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Moradi K, Badripour A, Moradi A, Bagheri S, Soltani ZE, Moassefi M, Faghani S, Dehpour AR. Sumatriptan attenuates fear-learning despair induced by social isolation stress in mice: Mediating role of hypothalamic-pituitary-adrenal axis. Psychoneuroendocrinology 2024; 164:107006. [PMID: 38432042 DOI: 10.1016/j.psyneuen.2024.107006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/28/2023] [Accepted: 02/26/2024] [Indexed: 03/05/2024]
Abstract
OBJECTIVES Research has demonstrated that chronic stress experienced early in life can lead to impairments in memory and learning. These deficits are attributed to an imbalance in the interaction between glucocorticoids, the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and glucocorticoid receptors in brain regions responsible for mediating memory, such as the hippocampus. This imbalance can result in detrimental conditions like neuroinflammation. The aim of this study was to assess the impact of sumatriptan, a selective agonist for 5-HT 1B/1D receptors, on fear learning capabilities in a chronic social isolation stress model in mice, with a particular focus on the role of the HPA axis. METHODS Mice were assigned to two opposing conditions, including social condition (SC) and isolated condition (IC) for a duration of five weeks. All mice underwent passive avoidance test, with their subsequent freezing behavior serving as an indicator of fear retrieval. Mice in the IC group were administered either a vehicle, sumatriptan, GR-127935 (a selective antagonist for 5-HT 1B/1D receptors), or a combination of sumatriptan and GR-127935 during the testing sessions. At the end, all mice were sacrificed and samples of their serum and hippocampus were collected for further analysis. RESULTS Isolation was found to significantly reduce freezing behavior (p<0.001). An increase in the freezing response among IC mice was observed following the administration of varying doses of sumatriptan, as indicated by a one-way ANOVA analysis (p<0.001). However, the mitigating effects of sumatriptan were reversed upon the administration of GR-127935. An ELISA assay conducted before and after the passive avoidance test revealed no significant change in serum corticosterone levels among SC mice. In contrast, a significant increase was observed among IC mice, suggesting hyper-responsiveness of the HPA axis in isolated animals. This hyper-responsiveness was ameliorated following the administration of sumatriptan. Furthermore, both the sumatriptan and SC groups exhibited a similar trend, showing a significant increase in the expression of hippocampal glucocorticoid receptors following the stress of the passive avoidance test. Lastly, the elevated production of inflammatory cytokines (TNF-α, IL-1β) observed following social isolation was attenuated in the sumatriptan group. CONCLUSION Sumatriptan improved fear learning probably through modulation of HPA axis and hippocampus neuroinflammation.
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Affiliation(s)
- Kamyar Moradi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Abolfazl Badripour
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Moradi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayna Bagheri
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Ebrahim Soltani
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mana Moassefi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahriar Faghani
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Shi TS, Li WY, Chen YM, Huang J, Guan W, Xu DW, Jiang B. The antidepressant-like effects of escitalopram in mice require salt-inducible kinase 1 and CREB-regulated transcription co-activator 1 in the paraventricular nucleus of the hypothalamus. J Affect Disord 2023; 338:228-238. [PMID: 37257779 DOI: 10.1016/j.jad.2023.05.085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND The salt-inducible kinase 1 (SIK1)-CREB-regulated transcription co-activator 1 (CRTC1) system in the paraventricular nucleus (PVN) of the hypothalamus has been demonstrated to participate in not only depression neurobiology but also the antidepressant mechanisms of fluoxetine, paroxetine, venlafaxine, and duloxetine. Like fluoxetine and paroxetine, escitalopram is also a well-known selective serotonin (5-HT) reuptake inhibitor (SSRI). However, recently it has been found that escitalopram can modulate a lot of targets other than the 5-HT system. Here, we speculate that escitalopram produces effects on the SIK1-CRTC1 system in the PVN. METHODS Two mice models of depression (chronic social defeat stress (CSDS) and chronic unpredictable mild stress (CUMS)), various behavioral tests, enzyme linked immunosorbent assay (ELISA), western blotting, co-immunoprecipitation (Co-IP), quantitative real-time reverse transcription PCR (qRT-PCR), immunofluorescence, and adeno-associated virus (AAV)-mediated gene transfer were used together in the present study. RESULTS It was found that escitalopram administration not only significantly prevented the hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis induced by CSDS and CUMS, but also notably reversed the effects of CSDS and CUMS on SIK1, CRTC1, and CRTC1-CREB binding in the PVN of mice. AAV-based genetic knock-down of SIK1 in PVN neurons evidently abolished the antidepressant-like effects of escitalopram in mice. LIMITATION A shortage of this study is that only rodent models of depression were used, while human samples were not included. CONCLUSIONS In summary, regulating the SIK1-CRTC1 system in the PVN participates in the antidepressant mechanism of escitalopram, which extends the knowledge of the pharmacological actions of escitalopram.
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Affiliation(s)
- Tian-Shun Shi
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Wei-Yu Li
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Yan-Mei Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Jie Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Wei Guan
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Da-Wei Xu
- Department of Orthopedics, Affiliated Hospital 2 of Nantong University, Nantong 226006, Jiangsu, China.
| | - Bo Jiang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China.
