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Philippe TJ, Bao L, Koblanski ME, Viau V. Sex Differences in Serotonin 5-HT 1A Receptor Responses to Repeated Restraint Stress in Adult Male and Female Rats. Int J Neuropsychopharmacol 2022; 25:863-876. [PMID: 35904324 PMCID: PMC9593217 DOI: 10.1093/ijnp/pyac046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/15/2022] [Accepted: 07/23/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Male and female rats were exposed to repeated restraint to determine how changes in serotonin (5-hydroxytryptamine; 5-HT) 1A receptors associate with stress hypothalamic-pituitary-adrenal (HPA) axis habituation. METHODS In response to 2-hour episodes of restraint, repeated daily for 5 consecutive days, males and females displayed reliable declines in HPA output, indicated by diminished adrenocorticotropin and corticosterone secretory responses. Using the 5-HT 1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) as a pharmacological challenge for inducing hypothermia and elevations in plasma corticosterone, males displayed sensitized hypothermal responses after repeated restraint, whereas corticosterone responses to 8-OH-DPAT were enhanced in both sexes following single or repeated exposure. RESULTS Only males showed elevations in 5-HT 1A receptor G-protein coupling responses in the dorsal raphe after repeated restraint, whereas only females showed an increase in 5-HT 1A receptor responses in the hippocampus following single or repeated exposure. G-protein coupling responses within both regions correlated positively with 5-HT 1A receptor binding capacity. Thus, despite expressing similar capacities for stress HPA axis habituation, males and females emerged from repeated restraint to show region-specific changes in 5-HT 1A receptor function that may be explained, at least in part, by changes in receptor availability. CONCLUSIONS Based on the hypothermal and corticosteroid responses to 8-OH-DPAT, the present data suggest that stress habituation is met by an increase in the sensitivity of presynaptic 5-HT 1A receptors in males and by an increase in the sensitivity of a population of postsynaptic receptors in both sexes.
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Affiliation(s)
- Tristan J Philippe
- Department of Cellular and Physiological Sciences, Neuroscience Program, University of British Columbia, Vancouver, Canada
| | - Lexia Bao
- Department of Cellular and Physiological Sciences, Neuroscience Program, University of British Columbia, Vancouver, Canada
| | - Maya E Koblanski
- Department of Cellular and Physiological Sciences, Neuroscience Program, University of British Columbia, Vancouver, Canada
| | - Victor Viau
- Correspondence: Victor Viau, PhD, Department of Cellular and Physiological Sciences, Life Sciences Centre, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada ()
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2
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Goel N, Philippe TJ, Chang J, Koblanski ME, Viau V. Cellular and serotonergic correlates of habituated neuroendocrine responses in male and female rats. Psychoneuroendocrinology 2022; 136:105599. [PMID: 34891046 DOI: 10.1016/j.psyneuen.2021.105599] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 11/17/2021] [Indexed: 02/06/2023]
Abstract
Male and females appear equally capable of showing habituated hypothalamic-pituitary-adrenal (HPA) axis output responses to repeated exposures of the same challenge. Whether this reflects, within males and females, common mechanisms of decreased neuronal activity within stress responding, afferents to the paraventricular hypothalamic nucleus (PVH), the final common pathway to the HPA axis, has not been examined. Here we compared in adult male and female rats the extent to which declines in HPA axis responses to repeated restraint are met by habituated cellular (Fos) responses, in addition to changes in serotonin (5-hydroxytryptamine; 5-HT) expression and signaling, which normally stimulates the HPA axis. Thus, alterations in this component of HPA axis drive could provide an underlying basis for sex differences in adaptive responses. Males and females showed reliable declines in ACTH and corticosterone responses after 10 daily episodes of repeated restraint, recapitulated, in largest part, by similar regional patterns of Fos habituation, including within the PVH, several stress sensitive cell groups of the limbic forebrain, as well as within the raphe nucleus. Serotonin staining in the dorsal raphe and terminal profiles in the forebrain continued to reflect a higher pre-synaptic capacity for the 5-HT system in females. The sexual dimorphism encountered within the lateral septum and medial preoptic area of control animals was less distinguished in the repeat condition, however, whereas 5-HT varicosities in the PVH increased after repeated restraint only in females. Relative to their singly restrained counterparts, males displayed an increase in 5-HT 1 A receptor expression in the raphe nucleus after repeated restraint, whereas females showed a decrease in 5-HT 1 A mRNA levels in the hippocampus and in the zona incerta, representing the most proximal of cell groups expressing the 5-HT 1 A receptor in the vicinity of the PVH. In conclusion, similar regional profiles of cellular habituation in males and females suggest common CNS substrates of neuroendocrine adaptation. However, this process may be met by underlying sex differences in serotonergic control, given the respective roles for pre- and postsynaptic 5-HT 1 A receptors in mediating serotonin availability and signal transfer.
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Affiliation(s)
- Nirupa Goel
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Tristan J Philippe
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Judy Chang
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Maya E Koblanski
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Victor Viau
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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3
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Hersey M, Hashemi P, Reagan LP. Integrating the monoamine and cytokine hypotheses of depression: Is histamine the missing link? Eur J Neurosci 2021; 55:2895-2911. [PMID: 34265868 DOI: 10.1111/ejn.15392] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 06/26/2021] [Accepted: 07/06/2021] [Indexed: 12/28/2022]
Abstract
Psychiatric diseases, like depression, largely affect the central nervous system (CNS). While the underlying neuropathology of depressive illness remains to be elucidated, several hypotheses have been proposed as molecular underpinnings for major depressive disorder, including the monoamine hypothesis and the cytokine hypothesis. The monoamine hypothesis has been largely supported by the pharmaceuticals that target monoamine neurotransmitters as a treatment for depression. However, these antidepressants have come under scrutiny due to their limited clinical efficacy, side effects, and delayed onset of action. The more recent, cytokine hypothesis of depression is supported by the ability of immune-active agents to induce "sickness behaviour" akin to that seen with depression. However, treatments that more selectively target inflammation have yielded inconsistent antidepressive results. As such, neither of these hypotheses can fully explain depressive illness pathology, implying that the underlying neuropathological mechanisms may encompass aspects of both theories. The goal of the current review is to integrate these two well-studied hypotheses and to propose a role for histamine as a potential unifying factor that links monoamines to cytokines. Additionally, we will focus on stress-induced depression, to provide an updated perspective of depressive illness research and thereby identify new potential targets for the treatment of major depressive disorder.
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Affiliation(s)
- Melinda Hersey
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA.,Department of Chemistry & Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Parastoo Hashemi
- Department of Chemistry & Biochemistry, University of South Carolina, Columbia, South Carolina, USA.,Department of Bioengineering, Imperial College, London, UK
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA.,WJB Dorn Veterans Affairs Medical Center, Columbia, South Carolina, USA
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4
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Aquili L. The Role of Tryptophan and Tyrosine in Executive Function and Reward Processing. Int J Tryptophan Res 2020; 13:1178646920964825. [PMID: 33149600 PMCID: PMC7586026 DOI: 10.1177/1178646920964825] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/10/2020] [Indexed: 01/31/2023] Open
Abstract
The serotonergic precursor tryptophan and the dopaminergic precursor tyrosine have been shown to be important modulators of mood, behaviour and cognition. Specifically, research on the function of tryptophan has characterised this molecule as particularly relevant in the context of pathological disorders such as depression. Moreover, a large body of evidence has now been accumulated to suggest that tryptophan may also be involved in executive function and reward processing. Despite some clear differentiation with tryptophan, the data reviewed in this paper illustrates that tyrosine shares similar functions with tryptophan in the regulation of executive function and reward, and that these processes in turn, rather than acting in isolation, causally influence each other.
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Affiliation(s)
- Luca Aquili
- College of Health & Human Sciences, Charles Darwin University, Darwin, Northern Territory, Australia
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5
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Francis-Oliveira J, Shieh IC, Vilar Higa GS, Barbosa MA, De Pasquale R. Maternal separation induces changes in TREK-1 and 5HT 1A expression in brain areas involved in the stress response in a sex-dependent way. Behav Brain Res 2020; 396:112909. [PMID: 32949645 DOI: 10.1016/j.bbr.2020.112909] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 08/09/2020] [Accepted: 09/13/2020] [Indexed: 12/25/2022]
Abstract
Depression is a prevalent disease in modern society, and has been linked to stressful events at early ages. Women are more susceptible to depression, and the neural basis for this are still under investigation. Serotonin is known to be involved in depression, and a decrease in 5HT1A expression is observed on temporal and cortical areas in both men and women with depression. As knockout animals for TREK-1 are resilient to depression, this channel has emerged as a new potential pharmacological target for depression treatment. In this study, maternal separation (MS) was used to emulate early-life stress, and evaluate behaviour, as well as TREK-1 and 5HT1A expression in the brain using immunohistochemistry. In juvenile females, 5HT1A reduction coupled to increased TREK-1 in the dentate gyrus (DG) was associated with behavioural despair, as well as increased TREK-1 expression in basolateral amygdala (BLA) and prelimbic cortex (PL). In juvenile males, MS induced an increase in 5HT1A in the BLA, and in TREK-1 in the PL, while no behavioural despair was observed. Anhedonia and anxiety-like behaviour were not induced by MS. We conclude stress-induced increase in TREK-1 in PL and GD is associated to depression, while 5HT1A changes coupled to TREK-1 changes may be necessary to induce depression, with females being more vulnerable to MS effects than males. Thus, TREK-1 and 5HT1A may be potential pharmacological targets for antidepressants development.
