in PD. In contrast to studies employing one-session fear conditioning paradigms, a differential fear conditioning and delayed extinction task was conducted for the purpose of disentangling neural networks involved in fear acquisition, extinction training and recall of extinction memories. Using functional magnetic resonance imaging (fMRI), quality-controlled datasets from 10 patients with PD and 10 healthy controls were available from three consecutive days (day 1: acquisition; day 2: extinction training; day 3: extinction recall) with neutral faces serving as CSs and an aversive auditory stimulus (panic scream) as US. PD patients showed heightened fear circuitry (e.g. right amygdala and left insula) activation during early acquisition and prolonged activation in the right insula, left inferior frontal operculum and left inferior frontal gyrus during extinction recall compared to healthy controls. Stronger neural activation in structures conferring defensive reactivity during early acquisition and extinction recall may indicate the accelerated acquisition of conditioned responses, while extinction recall may be attenuated as a function of PD pathophysiology. Future studies should investigate the predictive value of experimental measures of extinction recall for clinical relapse.
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Affiliation(s)
- H Schwarzmeier
- Center of Mental Health, Dept. of Psychiatry, Psychosomatics, and Psychotherapy, University Hospital of Würzburg, Margarete-Höppel-Platz 1, D-97080 Würzburg, Germany.
| | - N I Kleint
- Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden, Germany
| | - H U Wittchen
- Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden, Germany; Clinical Psychology & Psychotherapy RG, Department of Psychiatry & Psychotherapy, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - A Ströhle
- Dept. of Psychiatry and Psychotherapy, Charité - University Medicine Berlin, Berlin, Germany
| | - A O Hamm
- Dept. of Physiological and Clinical Psychology/Psychotherapy, University of Greifswald, Greifswald , Germany
| | - U Lueken
- Center of Mental Health, Dept. of Psychiatry, Psychosomatics, and Psychotherapy, University Hospital of Würzburg, Margarete-Höppel-Platz 1, D-97080 Würzburg, Germany; Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden, Germany; Dept. of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
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13
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van Alst TM, Wachsmuth L, Datunashvili M, Albers F, Just N, Budde T, Faber C. Anesthesia differentially modulates neuronal and vascular contributions to the BOLD signal. Neuroimage 2019; 195:89-103. [DOI: 10.1016/j.neuroimage.2019.03.057] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 03/06/2019] [Accepted: 03/25/2019] [Indexed: 11/27/2022] Open
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14
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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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15
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Zulfarina MS, Syarifah-Noratiqah SB, Nazrun SA, Sharif R, Naina-Mohamed I. Pharmacological Therapy in Panic Disorder: Current Guidelines and Novel Drugs Discovery for Treatment-resistant Patient. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2019; 17:145-154. [PMID: 30905115 PMCID: PMC6478076 DOI: 10.9758/cpn.2019.17.2.145] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/11/2018] [Accepted: 10/12/2018] [Indexed: 12/26/2022]
Abstract
Panic disorder (PD) being one of the most intensively investigated anxiety disorders is considered a heterogeneous psychiatric disease which has difficulties with early diagnosis. The disorder is recurrent and usually associated with low remission rates and high rates of relapse which may exacerbated social and quality of life, causes unnecessary cost and increased risk for complication and suicide. Current pharmacotherapy for PD are available but these drugs have slow therapeutic onset, several side effects and most patients do not fully respond to these standard pharmacological treatments. Ongoing investigations indicate the need for new and promising agents for the treatment of PD. This article will cover the importance of immediate and proper treatment, the gap in the current management of PD with special emphasis on pharmacotherapy, and evidence regarding the novel anti-panic drugs including the drugs in developments such as metabotropic glutamate (mGlu 2/3) agonist and levetiracetam. Preliminary results suggest the anti-panic properties and the efficacy of duloxetine, reboxetine, mirtazapine, nefazodone, risperidone and inositol as a monotherapy drug. Apart for their effectiveness, the aforementioned compounds were generally well tolerated compared to the standard available pharmacotherapy drugs, indicating their potential therapeutic usefulness for ambivalent and hypervigilance patient. Further strong clinical trials will provide an ample support to these novel compounds as an alternative monotherapy for PD treatment-resistant patient.
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Affiliation(s)
- Mohamed S Zulfarina
- Pharmacoepidemiology and Drug Safety Unit, Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Syed-Badrul Syarifah-Noratiqah
- Pharmacoepidemiology and Drug Safety Unit, Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Shuid A Nazrun
- Pharmacoepidemiology and Drug Safety Unit, Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Razinah Sharif
- Program of Nutritional Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Isa Naina-Mohamed
- Pharmacoepidemiology and Drug Safety Unit, Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
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16
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Ali SO, Fessas P, Kaggie JD, Zaccagna F, Houston G, Reid S, Graves MJ, Gallagher FA. Evaluation of the sensitivity of R 1ρ MRI to pH and macromolecular density. Magn Reson Imaging 2019; 58:156-161. [PMID: 30771445 PMCID: PMC6422633 DOI: 10.1016/j.mri.2019.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/17/2022]
Abstract
The tumor microenvironment is characteristically acidic and this extracellular acidosis is known to play a role in carcinogenesis and metastasis and can affect tumor chemosensitivity and radiosensitivity. Intracellular pH has been used as a possible biomarker of salvageable tissue in ischemic stroke. A non-invasive MRI-based approach for the determination and imaging of cerebral pH would be a powerful tool in cancer diagnosis and monitoring, as well as stroke treatment planning. Several pH-based MRI imaging approaches have been proposed but for these to be useful, disentangling the effects of pH from other parameters which may affect the measured MRI signal is crucial to ensure accuracy and specificity. R1 relaxation in the rotating frame (R1ρ) is an example of a method that has been proposed to probe pH in vivo using MRI. In this study, we have investigated the relationship between R1ρ, pH, and macromolecular density in vitro using phantoms and in human volunteers. Here we show that the rate of R1ρ relaxation (=1/T1ρ) varies with pH but only in the presence of macromolecules. At constant pH, phantom macromolecular density inversely correlated with R1ρ. R1ρ imaging of the normal human brain demonstrated regional heterogeneity with significant differences between structurally distinct regions, which are likely to be independent of pH. For example, R1ρ was higher in the basal ganglia compared to grey matter and higher in grey matter compared to white matter. We conclude that R1ρ cannot be reliably used to image tissue pH without deconvolution from the effects of local tissue macromolecular composition.