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Tallarico M, Pisano M, Leo A, Russo E, Citraro R, De Sarro G. Antidepressant Drugs for Seizures and Epilepsy: Where do we Stand? Curr Neuropharmacol 2023; 21:1691-1713. [PMID: 35761500 PMCID: PMC10514547 DOI: 10.2174/1570159x20666220627160048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/13/2022] [Accepted: 06/18/2022] [Indexed: 11/22/2022] Open
Abstract
People with epilepsy (PWE) are more likely to develop depression and both these complex chronic diseases greatly affect health-related quality of life (QOL). This comorbidity contributes to the deterioration of the QOL further than increasing the severity of epilepsy worsening prognosis. Strong scientific evidence suggests the presence of shared pathogenic mechanisms. The correct identification and management of these factors are crucial in order to improve patients' QOL. This review article discusses recent original research on the most common pathogenic mechanisms of depression in PWE and highlights the effects of antidepressant drugs (ADs) against seizures in PWE and animal models of seizures and epilepsy. Newer ADs, such as selective serotonin reuptake inhibitors (SRRI) or serotonin-noradrenaline reuptake inhibitors (SNRI), particularly sertraline, citalopram, mirtazapine, reboxetine, paroxetine, fluoxetine, escitalopram, fluvoxamine, venlafaxine, duloxetine may lead to improvements in epilepsy severity whereas the use of older tricyclic antidepressant (TCAs) can increase the occurrence of seizures. Most of the data demonstrate the acute effects of ADs in animal models of epilepsy while there is a limited number of studies about the chronic antidepressant effects in epilepsy and epileptogenesis or on clinical efficacy. Much longer treatments are needed in order to validate the effectiveness of these new alternatives in the treatment and the development of epilepsy, while further clinical studies with appropriate protocols are warranted in order to understand the real potential contribution of these drugs in the management of PWE (besides their effects on mood).
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Affiliation(s)
- Martina Tallarico
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Maria Pisano
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Antonio Leo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Emilio Russo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Giovambattista De Sarro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
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Wang Y, Liu L, Gu JH, Wang CN, Guan W, Liu Y, Tang WQ, Ji CH, Chen YM, Huang J, Li WY, Shi TS, Chen WJ, Zhu BL, Jiang B. Salt-inducible kinase 1-CREB-regulated transcription coactivator 1 signalling in the paraventricular nucleus of the hypothalamus plays a role in depression by regulating the hypothalamic-pituitary-adrenal axis. Mol Psychiatry 2022:10.1038/s41380-022-01881-4. [PMID: 36434056 DOI: 10.1038/s41380-022-01881-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/30/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022]
Abstract
Elucidating the molecular mechanism underlying the hyperactivity of the hypothalamic-pituitary-adrenal axis during chronic stress is critical for understanding depression and treating depression. The secretion of corticotropin-releasing hormone (CRH) from neurons in the paraventricular nucleus (PVN) of the hypothalamus is controlled by salt-inducible kinases (SIKs) and CREB-regulated transcription co-activators (CRTCs). We hypothesised that the SIK-CRTC system in the PVN might contribute to the pathogenesis of depression. Thus, the present study employed chronic social defeat stress (CSDS) and chronic unpredictable mild stress (CUMS) models of depression, various behavioural tests, virus-mediated gene transfer, enzyme-linked immunosorbent assay, western blotting, co-immunoprecipitation, quantitative real-time reverse transcription polymerase chain reaction, and immunofluorescence to investigate this connection. Our results revealed that both CSDS and CUMS induced significant changes in SIK1-CRTC1 signalling in PVN neurons. Both genetic knockdown of SIK1 and genetic overexpression of CRTC1 in the PVN simulated chronic stress, producing a depression-like phenotype in naive mice, and the CRTC1-CREB-CRH pathway mediates the pro-depressant actions induced by SIK1 knockdown in the PVN. In contrast, both genetic overexpression of SIK1 and genetic knockdown of CRTC1 in the PVN protected against CSDS and CUMS, leading to antidepressant-like effects in mice. Moreover, stereotactic infusion of TAT-SIK1 into the PVN also produced beneficial effects against chronic stress. Furthermore, the SIK1-CRTC1 system in the PVN played a role in the antidepressant actions of fluoxetine, paroxetine, venlafaxine, and duloxetine. Collectively, SIK1 and CRTC1 in PVN neurons are closely involved in depression neurobiology, and they could be viable targets for novel antidepressants.
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Affiliation(s)
- Yuan Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Ling Liu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Jiang-Hong Gu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Cheng-Niu Wang
- Basic Medical Research Centre, Medical College, Nantong University, Nantong, 226001, Jiangsu, China
| | - Wei Guan
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Yue Liu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Wen-Qian Tang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Chun-Hui Ji
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Yan-Mei Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Jie Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Wei-Yu Li
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Tian-Shun Shi
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China
| | - Wei-Jia Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Bao-Lun Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China
| | - Bo Jiang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, 226001, Jiangsu, China.
- Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu, China.