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Affiliation(s)
- J Francis-Oliveira
- Dept of Physiology and Biophysics, Biomedical Sciences Institute I, São Paulo University, Ave Lineu Prestes 1524, 05508-000, São Paulo, SP, Brazil.
| | - I C Shieh
- Dept of Physiology and Biophysics, Biomedical Sciences Institute I, São Paulo University, Ave Lineu Prestes 1524, 05508-000, São Paulo, SP, Brazil
| | - G S Vilar Higa
- Neurogenetics Laboratory, Mathematics Computation Cognition Center, Rua Arcturus 03, 09606-070, São Bernardo do Campo, SP, Brazil
| | - M A Barbosa
- Dept of Physiology and Biophysics, Biomedical Sciences Institute I, São Paulo University, Ave Lineu Prestes 1524, 05508-000, São Paulo, SP, Brazil
| | - R De Pasquale
- Dept of Physiology and Biophysics, Biomedical Sciences Institute I, São Paulo University, Ave Lineu Prestes 1524, 05508-000, São Paulo, SP, Brazil
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6
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Li X, Chen S, Yang H, Li X, So KF, Wang L. GABAergic Neurons in the Dorsal Raphe Nucleus that Express 5-HT3A Receptors Participate in Responses to Stress Hormones. Neuroscience 2020; 441:217-225. [PMID: 32512137 DOI: 10.1016/j.neuroscience.2020.05.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 11/18/2022]
Abstract
The dorsal raphe nucleus (DRN) participates in stress responses and in mood regulation via its ascending release of serotonin (5-HT) onto neural circuits within the forebrain. Although the 5-HT DRN region is easily defined via 5-HT-expressing DRN neurons, the neuroarchitecture and microcircuitry that confer its multifunctionality have remained incompletely understood and have required further investigation. In this present study, neurochemical interactions within different subregions of the rat DRN were precisely analyzed. We found that 97.5% of GABAergic neurons in the DRN expressed ionotropic 5-HT3A receptors (5-HT3ARs), whereas there were only rare parvalbumin (PV)-positive or somatostatin (SOM)-positive GABAergic neurons. Furthermore, corticosterone administration into male rats as a rodent model of depression induced significantly higher c-Fos expression in 5-HT3AR-positive GABAergic neurons compared to that in 5-HT neurons within the DRN. Taken together, our findings suggest that 5-HT3AR-positive GABAergic neurons in the DRN participate in responses to stress hormones in a rat model of depression.
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Affiliation(s)
- Xiaotao Li
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, CAS Center for Excellence in Brain Science and Intelligence Technology, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Shanping Chen
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, CAS Center for Excellence in Brain Science and Intelligence Technology, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Haiyang Yang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, CAS Center for Excellence in Brain Science and Intelligence Technology, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiang Li
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, CAS Center for Excellence in Brain Science and Intelligence Technology, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - Kwok-Fai So
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, GD, China
| | - Liping Wang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, CAS Center for Excellence in Brain Science and Intelligence Technology, the Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
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7
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Arnold MR, Greenwood BN, McArthur JA, Clark PJ, Fleshner M, Lowry CA. Effects of repeated voluntary or forced exercise on brainstem serotonergic systems in rats. Behav Brain Res 2019; 378:112237. [PMID: 31525404 DOI: 10.1016/j.bbr.2019.112237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 02/07/2023]
Abstract
Voluntary exercise increases stress resistance by modulating stress-responsive neurocircuitry, including brainstem serotonergic systems. However, it remains unknown how exercise produces adaptations to serotonergic systems. Recruitment of serotonergic systems during repeated, daily exercise could contribute to the adaptations in serotonergic systems following exercise, but whether repeated voluntary exercise recruits serotonergic systems is unknown. In this study, we investigated the effects of six weeks of voluntary or forced exercise on rat brain serotonergic systems. Specifically, we analyzed c-Fos and FosB/ΔFosB as markers of acute and chronic cellular activation, respectively, in combination with tryptophan hydroxylase, a marker of serotonergic neurons, within subregions of the dorsal raphe nucleus using immunohistochemical staining. Compared to sedentary controls, rats exposed to repeated forced exercise, but not repeated voluntary exercise, displayed decreased c-Fos expression in serotonergic neurons in the rostral dorsal portion of the dorsal raphe nucleus (DRD) and increased c-Fos expression in serotonergic neurons in the caudal DR (DRC), and interfascicular part of the dorsal raphe nucleus (DRI) during the active phase of the diurnal activity rhythm. Similarly, increases in c-Fos expression in serotonergic neurons in the DRC, DRI, and ventral portion of the dorsal raphe nucleus (DRV) were observed in rats exposed to repeated forced exercise, compared to rats exposed to repeated voluntary exercise. Six weeks of forced exercise, relative to the sedentary control condition, also increased FosB/ΔFosB expression in DRD, DRI, and DRV serotonergic neurons. While both voluntary and forced exercise increase stress resistance, these results suggest that repeated forced exercise, but not repeated voluntary exercise, increases activation of DRI serotonergic neurons, an effect that may contribute to the stress resistance effects of forced exercise. These results also suggest that mechanisms of exercise-induced stress resistance may differ depending on the controllability of the exercise.
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Affiliation(s)
- M R Arnold
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - B N Greenwood
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - J A McArthur
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - P J Clark
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - M Fleshner
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - C A Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA; Department of Physical Medicine & Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center, Rocky Mountain Regional Veterans Affairs Medical Center (RMRVAMC), Aurora, CO 80045, USA; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Aurora, CO 80045, USA; inVIVO Planetary Health of the Worldwide Universities Network (WUN), West New York, NJ 07093, USA.
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8
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Arnold MR, Williams PH, McArthur JA, Archuleta AR, O'Neill CE, Hassell JE, Smith DG, Bachtell RK, Lowry CA. Effects of chronic caffeine exposure during adolescence and subsequent acute caffeine challenge during adulthood on rat brain serotonergic systems. Neuropharmacology 2018; 148:257-271. [PMID: 30579884 DOI: 10.1016/j.neuropharm.2018.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/13/2018] [Accepted: 12/15/2018] [Indexed: 01/09/2023]
Abstract
Caffeine is the most commonly used drug in the world. However, animal studies suggest that chronic consumption of caffeine during adolescence can result in enhanced anxiety-like behavioral responses during adulthood. One mechanism through which chronic caffeine administration may influence subsequent anxiety-like responses is through actions on brainstem serotonergic systems. In order to explore potential effects of chronic caffeine consumption on brainstem serotonergic systems, we evaluated the effects of a 28-day exposure to chronic caffeine (0.3 g/L; postnatal day 28-56) or vehicle administration in the drinking water, followed by 24 h caffeine withdrawal, and subsequent challenge with caffeine (30 mg/kg; s.c.) or vehicle in adolescent male rats. In Experiment 1, acute caffeine challenge induced a widespread activation of serotonergic neurons throughout the dorsal raphe nucleus (DR); this effect was attenuated in rats that had been exposed to chronic caffeine consumption. In Experiment 2, acute caffeine administration profoundly decreased tph2 and slc22a3 mRNA expression throughout the DR, with no effects on htr1a or slc6a4 mRNA expression. Chronic caffeine exposure for four weeks during adolescence was sufficient to decrease tph2 mRNA expression in the DR measured 28 h after caffeine withdrawal. Chronic caffeine administration during adolescence did not impact the ability of acute caffeine to decrease tph2 or slc22a3 mRNA expression. Together, these data suggest that both chronic caffeine administration during adolescence and acute caffeine challenge during adulthood are important determinants of serotonergic function and serotonergic gene expression, effects that may contribute to chronic effects of caffeine on anxiety-like responses.
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Affiliation(s)
- M R Arnold
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - P H Williams
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - J A McArthur
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - A R Archuleta
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - C E O'Neill
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - J E Hassell
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - D G Smith
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - R K Bachtell
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - C A Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA; Center for Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Physical Medicine & Rehabilitation and Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA; Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center, Denver Veterans Affairs Medical Center (VAMC), Denver, CO, 80220, USA; Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE), Denver, CO, 80220, USA.
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9
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Long-term effects of pre-pubertal fluoxetine on behaviour and monoaminergic stress response in stress-sensitive rats. Acta Neuropsychiatr 2017; 29:222-235. [PMID: 27819195 DOI: 10.1017/neu.2016.53] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Although prescription rates of antidepressants for children and adolescents have increased, concerns have been raised regarding effects on neurodevelopment and long-term outcome. Using a genetic animal model of depression, this study investigated the long-term effects of pre-pubertal administration of fluoxetine (FLX) on depressive-like behaviour in early adulthood, as well as on central monoaminergic response to an acute stressor. We postulated that pre-pubertal FLX will have lasting effects on animal behaviour and monoaminergic stress responses in early adulthood. METHODS Flinders sensitive line (FSL) rats received 10 mg/kg/day FLX subcutaneously from postnatal day 21 (PnD21) to PnD34 (pre-pubertal). Thereafter, following normal housing, rats were either subjected to locomotor testing and the forced swim test (FST) on PnD60 (early adulthood), or underwent surgery for microdialysis, followed on PnD60 by exposure to acute swim stress and measurement of stressor-induced changes in plasma corticosterone and pre-frontal cortical monoamine concentrations. RESULTS Pre-pubertal FLX did not induce a late emergent effect on immobility in FSL rats on PnD60, whereas locomotor activity was significantly decreased. Acute swim stress on PnD60 significantly increased plasma corticosterone levels, and increased pre-frontal cortical norepinephrine (NE) and 5-hydroxyindole-3-acetic acid (5-HIAA) concentrations. Pre-pubertal FLX significantly blunted the pre-frontal cortical NE and 5-HIAA response following swim stress on PnD60. Baseline dopamine levels were significantly enhanced by pre-pubertal FLX, but no further changes were induced by swim stress. CONCLUSION Pre-pubertal FLX did not have lasting antidepressant-like behavioural effects in genetically susceptible, stress-sensitive FSL rats. However, such treatment reduced locomotor activity, abrogated noradrenergic and serotonergic stressor responses and elevated dopaminergic baseline levels in adulthood.
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10
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Benammi H, Erazi H, El Hiba O, Vinay L, Bras H, Viemari JC, Gamrani H. Disturbed sensorimotor and electrophysiological patterns in lead intoxicated rats during development are restored by curcumin I. PLoS One 2017; 12:e0172715. [PMID: 28267745 PMCID: PMC5340392 DOI: 10.1371/journal.pone.0172715] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 02/08/2017] [Indexed: 01/01/2023] Open
Abstract
Lead poisoning is one of the most significant health problem of environmental origin. It is known to cause different damages in the central and peripheral nervous system which could be represented by several neurophysiological and behavioral symptoms. In this study we firstly investigated the effect of lead prenatal exposure in rats to (3g/L), from neonatal to young age, on the motor/sensory performances, excitability of the spinal cord and gaits during development. Then we evaluated neuroprotective effects of curcumin I (Cur I) against lead neurotoxicity, by means of grasping and cliff avoidance tests to reveal the impairment of the sensorimotor functions in neonatal rats exposed prenatally to lead. In addition, extracellular recordings of motor output in spinal cord revealed an hyper-excitability of spinal networks in lead treated rats. The frequency of induced fictive locomotion was also increased in treated rats. At the young age, rats exhibited an impaired locomotor gait. All those abnormalities were attenuated by Cur I treatment at a dose of 16g/kg. Based on our finding, Cur I has shown features of a potent chemical compound able to restore the neuronal and the relative locomotor behaviors disturbances induced by lead intoxication. Therefore, this chemical can be recommended as a new therapeutic trial against lead induced neurotoxicity.