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Affiliation(s)
- Syed O Ali
- University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Rd, Cambridge CB2 0SP, United Kingdom
| | - Petros Fessas
- University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Rd, Cambridge CB2 0SP, United Kingdom
| | - Joshua D Kaggie
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ.
| | - Fulvio Zaccagna
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ
| | | | - Scott Reid
- GE Healthcare, Amersham, United Kingdom, HP7 9JQ
| | - Martin J Graves
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Ferdia A Gallagher
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ.
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17
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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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18
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Rajendran M, Claywell B, Haynes EP, Scales U, Henning CK, Tantama M. Imaging pH Dynamics Simultaneously in Two Cellular Compartments Using a Ratiometric pH-Sensitive Mutant of mCherry. ACS OMEGA 2018; 3:9476-9486. [PMID: 30197999 PMCID: PMC6120727 DOI: 10.1021/acsomega.8b00655] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/06/2018] [Indexed: 05/09/2023]
Abstract
The regulation of pH is essential for proper organelle function, and organelle-specific changes in pH often reflect the dynamics of physiological signaling and metabolism. For example, mitochondrial energy production depends on the proton gradient maintained between the alkaline mitochondrial matrix and neutral cytosol. However, we still lack a quantitative understanding of how pH dynamics are coupled between compartments and how pH gradients are regulated at organelle boundaries. Genetically encoded pH sensors are well suited to address this problem because they can be targeted to specific subcellular locations and they facilitate live, single-cell analysis. However, most of these pH sensors are derivatives of green and yellow fluorescent proteins that are not spectrally compatible for dual-compartment imaging. Therefore, there is a need for ratiometric red fluorescent protein pH sensors that enable quantitative multicolor imaging of spatially resolved pH dynamics. In this work, we demonstrate that the I158E/Q160A mutant of the red fluorescent protein mCherry is an effective ratiometric pH sensor. It has a pKa of 7.3 and a greater than 3-fold change in ratio signal. To demonstrate its utility in cells, we measured activity and metabolism-dependent pH dynamics in cultured primary neurons and neuroblastoma cells. Furthermore, we were able to image pH changes simultaneously in the cytosol and mitochondria by using the mCherryEA mutant together with the green fluorescent pH sensor, ratiometric-pHluorin. Our results demonstrate the feasibility of studying interorganelle pH dynamics in live cells over time and the broad applicability of these sensors in studying the role of pH regulation in metabolism and signaling.
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Affiliation(s)
- Megha Rajendran
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Benjamin Claywell
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Emily P. Haynes
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Umi Scales
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Chace K. Henning
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Mathew Tantama
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
- E-mail: . Phone: 765-494-5312
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19
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Intermittent living; the use of ancient challenges as a vaccine against the deleterious effects of modern life - A hypothesis. Med Hypotheses 2018; 120:28-42. [PMID: 30220336 DOI: 10.1016/j.mehy.2018.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/25/2018] [Accepted: 08/04/2018] [Indexed: 12/19/2022]
Abstract
Chronic non-communicable diseases (CNCD) are the leading cause of mortality in developed countries. They ensue from the sum of modern anthropogenic risk factors, including high calorie nutrition, malnutrition, sedentary lifestyle, social stress, environmental toxins, politics and economic factors. Many of these factors are beyond the span of control of individuals, suggesting that CNCD are inevitable. However, various studies, ours included, show that the use of intermittent challenges with hormetic effects improve subjective and objective wellbeing of individuals with CNCD, while having favourable effects on immunological, metabolic and behavioural indices. Intermittent cold, heat, fasting and hypoxia, together with phytochemicals in multiple food products, have widespread influence on many pathways related with overall health. Until recently, most of the employed challenges with hormetic effects belonged to the usual transient live experiences of our ancestors. Our hypothesis; we conclude that, whereas the total inflammatory load of multi-metabolic and psychological risk factors causes low grade inflammation and aging, the use of intermittent challenges, united in a 7-10 days lasting hormetic intervention, might serve as a vaccine against the deleterious effects of chronic low grade inflammation and it's metabolic and (premature) aging consequences.
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20
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Abstract
Unconscious patients are commonly seen by physicians. They are challenging to manage and in a time sensitive condition, a systematic, team approach is required. Early physiological stability and diagnosis are necessary to optimise outcome. This article focuses on unconscious patients where the initial cause appears to be non-traumatic and provides a practical guide for their immediate care.