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Gołyszny M, Zieliński M, Paul-Samojedny M, Filipczyk Ł, Pałasz A, Obuchowicz E. Escitalopram alters the hypothalamic OX system but does not affect its up-regulation induced by early-life stress in adult rats. Neurosci Res 2022; 180:58-71. [PMID: 35219722 DOI: 10.1016/j.neures.2022.02.005] [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: 07/21/2021] [Revised: 02/07/2022] [Accepted: 02/23/2022] [Indexed: 01/06/2023]
Abstract
We hypothesized that there is a relationship between the orexinergic system (OX) alterations and changes elicited by escitalopram or venlafaxine in adult rats subjected to maternal separation (MS). This animal model of childhood adversity induces long-lasting consequences in adult physiology and behavior. Male Wistar rats from the control and MS groups were injected with escitalopram or venlafaxine (10 mg/kg) IP from postnatal day (PND) 69-89. Adult rats were subjected to behavioral assessment, estimation of hypothalamic-pituitary-adrenal (HPA) axis activity and analysis of the OX system (quantitative PCR and immunohistochemistry) in the hypothalamus and amygdala. MS caused anxiety- and depressive-like behavior, endocrine stress-related response, and up-regulation of the OX system in the hypothalamus. Escitalopram, but not venlafaxine, increased the activity of hypothalamic OX system in the control rats and both drugs had no effect on OXs in the MS group. The disturbed signaling of the OX pathway may be significant for harmful long-term consequences of early-life stress. Our data show that the normal brain and brain altered by MS respond differently to escitalopram. Presumably, anti-anxiety and antidepressant effects of this drug do not depend on the activity of hypothalamic OX system.
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Affiliation(s)
- Miłosz Gołyszny
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland.
| | - Michał Zieliński
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Monika Paul-Samojedny
- Department of Medical Genetics, Faculty of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, Jedności 8, Sosnowiec 41-200, Poland
| | - Łukasz Filipczyk
- Department of Histology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Artur Pałasz
- Department of Histology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Ewa Obuchowicz
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
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Abstract
Stress is ubiquitous in chronic medical conditions; however, the connections to psychiatric and neurologic conditions are not always clearly established. Epilepsy is a unique illness that is intimately intertwined with stress and anxiety not only as a result of the disease process but also as a cause of disease exacerbation. Anxiety and depression also involve stress management and often overlap with epilepsy. Anxiety symptoms themselves may be present as intrinsic aspects of seizure phenomena, either during the events or closely related to them. The pathways of stress and anxiety involve the hypothalamic pituitary adrenal (HPA) axis and explain at least in part how stress may lead to worsening seizure control. Ultimately, the study of stress, anxiety, and epilepsy offers insight into mind and body connections, and furthers understanding of neuropsychiatric illness.
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Nguyen TA, Chow T, Riggs W, Rurak D. Postnatal outcomes in lambs exposed antenatally and acutely postnatally to fluoxetine. Pediatr Res 2019; 85:1032-1040. [PMID: 30739124 DOI: 10.1038/s41390-019-0309-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/31/2018] [Accepted: 01/16/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND Approximately 1/3 of newborns exposed antenatally to selective serotonin reuptake inhibitors (SSRIs) exhibit poor neonatal adaptation. Although several potential mechanisms have been proposed, the actual mechanism has not been elucidated. METHODS We investigated outcomes in neonatal lambs exposed prenatally or postnatally to fluoxetine (FX). Daily FX injections (50 mg) were given intravenously (i.v.) to five pregnant ewes via implanted catheters beginning at 131-132 days gestation (term = 147 days) for 2 weeks. In another group, lambs with implanted vascular catheters had sterile water (n = 9) or FX (1 mg/kg, n = 12) injected i.v. on ~postnatal day (PND) 4. RESULTS Prenatal FX-exposed lambs (n = 7) were hyperactive during PND 4 to 14 and their heart rate variability (HRV) was significantly lower than in control lambs (n = 7) on PND 2. In contrast, arterial pressure, heart rate, electrocardiogram, arterial blood gases, pH, glucose, lactate, cortisol, and sleep-activity cycles were not altered following postnatal FX injection. CONCLUSION This abnormal postnatal hyperactivity with antenatal FX exposure may reflect increased maturity in terms of locomotory activity. The results suggest that altered brain development may be involved in the poor neonatal adaptation in human infants exposed to FX in utero.
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Affiliation(s)
- Tuan Anh Nguyen
- Department of Obstetrics and Gynecology, Faculty of Medicine, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy Chow
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Wayne Riggs
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Dan Rurak
- Department of Obstetrics and Gynecology, Faculty of Medicine, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
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Renoir T. Selective serotonin reuptake inhibitor antidepressant treatment discontinuation syndrome: a review of the clinical evidence and the possible mechanisms involved. Front Pharmacol 2013; 4:45. [PMID: 23596418 PMCID: PMC3627130 DOI: 10.3389/fphar.2013.00045] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/27/2013] [Indexed: 12/17/2022] Open
Abstract
Besides demonstrated efficacy, selective serotonin reuptake inhibitors (SSRIs) hold other advantages over earlier antidepressants such as greater tolerability and a wider range of clinical applications. However, there is a growing body of clinical evidence which suggests that SSRIs could, in some cases, be associated with a withdrawal reaction upon cessation of regular use. In addition to sensory and gastrointestinal-related symptoms, the somatic symptoms of the SSRI discontinuation syndrome include dizziness, lethargy, and sleep disturbances. Psychological symptoms have also been documented, usually developing within 1–7 days following SSRI discontinuation. The characteristics of the discontinuation syndrome have been linked to the half-life of a given SSRI, with a greater number of reports emerging from paroxetine compared to other SSRIs. However, many aspects of the neurobiology of the SSRI discontinuation syndrome (or SSRI withdrawal syndrome) remain unresolved. Following a comprehensive overview of the clinical evidence, we will discuss the underlying pathophysiology of the SSRI discontinuation syndrome and comment on the use of animal models to better understand this condition.
