1
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Campos RDMM, Toscano AE, Gouveia HJCB, Lacerda DC, Pereira SDC, Paz IAADSG, Dantas Alves JS, Manhães-de-Castro R. Neonatal fluoxetine exposure delays reflex ontogeny, somatic development, and food intake similarly in male and female rats. Can J Physiol Pharmacol 2020; 99:490-498. [PMID: 32941740 DOI: 10.1139/cjpp-2020-0261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serotonin (5-HT) acts as a neuromodulator and plays a critical role in brain development. Changes in 5-HT signaling during the perinatal period can affect neural development and may result in behavioral changes in adulthood; however, further investigations are necessary including both sexes to study possible differences. Thus, the aim of this study was to investigate the impact of neonatal treatment with fluoxetine on the development of male and female offspring. The animals were divided into four groups according to sex and treatment. The experimental groups received fluoxetine at 10 mg·kg-1 (1 μL/g of body weight (bw)) and the animals of control group received saline solution 0.9% (1 μL/g of bw) from postnatal days 1-21. In the neonatal period, reflex ontogeny, somatic development, physical features, and food intake were recorded. In the postnatal period (until day 31) bw and post-weaning food intake were recorded. Chronic administration of fluoxetine in the neonatal period caused a delay in the reflex ontogeny and somatic development, as well as reduction of lactation, post-weaning bw, and post-weaning food intake in rats. No difference was found between the sexes. These changes reaffirm that serotonin plays an important role in regulating the plasticity of the brain during the early development period, but without sex differences.
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Affiliation(s)
| | - Ana Elisa Toscano
- Department of Nursing, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | | | - Diego Cabral Lacerda
- Post-Graduation Program in Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Sabrina da Conceição Pereira
- Post-Graduation in Neuropsychiatry and Behavioral Sciences, Health Sciences Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | | | | | - Raul Manhães-de-Castro
- Studies in Nutrition and Phenotypic Plasticity, Department of Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil
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2
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Vidal R, Diaz A, Pazos A, Castro E. Region-specific regulation of 5-HT1B receptors in the rat brain by chronic venlafaxine treatment. Psychopharmacology (Berl) 2013; 229:177-85. [PMID: 23609771 DOI: 10.1007/s00213-013-3104-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 03/26/2013] [Indexed: 11/29/2022]
Abstract
RATIONALE Venlafaxine is a non-selective serotonin and noradrenaline reuptake inhibitor antidepressant drug for which clinical studies have suggested a high level efficacy and a possible early action onset compared to the classical antidepressants. Its therapeutic effects might be due, at least in part, to adaptive changes in serotonergic neurotransmission, through the activation of the different 5-HT receptor subtypes. 5-HT(1B) receptors are located in the axon terminals of both serotonergic and non-serotonergic neurons, where they act as inhibitory autoreceptors or heteroreceptors, respectively. However, the information about the involvement of this subtype in the mechanism of action of antidepressants is limited and quite controversial. OBJECTIVES The aim of this study was to evaluate the effect of venlafaxine (10 mg kg⁻¹ day⁻¹, p.o.) after 21 days of treatment on the density of 5-HT(1B) receptors and their functionality in rat brain. METHODS Effects of chronic venlafaxine were evaluated at different levels of 5-HT(1B) receptor by using receptor autoradiography, [³⁵S]GTPγS binding, and the regulation of body temperature induced by selective 5-HT(1B) agonist. RESULTS Our results show that venlafaxine induced an increase in sensitivity of 5-HT(1B) receptors in hypothalamus both at G-protein level and the control of core temperature without affecting the receptor density. CONCLUSIONS These results demonstrate that adaptive changes on 5-HT(1B) receptors induced by chronic administration of venlafaxine exhibit regional differences suggesting that the hypothalamus might be an important site of drug action.