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Affiliation(s)
- Hind Benammi
- Neuroscience, Pharmacology and Environment Team, faculty of Science Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Hasna Erazi
- Neuroscience, Pharmacology and Environment Team, faculty of Science Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Omar El Hiba
- Neuroscience, Pharmacology and Environment Team, faculty of Science Semlalia, Cadi Ayyad University, Marrakech, Morocco
- Department of Biology, faculty of Sciences, Chouaib Doukkali University, EL Jadida, Morocco
| | - Laurent Vinay
- Institut de Neurosciences de la Timone, Unité Mixte de Recherche 7289, CNRS, Université Aix-Marseille, Marseille, France
| | - Hélène Bras
- Institut de Neurosciences de la Timone, Unité Mixte de Recherche 7289, CNRS, Université Aix-Marseille, Marseille, France
| | - Jean-Charles Viemari
- Institut de Neurosciences de la Timone, Unité Mixte de Recherche 7289, CNRS, Université Aix-Marseille, Marseille, France
- * E-mail: (HG); (JCV)
| | - Halima Gamrani
- Neuroscience, Pharmacology and Environment Team, faculty of Science Semlalia, Cadi Ayyad University, Marrakech, Morocco
- * E-mail: (HG); (JCV)
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Lebedev AV, Kaelen M, Lövdén M, Nilsson J, Feilding A, Nutt DJ, Carhart-Harris RL. LSD-induced entropic brain activity predicts subsequent personality change. Hum Brain Mapp 2016; 37:3203-13. [PMID: 27151536 DOI: 10.1002/hbm.23234] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/24/2016] [Accepted: 04/18/2016] [Indexed: 02/05/2023] Open
Abstract
Personality is known to be relatively stable throughout adulthood. Nevertheless, it has been shown that major life events with high personal significance, including experiences engendered by psychedelic drugs, can have an enduring impact on some core facets of personality. In the present, balanced-order, placebo-controlled study, we investigated biological predictors of post-lysergic acid diethylamide (LSD) changes in personality. Nineteen healthy adults underwent resting state functional MRI scans under LSD (75µg, I.V.) and placebo (saline I.V.). The Revised NEO Personality Inventory (NEO-PI-R) was completed at screening and 2 weeks after LSD/placebo. Scanning sessions consisted of three 7.5-min eyes-closed resting-state scans, one of which involved music listening. A standardized preprocessing pipeline was used to extract measures of sample entropy, which characterizes the predictability of an fMRI time-series. Mixed-effects models were used to evaluate drug-induced shifts in brain entropy and their relationship with the observed increases in the personality trait openness at the 2-week follow-up. Overall, LSD had a pronounced global effect on brain entropy, increasing it in both sensory and hierarchically higher networks across multiple time scales. These shifts predicted enduring increases in trait openness. Moreover, the predictive power of the entropy increases was greatest for the music-listening scans and when "ego-dissolution" was reported during the acute experience. These results shed new light on how LSD-induced shifts in brain dynamics and concomitant subjective experience can be predictive of lasting changes in personality. Hum Brain Mapp 37:3203-3213, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- A V Lebedev
- Aging Research Center, Karolinska Institutet (Department of Neurobiology, Care Sciences and Society) & Stockholm University, Stockholm, Sweden
| | - M Kaelen
- Division of Brain Sciences, Department of Medicine, Centre for Neuropsychopharmacology, Imperial College London, United Kingdom
| | - M Lövdén
- Aging Research Center, Karolinska Institutet (Department of Neurobiology, Care Sciences and Society) & Stockholm University, Stockholm, Sweden
| | - J Nilsson
- Aging Research Center, Karolinska Institutet (Department of Neurobiology, Care Sciences and Society) & Stockholm University, Stockholm, Sweden
| | - A Feilding
- The Beckley Foundation, Beckley Park, United Kingdom
| | - D J Nutt
- Division of Brain Sciences, Department of Medicine, Centre for Neuropsychopharmacology, Imperial College London, United Kingdom
| | - R L Carhart-Harris
- Division of Brain Sciences, Department of Medicine, Centre for Neuropsychopharmacology, Imperial College London, United Kingdom
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12
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Steenbergen L, Jongkees BJ, Sellaro R, Colzato LS. Tryptophan supplementation modulates social behavior: A review. Neurosci Biobehav Rev 2016; 64:346-58. [DOI: 10.1016/j.neubiorev.2016.02.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 02/22/2016] [Accepted: 02/23/2016] [Indexed: 01/09/2023]
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aan het Rot M, Moskowitz D, Hsu ZY, Young SN. Eating a meal is associated with elevations in agreeableness and reductions in dominance and submissiveness. Physiol Behav 2015; 144:103-9. [DOI: 10.1016/j.physbeh.2015.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 02/27/2015] [Accepted: 03/10/2015] [Indexed: 12/01/2022]
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Kim JY, Kim A, Zhao ZQ, Liu XY, Chen ZF. Postnatal maintenance of the 5-Ht1a-Pet1 autoregulatory loop by serotonin in the raphe nuclei of the brainstem. Mol Brain 2014; 7:48. [PMID: 24972638 PMCID: PMC4086287 DOI: 10.1186/1756-6606-7-48] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/24/2014] [Indexed: 01/06/2023] Open
Abstract
Background Despite the importance of 5-HT1A as a major target for the action of several anxiolytics/antidepressant drugs, little is known about its regulation in central serotonin (5-hydroxytryptamine, 5-HT) neurons. Results We report that expression of 5-HT1A and the transcription factor Pet1 was impaired in the rostral raphe nuclei of mice lacking tryptophan hydroxylase 2 (Tph2) after birth. The downregulation of Pet1 was recapitulated in 5-Ht1a-/- mice. Using an explant culture system, we show that reduction of Pet1 and 5-HT1A was rescued in Tph2-/- brainstem by exogenous 5-HT. In contrast, 5-HT failed to rescue reduced expression of Pet1 in 5-Ht1a-/- brainstem explant culture. Conclusions These results suggest a causal relationship between 5-HT1A and Pet1, and reveal a potential mechanism by which 5-HT1A-Pet1 autoregulatory loop is maintained by 5-HT in a spatiotemporal-specific manner during postnatal development. Our results are relevant to understanding the pathophysiology of certain psychiatric and developmental disorders.
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Affiliation(s)
| | | | | | | | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St, Louis 63110, USA.
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15
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The role of serotonin in drug use and addiction. Behav Brain Res 2014; 277:146-92. [PMID: 24769172 DOI: 10.1016/j.bbr.2014.04.007] [Citation(s) in RCA: 209] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/26/2022]
Abstract
The use of psychoactive drugs is a wide spread behaviour in human societies. The systematic use of a drug requires the establishment of different drug use-associated behaviours which need to be learned and controlled. However, controlled drug use may develop into compulsive drug use and addiction, a major psychiatric disorder with severe consequences for the individual and society. Here we review the role of the serotonergic (5-HT) system in the establishment of drug use-associated behaviours on the one hand and the transition and maintenance of addiction on the other hand for the drugs: cocaine, amphetamine, methamphetamine, MDMA (ecstasy), morphine/heroin, cannabis, alcohol, and nicotine. Results show a crucial, but distinct involvement of the 5-HT system in both processes with considerable overlap between psychostimulant and opioidergic drugs and alcohol. A new functional model suggests specific adaptations in the 5-HT system, which coincide with the establishment of controlled drug use-associated behaviours. These serotonergic adaptations render the nervous system susceptible to the transition to compulsive drug use behaviours and often overlap with genetic risk factors for addiction. Altogether we suggest a new trajectory by which serotonergic neuroadaptations induced by first drug exposure pave the way for the establishment of addiction.
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16
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Young SN. Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects. J Psychiatry Neurosci 2013; 38:294-305. [PMID: 23428157 PMCID: PMC3756112 DOI: 10.1503/jpn.120209] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The acute tryptophan depletion (ATD) technique has been used extensively to study the effect of low serotonin in the human brain. This review assesses the validity of a number of published criticisms of the technique and a number of previously unpublished potential criticisms. The conclusion is that ATD can provide useful information when results are assessed in conjunction with results obtained using other techniques. The best-established conclusion is that low serotonin function after tryptophan depletion lowers mood in some people. However, this does not mean that other variables, altered after tryptophan depletion, are necessarily related to low serotonin. Each aspect of brain function has to be assessed separately. Furthermore, a negative tryptophan depletion study does not mean that low serotonin cannot influence the variable studied. This review suggests gaps in knowledge that need to be filled and guidelines for carrying out ATD studies.
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Affiliation(s)
- Simon N. Young
- Correspondence to: S.N. Young, Department of Psychiatry, McGill University, 1033 Pine Ave. W, Montréal QC H3A 1A1;
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17
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Krystal AD, Richelson E, Roth T. Review of the histamine system and the clinical effects of H1 antagonists: Basis for a new model for understanding the effects of insomnia medications. Sleep Med Rev 2013; 17:263-72. [DOI: 10.1016/j.smrv.2012.08.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 08/09/2012] [Accepted: 08/09/2012] [Indexed: 11/27/2022]
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18
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Müller CP. Episodic memories and their relevance for psychoactive drug use and addiction. Front Behav Neurosci 2013; 7:34. [PMID: 23734106 PMCID: PMC3661997 DOI: 10.3389/fnbeh.2013.00034] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/09/2013] [Indexed: 01/06/2023] Open
Abstract
The majority of adult people in western societies regularly consume psychoactive drugs. While this consumption is integrated in everyday life activities and controlled in most consumers, it may escalate and result in drug addiction. Non-addicted drug use requires the systematic establishment of highly organized behaviors, such as drug-seeking and -taking. While a significant role for classical and instrumental learning processes is well established in drug use and abuse, declarative drug memories have largely been neglected in research. Episodic memories are an important part of the declarative memories. Here a role of episodic drug memories in the establishment of non-addicted drug use and its transition to addiction is suggested. In relation to psychoactive drug consumption, episodic drug memories are formed when a person prepares for consumption, when the drug is consumed and, most important, when acute effects, withdrawal, craving, and relapse are experienced. Episodic drug memories are one-trial memories with emotional components that can be much stronger than "normal" episodic memories. Their establishment coincides with drug-induced neuronal activation and plasticity. These memories may be highly extinction resistant and influence psychoactive drug consumption, in particular during initial establishment and at the transition to "drug instrumentalization." In that, understanding how addictive drugs interact with episodic memory circuits in the brain may provide crucial information for how drug use and addiction are established.