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Affiliation(s)
- Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne Melbourne, VIC, Australia
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Cardamone L, Salzberg MR, O'Brien TJ, Jones NC. Antidepressant therapy in epilepsy: can treating the comorbidities affect the underlying disorder? Br J Pharmacol 2013; 168:1531-54. [PMID: 23146067 PMCID: PMC3605864 DOI: 10.1111/bph.12052] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 12/20/2022] Open
Abstract
There is a high incidence of psychiatric comorbidity in people with epilepsy (PWE), particularly depression. The manifold adverse consequences of comorbid depression have been more clearly mapped in recent years. Accordingly, considerable efforts have been made to improve detection and diagnosis, with the result that many PWE are treated with antidepressant drugs, medications with the potential to influence both epilepsy and depression. Exposure to older generations of antidepressants (notably tricyclic antidepressants and bupropion) can increase seizure frequency. However, a growing body of evidence suggests that newer ('second generation') antidepressants, such as selective serotonin reuptake inhibitors or serotonin-noradrenaline reuptake inhibitors, have markedly less effect on excitability and may lead to improvements in epilepsy severity. Although a great deal is known about how antidepressants affect excitability on short time scales in experimental models, little is known about the effects of chronic antidepressant exposure on the underlying processes subsumed under the term 'epileptogenesis': the progressive neurobiological processes by which the non-epileptic brain changes so that it generates spontaneous, recurrent seizures. This paper reviews the literature concerning the influences of antidepressants in PWE and in animal models. The second section describes neurobiological mechanisms implicated in both antidepressant actions and in epileptogenesis, highlighting potential substrates that may mediate any effects of antidepressants on the development and progression of epilepsy. Although much indirect evidence suggests the overall clinical effects of antidepressants on epilepsy itself are beneficial, there are reasons for caution and the need for further research, discussed in the concluding section.
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Affiliation(s)
- L Cardamone
- Department of Medicine (RMH), University of Melbourne, Melbourne, Victoria, Australia
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Knorr U, Vinberg M, Gether U, Winkel P, Gluud C, Wetterslev J, Kessing LV. The effect of escitalopram versus placebo on perceived stress and salivary cortisol in healthy first-degree relatives of patients with depression-A randomised trial. Psychiatry Res 2012; 200:354-60. [PMID: 22703642 DOI: 10.1016/j.psychres.2012.05.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 12/31/2022]
Abstract
The effect of selective serotonin reuptake inhibitors (SSRI) on healthy individuals remains unclear. We tested the hypothesis that escitalopram decreases perceived stress and salivary cortisol. The trial has a randomised, blinded, placebo-controlled, parallel-group design. After informed consent 80 healthy first-degree relatives to patients with depression were randomly allocated to receive daily tablets of escitalopram 10mg or placebo for 4 weeks. The area under the curve (AUC) for awakening and all day salivary cortisol was analysed in samples taken immediately after awakening and at 15-min intervals for the next hour, and at 12:00, 18:00 and 23:00. The salivary cortisol awakening response, all day salivary cortisol, and scale scores on sleep, pain, aggression, quality of life, and perceived stress assessed at entry were compared to values following 4 weeks of intervention. Statistically significant decreases were found in awakening salivary cortisol (P=0.04) and in all day salivary cortisol (P=0.02) in the escitalopram group compared with the placebo group. There were no statistically significant differences in perceived stress between the intervention groups. These findings from a randomised clinical trial suggest that a long-term escitalopram administration to healthy participants results in a decrease in the hypothalamic-pituitary-adrenal (HPA) activity measured by salivary cortisol compared with inert placebo. However, change in salivary cortisol was one out of multiple outcome measures. The results of the present trial do not refute salivary cortisol as a potential endophenotype for depression.
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Affiliation(s)
- Ulla Knorr
- Psychiatric Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark.