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Affiliation(s)
- R Vidal
- Instituto de Biomedicina y Biotecnología-IBBTEC, UC-CSIC-SODERCAN, Santander, Cantabria, Spain
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3
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Pitychoutis P, Dalla C, Sideris A, Tsonis P, Papadopoulou-Daifoti Z. 5-HT1A, 5-HT2A, and 5-HT2C receptor mRNA modulation by antidepressant treatment in the chronic mild stress model of depression: sex differences exposed. Neuroscience 2012; 210:152-67. [DOI: 10.1016/j.neuroscience.2012.03.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 02/06/2023]
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4
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Pitychoutis PM, Pallis EG, Mikail HG, Papadopoulou-Daifoti Z. Individual differences in novelty-seeking predict differential responses to chronic antidepressant treatment through sex- and phenotype-dependent neurochemical signatures. Behav Brain Res 2011; 223:154-68. [DOI: 10.1016/j.bbr.2011.04.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 04/12/2011] [Accepted: 04/18/2011] [Indexed: 01/05/2023]
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5
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Perroud N, Bondolfi G, Uher R, Gex-Fabry M, Aubry JM, Bertschy G, Malafosse A, Kosel M. Clinical and genetic correlates of suicidal ideation during antidepressant treatment in a depressed outpatient sample. Pharmacogenomics 2011; 12:365-77. [PMID: 21449676 DOI: 10.2217/pgs.10.189] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
AIMS This study investigated clinical and genetic predictors of increasing suicidal ideation during antidepressant treatment. MATERIALS & METHODS A total of 131 depressed outpatients were allocated to four antidepressants (paroxetine, venlafaxine, clomipramine or nefazodone) in a sequential step procedure until remission. Suicidality was assessed using the 10th item of the Montgomery-Asberg Depression Rating Scale (MADRS). A total of 11 candidate genes involved in different mechanisms of antidepressant action were selected for association with increasing suicidality. RESULTS Increasing suicidality correlated with depression severity and higher antidepressant blood levels. Risk of increasing suicidal ideation was higher in subjects taking antidepressants other than paroxetine (odds ratio: 1.11). The strongest genetic predictor was found to be rs1360780 within the FKBP5 gene (p = 2.9 × 10(-5)), followed by 2677G>T in the ABCB1 gene. The rs130058 SNP within the 5-HTR1B gene demonstrated a differential association with increasing suicidal ideation depending on antidepressant type. CONCLUSION Increasing suicidal ideation might be an adverse effect of antidepressants. The involvement of FKBP5 indicates that dysregulation of the hypothalamic-pituitary-adrenal axis is involved in treatment increasing suicidal ideation.
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Affiliation(s)
- Nader Perroud
- Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
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6
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Kokras N, Antoniou K, Dalla C, Bekris S, Xagoraris M, Ovestreet DH, Papadopoulou-Daifoti Z. Sex-related differential response to clomipramine treatment in a rat model of depression. J Psychopharmacol 2009; 23:945-56. [PMID: 18755816 DOI: 10.1177/0269881108095914] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Research in affective disorders is often performed without considering sex differences, although women are predominantly affected. Consequently, the potential sex-dependent action of antidepressants remains elusive. We investigated whether Flinders sensitive line (FSL) of rats, a model of depression, would present sex-differentiated responses to antidepressant treatment. FSL and Sprague-Dawley rats were treated with clomipramine 10 mg/kg/day for 14 days. Subsequently, they were subjected to either a single session of the forced swim test or an estimation of serotonergic function in the prefrontal cortex, hippocampus, amygdala and hypothalamus. Male FSL displayed increased immobility duration, decreased active behaviours, increased serotonin tissue levels and a reduced serotonin turnover rate in most brain areas studied. Female FSL showed a distinct profile, consisting of decreased immobility latency, increased climbing duration, limited serotonergic deviations and no difference in the serotonin turnover rate in comparison with controls. Interestingly, despite baseline differences, clomipramine treatment reversed all relevant behavioural responses and increased the serotonin turnover rate in both sexes. However, the latter effect was remarkably more pronounced in females. It is concluded that, in this animal model of depression, chronic clomipramine treatment attenuated baseline sex differences in the phenotype while maintaining or intensifying the sex differentiation in the serotonergic endophenotype.