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21
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Battaglia M, Khan WU. Reappraising Preclinical Models of Separation Anxiety Disorder, Panic Disorder, and CO 2 Sensitivity: Implications for Methodology and Translation into New Treatments. Curr Top Behav Neurosci 2018; 40:195-217. [PMID: 29696603 DOI: 10.1007/7854_2018_42] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Separation anxiety applies to multiple forms of distress responses seen in mammals during postnatal development, including separation from a caregiver. Childhood separation anxiety disorder is an important risk factor for developing panic disorder in early adulthood, and both conditions display an increased sensitivity to elevated CO2 concentrations inhaled from the air. By interfacing epidemiological, genetic, and physiological knowledge with preclinical animal research models, it is possible to decipher the mechanisms that are central to separation anxiety and panic disorders while also suggesting possible therapies. Preclinical research models allow for environmentally controlled studies of early interferences with parental care. These models have shown that different forms of early maternal separation in mice and rats induce elevated CO2 respiratory sensitivity, an important biomarker of separation anxiety and panic disorders. In mice, this is likely due to gene-environment interactions that affect multiple behavioural and physical phenotypes after exposure to this early adversity. Although several questions regarding the causal mechanism of separation anxiety and panic disorder remain unanswered, the identification and improved understanding of biomarkers that link these mental health conditions under the guise of preclinical research models in conjunction with human longitudinal cohort studies can help resolve these issues.
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Affiliation(s)
- Marco Battaglia
- Division of Child, Youth and Emerging Adulthood Psychiatry, Centre for Addiction & Mental Health, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Waqas Ullah Khan
- Division of Child, Youth and Emerging Adulthood Psychiatry, Centre for Addiction & Mental Health, Toronto, ON, Canada
- School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
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22
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Feldker K, Heitmann CY, Neumeister P, Brinkmann L, Bruchmann M, Zwitserlood P, Straube T. Cardiorespiratory concerns shape brain responses during automatic panic-related scene processing in patients with panic disorder. J Psychiatry Neurosci 2018; 43. [PMID: 29252163 PMCID: PMC5747532 DOI: 10.1503/jpn.160226] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Increased automatic processing of threat-related stimuli has been proposed as a key element in panic disorder. Little is known about the neural basis of automatic processing, in particular to task-irrelevant, panic-related, ecologically valid stimuli, or about the association between brain activation and symptomatology in patients with panic disorder. METHODS The present event-related functional MRI (fMRI) study compared brain responses to task-irrelevant, panic-related and neutral visual stimuli in medication-free patients with panic disorder and healthy controls. Panic-related and neutral scenes were presented while participants performed a spatially nonoverlapping bar orientation task. Correlation analyses investigated the association between brain responses and panic-related aspects of symptomatology, measured using the Anxiety Sensitivity Index (ASI). RESULTS We included 26 patients with panic disorder and 26 heatlhy controls in our analysis. Compared with controls, patients with panic disorder showed elevated activation in the amygdala, brainstem, thalamus, insula, anterior cingulate cortex and midcingulate cortex in response to panic-related versus neutral task-irrelevant stimuli. Furthermore, fear of cardiovascular symptoms (a subcomponent of the ASI) was associated with insula activation, whereas fear of respiratory symptoms was associated with brainstem hyperactivation in patients with panic disorder. LIMITATIONS The additional implementation of measures of autonomic activation, such as pupil diameter, heart rate, or electrodermal activity, would have been informative during the fMRI scan as well as during the rating procedure. CONCLUSION Results reveal a neural network involved in the processing of panic-related distractor stimuli in patients with panic disorder and suggest an automatic weighting of panic-related information depending on the magnitude of cardiovascular and respiratory symptoms. Insula and brainstem activations show function-related associations with specific components of panic symptomatology.
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Affiliation(s)
- Katharina Feldker
- Correspondence to: K. Feldker, Institute of Medical Psychology and Systems Neuroscience, Von-Esmarch-Straße 52, D-48149 Muenster, Germany;
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23
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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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24
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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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25
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Hao J, Xiao T, Wu F, Yu P, Mao L. High Antifouling Property of Ion-Selective Membrane: toward In Vivo Monitoring of pH Change in Live Brain of Rats with Membrane-Coated Carbon Fiber Electrodes. Anal Chem 2016; 88:11238-11243. [DOI: 10.1021/acs.analchem.6b03854] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jie Hao
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Analytical Chemistry for
Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese
Academy of Sciences, Beijing 100049, China
| | - Tongfang Xiao
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Analytical Chemistry for
Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese
Academy of Sciences, Beijing 100049, China
| | - Fei Wu
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Analytical Chemistry for
Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese
Academy of Sciences, Beijing 100049, China
| | - Ping Yu
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Analytical Chemistry for
Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese
Academy of Sciences, Beijing 100049, China
| | - Lanqun Mao
- Beijing National Laboratory
for Molecular Sciences, Key Laboratory of Analytical Chemistry for
Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences (CAS), Beijing 100190, China
- University of Chinese
Academy of Sciences, Beijing 100049, China
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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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Panic Anxiety in Humans with Bilateral Amygdala Lesions: Pharmacological Induction via Cardiorespiratory Interoceptive Pathways. J Neurosci 2016; 36:3559-66. [PMID: 27013684 DOI: 10.1523/jneurosci.4109-15.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/12/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED We previously demonstrated that carbon dioxide inhalation could induce panic anxiety in a group of rare lesion patients with focal bilateral amygdala damage. To further elucidate the amygdala-independent mechanisms leading to aversive emotional experiences, we retested two of these patients (B.G. and A.M.) to examine whether triggering palpitations and dyspnea via stimulation of non-chemosensory interoceptive channels would be sufficient to elicit panic anxiety. Participants rated their affective and sensory experiences following bolus infusions of either isoproterenol, a rapidly acting peripheral β-adrenergic agonist akin to adrenaline, or saline. Infusions were administered during two separate conditions: a panic induction and an assessment of cardiorespiratory interoception. Isoproterenol infusions induced anxiety in both patients, and full-blown panic in one (patient B.G.). Although both patients demonstrated signs of diminished awareness for cardiac sensation, patient A.M., who did not panic, reported a complete lack of awareness for dyspnea, suggestive of impaired respiratory interoception. These findings indicate that the amygdala may play a role in dynamically detecting changes in cardiorespiratory sensation. The induction of panic anxiety provides further evidence that the amygdala is not required for the conscious experience of fear induced via interoceptive sensory channels. SIGNIFICANCE STATEMENT We found that monozygotic twins with focal bilateral amygdala lesions report panic anxiety in response to intravenous infusions of isoproterenol, a β-adrenergic agonist similar to adrenaline. Heightened anxiety was evident in both twins, with one twin experiencing a panic attack. The twin who did not panic displayed signs of impaired cardiorespiratory interoception, including a complete absence of dyspnea sensation. These findings highlight that the amygdala is not strictly required for the experience of panic anxiety, and suggest that neural systems beyond the amygdala are also involved. Determining these additional systems could provide key neural modulation targets for future anxiolytic treatments.