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Schaefer TL, Grace CE, Skelton MR, Graham DL, Gudelsky GA, Vorhees CV, Williams MT. Neonatal citalopram treatment inhibits the 5-HT depleting effects of MDMA exposure in rats. ACS Chem Neurosci 2012; 3:12-21. [PMID: 22582138 DOI: 10.1021/cn2000553] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Neonatal exposure to 3,4-methylenedioxymethamphetamine (MDMA) produces long-term learning and memory deficits and increased anxiety-like behavior. The mechanism underlying these behavioral changes is unknown but we hypothesized that it involves perturbations to the serotonergic system as this is the principle mode of action of MDMA in the adult brain. During development 5-HT is a neurotrophic factor involved in neurogenesis, synaptogenesis, migration, and target region specification. We have previously showed that MDMA exposure (4×10 mg/kg/day) from P11-20 (analogous to human third trimester exposure) induces ~50% decreases in hippocampal 5-HT throughout treatment. To determine whether MDMA-induced 5-HT changes are determinative, we tested if these changes could be prevented by treatment with a selective serotonin reuptake inhibitor (citalopram: CIT). In a series of experiments we evaluated the effects of different doses and dose regimens of CIT on MDMA-induced 5-HT depletions in three brain regions (hippocampus, entorhinal cortex, and neostriatum) at three time-points (P12, P16, P21) during the treatment interval (P11-20) known to induce behavioral alterations when animals are tested as adults. We found that 5 mg/kg CIT administered twice daily significantly attenuated MDMA-induced 5-HT depletions in all three regions at all three ages but that the protection was not complete at all ages. Striatal dopamine was unaffected. We also found increases in hippocampal NGF and plasma corticosterone following MDMA treatment on P16 and P21, respectively. No changes in BDNF were observed. CIT treatment may be a useful means of interfering with MDMA-induced 5-HT reductions and thus permit tests of the hypothesis that the drug's cognitive and/or anxiety effects are mediated through early disruptions to 5-HT dependent developmental processes.
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Affiliation(s)
- Tori L. Schaefer
- Division of Neurology, Department
of Pediatrics, Cincinnati Children’s Research Foundation and University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, United States
| | - Curtis E. Grace
- United States Environmental Protection Agency, Durham, North Carolina 27713, United
States
| | - Matthew R. Skelton
- Division of Neurology, Department
of Pediatrics, Cincinnati Children’s Research Foundation and University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, United States
| | - Devon L. Graham
- Vanderbilt University College of Medicine, Nashville, Tennessee 32732, United
States
| | - Gary A. Gudelsky
- James L. Winkle
College of Pharmacy, University of Cincinnati, Ohio 45267-0004, United States
| | - Charles V. Vorhees
- Division of Neurology, Department
of Pediatrics, Cincinnati Children’s Research Foundation and University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, United States
| | - Michael T. Williams
- Division of Neurology, Department
of Pediatrics, Cincinnati Children’s Research Foundation and University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, United States
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Drug withdrawal-induced depression: Serotonergic and plasticity changes in animal models. Neurosci Biobehav Rev 2012; 36:696-726. [DOI: 10.1016/j.neubiorev.2011.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 10/06/2011] [Accepted: 10/15/2011] [Indexed: 12/17/2022]
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Knorr U, Vinberg M, Hansen A, Klose M, Feldt-Rasmussen U, Hilsted L, Hasselstrøm J, Gether U, Winkel P, Gluud C, Wetterslev J, Kessing LV. Escitalopram and neuroendocrine response in healthy first-degree relatives to depressed patients--a randomized placebo-controlled trial. PLoS One 2011; 6:e21224. [PMID: 21738622 PMCID: PMC3124484 DOI: 10.1371/journal.pone.0021224] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 05/23/2011] [Indexed: 01/30/2023] Open
Abstract
INTRODUCTION The mechanisms by which selective serotonin re-uptake inhibitors (SSRI) act in depressed patients remain unknown. The serotonergic neurotransmitter system and the hypothalamic-pituitary-adrenal (HPA) system may interact. The aim of the AGENDA trial was to investigate whether long-term intervention with SSRI versus placebo affects the cortisol response in the dexamethasone corticotropin-releasing hormone (DEX-CRH) test in healthy first-degree relatives to patients with major depressive disorder (MDD). METHODS Eighty healthy first-degree relatives to patients with MDD were randomized to escitalopram 10 mg versus matching placebo daily for four weeks. The primary outcome measure was the intervention difference in the change of the total area under the curve (CorAUC(total)) for plasma cortisol in the DEX-CRH test at entry to after four weeks of intervention. RESULTS Change in CorAUC(total) showed no statistically significant difference between the escitalopram and the placebo group, p = 0.47. There were large intra- and inter-individual differences in the results of the DEX-CRH test. There was statistically significant negative correlation between the plasma escitalopram concentration and change in CorAUC(total), rho = -0.41, p = 0.01. Post-hoc analyses showed a statistically significant interaction between age and intervention group and change in log CorAUC(total). CONCLUSION The present trial does not support an effect of escitalopram 10 mg daily compared with placebo on the HPA-axis in healthy first-degree relatives to patients with MDD. Increasing levels of escitalopram tended to decrease the HPA-response in the DEX-CRH test and this effect increased with age. TRIAL REGISTRATION ClinicalTrials.gov NCT00386841.