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Affiliation(s)
- N Kokras
- Department of Experimental Pharmacology, Medical School, University of Athens, Athens, Greece
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7
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Cooper JD, Heppert KE, Davies MI, Lunte SM. Evaluation of an osmotic pump for microdialysis sampling in an awake and untethered rat. J Neurosci Methods 2006; 160:269-75. [PMID: 17079021 PMCID: PMC1945051 DOI: 10.1016/j.jneumeth.2006.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 09/09/2006] [Accepted: 09/21/2006] [Indexed: 12/21/2022]
Abstract
The feasibility of using an osmotic pump in place of a syringe pump for microdialysis sampling in rat brain was investigated. The use of an osmotic pump permits the rat to be free from the constraints of the standard tethered system. The in vitro flow rates of a microdialysis syringe pump (set at 10.80 microl/h) and the osmotic pump (pump specifications were 11.35 microl/h) with no probe attached were compared, yielding results of 10.87 microl/h+/-1.7% and 10.95 microl/h+/-8.0%, respectively. The average of four flow rate experiments in vivo yielded R.S.D.s less than 10% and an average flow rate of 11.1 microl/h. Following the flow rate studies, in vivo sampling of neurotransmitters was accomplished with the osmotic pump coupled to a microdialysis probe implanted in the brain. Finally, after determination of basal levels of 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindole-3-acetic acid (5-HIAA) in the rats, the rats were dosed with benserazide followed by l-3,4-dihydroxyphenylalanine (l-DOPA). The results from the dosing study showed at least a 10-fold increase in compounds in the l-DOPA metabolic pathway (DOPAC and HVA) and a slight or no increase in 5-HIAA (serotonin metabolic pathway.) These results indicate that the osmotic pump is a viable alternative to the syringe pump for use in microdialysis sampling.
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Affiliation(s)
- Joshua D Cooper
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, KS 66047, USA
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8
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Lechin F, van der Dijs B, Hernández-Adrián G. Dorsal raphe vs. median raphe serotonergic antagonism. Anatomical, physiological, behavioral, neuroendocrinological, neuropharmacological and clinical evidences: relevance for neuropharmacological therapy. Prog Neuropsychopharmacol Biol Psychiatry 2006; 30:565-85. [PMID: 16436311 DOI: 10.1016/j.pnpbp.2005.11.025] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/30/2005] [Indexed: 01/28/2023]
Abstract
Monoaminergic neurons located in the central nervous system (CNS) are organized into complex circuits which include noradrenergic (NA), adrenergic (Ad), dopaminergic (DA), serotonergic (5-HT), histaminergic (H), GABA-ergic and glutamatergic systems. Most of these circuits are composed of more than one and often several types of the above neurons. Such physiologically flexible circuits respond appropriately to both external and internal stimuli which, if not modulated adequately, can trigger pathophysiologic responses. A great deal of research has been devoted to mapping the multiple functions of the CNS circuitry, thereby forming the basis for effective neuropharmacological therapeutic approaches. Such lineal strategies that seek to normalize complex and mixed physiological disorders, however, meet only partial therapeutic success and are often followed by undesirable side effects and/or total failure. In light of these, we have worked to develop possible models of CNS circuitry that are less affected by physiological interaction using the models to design more effective therapeutic approaches. In the present review, we cite and present evidence supporting the dorsal raphe versus median raphe serotonergic circuitry as one model of a reliable paradigm, necessary to the clear understanding and therapy of many psychiatric and even non-psychiatric disturbances.
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Affiliation(s)
- Fuad Lechin
- Department of Physiological Sciences, Section of Neurochemical, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas, Venezuela.
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9
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Uphouse L, Hensler JG, Sarkar J, Grossie B. Fluoxetine disrupts food intake and estrous cyclicity in Fischer female rats. Brain Res 2006; 1072:79-90. [PMID: 16423328 DOI: 10.1016/j.brainres.2005.12.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 12/03/2005] [Accepted: 12/06/2005] [Indexed: 10/25/2022]
Abstract
Adult, regularly cycling female Fischer rats were injected daily with 10 mg/kg fluoxetine for 12-23 days. In the first experiment, body weight and vaginal smears were monitored daily. Fluoxetine treatment reduced body weight within the first 24 h of treatment. Fluoxetine treatment also elongated the estrous cycle, reduced blood levels of progesterone, and eliminated lordosis behavior. In the second experiment, body weight and food intake were examined and a pair-fed group was included to determine if fluoxetine-induced anorexia contributed to the disturbance of the estrous cycle. In pair-fed rats, effects similar to fluoxetine treatment were present. These results lead to the suggestion that fluoxetine's anorectic properties could disrupt the female's normal endocrine cyclicity and that this disruption could be relevant to the reduction in sexual behavior and motivation. However, when the duration of fluoxetine treatment was extended beyond 16 to 17 days, fluoxetine-treated female rats reinitiated vaginal cyclicity and showed evidence of normal sexual receptivity. In contrast, the estrous cycles of their pair-fed counterparts remained disrupted. Thus, restricted food intake appears to contribute to the disruption of the estrous cycle and elimination of sexual receptivity during fluoxetine treatment. However, compensatory changes in the serotonergic system that are associated with chronic fluoxetine administration may contribute to the gradual recovery of estrous cyclicity and sexual receptivity of the fluoxetine-treated animals.