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Affiliation(s)
- Christian P. Müller
- Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University of Erlangen-NurembergErlangen, Germany
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Young SN. The effect of raising and lowering tryptophan levels on human mood and social behaviour. Philos Trans R Soc Lond B Biol Sci 2013; 368:20110375. [PMID: 23440461 DOI: 10.1098/rstb.2011.0375] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Acute tryptophan depletion (ATD) studies indicate that low serotonin can lower mood and also increase aggression, although results vary somewhat between studies with similar participants. Lowering of mood after ATD is related to the susceptibility of the study participants to clinical depression, and some participants show no effect on mood. This indicates that low serotonin can contribute to lowered mood, but cannot-by itself-cause lowered mood, unless other unknown systems interact with serotonin to lower mood. Studies using tryptophan supplementation demonstrate that increased serotonin can decrease quarrelsomeness and increase agreeableness in everyday life. Social interactions that are more agreeable and less quarrelsome are associated with better mood. Thus, serotonin may have direct effects on mood, but may also be able to influence mood through changes in social behaviour. The increased agreeableness and decreased quarrelsomeness resulting from increases in serotonin will help foster congenial relations with others and should help to increase social support. As social support and social isolation have an important relationship with both physical and mental health, more research is needed on the implications of the ability of serotonin to modulate social behaviour for the regulation of mood, and for future physical and mental health.
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Affiliation(s)
- Simon N Young
- Department of Psychiatry, McGill University, Montréal, Québec, Canada.
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20
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Zhou FM, Lee CR. Intrinsic and integrative properties of substantia nigra pars reticulata neurons. Neuroscience 2011; 198:69-94. [PMID: 21839148 PMCID: PMC3221915 DOI: 10.1016/j.neuroscience.2011.07.061] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/07/2011] [Accepted: 07/14/2011] [Indexed: 11/27/2022]
Abstract
The GABA projection neurons of the substantia nigra pars reticulata (SNr) are output neurons for the basal ganglia and thus critical for movement control. Their most striking neurophysiological feature is sustained, spontaneous high frequency spike firing. A fundamental question is: what are the key ion channels supporting the remarkable firing capability in these neurons? Recent studies indicate that these neurons express tonically active type 3 transient receptor potential (TRPC3) channels that conduct a Na-dependent inward current even at hyperpolarized membrane potentials. When the membrane potential reaches -60 mV, a voltage-gated persistent sodium current (I(NaP)) starts to activate, further depolarizing the membrane potential. At or slightly below -50 mV, the large transient voltage-activated sodium current (I(NaT)) starts to activate and eventually triggers the rapid rising phase of action potentials. SNr GABA neurons have a higher density of I(NaT), contributing to the faster rise and larger amplitude of action potentials, compared with the slow-spiking dopamine neurons. I(NaT) also recovers from inactivation more quickly in SNr GABA neurons than in nigral dopamine neurons. In SNr GABA neurons, the rising phase of the action potential triggers the activation of high-threshold, inactivation-resistant Kv3-like channels that can rapidly repolarize the membrane. These intrinsic ion channels provide SNr GABA neurons with the ability to fire spontaneous and sustained high frequency spikes. Additionally, robust GABA inputs from direct pathway medium spiny neurons in the striatum and GABA neurons in the globus pallidus may inhibit and silence SNr GABA neurons, whereas glutamate synaptic input from the subthalamic nucleus may induce burst firing in SNr GABA neurons. Thus, afferent GABA and glutamate synaptic inputs sculpt the tonic high frequency firing of SNr GABA neurons and the consequent inhibition of their targets into an integrated motor control signal that is further fine-tuned by neuromodulators including dopamine, serotonin, endocannabinoids, and H₂O₂.
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Affiliation(s)
- F-M Zhou
- Department of Pharmacology, University of Tennessee College of Medicine, Memphis, TN 38163, USA.
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21
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Hashemi P, Dankoski EC, Wood KM, Ambrose RE, Wightman RM. In vivo electrochemical evidence for simultaneous 5-HT and histamine release in the rat substantia nigra pars reticulata following medial forebrain bundle stimulation. J Neurochem 2011; 118:749-59. [PMID: 21682723 PMCID: PMC3155665 DOI: 10.1111/j.1471-4159.2011.07352.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exploring the mechanisms of serotonin [5-hydroxytryptamine (5-HT)] in the brain requires an in vivo method that combines fast temporal resolution with chemical selectivity. Fast-scan cyclic voltammetry is a technique with sufficient temporal and chemical resolution for probing dynamic 5-HT neurotransmission events; however, traditionally it has not been possible to probe in vivo 5-HT mechanisms. Recently, we optimized fast-scan cyclic voltammetry for measuring 5-HT release and uptake in vivo in the substantia nigra pars reticulata (SNR) with electrical stimulation of the dorsal raphe nucleus (DRN) in the rat brain. Here, we address technical challenges associated with rat DRN surgery by electrically stimulating 5-HT projections in the medial forebrain bundle (MFB), a more accessible anatomical location. MFB stimulation elicits 5-HT in the SNR; furthermore, we find simultaneous release of an additional species. We use electrochemical and pharmacological methods and describe physiological, anatomical and independent chemical analyses to identify this species as histamine. We also show pharmacologically that increasing the lifetime of extracellular histamine significantly decreases 5-HT release, most likely because of increased activation of histamine H-3 receptors that inhibit 5-HT release. Despite this, under physiological conditions, we find by kinetic comparisons of DRN and MFB stimulations that the simultaneous release of histamine does not interfere with the quantitative 5-HT concentration profile. We therefore present a novel and robust electrical stimulation of the MFB that is technically less challenging than DRN stimulation to study 5-HT and histamine release in the SNR.
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Affiliation(s)
- Parastoo Hashemi
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, 27599
| | - Elyse C. Dankoski
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, 27599
| | - Kevin M. Wood
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, 27599
| | - R. Ellen Ambrose
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, 27599
| | - R. Mark Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, 27599
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, 27599
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22
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Hao K, Gong P, Sun SQ, Hao HP, Wang GJ, Dai Y, Chen YC, Liang Y, Xie L, Li FY, Li HY. Mechanism-based pharmacokinetic-pharmacodynamic modeling of the estrogen-like effect of ginsenoside Rb1 on neural 5-HT in ovariectomized mice. Eur J Pharm Sci 2011; 44:117-26. [PMID: 21740969 DOI: 10.1016/j.ejps.2011.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 04/15/2011] [Accepted: 06/22/2011] [Indexed: 11/18/2022]
Abstract
We sought to develop a mechanism-based pharmacokinetic-pharmacodynamic (PK-PD) model to characterize the effects of ginsenoside Rb1 (Rb1) and estradiol (E(2)) on neural 5-hydroxytryptamine (5-HT) concentration in ovariectomized mice. PK data of Rb1 and E(2) were obtained in plasma and brain. Brain levels of 5-HT, tryptophan (TRP), 5-hydroxytryptophan (5-HTP), and 5-hydroxyindoleacetic acid (5-HIAA) were determined after a single intravenous injection of Rb1 (20mg/kg) and E(2) (0.2mg/kg) in ovariectomized mice. The activities of tryptophan hydroxylase (TPH), aromatic amino acid decarboxylase (AAAD), and monoamine oxidase (MAO) were also evaluated. Rb1 and E(2) elevated neural 5-HT levels via TPH activation and MAO inhibition, respectively. Effects were well described by the mechanism-based PK-PD model. The net effect of increased 5-HT induced by MAO inhibition is greater than TPH activation. The increased brain levels of 5-HT induced by Rb1 and E(2) were well described by the present PK-PD model, suggesting the use and further development of this mechanism-based model for the effects of ginsenoside on brain 5-HT levels.
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Affiliation(s)
- Kun Hao
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
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23
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Hale MW, Shekhar A, Lowry CA. Development by environment interactions controlling tryptophan hydroxylase expression. J Chem Neuroanat 2011; 41:219-26. [PMID: 21640184 DOI: 10.1016/j.jchemneu.2011.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/19/2011] [Accepted: 05/06/2011] [Indexed: 11/17/2022]
Abstract
Tryptophan hydroxylase is the rate-limiting enzyme in the biosynthesis of serotonin (5-hydroxytryptamine; 5-HT). Two isoforms of tryptophan hydroxylase, derived from different genes, tph1 and tph2, have been identified. The tph1 isoform is expressed in peripheral tissues, whereas tph2 is brain and neuron-specific. Recent studies suggest that tph2 expression and brain serotonin turnover are upregulated in depressed suicide patients, and drug-free depressed patients, respectively. Increased tph2 expression could result from genetic influences, early life developmental influences, adverse experience during adulthood, or interactions among these factors. Studies in rodents support the hypothesis that interactions between early life developmental influences and adverse experience during adulthood play an important role in determining tph2 expression. In this review, we highlight the evidence for the effects of adverse early life experience and stressful experience during adulthood on both tph1 and tph2 expression.
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Affiliation(s)
- Matthew W Hale
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, USA
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24
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Functional organization of the dorsal raphe efferent system with special consideration of nitrergic cell groups. J Chem Neuroanat 2011; 41:281-93. [PMID: 21640185 DOI: 10.1016/j.jchemneu.2011.05.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 05/10/2011] [Accepted: 05/16/2011] [Indexed: 11/22/2022]
Abstract
The serotonin (5HT) system of the brain is involved in many CNS functions including sensory perception, stress responses and psychological disorders such as anxiety and depression. Of the nine 5HT nuclei located in the mammalian brain, the dorsal raphe nucleus (DRN) has the most extensive forebrain connectivity and is implicated in the manifestation of stress-related psychological disturbances. Initial investigations of DRN efferent connections failed to acknowledge the rostrocaudal and mediolateral organization of the nucleus or its neurochemical heterogeneity. More recent studies have focused on the non-5HT contingent of DRN cells and have revealed an intrinsic intranuclear organization of the DRN which has specific implications for sensory signal processing and stress responses. Of particular interest are spatially segregated subsets of nitric oxide producing neurons that are activated by stressors and that have unique efferent projection fields. In this regard, both the midline and lateral wing subregions of the DRN have emerged as prominent loci for future investigation of nitric oxide function and modulation of sensory- and stressor-related signals in the DRN and coinciding terminal fields.