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Affiliation(s)
- Ulla Knorr
- Department of Psychiatry Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
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Vinkers CH, Groenink L, Pattij T, Olivier B, Bouwknecht JA. 5-HT(1A) receptor sensitivity in 5-HT(1B) receptor KO mice is unaffected by chronic fluvoxamine treatment. Eur J Pharmacol 2011; 667:250-7. [PMID: 21723276 DOI: 10.1016/j.ejphar.2011.06.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/19/2011] [Accepted: 06/14/2011] [Indexed: 10/18/2022]
Abstract
The 5-HT(1B) receptor has been implicated in disorders such as depression, anxiety and obsessive-compulsive disorder. In mice lacking the 5-HT(1B) receptor (5-HT(1B) knockout mice), important changes in physiology and behavior exist. In the absence of presynaptic 5-HT(1B) receptor inhibition, chronic SSRI treatment may differentially affect 5-HT(1A) receptor functionality. The present studies tested the hypothesis that chronically reducing 5-HT transporter (5-HTT) function with selective serotonin reuptake inhibitor (SSRI) treatment would accelerate 5-HT(1A) receptor desensitization in 5-HT(1B) knockout mice. Moreover, as 5-HT(1B) knockout mice have been found to display exaggerated autonomic and locomotor responses to environmental stressors, the effects of chronic SSRI treatment on the hyperreactive phenotype of 5-HT(1B) knockout mice were investigated. The stress-reducing effect of the 5-HT(1A) receptor agonist flesinoxan on increases in body temperature, heart rate and locomotor activity was similar in wild type and 5-HT(1B) knockout mice before and after chronic 21-day treatment with the SSRI fluvoxamine, indicating no apparent alteration of 5-HT(1A) receptor sensitivity in 5-HT(1B) knockout mice. Also, chronic SSRI treatment did not alter the increased stress reactivity to mild environmental stressors in 5-HT(1B) knockout mice. We demonstrate that no apparent differences in 5-HT(1A) receptor sensitivity occur between 5-HT(1B) knockout and wild type mice after chronic fluvoxamine treatment. Also, the hyperreactive phenotype of 5-HT(1B) knockout mice is unresponsive to chronic SSRI treatment. Taken together, these results indicate that constitutive absence of 5-HT(1B) receptors does not result in adaptive changes in 5-HT(1A) receptor functionality and that chronic SSRI treatment does not modify stress reactivity in 5-HT(1B) knockout mice.
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Affiliation(s)
- Christiaan H Vinkers
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences and Rudolf Magnus Institute of Neuroscience, Utrecht University, Utrecht, The Netherlands.
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15
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McDevitt RA, Neumaier JF. Regulation of dorsal raphe nucleus function by serotonin autoreceptors: a behavioral perspective. J Chem Neuroanat 2011; 41:234-46. [PMID: 21620956 DOI: 10.1016/j.jchemneu.2011.05.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 04/22/2011] [Accepted: 05/02/2011] [Indexed: 11/26/2022]
Abstract
Neurotransmission by serotonin (5-HT) is tightly regulated by several autoreceptors that fine-tune serotonergic neurotransmission through negative feedback inhibition at the cell bodies (predominantly 5-HT(1A)) or at the axon terminals (predominantly 5-HT(1B)); however, more subtle roles for 5-HT(1D) and 5-HT(2B) autoreceptors have also been detected. This review provides an overview of 5-HT autoreceptors, focusing on their contribution in animal behavioral models of stress and emotion. Experiments targeting 5-HT autoreceptors in awake, behaving animals have generally shown that increasing autoreceptor feedback is anxiolytic and rewarding, while enhanced 5-HT function is aversive and anxiogenic; however, the role of serotonergic activity in behavioral models of helplessness is more complex. The prevailing model suggests that 5-HT autoreceptors become desensitized in response to stress exposure and antidepressant administration, two seemingly opposite manipulations. Thus there are still unresolved questions regarding the role of these receptors-and serotonin in general-in normal and pathological states.
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Affiliation(s)
- Ross A McDevitt
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98104, USA
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Ferdyn-Drosik M, Nowak P, Bojanek K, Bałasz M, Kasperski J, Skaba D, Muchacki R, Kostrzewa RM. Neonatal DSP-4 treatment impairs 5-HT1B receptor reactivity in adult rats. Behavioral and biochemical studies. Pharmacol Rep 2010; 62:608-20. [DOI: 10.1016/s1734-1140(10)70318-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 11/19/2009] [Indexed: 10/25/2022]
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Rea K, Folgering J, Westerink BH, Cremers TI. α1-Adrenoceptors modulate citalopram-induced serotonin release. Neuropharmacology 2010; 58:962-71. [DOI: 10.1016/j.neuropharm.2009.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 12/12/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
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Honig G, Jongsma ME, van der Hart MCG, Tecott LH. Chronic citalopram administration causes a sustained suppression of serotonin synthesis in the mouse forebrain. PLoS One 2009; 4:e6797. [PMID: 19710918 PMCID: PMC2728775 DOI: 10.1371/journal.pone.0006797] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/04/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Serotonin (5-HT) is a neurotransmitter with important roles in the regulation of neurobehavioral processes, particularly those regulating affect in humans. Drugs that potentiate serotonergic neurotransmission by selectively inhibiting the reuptake of serotonin (SSRIs) are widely used for the treatment of psychiatric disorders. Although the regulation of serotonin synthesis may be an factor in SSRI efficacy, the effect of chronic SSRI administration on 5-HT synthesis is not well understood. Here, we describe effects of chronic administration of the SSRI citalopram (CIT) on 5-HT synthesis and content in the mouse forebrain. METHODOLOGY/PRINCIPAL FINDINGS Citalopram was administered continuously to adult male C57BL/6J mice via osmotic minipump for 2 days, 14 days or 28 days. Plasma citalopram levels were found to be within the clinical range. 5-HT synthesis was assessed using the decarboxylase inhibition method. Citalopram administration caused a suppression of 5-HT synthesis at all time points. CIT treatment also caused a reduction in forebrain 5-HIAA content. Following chronic CIT treatment, forebrain 5-HT stores were more sensitive to the depleting effects of acute decarboxylase inhibition. CONCLUSIONS/SIGNIFICANCE Taken together, these results demonstrate that chronic citalopram administration causes a sustained suppression of serotonin synthesis in the mouse forebrain. Furthermore, our results indicate that chronic 5-HT reuptake inhibition renders 5-HT brain stores more sensitive to alterations in serotonin synthesis. These results suggest that the regulation of 5-HT synthesis warrants consideration in efforts to develop novel antidepressant strategies.