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Affiliation(s)
- Lynda Uphouse
- Department of Biology, Texas Woman's University, Denton, TX 76204, USA.
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10
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Pitchot W, Hansenne M, Pinto E, Reggers J, Fuchs S, Ansseau M. 5-Hydroxytryptamine 1A receptors, major depression, and suicidal behavior. Biol Psychiatry 2005; 58:854-8. [PMID: 16139805 DOI: 10.1016/j.biopsych.2005.05.042] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 05/17/2005] [Accepted: 05/27/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND Several lines of evidence suggest a clear relationship between serotonin (5-hydroxytryptamine, 5-HT) hypoactivity and suicidal behavior across several psychiatric diagnoses. Few data are available, however, regarding the possible specific role of 5-HT1A receptors in the biology of suicidality. Therefore, the aim of our study was to use a neuroendocrine strategy to test the hypothesis of a role for 5-HT1A receptors in the biology of suicidal behavior. METHODS Hormonal (adrenocorticotropic hormone [ACTH], cortisol, prolactin [PRL]) and temperature responses after administration of flesinoxan, a highly potent and selective 5-HT1A receptor full agonist, were assessed in 40 inpatients with major depression, divided into two subgroups (20 suicide attempters and 20 nonattempters), compared with 20 normal control subjects matched for gender and age. RESULTS Compared with nonattempters, suicide attempters exhibited significantly lower PRL (p = .01), cortisol (p = .014), and temperature (p = .0002) responses. Prolactin (p = .007), cortisol (p = .04), and temperature (p = .00003) responses were also decreased in suicide attempters compared with normal control subjects. In contrast, we did not observe any significant differences in hormonal or temperature responses to flesinoxan between depressed patients without a history of suicide attempt and normal control subjects. CONCLUSIONS The present study tends to confirm the role of 5-HT and more specifically 5-HT1A receptors in the biology of suicidal behavior in major depression.
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Affiliation(s)
- William Pitchot
- Psychiatric Unit, Centre Hospitalier Universitaire Sart Tilman, Liège, Belgium.
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11
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Hsieh YS, Yang SF, Kuo DY. Amphetamine, an appetite suppressant, decreases neuropeptide Y immunoreactivity in rat hypothalamic paraventriculum. ACTA ACUST UNITED AC 2005; 127:169-76. [PMID: 15680483 DOI: 10.1016/j.regpep.2004.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 11/10/2004] [Accepted: 11/18/2004] [Indexed: 11/17/2022]
Abstract
Amphetamine (AMPH) is a well-known anorectic agent. The mechanism underlying the anorectic response of AMPH has been attributed to its inhibitory effect on hypothalamic neuropeptide Y (NPY), an orexigenic peptide in the brain. However, there is still lack of genomic or in situ immunohistochemical evidence to prove it. The present study was aimed to assess the molecular mechanism of AMPH anorexia by immunostaining of hypothalamic NPY protein in the area of paraventricular nucleus (PVN) and by detecting the change of hypothalamic NPY mRNA level using RT-PCR. Results revealed that an AMPH treatment might reduce the expression of NPY at both transcriptional and posttranslational levels. Comparatively, a treatment of clomipramine, a serotonin transporter inhibitor, was unable to reduce NPY mRNA level, revealing the noninvolvement of hypothalamic NPY gene in serotonin anorexia. Our results provided genomic and in situ immunohistochemical evidence to confirm the mediation of hypothalamic NPY neurons in the anorectic action of AMPH.