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25
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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: 64] [Impact Index Per Article: 4.9] [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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26
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Hernández L, Paredes D, Rada P. Feeding behavior as seen through the prism of brain microdialysis. Physiol Behav 2011; 104:47-56. [PMID: 21549733 DOI: 10.1016/j.physbeh.2011.04.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/28/2022]
Abstract
The knowledge of feeding behavior mechanisms gained through brain microdialysis is reviewed. Most of the chemical changes so far reported concern to the limbic system in rodents. A picture showing increases and decreases of extracellular neurotransmitters correlating to different aspects of feeding behavior is gradually emerging. Depending on the region, the same neurotransmitter may signal opposite aspects of feeding. Dopamine (DA) in the nucleus accumbens (NAC) correlates with food reward, stimulus saliency, and goal directed hyperlocomotion but in the ventromedial hypothalamus DA correlates with satiety and hypolocomotion. The findings accumulated in the last 25 years suggest that the control of a particular function relies on the interaction of several neurotransmitters rather than on a single neurotransmitter. The poor sensitivity of most analytical techniques hinders time and spatial resolution of microdialysis. Therefore, neurochemical correlates of short lasting behaviors are hard to figure out. As new and more sensitive analytical techniques are applied, new neurochemical correlates of feeding show up. Sometimes the proper analytical techniques are simply not available. As a consequence, critical signals such as neuropeptides are not yet completely placed in the puzzle. Despite such limitations, brain microdialysis has yielded a great deal of knowledge on the neurochemical basis of feeding.
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Affiliation(s)
- Luis Hernández
- Laboratory of Behavioral Physiology, School of Medicine, Universidad de los Andes, Mérida, Venezuela
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27
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Hao K, Gong P, Sun SQ, Hao HP, Wang GJ, Dai Y, Liang Y, Xie L, Li FY. Beneficial estrogen-like effects of ginsenoside Rb1, an active component of Panax ginseng, on neural 5-HT disposition and behavioral tasks in ovariectomized mice. Eur J Pharmacol 2011; 659:15-25. [PMID: 21414307 DOI: 10.1016/j.ejphar.2011.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 02/08/2011] [Accepted: 03/01/2011] [Indexed: 11/29/2022]
Abstract
Decreased 5-hydroxytryptamine (5-HT) concentration in the brain has been linked to central nervous system dysfunctions, especially in menopausal women. Ginsenoside Rb1, a potential phytoestrogen, has been shown to improve central nervous system dysfunctions, comparable to the estrogen treatment. To investigate the estrogen-like effects of ginsenoside Rb1 on neural 5-HT disposition and behavioral tasks, we quantified the concentrations of 5-HT and other related endogenous substances in the frontal cortex and striatum of ovariectomized mice. The activities of tryptophan hydroxylase (TPH), aromatic amino acid decarboxylase (AAAD) and monoamine oxidase (MAO) were also measured to evaluate the synthesis and metabolism of neural 5-HT. Our work shows that both ginsenoside Rb1 and estradiol increased the neural 5-HT concentration. Ginsenoside Rb1 and estradiol administration resulted in elevated TPH and depressed MAO activities, indicating that modulating the synthesis and metabolism of neural 5-HT successfully elevated 5-HT concentration. Ginsenoside Rb1 and estradiol also improved object recognition and decreased immobility time in the forced swimming test. However, a pretreatment with clomiphene (an estrogen receptor antagonist) blocked the beneficial effects of ginsenoside Rb1 and estradiol, suggesting that the estrogen-like effects of ginsenoside Rb1 were estrogen receptor-dependent.
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Affiliation(s)
- Kun Hao
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Ping Gong
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Shi-Qing Sun
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Hai-Ping Hao
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Guang-Ji Wang
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Yue Dai
- College of Traditional Chinese Materia Medica, China Pharmaceutical University, Nanjing, PR China
| | - Yan Liang
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Lin Xie
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
| | - Fei-Yan Li
- Key Lab of Drug Metabolism & Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China
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28
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Il-Han J, Janes T, Lukowiak K. The role of serotonin in the enhancement of long-term memory resulting from predator detection in Lymnaea. J Exp Biol 2010; 213:3603-14. [DOI: 10.1242/jeb.048256] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SUMMARY
Serotonergic systems play important roles in modulating stress-induced arousal and vigilance behaviours. The pond snail, Lymnaea, shows multiple defensive vigilance behaviours in response to the stress associated with predator detection. Predator detection elicited by crayfish effluent (CE), increases the time to re-emerge from the shell and enhances the shadow withdrawal response. More importantly, in Lymnaea, CE enhances the ability to form long-term memory (LTM). We investigated the role of the serotonergic system in these anti-predator responses in Lymnaea. Using a serotonin-receptor antagonist, mianserin, we found that two defensive vigilance behaviours (e.g. increasing the time to re-emerge from their shell and shadow response) elicited by CE were not observed when the serotonergic system was disrupted. Also, methysergide, another serotonin antagonist, blocked the enhanced LTM formation after training in CE. Importantly, mianserin did not alter LTM formation in pond water (PW). These data suggest that a serotonergic system is activated only when Lymnaea detect a predator. When snails were trained in CE using a training procedure that in PW produces a 24-h LTM, a more persistent form of LTM (5 days) occurred. This more persistent form of LTM was abolished after mianserin treatment. Increasing 5-HT levels in the snail by the injection of 5-HT was also associated with enhanced LTM formation. Lastly, we tested whether the osphradium is implicated in CE detection and subsequent enhanced formation of LTM. Cutting the osphradial nerve to the CNS resulted in the loss of the ability to form enhanced LTM in CE. Together, these findings support the hypothesis that the serotonergic system plays a key role in modulating the predator-induced stress responses in Lymnaea.
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Affiliation(s)
- Jae Il-Han
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
| | - Tara Janes
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
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Su CK, Sun YC, Tzeng SF, Yang CS, Wang CY, Yang MH. In vivo monitoring of the transfer kinetics of trace elements in animal brains with hyphenated inductively coupled plasma mass spectrometry techniques. MASS SPECTROMETRY REVIEWS 2010; 29:392-424. [PMID: 19437493 DOI: 10.1002/mas.20240] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The roles of metal ions to sustain normal function and to cause dysfunction of neurological systems have been confirmed by various studies. However, because of the lack of adequate analytical method to monitor the transfer kinetics of metal ions in the brain of a living animal, research on the physiopathological roles of metal ions in the CNS remains in its early stages and more analytical efforts are still needed. To explicitly model the possible links between metal ions and physiopathological alterations, it is essential to develop in vivo monitoring techniques that can bridge the gap between metalloneurochemistry and neurophysiopathology. Although inductively coupled plasma mass spectrometry (ICP-MS) is a very powerful technique for multiple trace element analyses, when dealing with chemically complex microdialysis samples, the detection capability is largely limited by instrumental sensitivity, selectivity, and contamination that arise from the experimental procedure. As a result, in recent years several high efficient and clean on-line sample pretreatment systems have been developed and combined with microdialysis and ICP-MS for the continuous and in vivo determination of the concentration-time profiles of metal ions in the extracellular space of rat brain. This article reviews the research relevant to the development of analytical techniques for the in vivo determination of dynamic variation in the concentration levels of metal ions in a living animal.
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Affiliation(s)
- Cheng-Kuan Su
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
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30
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Devadoss T, Pandey DK, Mahesh R, Yadav SK. Effect of acute and chronic treatment with QCF-3 (4-benzylpiperazin-1-yl) (quinoxalin-2-yl) methanone, a novel 5-HT3 receptor antagonist, in animal models of depression. Pharmacol Rep 2010; 62:245-57. [DOI: 10.1016/s1734-1140(10)70263-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 11/18/2009] [Indexed: 10/25/2022]
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31
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Feng N, Lowry CA, Lukkes JL, Orchinik M, Forster GL, Renner KJ. Organic cation transporter inhibition increases medial hypothalamic serotonin under basal conditions and during mild restraint. Brain Res 2010; 1326:105-13. [PMID: 20171957 DOI: 10.1016/j.brainres.2010.02.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/10/2010] [Accepted: 02/10/2010] [Indexed: 01/01/2023]
Abstract
The dorsomedial hypothalamus (DMH) has been implicated in the coordination of stress responses. Restraint stress or systemic corticosterone (CORT) treatment induces a rapid increase in tissue concentrations of serotonin (5-hydroxytryptamine; 5-HT) in the DMH. Although the mechanism for rapid changes in 5-HT concentrations in the DMH is not clear, earlier results suggest that stress-induced increases in CORT may inhibit 5-HT transport from the extracellular fluid by acting on corticosterone-sensitive organic cation transporters (OCTs). We tested the hypothesis that perfusion of the medial hypothalamus (MH), which includes the DMH, with the OCT blocker decynium 22 (D-22) would potentiate the effects of mild restraint on extracellular 5-HT. Male Sprague-Dawley rats, implanted with a microdialysis probe into the MH, were treated with reverse-dialysis of D-22 (20 microM; 40 min) or vehicle and subjected to either 40 min mild restraint or undisturbed control conditions. Perfusates collected from a separate group of rats were evaluated for the effect of restraint on extracellular CORT concentrations in the MH. Reverse-dialysis of D-22 induced an increase (200%) in extracellular 5-HT concentrations in the MH in undisturbed control rats. Restraint in the absence of D-22 did not significantly affect MH CORT or 5-HT concentrations. However, perfusion of the MH with D-22 during restraint led to an increased magnitude and duration of extracellular 5-HT concentrations, relative to D-22 by itself. These results are consistent with the hypothesis that OCTs in the DMH contribute to the clearance of 5-HT from the extracellular fluid under both baseline conditions and mild restraint.
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Affiliation(s)
- Na Feng
- Department of Biology, University of South Dakota, Vermillion, SD 57069-2390, USA
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32
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Christianson JP, Ragole T, Amat J, Greenwood BN, Strong PV, Paul ED, Fleshner M, Watkins LR, Maier SF. 5-hydroxytryptamine 2C receptors in the basolateral amygdala are involved in the expression of anxiety after uncontrollable traumatic stress. Biol Psychiatry 2010; 67:339-45. [PMID: 19914601 PMCID: PMC3278236 DOI: 10.1016/j.biopsych.2009.09.011] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 09/10/2009] [Accepted: 09/11/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND Exposure to uncontrollable stressors often increases anxiety-like behavior in both humans and rodents. In rat, this effect depends on stress-induced activity within the dorsal raphe nucleus (DRN). However, the role of serotonin in DRN projection regions is largely unknown. The goals of this study were to 1) assess the effect of uncontrollable stress on extracellular serotonin in the basolateral amygdala during the anxiety test, 2) determine whether DRN activity during a poststress anxiety test is involved in anxiety-like behavior, and 3) determine the role of the serotonin 2C receptor (5-HT(2C)) in uncontrollable stress-induced anxiety. METHOD Rats were exposed to tail shocks that were either controllable or uncontrollable. On the following day, anxiety-like behavior was assessed in a Juvenile Social Exploration (JSE) test. Basolateral amygdala (BLA) extracellular serotonin concentrations were assessed during JSE by in vivo microdialysis 24 hours after uncontrollable stress, controllable stress, or no stress. In separate experiments, drugs were administered before the JSE test to inhibit the DRN or to block 5-HT(2C) receptors. RESULTS Exposure to uncontrollable shock reduced later social exploration. Prior uncontrollable stress potentiated serotonin efflux in the BLA during social exploration, but controllable stress did not. Intra-DRN 8-OH-DPAT and systemic and intra-BLA 5-HT(2C) receptor antagonist SB 242,084 prevented the expression of potentiated anxiety in uncontrollably stressed rats. Intra-BLA injection of the 5-HT(2C) agonist CP 809,101 mimicked the effect of stress. CONCLUSIONS These results suggest that the anxiety-like behavior observed after uncontrollable stress is mediated by exaggerated 5-HT acting at BLA 5-HT(2C) receptors.