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Affiliation(s)
- Gerard Honig
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA, USA.
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MacQueen GM, Yucel K, Taylor VH, Macdonald K, Joffe R. Posterior hippocampal volumes are associated with remission rates in patients with major depressive disorder. Biol Psychiatry 2008; 64:880-3. [PMID: 18722590 DOI: 10.1016/j.biopsych.2008.06.027] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/09/2008] [Accepted: 06/29/2008] [Indexed: 01/09/2023]
Abstract
BACKGROUND The hippocampus (HC) is smaller in patients with recurrent major depressive disorder (MDD), but few longitudinal studies have examined whether volume is associated with clinically meaningful outcomes such as response to treatment. METHODS We compared regional (head and body/tail) HC volumes in 46 patients with MDD, 14 of whom remitted after 8 weeks of first treatment to HC volumes of 32 patients who were not in remission after 8 weeks. RESULTS Patients who remitted had larger pretreatment hippocampal body/tail volumes bilaterally compared with those who were not in remission at 8 weeks. This difference was not apparent in either the right or left hippocampal head. CONCLUSIONS These findings extend a small number of previous reports, suggesting that regional brain volumes might be associated with rate and extent of clinical response to antidepressant medication.
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Affiliation(s)
- Glenda M MacQueen
- Mood Disorders Program, St. Joseph's Healthcare Hamilton, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.
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Günther L, Liebscher S, Jähkel M, Oehler J. Effects of chronic citalopram treatment on 5-HT1A and 5-HT2A receptors in group- and isolation-housed mice. Eur J Pharmacol 2008; 593:49-61. [PMID: 18657534 DOI: 10.1016/j.ejphar.2008.07.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 06/27/2008] [Accepted: 07/09/2008] [Indexed: 01/01/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRI) are characterized by high clinical effectiveness and good tolerability. A 2-3 week delay in the onset of effects is caused by adaptive mechanisms, probably at the serotonergic (5-HT) receptor level. To analyze this in detail, we measured 5-HT(1A) and 5-HT(2A) receptor bindings in vitro after 3 weeks of citalopram treatment (20 mg/kg i.p. daily) in group-housed as well as isolation-housed mice, reflecting neurobiological aspects seen in psychiatric patients. Isolation housing increased somatodendritic (+52%) and postsynaptic (+30-95%) 5-HT(1A) as well as postsynaptic 5-HT(2A) receptor binding (+25-34%), which confirms previous findings. Chronic citalopram treatment did not induce alterations in raphe 5-HT(1A) autoreceptor binding, independent of housing conditions. Housing-dependent citalopram effects on postsynaptic 5-HT(1A) receptor binding were found with increases in group- (+11-42%) but decreases in isolation-housed (-11 to 35%) mice. Forebrain 5-HT(2A) receptor binding decreased between 11 and 38% after chronic citalopram administration, independent of housing conditions. Citalopram's long-term action comprises alterations at the postsynaptic 5-HT(1A) and 5-HT(2A) receptor binding levels. Housing conditions interact with citalopram effects, especially on 5-HT(1A) receptor binding, and should be more strongly considered in pharmacological studies. In general, SSRI-induced alterations were more pronounced and affected more brain regions in isolates, supporting the concept of a higher responsiveness in "stressed" animals. Isolation-induced receptor binding changes were partly normalized by chronic citalopram treatment, suggesting the isolation housing model for further analyses of SSRI effects, especially at the behavioral level.
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Affiliation(s)
- Lydia Günther
- AG Neurobiologie, Klinik für Psychiatrie, Universitätsklinikum der TU Dresden, Fetscherstrasse 74, Dresden, Germany.