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Battaglia M. Separation anxiety: at the neurobiological crossroads of adaptation and illness. DIALOGUES IN CLINICAL NEUROSCIENCE 2016. [PMID: 26487808 PMCID: PMC4610612 DOI: 10.31887/dcns.2015.17.3/mbattaglia] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Physiological and adaptive separation anxiety (SA) is intimately connected with the evolutionary emergence of new brain structures specific of paleomammalians, the growth of neomammalian—and later hominid—brain and skull size, and the appearance of bipedalism. All these evolutionary milestones have contributed to expanding the behavioral repertoire and plasticity of prehuman and human beings, at the cost of more prolonged dependency of the infant and of the child on parental care. Separation anxiety disorder (SAD) can be seen as an exaggerated/inappropriate manifestation of SA that constitutes a gateway to poorer mental and physical health. By blending epidemiological, genetic-epidemiological, endophenotypic, and animal laboratory approaches, it is possible to delineate some of the mechanisms that link childhood-adolescence SA and SAD to health problems later in life. Causal mechanisms include gene-environment interplays and likely differential regulation of genes and functional net-works that simultaneously affect multiple behavioral and physical phenotypes after exposure to early-life adversity, including parental separation/loss.
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Affiliation(s)
- Marco Battaglia
- Department of Psychiatry and Neurosciences, Laval University, Québec, Canada; Centre de Recherche Institut Universitaire en Santé Mentale de Québec, Canada
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Cittaro D, Lampis V, Luchetti A, Coccurello R, Guffanti A, Felsani A, Moles A, Stupka E, D' Amato FR, Battaglia M. Histone Modifications in a Mouse Model of Early Adversities and Panic Disorder: Role for Asic1 and Neurodevelopmental Genes. Sci Rep 2016; 6:25131. [PMID: 27121911 PMCID: PMC4848503 DOI: 10.1038/srep25131] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/12/2016] [Indexed: 11/20/2022] Open
Abstract
Hyperventilation following transient, CO2-induced acidosis is ubiquitous in mammals and heritable. In humans, respiratory and emotional hypersensitivity to CO2 marks separation anxiety and panic disorders, and is enhanced by early-life adversities. Mice exposed to the repeated cross-fostering paradigm (RCF) of interference with maternal environment show heightened separation anxiety and hyperventilation to 6% CO2-enriched air. Gene-environment interactions affect CO2 hypersensitivity in both humans and mice. We therefore hypothesised that epigenetic modifications and increased expression of genes involved in pH-detection could explain these relationships. Medullae oblongata of RCF- and normally-reared female outbred mice were assessed by ChIP-seq for H3Ac, H3K4me3, H3K27me3 histone modifications, and by SAGE for differential gene expression. Integration of multiple experiments by network analysis revealed an active component of 148 genes pointing to the mTOR signalling pathway and nociception. Among these genes, Asic1 showed heightened mRNA expression, coherent with RCF-mice’s respiratory hypersensitivity to CO2 and altered nociception. Functional enrichment and mRNA transcript analyses yielded a consistent picture of enhancement for several genes affecting chemoception, neurodevelopment, and emotionality. Particularly, results with Asic1 support recent human findings with panic and CO2 responses, and provide new perspectives on how early adversities and genes interplay to affect key components of panic and related disorders.