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Affiliation(s)
- Yih-Shou Hsieh
- Institute of Biochemistry, Chung Shan Medical University, Taichung 40201, Taiwan
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12
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Greenwood BN, Foley TE, Day HEW, Burhans D, Brooks L, Campeau S, Fleshner M. Wheel running alters serotonin (5-HT) transporter, 5-HT1A, 5-HT1B, and alpha 1b-adrenergic receptor mRNA in the rat raphe nuclei. Biol Psychiatry 2005; 57:559-68. [PMID: 15737672 DOI: 10.1016/j.biopsych.2004.11.025] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 09/03/2004] [Accepted: 11/16/2004] [Indexed: 10/25/2022]
Abstract
BACKGROUND Altered serotonergic (5-HT) neurotransmission is implicated in the antidepressant and anxiolytic properties of physical activity. In the current study, we investigated whether physical activity alters factors involved in the regulation of central 5-HT neural activity. METHODS In situ hybridization was used to quantify levels of 5-HT transporter (5-HTT), 5-HT(1A), 5-HT(1B), and alpha(1b)-adrenergic receptor (alpha(1b) ADR) messenger ribonucleic acids (mRNAs) in the dorsal (DRN) and median raphe (MR) nuclei of male Fischer rats after either sedentary housing or 3 days, 3 weeks, or 6 weeks of wheel running. RESULTS Wheel running produced a rapid and lasting reduction of 5-HT(1B) mRNA in the ventral DRN. Three weeks of wheel running decreased 5-HTT mRNA in the DRN and MR and increased alpha(1b) ADR mRNA in the DRN. After 6 weeks of wheel running, 5-HTT mRNA remained reduced, but alpha(1b) ADR mRNA returned to sedentary levels. Serotonin(1A) mRNA was increased in the MR and certain DRN subregions after 6 weeks only. CONCLUSIONS Data suggest that the central 5-HT system is sensitive to wheel running in a time-dependent manner. The observed changes in mRNA regulation in a subset of raphe nuclei might contribute to the stress resistance produced by wheel running and the antidepressant and anxiolytic effects of physical activity.
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MESH Headings
- Analysis of Variance
- Animals
- Behavior, Animal
- Body Weight/physiology
- Gene Expression Regulation/physiology
- In Situ Hybridization/methods
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Motor Activity/physiology
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- RNA, Messenger/metabolism
- Raphe Nuclei/anatomy & histology
- Raphe Nuclei/metabolism
- Rats
- Rats, Inbred F344
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT1B/genetics
- Receptor, Serotonin, 5-HT1B/metabolism
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/metabolism
- Running
- Serotonin Plasma Membrane Transport Proteins
- Time Factors
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Affiliation(s)
- Benjamin N Greenwood
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado 80309-0354, USA
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13
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Andersen SL, Navalta CP. Altering the course of neurodevelopment: a framework for understanding the enduring effects of psychotropic drugs. Int J Dev Neurosci 2004; 22:423-40. [PMID: 15380841 DOI: 10.1016/j.ijdevneu.2004.06.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 06/07/2004] [Accepted: 06/07/2004] [Indexed: 12/13/2022] Open
Abstract
Childhood is a time filled with wondrous changes, as brain plasticity permits experiences to shape the immature brain to meet the demands of the environment. Change occurs at various levels--from neuroanatomy, including within a given region and its connectivity to other regions, to the function of neurotransmitter systems and their reactivity to pharmacological agents in the short- and long-term. The nature and degree to which drug exposure influences the final adult topography is influenced greatly by the maturational phase of these critical factors. Moreover, evidence is slowly emerging that suggests that the long-term effects of drug exposure are delayed and expressed once the vulnerable system reaches maturation (i.e., typically during adulthood). This phenomenon is known as neuronal imprinting and occurs when the effects of drug exposure outlast the drug itself. Thus, understanding the persistent effects critically depends on the window of observation. Embracing this concept should influence how we conduct preclinical assessments of developmental drug exposure, and ultimately how we conduct clinical assessments of drug efficacy, effectiveness, and safety for the treatment of childhood psychiatric disorders. In this article, we present a model to provide a heuristic framework for making predictions about imprinted effects of childhood drug exposure. We then review epidemiological data on attention deficit hyperactivity disorder (ADHD) and childhood depression, prescription practices, and what is known regarding the long-term consequences of drug exposure in these populations. We conclude with a discussion of the current status of preclinical studies on juvenile stimulant exposure.
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Affiliation(s)
- Susan L Andersen
- Department of Psychiatry, McLean Hospital and Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA.