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Kawahara Y, Kawahara H, Kaneko F, Tanaka M. Long-term administration of citalopram reduces basal and stress-induced extracellular noradrenaline levels in rat brain. Psychopharmacology (Berl) 2007; 194:73-81. [PMID: 17534604 DOI: 10.1007/s00213-007-0826-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Accepted: 05/07/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Panic disorders are commonly treated with selective serotonin reuptake inhibitors (SSRIs). However, the effect of SSRIs on noradrenaline systems in the brain has not been fully elucidated at the present time. OBJECTIVES The effects of long-term administration of citalopram, an SSRI, on basal as well as stress-induced extracellular noradrenaline levels in the basolateral nucleus of the amygdala (BLA) and the locus coeruleus (LC) were determined. In addition, the responsiveness of noradrenaline transporters and alpha2-adrenoceptors were determined after long-term administration of citalopram. MATERIALS AND METHODS Brain microdialysis was used to assess the extracellular levels of noradrenaline in conscious rats. Desipramine and clonidine were used to functionally evaluate the noradrenaline transporter and alpha2-adrenoreceptor, respectively. RESULTS In rats treated daily for 14 days with citalopram (10 mg kg(-1) day(-1) s.c.), dialysate noradrenaline levels showed remarkable decreases in both the BLA and the LC to about 25 and 45% of controls, respectively. The stress-induced increase of noradrenaline was almost completely abolished in the BLA, but was relatively stable in the LC. The effect of local application of desipramine tended to be suppressed only in the LC. The effect of local application of clonidine was enhanced only in the BLA. CONCLUSION The present results indicate that chronic administration of citalopram strongly decreases the extracellular levels of noradrenaline in the brain. The anti-panic effect of citalopram might be due to sensitization of the alpha2-adrenoceptors leading to suppression of the stress response through noradrenergic activity. This mechanism is specific for the BLA.
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Affiliation(s)
- Yukie Kawahara
- Department of Pharmacology, Kurume University School of Medicine, Kurume 830 0011, Japan.
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Huang Y, Williams WA. Enhanced selective serotonin re-uptake inhibitors as antidepressants: 2004 – 2006. Expert Opin Ther Pat 2007; 17:889-907. [DOI: 10.1517/13543776.17.8.889] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Jabbi M, Kema IP, van der Pompe G, te Meerman GJ, Ormel J, den Boer JA. Catechol-o-methyltransferase polymorphism and susceptibility to major depressive disorder modulates psychological stress response. Psychiatr Genet 2007; 17:183-93. [PMID: 17417063 DOI: 10.1097/ypg.0b013e32808374df] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The stress response is related to both physiological and psychological factors and is strongly marked by a neuroendocrine component. Genetic factors are believed to underlie individual differences in the degree of stress resilience and thereby contribute in determining susceptibility to stress-related pathologies like major depressive disorder (MDD). Little, however, is known about the genetic influence on the endocrine and behavioural stress response in relation to MDD. METHODS Here, we sought to examine the effects of the catechol-o-methyltransferase polymorphism on psychological stress in three groups of individuals with different degrees of susceptibility to MDD (i.e. healthy controls, healthy high risk probands to MDD and those suffering from MDD). This genotype is involved in the metabolism of catecholamines (dopamine, norepinephrine and epinephrine). RESULTS Allelic variations of this polymorphism were found to influence the degree of subjective stress experience and plasma epinephrine stress response. Interactions between catechol-o-methyltransferase polymorphism and diagnostic group in measures of plasma epinephrine, cortisol and subjective responses to psychological stress were also found, with the influence of the different alleles on these measures differing between healthy controls relative to MDD patients and high risk probands. CONCLUSION These observations support a possible role for catechol-o-methyltransferase polymorphism in the endocrine and subjective response to psychological stress and thus may qualify as a possible candidate gene involved in the pathogenesis of MDD.
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Affiliation(s)
- Mbemba Jabbi
- Departments of Psychiatry, University Medical Center Groningen, UMCG dBCN NeuroImaging Center, Groningen, Netherlands.
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Bundgaard C, Larsen F, Jørgensen M, Mørk A. Pharmacokinetic/Pharmacodynamic Feedback Modelling of the Functional Corticosterone Response in Rats after Acute Treatment with Escitalopram. Basic Clin Pharmacol Toxicol 2007; 100:182-9. [PMID: 17309522 DOI: 10.1111/j.1742-7843.2006.00029.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The objective of this study was to characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship of the drug-induced corticosterone response after administration of escitalopram in rats. To achieve this, a mechanistic feedback turnover model mimicking the acute mechanism of action of selective serotonin reuptake inhibitors was assessed. Conscious and freely moving rats received constant rate infusions of 2.5, 5 or 10 mg/kg escitalopram or vehicle over 60 min. Automated serial blood sampling was conducted to determine escitalopram and corticosterone concentrations. The PK/PD model consisted of a turnover model of escitalopram-evoked changes in response, which included an inhibitory feedback moderator function. Accordingly, response acted linearly on the production (k(tol)) of the moderator, which acted inversely on the production (k(in)) of response. The escitalopram plasma kinetics served as input to an inhibitory function acting on the loss (k(out)) of response. The corticosterone responses were successfully described using the model by fitting responses from all doses simultaneously resulting in estimation of drug parameters (I(max), IC(50) and n) in addition to system parameters (k(in), k(out) and k(tol)) for the whole exposure range. Thus, the applicability of the model for analysis of the acute selective serotonin reuptake inhibitor-induced corticosterone response including acute auto-inhibitory feedback was demonstrated.
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