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Affiliation(s)
- John P Christianson
- Department of Psychology and Neuroscience, University of Colorado, Boulder, 80309, USA.
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33
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Webb IC, Patton DF, Landry GJ, Mistlberger RE. Circadian clock resetting by behavioral arousal: neural correlates in the midbrain raphe nuclei and locus coeruleus. Neuroscience 2010; 166:739-51. [PMID: 20079808 DOI: 10.1016/j.neuroscience.2010.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 10/19/2022]
Abstract
Some procedures for stimulating arousal in the usual daily rest period (e.g., gentle handling, novel wheel-induced running) can phase shift circadian rhythms in Syrian hamsters, while other arousal procedures are ineffective (inescapable stress, caffeine, modafinil). The dorsal and median raphe nuclei (DRN, MnR) have been implicated in clock resetting by arousal and, in rats and mice, exhibit strong regionally specific responses to inescapable stress and anxiogenic drugs. To examine a possible role for the midbrain raphe nuclei in the differential effects of arousal procedures on circadian rhythms, hamsters were aroused for 3 h in the mid-rest period by confinement to a novel running wheel, gentle handling (with minimal activity) or physical restraint (with intermittent, loud compressed air stimulation) and sacrificed immediately thereafter. Regional expression of c-fos and tryptophan hydroxylase (TrpOH) were quantified immunocytochemically in the DRN, MnR and locus coeruleus (LC). Neither gentle handling nor wheel running had a large impact on c-fos expression in these areas, although the manipulations were associated with a small increase in c-Fos in TrpOH-like and TrpOH-negative cells, respectively, in the caudal interfascicular DRN region. By contrast, restraint stress significantly increased c-Fos in both TrpOH-like and TrpOH-negative cells in the rostral DRN and LC. c-Fos-positive cells in the DRN did not express tyrosine hydroxylase. These results reveal regionally specific monoaminergic correlates of arousal-induced circadian clock resetting, and suggest a hypothesis that strong activation of some DRN and LC neurons by inescapable stress may oppose clock resetting in response to arousal during the daily sleep period. More generally, these results complement evidence from other rodent species for functional topographic organization of the DRN.
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Affiliation(s)
- I C Webb
- Department of Psychology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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34
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Müller CP, Pum ME, Schumann G, Huston JP. The Role of Serotonin in Drug Addiction. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70099-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Amat J, Aleksejev RM, Paul E, Watkins LR, Maier SF. Behavioral control over shock blocks behavioral and neurochemical effects of later social defeat. Neuroscience 2009; 165:1031-8. [PMID: 19909791 DOI: 10.1016/j.neuroscience.2009.11.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/29/2009] [Accepted: 11/04/2009] [Indexed: 11/16/2022]
Abstract
Experience with behavioral control over tailshock (escapable shock, ES) has been shown to block the behavioral and neurochemical changes produced by later uncontrollable tail shock (inescapable shock, IS). The present experiments tested, in rats, whether the protective effect of control over tailshock extends beyond reducing the behavioral and neurochemical impact of a subsequent tailshock experience to stressors that are quite different. Social defeat (SD) was chosen as the second stress experience because it has few if any cues in common with tailshock. SD produced shuttlebox escape learning deficits ("learned helplessness") and reduced juvenile social investigation 24 h later, as does IS. IS is notable for inducing a large increase in dorsal raphe nucleus (DRN) serotonergic (5-HT) activity as measured by extracellular levels of 5-HT within the DRN, and SD did so as well. ES occurring 7 days before SD blocked this SD-induced DRN activation, as well as the SD-induced interference with shuttlebox escape and reduction in social investigation. Prior exposure to yoked IS did not reduce the DRN 5-HT activation or later behavioral effects produced by SD, and thus the proactive stress-blunting effects of ES can be attributed to it's controllability. Thus, ES confers a very general protection to the impact of a subsequent stress experience.
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Affiliation(s)
- J Amat
- Department of Psychology and Center for Neuroscience, University of Colorado, Boulder, CO, USA.
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36
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Feng N, Telefont M, Kelly KJ, Orchinik M, Forster GL, Renner KJ, Lowry CA. Local perfusion of corticosterone in the rat medial hypothalamus potentiates D-fenfluramine-induced elevations of extracellular 5-HT concentrations. Horm Behav 2009; 56:149-57. [PMID: 19371745 DOI: 10.1016/j.yhbeh.2009.03.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 03/27/2009] [Accepted: 03/31/2009] [Indexed: 01/11/2023]
Abstract
The dorsomedial hypothalamus (DMH) plays an important role in coordinating physiological and behavioral responses to stress-related stimuli. In vertebrates, DMH serotonin (5-HT) concentrations increase rapidly in response to acute stressors or corticosterone (CORT). Recent studies suggest that CORT inhibits postsynaptic clearance of 5-HT from the extracellular fluid in the DMH by blocking organic cation transporter 3 (OCT3), a polyspecific CORT-sensitive transport protein. Because OCTs are low-affinity, high-capacity transporters, we hypothesized that CORT effects on extracellular 5-HT are most pronounced in the presence of elevated 5-HT release. We predicted that local application of CORT into the DMH would potentiate the effects of d-fenfluramine, a 5-HT-releasing agent, on extracellular 5-HT. These experiments were conducted using in vivo microdialysis in freely-moving male Sprague-Dawley rats implanted with a microdialysis probe into the medial hypothalamus (MH), which includes the DMH. In Experiment 1, rats simultaneously received intraperitoneal (i.p.) injections of 1 mg/kg D-fenfluramine or saline and either 200 ng/mL CORT or dilute ethanol (EtOH) vehicle delivered to the MH by reverse-dialysis for 40 min. In Experiment 2, 5 microM D-fenfluramine and either 200 ng/mL CORT or EtOH vehicle were concurrently delivered to the MH for 40 min using reverse-dialysis. CORT potentiated the increases in extracellular 5-HT concentrations induced by either i.p. or intra-MH administration of D-fenfluramine. Furthermore, CORT and D-fenfluramine interacted to alter home cage behaviors. Our results support the hypothesis that CORT inhibition of OCT3-mediated 5-HT clearance from the extracellular fluid contributes to stress-induced increases in extracellular 5-HT and 5-HT signaling.
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Affiliation(s)
- Na Feng
- Department of Biology and Neuroscience Group, University of South Dakota, Vermillion, SD 57069, USA
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37
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Qu Y, Aluisio L, Lord B, Boggs J, Hoey K, Mazur C, Lovenberg T. Pharmacokinetics and pharmacodynamics of norfluoxetine in rats: Increasing extracellular serotonin level in the frontal cortex. Pharmacol Biochem Behav 2009; 92:469-73. [DOI: 10.1016/j.pbb.2009.01.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 01/12/2009] [Accepted: 01/16/2009] [Indexed: 10/21/2022]
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38
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Shaw JC, Korzan WJ, Carpenter RE, Kuris AM, Lafferty KD, Summers CH, Øverli Ø. Parasite manipulation of brain monoamines in California killifish (Fundulus parvipinnis) by the trematode Euhaplorchis californiensis. Proc Biol Sci 2009; 276:1137-46. [PMID: 19129105 DOI: 10.1098/rspb.2008.1597] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
California killifish (Fundulus parvipinnis) infected with the brain-encysting trematode Euhaplorchis californiensis display conspicuous swimming behaviours rendering them more susceptible to predation by avian final hosts. Heavily infected killifish grow and reproduce normally, despite having thousands of cysts inside their braincases. This suggests that E. californiensis affects only specific locomotory behaviours. We hypothesised that changes in the serotonin and dopamine metabolism, essential for controlling locomotion and arousal may underlie this behaviour modification. We employed micropunch dissection and HPLC to analyse monoamine and monoamine metabolite concentrations in the brain regions of uninfected and experimentally infected fish. The parasites exerted density-dependent changes in monoaminergic activity distinct from those exhibited by fish subjected to stress. Specifically, E. californiensis inhibited a normally occurring, stress-induced elevation of serotonergic metabolism in the raphae nuclei. This effect was particularly evident in the experimentally infected fish, whose low-density infections were concentrated on the brainstem. Furthermore, high E. californiensis density was associated with increased dopaminergic activity in the hypothalamus and decreased serotonergic activity in the hippocampus. In conclusion, the altered monoaminergic metabolism may explain behavioural differences leading to increased predation of the infected killifish by their final host predators.
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Affiliation(s)
- J C Shaw
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106-7130, USA.
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Shiraishi M, Takizawa Y, Ide S, Obonai T, Goto YI, Itoh M. Brainstem monoamine pathology of neonatal hypoxic-ischemic brain damage: a model of acute stage of neonatal asphyxia. Brain Res 2008; 1213:120-6. [PMID: 18455708 DOI: 10.1016/j.brainres.2008.03.068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Revised: 03/21/2008] [Accepted: 03/27/2008] [Indexed: 10/22/2022]
Abstract
Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the most severe perinatal diseases and leads to high mortality and sometimes severe neurological sequelae. At the acute stage of HIE, it is thought to be the damage of catecholaminergic system in the brainstem. And then, HIE reflects mental development throughout the norepinephrine and serotonin systems, which mainly originates in the brainstem. Therefore, we studied both systems in the brainstem of neonatal HIE model rats with tyrosine hydroxylase (TH) and tryptophan hydroxylase (TpH) immunohistochemistry and a high-performance liquid column (HPLC) to measure norepinephrine and serotonin and their metabolism. As a result, the TH-positive and TpH-positive cell numbers significantly decreased 2 days after hypoxic-ischemic (HI) insult (n=10). However, 7 days after insult (n=10), the TH-positive and TpH-positive cell numbers had recovered in most regions. HPLC demonstrated a significant difference in the norepinephrine concentration 2 days after HI insult, but not in the other monoamines.