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Affiliation(s)
- Davide Cittaro
- Centre for Translational Genomics and Bioinformatics, San Raffaele Scientific Institute, Milan, Italy
| | - Valentina Lampis
- Developmental Psychopathology Unit, Vita-Salute San Raffaele University, Milan, Italy
| | - Alessandra Luchetti
- Institute of Cell Biology and Neurobiology, National Research Council/Fondazione Santa Lucia, Rome, Italy
| | - Roberto Coccurello
- Institute of Cell Biology and Neurobiology, National Research Council/Fondazione Santa Lucia, Rome, Italy
| | - Alessandro Guffanti
- Laboratory of Molecular Neuroscience, Department of Biological Chemistry, The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, Jerusalem, Israel.,Genomnia srl, Lainate, Italy
| | - Armando Felsani
- Institute of Cell Biology and Neurobiology, National Research Council/Fondazione Santa Lucia, Rome, Italy.,Genomnia srl, Lainate, Italy
| | - Anna Moles
- Institute of Cell Biology and Neurobiology, National Research Council/Fondazione Santa Lucia, Rome, Italy.,Genomnia srl, Lainate, Italy
| | - Elia Stupka
- Centre for Translational Genomics and Bioinformatics, San Raffaele Scientific Institute, Milan, Italy
| | - Francesca R D' Amato
- Institute of Cell Biology and Neurobiology, National Research Council/Fondazione Santa Lucia, Rome, Italy
| | - Marco Battaglia
- Department of Psychiatry, University Of Toronto, Toronto, Canada.,Division of Child and Youth Mental Health, Centre for Addiction and Mental Health, Toronto, Canada
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30
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Flores Á, Saravia R, Maldonado R, Berrendero F. Orexins and fear: implications for the treatment of anxiety disorders. Trends Neurosci 2015. [DOI: 10.1016/j.tins.2015.06.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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31
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Grassi M, Caldirola D, Di Chiaro NV, Riva A, Daccò S, Pompili M, Perna G. Are respiratory abnormalities specific for panic disorder? A meta-analysis. Neuropsychobiology 2015; 70:52-60. [PMID: 25247676 DOI: 10.1159/000364830] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/24/2014] [Indexed: 11/19/2022]
Abstract
OBJECTIVES There is evidence of baseline respiratory abnormalities in panic disorder (PD), but whether they are specific to PD remains unclear. To investigate this issue, we meta-analyzed results from studies comparing baseline respiratory and hematic variables between subjects with PD and subjects with other anxiety disorders. METHODS A literature search in bibliographic databases was performed. Fixed-effects models were applied. Several moderator analyses and publication bias diagnostics were performed. RESULTS We found: (1) significantly lower mean end-tidal partial pressure of CO(2) (et-pCO(2)) in subjects with PD than in those with social phobia (SP) or generalized anxiety disorder (GAD), and (2) higher mean respiratory rate, lower venous et-pCO(2) and HCO(3)(-) concentration in subjects with PD than in those with SP. No publication bias was found. CONCLUSIONS Subjects with PD show a condition of baseline hyperventilation when compared to subjects with SP or GAD. Hematic variables suggest that the hyperventilation may be chronic. These results support the idea that baseline respiratory abnormalities are specific to PD pathophysiology. Further studies are needed to clarify whether these abnormalities are related to a malfunction of the respiratory system or to specific cognitive/emotional/behavioral factors in this population.
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Affiliation(s)
- Massimiliano Grassi
- Department of Clinical Neurosciences, Villa San Benedetto Hospital, Hermanas Hospitalarias, FoRiPsi, Albese con Cassano, Italy
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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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33
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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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35
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Geiger MJ, Neufang S, Stein DJ, Domschke K. Arousal and the attentional network in panic disorder. Hum Psychopharmacol 2014; 29:599-603. [PMID: 25311787 DOI: 10.1002/hup.2436] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 08/13/2014] [Accepted: 08/18/2014] [Indexed: 12/30/2022]
Abstract
Although a great deal of information about the neurobiology of panic disorder is now available, there is a need for an updated etiological model integrating recent findings on the neurobiology of the arousal system and its relationship with higher cortical functions in panic disorder. The current mini-review presents psychophysiological, molecular biological/genetic and functional neuroimaging evidence for dysfunction in major arousal systems of the brain. Such dysfunction may influence the development of panic disorder by precipitating autonomic bodily symptoms and at the same time increasing vigilance to these sensations by modulating cortical attentional networks. A multilevel model of arousal, attention and anxiety-including the norepinephrine, orexin, neuropeptide S and caffeine-related adenosine systems-may be useful in integrating a range of data available on the pathogenesis of panic disorder.
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36
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Pinkney V, Wickens R, Bamford S, Baldwin DS, Garner M. Defensive eye-blink startle responses in a human experimental model of anxiety. J Psychopharmacol 2014; 28:874-80. [PMID: 24899597 PMCID: PMC4876426 DOI: 10.1177/0269881114532858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inhalation of low concentrations of carbon dioxide (CO2) triggers anxious behaviours in rodents via chemosensors in the amygdala, and increases anxiety, autonomic arousal and hypervigilance in healthy humans. However, it is not known whether CO2 inhalation modulates defensive behaviours coordinated by this network in humans. We examined the effect of 7.5% CO2 challenge on the defensive eye-blink startle response. A total of 27 healthy volunteers completed an affective startle task during inhalation of 7.5% CO2 and air. The magnitude and latency of startle eye-blinks were recorded whilst participants viewed aversive and neutral pictures. We found that 7.5% CO2 increased state anxiety and raised concurrent measures of skin conductance and heart rate (HR). CO2 challenge did not increase startle magnitude, but slowed the onset of startle eye-blinks. The effect of CO2 challenge on HR covaried with its effects on both subjective anxiety and startle latency. Our findings are discussed with reference to startle profiles during conditions of interoceptive threat, increased cognitive load and in populations characterised by anxiety, compared with acute fear and panic.
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Affiliation(s)
| | - Robin Wickens
- Department of Pharmacy and Pharmacology, University of Bath, Bath, UK
| | - Susan Bamford
- Psychology, University of Southampton, Southampton, UK
| | - David S Baldwin
- Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Matthew Garner
- Psychology, University of Southampton, Southampton, UK Clinical and Experimental Sciences, University of Southampton, Southampton, UK
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Abstract
BACKGROUND Abnormal brain pH has been suggested to play a critical role in panic disorder. To investigate this possibility, we employed a pH-sensitive magnetic resonance (MR) imaging strategy (T1 relaxation in the rotating frame [T1ρ]) and conventional blood oxygen level-dependent (BOLD) imaging. METHODS Thirteen panic disorder participants and 13 matched control subjects were enrolled in the study. T1ρ and BOLD were used to study the functional response to a visual flashing checkerboard and their relationship to panic symptoms assessed using the Beck Anxiety Inventory. RESULTS In response to visual stimulation, T1ρ imaging revealed a significantly greater increase in the visual cortex of panic disorder participants. T1ρ also detected a stimulus-evoked decrease in the anterior cingulate cortex. Blood oxygen level-dependent imaging detected no functional differences between groups. The correspondence between panic symptoms and functional T1ρ response identified significant relationships within the left inferior parietal lobe, left middle temporal gyrus, and right insula. No relationships were found between panic symptoms and the BOLD signal. CONCLUSIONS The data suggest greater activity-evoked T1ρ changes in the visual cortex and anterior cingulate cortex of panic disorder participants. These observations are consistent with a pH dysregulation in panic disorder. In addition, our data suggest that T1ρ imaging may provide information about panic disorder that is distinct from conventional BOLD imaging and may reflect abnormalities in pH and/or brain metabolism.
