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Frick A, Åhs F, Palmquist ÅM, Pissiota A, Wallenquist U, Fernandez M, Jonasson M, Appel L, Frans Ö, Lubberink M, Furmark T, von Knorring L, Fredrikson M. Overlapping expression of serotonin transporters and neurokinin-1 receptors in posttraumatic stress disorder: a multi-tracer PET study. Mol Psychiatry 2016; 21:1400-7. [PMID: 26619809 DOI: 10.1038/mp.2015.180] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/10/2015] [Accepted: 10/06/2015] [Indexed: 02/07/2023]
Abstract
The brain serotonergic system is colocalized and interacts with the neuropeptidergic substance P/neurokinin-1 (SP/NK1) system. Both these neurochemical systems have independently been implicated in stress and anxiety, but interactions between them might be crucial for human anxiety conditions. Here, we examined the serotonin and substance P/neurokinin-1 (SP/NK1) systems individually as well as their overlapping expression in 16 patients with posttraumatic stress disorder (PTSD) and 16 healthy controls. Participants were imaged with the highly selective radiotracers [(11)C]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile (DASB) and [(11)C]GR205171 assessing serotonin transporter (SERT) and NK1 receptor availability, respectively. Voxel-wise analyses in the amygdala, our a priori-defined region of interest, revealed increased number of NK1 receptors, but not SERT in the PTSD group. Symptom severity, as indexed by the Clinician-administered PTSD Scale, was negatively related to SERT availability in the amygdala, and NK1 receptor levels moderated this relationship. Exploratory, voxel-wise whole-brain analyses revealed increased SERT availability in the precentral gyrus and posterior cingulate cortex of PTSD patients. Patients, relative to controls, displayed lower degree of overlapping expression between SERT and NK1 receptors in the putamen, thalamus, insula and lateral orbitofrontal gyrus, lower overlap being associated with higher PTSD symptom severity. Expression overlap also explained more of the symptomatology than did either system individually, underscoring the importance of taking interactions between the neurochemical systems into account. Thus, our results suggest that aberrant serotonergic-SP/NK1 couplings contribute to the pathophysiology of PTSD and, consequently, that normalization of these couplings may be therapeutically important.
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Affiliation(s)
- A Frick
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - F Åhs
- Department of Psychology, Uppsala University, Uppsala, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Å M Palmquist
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - A Pissiota
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - U Wallenquist
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - M Fernandez
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - M Jonasson
- Department of Nuclear Medicine and PET, Uppsala University, Uppsala, Sweden
| | - L Appel
- Department of Nuclear Medicine and PET, Uppsala University, Uppsala, Sweden
| | - Ö Frans
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - M Lubberink
- Department of Nuclear Medicine and PET, Uppsala University, Uppsala, Sweden
| | - T Furmark
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - L von Knorring
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - M Fredrikson
- Department of Psychology, Uppsala University, Uppsala, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Prager EM, Bergstrom HC, Wynn GH, Braga MFM. The basolateral amygdala γ-aminobutyric acidergic system in health and disease. J Neurosci Res 2015; 94:548-67. [PMID: 26586374 DOI: 10.1002/jnr.23690] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/01/2015] [Accepted: 10/18/2015] [Indexed: 01/13/2023]
Abstract
The brain comprises an excitatory/inhibitory neuronal network that maintains a finely tuned balance of activity critical for normal functioning. Excitatory activity in the basolateral amygdala (BLA), a brain region that plays a central role in emotion and motivational processing, is tightly regulated by a relatively small population of γ-aminobutyric acid (GABA) inhibitory neurons. Disruption in GABAergic inhibition in the BLA can occur when there is a loss of local GABAergic interneurons, an alteration in GABAA receptor activation, or a dysregulation of mechanisms that modulate BLA GABAergic inhibition. Disruptions in GABAergic control of the BLA emerge during development, in aging populations, or after trauma, ultimately resulting in hyperexcitability. BLA hyperexcitability manifests behaviorally as an increase in anxiety, emotional dysregulation, or development of seizure activity. This Review discusses the anatomy, development, and physiology of the GABAergic system in the BLA and circuits that modulate GABAergic inhibition, including the dopaminergic, serotonergic, noradrenergic, and cholinergic systems. We highlight how alterations in various neurotransmitter receptors, including the acid-sensing ion channel 1a, cannabinoid receptor 1, and glutamate receptor subtypes, expressed on BLA interneurons, modulate GABAergic transmission and how defects of these systems affect inhibitory tonus within the BLA. Finally, we discuss alterations in the BLA GABAergic system in neurodevelopmental (autism/fragile X syndrome) and neurodegenerative (Alzheimer's disease) diseases and after the development of epilepsy, anxiety, and traumatic brain injury. A more complete understanding of the intrinsic excitatory/inhibitory circuit balance of the amygdala and how imbalances in inhibitory control contribute to excessive BLA excitability will guide the development of novel therapeutic approaches in neuropsychiatric diseases.
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Affiliation(s)
- Eric M Prager
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland
| | | | - Gary H Wynn
- Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland.,Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Asan E, Steinke M, Lesch KP. Serotonergic innervation of the amygdala: targets, receptors, and implications for stress and anxiety. Histochem Cell Biol 2013; 139:785-813. [DOI: 10.1007/s00418-013-1081-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2013] [Indexed: 01/09/2023]
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