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Affiliation(s)
- Mika Shiraishi
- Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Japan
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40
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Pum ME, Huston JP, De Souza Silva MA, Müller CP. Visual sensory-motor gating by serotonin activation in the medial prefrontal and occipital, but not in the rhinal, cortices in rats. Neuroscience 2008; 153:361-72. [PMID: 18378406 DOI: 10.1016/j.neuroscience.2008.02.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 02/11/2008] [Accepted: 02/20/2008] [Indexed: 11/26/2022]
Abstract
A behavioral reaction to sensory stimulation is a basic mechanism which is pivotal to many complex behavioral responses. In previous studies we found that visual stimulation induces a selective serotonergic and dopaminergic activation in the occipital (OccC), but not temporal (TempC) cortex in freely moving rats. In a behavioral study in rats we demonstrate now that visual stimulation (0, 8, 22, 82, 155 or 440 lux) activates behavioral activity in an intensity-dependent manner. Behavior activating visual stimulation with 82 lux, but not 22 lux or 82 dB white noise, increased extracellular serotonin (5-HT), but not dopamine (DA), in the medial prefrontal cortex (mPFC) in freely moving animals measured by in vivo microdialysis. There was no effect on 5-HT or DA in the entorhinal and perirhinal cortex. Visual stimulation with 82 lux increased extracellular 5-HT in the mPFC and OccC also in anesthetized animals, but had no effect in the TempC. Auditory stimulation reduced 5-HT in the TempC, but had no effect in the mPFC or OccC. Neither visual nor auditory stimulation had a significant effect on DA in all three cortical areas. We conclude that visual stimulation induces behavioral activation by increasing 5-HT activity in the mPFC and OccC.
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Affiliation(s)
- M E Pum
- Institute of Physiological Psychology and Center for Biological and Medical Research, University of Düsseldorf, Universitätsstrasse 1, Düsseldorf, Germany
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41
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Smolin B, Klein E, Levy Y, Ben-Shachar D. Major depression as a disorder of serotonin resistance: inference from diabetes mellitus type II. Int J Neuropsychopharmacol 2007; 10:839-50. [PMID: 17250776 DOI: 10.1017/s1461145707007559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The multifactorial nature of depression resembles that of other complex disorders such as diabetes mellitus or coronary artery disease. However, while for the latter disorders predisposing and risk factors have been identified, such knowledge is still scarce in depression. In this review we propose to use diabetes mellitus, for which characteristic milestones have been condensed to obesity-hyperinsulinaemia-insulin resistance-diabetes mellitus, as a conceptual analogical model. Based on this model we hypothesize that depression develops according to a similar pattern: prolonged psychological stress-hyperserotonism-serotonin resistance-major depression. We review extensive supporting evidence from human studies and animal models of depression, including stress involvement in the aetiology of depression, evidence for increased synaptic serotonin and decreased 5-HT1A receptor activity. Conceptualizing the pathogenesis of depression as a multi-step process may inspire new concepts, which will eventually lead to delineation of additional preventive and therapeutic interventions similar to those currently practised in diabetes.
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Affiliation(s)
- Bella Smolin
- Department of Internal Medicine Rambam Medical Center, B. Rappaport Faculty of Medicine, Technion, Haifa, Israel
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Der-Avakian A, Rozeske RR, Bland ST, Watkins LR, Maier SF. The effects of a single session of inescapable tailshock on the subsequent locomotor response to brief footshock and cocaine administration in rats. Psychopharmacology (Berl) 2007; 191:899-907. [PMID: 17211648 DOI: 10.1007/s00213-006-0677-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 12/12/2006] [Indexed: 11/25/2022]
Abstract
RATIONALE We have previously shown that exposure to a single session of inescapable (IS), but not escapable (ES), tailshock can sensitize the subsequent conditioned place preference and locomotor responses to opioids, but not other drug classes. However, prior work suggests that IS might sensitize nonopioid drug responding if the drug were to be preceded by a mild stressor. OBJECTIVES In the following experiments, we examined the effects of IS and ES on the subsequent locomotor response to brief footshock and/or cocaine administration. METHODS First, we measured the locomotor response to cocaine (0, 1, 5, 10 mg/kg, intraperitoneally) 48 h after a single session of IS in adult, male Sprague-Dawley rats. Then, this procedure was repeated with 10 mg/kg cocaine, except that half of the rats received two footshocks immediately before drug administration. Finally, we manipulated the escapability of the initial stressor, as rats received either ES or yoked IS 48 h prior to footshock and cocaine administration. RESULTS IS did not affect the subsequent locomotor response to cocaine, but did enhance this response when cocaine administration was immediately preceded by two footshocks. The footshocks alone were without effect. This sensitizing effect was dependent on the escapability of the initial stressor, as ES did not alter the locomotor response to footshock and cocaine administration. CONCLUSIONS These results indicate that acute exposure to IS, but not ES, can sensitize the locomotor response to cocaine 48 h later, but only when cocaine administration is immediately preceded by a brief stressor.
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Affiliation(s)
- Andre Der-Avakian
- Department of Psychology and Center for Neuroscience, University of Colorado, UCB 345, Boulder, CO 80309-0345, USA.
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Der-Avakian A, Bland ST, Rozeske RR, Tamblyn JP, Hutchinson MR, Watkins LR, Maier SF. The effects of a single exposure to uncontrollable stress on the subsequent conditioned place preference responses to oxycodone, cocaine, and ethanol in rats. Psychopharmacology (Berl) 2007; 191:909-17. [PMID: 17211647 DOI: 10.1007/s00213-006-0678-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 12/12/2006] [Indexed: 01/13/2023]
Abstract
RATIONALE Acute stress has been shown to facilitate the rewarding effects of a number of commonly abused drugs, although the stressor typically must be administered either immediately before or during drug administration and often in the same environment. We have previously reported that a single session of an uncontrollable (inescapable tailshock, IS), but not controllable (escapable tailshock, ES), stressor can enhance the conditioned place preference (CPP) response to morphine, even when stressor and drug administration are separated temporally and spatially. However, this persistent, trans-situational enhancement did not occur to amphetamine CPP. OBJECTIVES The following experiments were conducted to determine whether the long-term effects of IS on drug reward are specific to opioids. MATERIALS AND METHODS Adult, male Sprague-Dawley rats were exposed to a single session of IS or remained in their home cages (HC). Twenty-four hours later, using an unbiased procedure, CPP conditioning was conducted with either oxycodone (0, 2, or 5 mg/kg, sc), cocaine (0, 1, 5, or 10 mg/kg, ip), or ethanol (0.3, 1, or 2 g/kg, ip). Another group of rats were exposed to IS, ES, or HC treatment and conditioned with oxycodone (5 mg/kg, sc) 24 h later. RESULTS IS enhanced the subsequent CPP response to oxycodone, but not cocaine or ethanol. This enhancement was dependent on the controllability of the stressor, as ES did not affect oxycodone CPP. CONCLUSIONS These results indicate that the long-term, trans-situational enhancing effect of uncontrollable stress on drug reward is specific to opioids.
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Affiliation(s)
- Andre Der-Avakian
- Department of Psychology and Center for Neuroscience, University of Colorado, UCB 345, Boulder, CO 80309-0345, USA.
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Müller CP, Carey RJ, Huston JP, De Souza Silva MA. Serotonin and psychostimulant addiction: Focus on 5-HT1A-receptors. Prog Neurobiol 2007; 81:133-78. [PMID: 17316955 DOI: 10.1016/j.pneurobio.2007.01.001] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 12/04/2006] [Accepted: 01/03/2007] [Indexed: 01/03/2023]
Abstract
Serotonin(1A)-receptors (5-HT(1A)-Rs) are important components of the 5-HT system in the brain. As somatodendritic autoreceptors they control the activity of 5-HT neurons, and, as postsynaptic receptors, the activity in terminal areas. Cocaine (COC), amphetamine (AMPH), methamphetamine (METH) and 3,4-methylenedioxymethamphetamine ("Ecstasy", MDMA) are psychostimulant drugs that can lead to addiction-related behavior in humans and in animals. At the neurochemical level, these psychostimulant drugs interact with monoamine transporters and increase extracellular 5-HT, dopamine and noradrenalin activity in the brain. The increase in 5-HT, which, in addition to dopamine, is a core mechanism of action for drug addiction, hyperactivates 5-HT(1A)-Rs. Here, we first review the role of the various 5-HT(1A)-R populations in spontaneous behavior to provide a background to elucidate the contribution of the 5-HT(1A)-Rs to the organization of psychostimulant-induced addiction behavior. The progress achieved in this field shows the fundamental contribution of brain 5-HT(1A)-Rs to virtually all behaviors associated with psychostimulant addiction. Importantly, the contribution of pre- and postsynaptic 5-HT(1A)-Rs can be dissociated and frequently act in opposite directions. We conclude that 5-HT(1A)-autoreceptors mainly facilitate psychostimulant addiction-related behaviors by a limitation of the 5-HT response in terminal areas. Postsynaptic 5-HT(1A)-Rs, in contrast, predominantly inhibit the expression of various addiction-related behaviors directly. In addition, they may also influence the local 5-HT response by feedback mechanisms. The reviewed findings do not only show a crucial role of 5-HT(1A)-Rs in the control of brain 5-HT activity and spontaneous behavior, but also their complex role in the regulation of the psychostimulant-induced 5-HT response and subsequent addiction-related behaviors.
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Affiliation(s)
- Christian P Müller
- Institute of Physiological Psychology I, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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Bouwknecht JA, Spiga F, Staub DR, Hale MW, Shekhar A, Lowry CA. Differential effects of exposure to low-light or high-light open-field on anxiety-related behaviors: relationship to c-Fos expression in serotonergic and non-serotonergic neurons in the dorsal raphe nucleus. Brain Res Bull 2007; 72:32-43. [PMID: 17303505 PMCID: PMC1800906 DOI: 10.1016/j.brainresbull.2006.12.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 12/12/2006] [Accepted: 12/13/2006] [Indexed: 11/19/2022]
Abstract
Serotonergic systems arising from the mid-rostrocaudal and caudal dorsal raphe nucleus (DR) have been implicated in the facilitation of anxiety-related behavioral responses to anxiogenic drugs or aversive stimuli. In this study we attempted to determine a threshold to engage serotonergic neurons in the DR following exposure to aversive conditions in an anxiety-related behavioral test. We manipulated the intensity of anxiogenic stimuli in studies of male Wistar rats by leaving them undisturbed (CO), briefly handling them (HA), or exposing them to an open-field arena for 15-min under low-light (LL: 8-13 lx) or high-light (HL: 400-500 lx) conditions. Rats exposed to HL conditions responded with reduced locomotor activity, reduced time spent exploring the center of the arena, a lower frequency of rearing and grooming, and an increased frequency of facing the corner of the arena compared to LL rats. Rats exposed to HL conditions had small but significant increases in c-Fos expression within serotonergic neurons in subdivisions of the rostral DR. Exposure to HL conditions did not alter c-Fos responses in serotonergic neurons in any other DR subdivision. In contrast, rats exposed to the open-field arena had increased c-Fos expression in non-serotonergic cells throughout the DR compared to CO rats, and this effect was particularly apparent in the dorsolateral part of the DR. We conclude that exposure to HL conditions, compared to LL conditions, increased anxiety-related behavioral responses in an open-field arena but this stimulus was at or below the threshold required to increase c-Fos expression in serotonergic neurons.