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38
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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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Freire RC, Nascimento I, Valença AM, Lopes FL, Mezzasalma MA, Melo Neto VLD, Zin WA, Nardi AE. The panic disorder respiratory ratio: a dimensional approach to the respiratory subtype. BRAZILIAN JOURNAL OF PSYCHIATRY 2013; 35:57-62. [PMID: 23567601 DOI: 10.1016/j.rbp.2012.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 02/23/2012] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The respiratory ratio is a dimensional construct of the respiratory subtype of panic disorder (PD). The respiratory subtype has been correlated with an increased sensitivity to CO₂ inhalation, positive family history of PD and low comorbidity with depression. The objective of our study was to determine whether the respiratory ratio is correlated with CO₂-induced panic attacks and other clinical and demographic features. METHODS We examined 91 patients with PD and submitted them to a double-breath 35% CO₂ challenge test. The respiratory ratio was calculated based on the Diagnostic Symptom Questionnaire (DSQ) scores recorded in a diary in the days preceding the CO₂ challenge. The scores of the respiratory symptoms were summed and divided by the total DSQ score. RESULTS The respiratory ratio was correlated with CO₂ sensitivity, and there was a non-statistically significant trend towards a correlation with a family history of PD. CONCLUSIONS The positive correlation between the respiratory ratio and the anxiety elicited by the CO₂ inhalation indicates that the intensity of respiratory symptoms may be proportional to the sensitivity to carbon dioxide.
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Carbon dioxide inhalation as a human experimental model of panic: The relationship between emotions and cardiovascular physiology. Biol Psychol 2013; 94:331-40. [DOI: 10.1016/j.biopsycho.2013.06.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 05/28/2013] [Accepted: 06/19/2013] [Indexed: 11/23/2022]
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41
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Magnetic resonance spectroscopy imaging of lactate in patients with bipolar disorder. Psychiatry Res 2013; 213:230-4. [PMID: 23810640 DOI: 10.1016/j.pscychresns.2013.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 03/05/2013] [Accepted: 03/18/2013] [Indexed: 01/02/2023]
Abstract
Although brain lactate levels are typically low and difficult to measure, a few previous investigators have reported that brain lactate levels are elevated in patients with bipolar disorder. The present study investigated the distribution of lactate in bipolar and healthy brains using 2D proton magnetic resonance spectroscopic imaging on a 4-Tesla magnetic resonance imaging system. Ratios of the concentration of lactate to N-acetylaspartate, and of lactate to total creatine, were significantly higher in bipolar than in healthy subjects. Lactate signals were primarily localized to the bipolar subjects' caudate and anterior cingulate cortices, components of the frontal-subcortical circuit, suggesting that affective dysregulation may be related to metabolic abnormalities in this network.
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Maddock RJ, Buonocore MH, Miller AR, Yoon JH, Soosman SK, Unruh AM. Abnormal activity-dependent brain lactate and glutamate+glutamine responses in panic disorder. Biol Psychiatry 2013; 73:1111-9. [PMID: 23332354 PMCID: PMC3636170 DOI: 10.1016/j.biopsych.2012.12.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 12/02/2012] [Accepted: 12/27/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND Prior evidence suggests panic disorder (PD) is characterized by neurometabolic abnormalities, including increased brain lactate responses to neural activation. Increased lactate responses could reflect a general upregulation of metabolic responses to neural activation. However, prior studies in PD have not measured activity-dependent changes in brain metabolites other than lactate. Here we examine activity-dependent changes in both lactate and glutamate plus glutamine (glx) in PD. METHODS Twenty-one PD patients (13 remitted, 8 symptomatic) and 12 healthy volunteers were studied. A single-voxel, J-difference, magnetic resonance spectroscopy editing sequence was used to measure lactate and glx changes in visual cortex induced by visual stimulation. RESULTS The PD patients had significantly greater activity-dependent increases in brain lactate than healthy volunteers. The differences were significant for both remitted and symptomatic PD patients, who did not differ from each other. Activity-dependent changes in glx were significantly smaller in PD patients than in healthy volunteers. The temporal correlation between lactate and glx changes was significantly stronger in control subjects than in PD patients. CONCLUSIONS The novel demonstration that glx responses are diminished and temporally decoupled from lactate responses in PD contradicts the model of a general upregulation of activity-dependent brain metabolic responses in PD. The increase in activity-dependent brain lactate accumulation appears to be a trait feature of PD. Given the close relationship between lactate and pH in the brain, the findings are consistent with a model of brain metabolic and pH dysregulation associated with altered function of acid-sensitive fear circuits contributing to trait vulnerability in PD.