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Affiliation(s)
- J. Adriaan Bouwknecht
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol, BS1 3NY, United Kingdom
| | - Francesca Spiga
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol, BS1 3NY, United Kingdom
| | - Daniel R. Staub
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol, BS1 3NY, United Kingdom
| | - Matthew W. Hale
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol, BS1 3NY, United Kingdom
| | - Anantha Shekhar
- Department of Psychiatry, Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Christopher A. Lowry
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Whitson Street, Bristol, BS1 3NY, United Kingdom
- Present Address Corresponding author: Dr. Christopher A. Lowry Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology University of Bristol Whitson Street Bristol, BS1 3NY United Kingdom Tel: +44 117 331 3119 Fax: +44 117 331 3120
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Smith VA, Beyer CE, Brandt MR. Neurochemical changes in the RVM associated with peripheral inflammatory pain stimuli. Brain Res 2006; 1095:65-72. [PMID: 16730668 DOI: 10.1016/j.brainres.2006.04.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 03/31/2006] [Accepted: 04/04/2006] [Indexed: 11/20/2022]
Abstract
A greater knowledge of the neurochemical changes occurring during pain states will undoubtedly aid in the discovery of effective pain pharmacotherapies. This study highlights the acute effects of inflammatory agents on neurochemical changes in the rostral ventromedial medulla (RVM), a supraspinal site involved in the processing of painful stimuli. Consistent with previous reports, a peripheral injection of 0.1 mg prostaglandin E(2) (PGE(2)) into the intraplantar area of the rat paw produced thermal hypersensitivity that peaked 10 min after administration. In vivo microdialysis studies in the same animals revealed that this behavioral response correlated with a greater than 2-fold increase (230%) in extracellular serotonin (5-HT) levels in the RVM. In contrast, levels of other neurotransmitters measured, including norepinephrine and dopamine, were not altered in animals receiving this inflammatory agent. Similar to PGE(2), an intraplantar injection of capsaicin (0.1 mg) produced a robust thermal hypersensitivity that was paralleled by a 3-fold increase in levels of 5-HT in the RVM. The next series of experiments showed that acute administration of the opioid analgesic, morphine (5.6 mg/kg; IP), attenuated PGE(2)-induced thermal hypersensitivity and reversed the increase in extracellular 5-HT observed in the RVM. Taken together, these findings extend previous reports of central neurochemical changes during inflammatory pain conditions and show that the combination of behavioral endpoints with microdialysis can yield important insights into the neurochemical environment of the pain circuitry.
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Affiliation(s)
- Valerie A Smith
- Discovery Neuroscience, Wyeth Research, Princeton, NJ 08543-8000, USA
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Lê AD, Funk D, Harding S, Juzytsch W, Fletcher PJ, Shaham Y. Effects of dexfenfluramine and 5-HT3 receptor antagonists on stress-induced reinstatement of alcohol seeking in rats. Psychopharmacology (Berl) 2006; 186:82-92. [PMID: 16521030 DOI: 10.1007/s00213-006-0346-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2005] [Accepted: 02/03/2006] [Indexed: 12/21/2022]
Abstract
RATIONALE AND OBJECTIVES We previously found that systemic injections of the 5-HT uptake blocker fluoxetine attenuate intermittent footshock stress-induced reinstatement of alcohol seeking in rats, while inhibition of 5-HT neurons in the median raphe induces reinstatement of alcohol seeking. In this study, we further explored the role of 5-HT in footshock stress-induced reinstatement of alcohol seeking by determining the effects of the 5-HT releaser and reuptake blocker dexfenfluramine, and the 5-HT receptor antagonists ondansetron and tropisetron, which decrease alcohol self-administration and anxiety-like responses in rats, on this reinstatement. METHODS Different groups of male Wistar rats were trained to self-administer alcohol (12% v/v) for 28-31 days (1 h/day, 0.19 ml per alcohol delivery) and then their lever responding for alcohol was extinguished over 9-10 days. Subsequently, the effect of systemic injections of vehicle or dexfenfluramine (0.25 or 0.5 mg/kg, i.p), ondansetron (0.001, 0.01, or 0.1 mg/kg, i.p), or tropisetron (0.001, 0.01, and 0.1 mg/kg, i.p) on reinstatement induced by 10 min of intermittent footshock (0.8 mA) was determined. RESULTS Systemic injections of dexfenfluramine, ondansetron or tropisetron attenuated footshock-induced reinstatement of alcohol seeking. Injections of dexfenfluramine, ondansetron, or tropisetron had no effect on extinguished lever responding in the absence of footshock. CONCLUSIONS The present results provide additional support for the hypothesis that brain 5-HT systems are involved in stress-induced reinstatement of alcohol seeking. The neuronal mechanisms that potentially mediate the unexpected observation that both stimulation of 5-HT release and blockade of 5-HT3 receptors attenuate footshock-induced reinstatement are discussed.
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Affiliation(s)
- Anh Dzung Lê
- Department of Neuroscience, Centre for Addiction and Mental Health, 33 Russell Street, Toronto, Ontario, M5S 2S1, Canada.
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Swain MG. Fatigue in liver disease: pathophysiology and clinical management. CANADIAN JOURNAL OF GASTROENTEROLOGY = JOURNAL CANADIEN DE GASTROENTEROLOGIE 2006; 20:181-8. [PMID: 16550262 PMCID: PMC2582971 DOI: 10.1155/2006/624832] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 10/12/2005] [Indexed: 11/18/2022]
Abstract
Fatigue is the most commonly encountered symptom in patients with liver disease, and it has a significant impact on their quality of life. However, although some progress has been made with regard to the understanding of the processes which may generate fatigue in general, the underlying cause(s) of liver disease-associated fatigue remain incompletely understood. The present review describes recent advances which have been made in our ability to measure fatigue in patients with liver disease in the clinical setting, as well as in our understanding of potential pathways which are likely important in the pathogenesis of fatigue associated with liver disease. Specifically, experimental findings suggest that fatigue associated with liver disease likely occurs as a result of changes in neurotransmission within the brain. In conclusion, a reasonable approach to help guide in the management of the fatigued patient with liver disease is presented.
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Affiliation(s)
- Mark G Swain
- University of Calgary, Liver Unit, Health Sciences Centre, Alberta.
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Rothstein MA. Science and society: applications of behavioural genetics: outpacing the science? Nat Rev Genet 2005; 6:793-8. [PMID: 16136076 DOI: 10.1038/nrg1687] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Human behavioural genetics is an established research discipline of the genomic age, and applications for behavioural genetic information are most likely to emerge in areas such as criminal justice, education, employment and insurance. However, behavioural genetic research into personality traits and antisocial behaviour poses several risks; for example, tentative or preliminary research findings might be misused in legal and commercial settings. Scientific caution, public and media education, expert consultation and confidentiality protection are essential for the responsible use of behavioural genetics.
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Affiliation(s)
- Mark A Rothstein
- Institute for Bioethics, Health Policy and Law, University of Louisville School of Medicine, 501 East Broadway #310, Louisville, Kentucky 40202, USA.
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Ripoll N, Hascoët M, Bourin M. Implication of 5-HT2A subtype receptors in DOI activity in the four-plates test-retest paradigm in mice. Behav Brain Res 2005; 166:131-9. [PMID: 16154212 DOI: 10.1016/j.bbr.2005.07.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 07/22/2005] [Accepted: 07/22/2005] [Indexed: 11/19/2022]
Abstract
The four-plates test (FPT) is an animal model of anxiety which allows the detection of anxiolytic effect not only of benzodiazepines (BZDs) but also of other non-BZDs anxiolytic compounds such as antidepressants (ADs). Furthermore, DOI, a 5-HT(2A/2C) agonist, has been shown to exert an anxiolytic-like effect in this model. Retesting mice in animal models of anxiety (test-retest paradigm) induces an anxiogenic-like and a loss of anxiolytic-like effects in response to BZDs and ADs. On the contrary, DOI has been reported to oppose the fear potentiation induced by trial 1 in the FPT. Despite DOI is considered as one of the most selective 5-HT(2A) available, it acts as agonist at all three 5-HT(2) receptor subtypes (5-HT(2A), 5-HT(2B) and 5-HT(2C)). The aim of this study was thus to investigate in the FPT test-retest paradigm, which 5-HT(2) receptor subtype(s) was involved in the DOI-induced effect in experienced mice. The effect of DOI (0.25-4 mg/kg) and the agonists, 5-HT(2B), BW 723C86 (1-16 mg/kg) and 5-HT(2C), RO 60-0175 (0.25-4 mg/kg) have also been studied. Then, antagonism studies were conducted combinating the 5-HT(2A) receptor antagonist SR 46349B, the 5-HT(2B/2C) receptor antagonist SB 206553 or the selective 5-HT(2C) receptor antagonist RS 10-2221 (at the doses of 0.1 and 1 mg/kg) with the DOI (1 mg/kg). Our study shows that the BW 723C86 had no effect on retesting mice, whereas it exerted an anxiolytic-like effect in naive mice. By contrast to DOI, the RO 60-0175 had no effect neither in naive nor experienced mice. Furthermore, only the SR 46349B antagonized the DOI-induced anti-punishment effect. Diazepam included as a positive control also increased in each case the number of punished passages in naive mice. Our findings altogether also suggest that DOI exerts its anxiolytic-like effect in the FPT test-retest paradigm through 5-HT(2A) receptors.
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Affiliation(s)
- Nadège Ripoll
- Research Group, EA 3256, Neurobiologie de l'anxiété et de la dépression, Faculté de Médecine, BP 53508, 1 rue Gaston Veil, F44035 Nantes Cedex 01, France
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