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Affiliation(s)
- Richard J. Maddock
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Michael H. Buonocore
- Department of Radiology, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Amber R. Miller
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Jong H. Yoon
- Department of Psychiatry, University of California Davis Medical Center, Sacramento, CA 95817, USA,Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - Steffan K. Soosman
- Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
| | - April M. Unruh
- Imaging Research Center, University of California Davis Medical Center, Sacramento, CA 95817, USA
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43
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Grassi M, Caldirola D, Vanni G, Guerriero G, Piccinni M, Valchera A, Perna G. Baseline respiratory parameters in panic disorder: a meta-analysis. J Affect Disord 2013; 146:158-73. [PMID: 23107756 DOI: 10.1016/j.jad.2012.08.034] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/21/2012] [Accepted: 08/21/2012] [Indexed: 02/01/2023]
Abstract
BACKGROUND The presence of abnormalities in baseline respiratory function of subjects with panic disorder (PD) is expected according to PD respiratory theories. We aimed to meta-analyze results from studies comparing baseline respiratory and hematic parameters related to respiration between subjects with PD and controls. METHODS A literature research in bibliographic databases was performed. Fixed-effects models were applied for all parameters while random-effects models only when suitable (at least 10 independent studies). Several moderator analyses and publication bias diagnostics were performed. RESULTS We found significantly higher mean minute ventilation and lower et-pCO(2) in subjects with PD than controls. Moreover we also found evidences of reduced HCO(3)(-) and PO(4)(-) hematic concentrations, higher indexes of respiratory variability/irregularity and higher rate of sighs and apneas. Evidence of heterogeneity was partly explained by moderator analyses. No relevant publication bias was found. LIMITATIONS Several shortcomings affected the included studies, such as over-inclusive recruitment criteria, samples unbalanced for socio-demographic characteristics, lack of statistical details and small number of studies available for several parameters. DISCUSSION Our results support the idea of abnormalities in respiratory function of subjects with PD. Compared to controls, they showed baseline hyperventilation; the results from hematic parameters suggest that hyperventilation may be chronic and not simply caused by their high anxiety levels during respiratory assessment. Evidences of higher variability and irregularity in respiratory patterns of subjects with PD were also found. It is unclear to what extent the higher rate of sighs and apneas may explain the other baseline respiratory abnormalities found in PD.
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Affiliation(s)
- Massimiliano Grassi
- Department of Clinical Neurosciences, Villa San Benedetto Hospital, Hermanas Hospitalarias, FoRiPsi, Albese con Cassano, Italy.
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Vickers K. Hypersensitivity to hypercapnia: definition/(s). Psychiatry Res 2012; 197:7-12. [PMID: 22401967 DOI: 10.1016/j.psychres.2011.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/29/2011] [Accepted: 11/08/2011] [Indexed: 10/28/2022]
Abstract
Empirical evidence indicates that panic disorder (PD) patients experience hypersensitivity to hypercapnia, a condition in which the blood level of carbon dioxide exceeds the normal value. The importance of this research line is substantial and indeed, hypercapnic hypersensitivity has been advanced as a possible endophenotype of panic. Definitions of "hypersensitivity," however, have varied. The purpose of this brief review is to delineate and critique different definitions of hypercapnic hypersensitivity. Several definitions - panic attack rate, panic symptoms including dyspnea, subjective anxiety, and respiratory disturbance - are explored. The review concludes that although no ideal definition has emerged, marked anxiety post-hypercapnia has substantial support as a putative trait marker of PD. The term "subjective hypersensitivity" (Coryell et al., 2001) is re-introduced to denote pronounced anxiety post-hypercapnia and recommended for use along with its previous definition: increased self-reported anxiety measured on a continuous visual analog scale, already widely in use. Due to the well-established link between panic and respiration, definitional candidates focusing on aberrant respiratory response - less investigated as trait markers of PD in high risk studies - warrant scrutiny as well. Several reasons why definitional clarity might be beneficial are presented, along with ideas for future research.
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Affiliation(s)
- Kristin Vickers
- Department of Psychology, Ryerson University, Toronto, ON, Canada.
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Abstract
Localized pH changes have been suggested to occur in the brain during normal function. However, the existence of such pH changes has also been questioned. Lack of methods for noninvasively measuring pH with high spatial and temporal resolution has limited insight into this issue. Here we report that a magnetic resonance imaging (MRI) strategy, T(1) relaxation in the rotating frame (T(1)ρ), is sufficiently sensitive to detect widespread pH changes in the mouse and human brain evoked by systemically manipulating carbon dioxide or bicarbonate. Moreover, T(1)ρ detected a localized acidosis in the human visual cortex induced by a flashing checkerboard. Lactate measurements and pH-sensitive (31)P spectroscopy at the same site also identified a localized acidosis. Consistent with the established role for pH in blood flow recruitment, T(1)ρ correlated with blood oxygenation level-dependent contrast commonly used in functional MRI. However, T(1)ρ was not directly sensitive to blood oxygen content. These observations indicate that localized pH fluctuations occur in the human brain during normal function. Furthermore, they suggest a unique functional imaging strategy based on pH that is independent of traditional functional MRI contrast mechanisms.
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Schutters SIJ, Viechtbauer W, Knuts IJ, Griez EJL, Schruers KRJ. 35% CO2 sensitivity in social anxiety disorder. J Psychopharmacol 2012; 26:479-86. [PMID: 22228835 DOI: 10.1177/0269881111430750] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The 35% carbon dioxide (CO(2)) challenge is a well-established model of panic. This study aimed to investigate 35% CO(2) sensitivity in patients with social anxiety disorder (SAD) compared with patients with panic disorder (PD) and normal controls. First, a 35% CO(2) challenge was conducted including 16 patients with generalized SAD, 16 with PD and 16 normal subjects. Outcome was assessed by a Visual Analogue Scale for Fear (VAS-F) and the Panic Symptom List (PSL). Second, meta-analyses of fear and panic scores were performed, including data from the present experiment and from previous 35% CO(2) challenge studies in patients with SAD. The present 35% CO(2) challenge found equal increases in VAS-F and PSL in patients with SAD compared with normal controls, whereas the CO(2) response in patients with PD was significantly stronger than in controls. The meta-analyses confirmed the experimental data from this study, and in addition showed an intermediate panic rate in SAD patients, in between that of normal controls and patients with PD. In conclusion, neither our experiment nor the meta-analyses found evidence for a similarly exaggerated 35% CO(2) sensitivity in SAD and PD, suggesting that the pathogenesis of SAD is different from PD, although patients with SAD may be slightly more sensitive than non-anxious controls.
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Affiliation(s)
- Sara I J Schutters
- Department of Psychiatry and Psychology, Maastricht University, Maastricht, the Netherlands.
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The 35% carbon dioxide test in stress and panic research: Overview of effects and integration of findings. Clin Psychol Rev 2012; 32:153-64. [DOI: 10.1016/j.cpr.2011.12.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Revised: 11/30/2011] [Accepted: 12/13/2011] [Indexed: 11/19/2022]
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Abstract
Panic disorder is a common and disabling illness for which treatments are too frequently ineffective. Greater knowledge of the underlying biology could aid the discovery of better therapies. Although panic attacks occur unpredictably, the ability to provoke them in the laboratory with challenge protocols provides an opportunity for crucial insight into the neurobiology of panic. Two of the most well-studied panic provocation challenges are CO(2) inhalation and lactate infusion. Although it remains unclear how these challenges provoke panic animal models of CO(2) and lactate action are beginning to emerge, and offer unprecedented opportunities to probe the molecules and circuits underlying panic attacks. Both CO(2) and lactate alter pH balance and may generate acidosis that can influence neuron function through a growing list of pH-sensitive receptors. These observations suggest that a key to better understanding of panic disorder may He in more knowledge of brain pH regulation and pH-sensitive receptors.
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Affiliation(s)
- John A Wemmie
- Department of Psychiatry, Interdisciplinary Graduate Program in Neuroscience, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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De Cort K, Griez E, Büchler M, Schruers K. The role of "interoceptive" fear conditioning in the development of panic disorder. Behav Ther 2012; 43:203-15. [PMID: 22304891 DOI: 10.1016/j.beth.2011.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 06/07/2011] [Accepted: 06/12/2011] [Indexed: 11/19/2022]
Abstract
More than 20% of the general population experience a panic attack at least once in their lives; however, only a minority goes on to develop panic disorder (PD). Conditioning mechanisms have been proposed to explain this evolution in persons who are susceptible to developing panic disorder upon a "traumatic" panic attack. According to preparedness theory, some cues are more likely to condition than others, namely, those referring to internal, bodily signals of danger. The aim of the present study was to test this theory in a differential conditioning paradigm, making use of scripts referring to different internal, bodily sensations as conditioned stimulus (CS) and inhalation of 35% CO(2) as unconditioned stimulus (UCS). Thirty-three healthy volunteers were assigned to three scripts conditions: "suffocation," "neutral," or "urgency." During acquisition, one of two versions of a particular script was always followed by an inhalation of 35% CO(2) (CS+) and the other by room air (CS-). Acquisition was followed by a test phase, where only inhalations of room air were administered. In line with our hypothesis, only participants in the suffocation condition exhibited a selective conditioning effect. They were more fearful and showed a significantly higher increase in tidal volume than participants in the two control conditions. Results are discussed with relation to interoceptive conditioning, preparedness, and the possible role of tidal volume in PD.
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Affiliation(s)
- Klara De Cort
- Academic Anxiety Center, School for Mental Health and Neuroscience, Maastricht University, PO 88, 6200 AB Maastricht, The Netherlands.
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Maddock RJ, Buonocore MH. MR spectroscopic studies of the brain in psychiatric disorders. Curr Top Behav Neurosci 2012; 11:199-251. [PMID: 22294088 DOI: 10.1007/7854_2011_197] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The measurement of brain metabolites with magnetic resonance spectroscopy (MRS) provides a unique perspective on the brain bases of neuropsychiatric disorders. As a context for interpreting MRS studies of neuropsychiatric disorders, we review the characteristic MRS signals, the metabolic dynamics,and the neurobiological significance of the major brain metabolites that can be measured using clinical MRS systems. These metabolites include N-acetylaspartate(NAA), creatine, choline-containing compounds, myo-inositol, glutamate and glutamine, lactate, and gamma-amino butyric acid (GABA). For the major adult neuropsychiatric disorders (schizophrenia, bipolar disorder, major depression, and the anxiety disorders), we highlight the most consistent MRS findings, with an emphasis on those with potential clinical or translational significance. Reduced NAA in specific brain regions in schizophrenia, bipolar disorder, post-traumatic stress disorder, and obsessive–compulsive disorder corroborate findings of reduced brain volumes in the same regions. Future MRS studies may help determine the extent to which the neuronal dysfunction suggested by these findings is reversible in these disorders. Elevated glutamate and glutamine (Glx) in patients with bipolar disorder and reduced Glx in patients with unipolar major depression support models of increased and decreased glutamatergic function, respectively, in those conditions. Reduced phosphomonoesters and intracellular pH in bipolar disorder and elevated dynamic lactate responses in panic disorder are consistent with metabolic models of pathogenesis in those disorders. Preliminary findings of an increased glutamine/glutamate ratio and decreased GABA in patients with schizophrenia are consistent with a model of NMDA hypofunction in that disorder. As MRS methods continue to improve, future studies may further advance our understanding of the natural history of psychiatric illnesses, improve our ability to test translational models of pathogenesis, clarify therapeutic mechanisms of action,and allow clinical monitoring of the effects of interventions on brain metabolicmarkers
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