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14
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Tatarczyńska E, Kłodzińska A, Stachowicz K, Chojnacka-Wójcik E. Effects of a selective 5-HT1B receptor agonist and antagonists in animal models of anxiety and depression. Behav Pharmacol 2004; 15:523-34. [PMID: 15577451 DOI: 10.1097/00008877-200412000-00001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The purpose of the present study was to investigate the effects of the selective 5-HT1B receptor agonist CP 94253, the selective 5-HT1B receptor antagonist SB 216641, and the 5-HT1B/1D receptor antagonist GR 127935 in behavioral tests commonly used to predict anxiolytic- and antidepressant-like activity. Diazepam and imipramine were used as reference drugs. In the Vogel conflict drinking test, CP 94253 (1.25-5 mg/kg), SB 216641 (2.5-5 mg/kg) and GR 127935 (5-10 mg/kg) showed anxiolytic-like effects comparable to that of diazepam (2.5-5 mg/kg). In the elevated plus-maze test, antianxiety-like activity of all the compounds tested was also observed: the effects of CP 94253 (2.5 mg/kg) and SB 216641 (5 mg/kg) were similar to that of diazepam (5 mg/kg), while GR 127935 (up to 40 mg/kg) was less active. In the four-plate test, the compounds tested (5-10 mg/kg) produced anxiolytic-like effects which were weaker than that of diazepam (2.5-5 mg/kg). In the forced swimming test, CP 94253 (5-10 mg/kg), like imipramine (30 mg/kg), showed anti-immobility action, whereas SB 216641 (2.5-10 mg/kg) and GR 127935 (20-40 mg/kg) did not affect the immobility time in mice. The results indicate that the selective agonist (CP 94253) and antagonists (SB 216641 and GR 127935) of 5-HT1B receptors produce effects that are characteristic of anxiolytics, in the preclinical models used; however, CP 94253 also behaves like an antidepressant drug.
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Affiliation(s)
- E Tatarczyńska
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smêtna Street, 31-343 Kraków, Poland.
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15
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Lifschytz T, Gur E, Lerer B, Newman ME. Effects of triiodothyronine and fluoxetine on 5-HT1A and 5-HT1B autoreceptor activity in rat brain: regional differences. J Neurosci Methods 2004; 140:133-9. [PMID: 15589343 DOI: 10.1016/j.jneumeth.2004.03.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2003] [Accepted: 03/18/2004] [Indexed: 11/16/2022]
Abstract
The thyroid hormone triiodothyronine (T3) augments and accelerates the effects of antidepressant drugs. Although the majority of studies showing this have used tricyclics, a few studies have shown similar effects with the selective serotonin re-uptake inhibitor (SSRI) fluoxetine. In this study we investigated the effects of fluoxetine (5 mg/kg), T3 (20 microg/kg) and the combination of these drugs, each administered daily for 7 days, on serotonergic function in the rat brain, using in vivo microdialysis. Fluoxetine alone induced a trend towards desensitization of 5-HT1A autoreceptors as shown by a reduction in the effect of 8-OH-DPAT to lower 5-HT levels in frontal cortex, and desensitized 5-HT1B autoreceptors in frontal cortex. The combination of fluoxetine and T3 induced desensitization of 5-HT1B autoreceptors in hypothalamus. Since there is evidence linking hypothalamic function and depression, we suggest that this effect may partly account for the therapeutic efficacy of the combination of an SSRI and T3.
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MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology
- Animals
- Autoreceptors/drug effects
- Autoreceptors/metabolism
- Brain/drug effects
- Brain/metabolism
- Brain Chemistry/drug effects
- Brain Chemistry/physiology
- Depressive Disorder/drug therapy
- Depressive Disorder/metabolism
- Depressive Disorder/physiopathology
- Down-Regulation/drug effects
- Down-Regulation/physiology
- Drug Synergism
- Drug Therapy, Combination
- Fluoxetine/pharmacology
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Male
- Microdialysis/instrumentation
- Microdialysis/methods
- Neurochemistry/instrumentation
- Neurochemistry/methods
- Prefrontal Cortex/drug effects
- Prefrontal Cortex/metabolism
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT1A/drug effects
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT1B/drug effects
- Receptor, Serotonin, 5-HT1B/metabolism
- Serotonin/metabolism
- Selective Serotonin Reuptake Inhibitors/pharmacology
- Triiodothyronine/metabolism
- Triiodothyronine/pharmacology
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Affiliation(s)
- Tzuri Lifschytz
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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16
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Gur E, Lifschytz T, Van De Kar LD, Lerer B, Newman ME. Effects of triiodothyronine on 5-HT(1A) and 5-HT(1B) autoreceptor activity, and postsynaptic 5-HT(1A) receptor activity, in rat hypothalamus: lack of interaction with imipramine. Psychoneuroendocrinology 2004; 29:1172-83. [PMID: 15219641 DOI: 10.1016/j.psyneuen.2004.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Revised: 10/23/2003] [Accepted: 01/26/2004] [Indexed: 10/26/2022]
Abstract
Triiodothyronine (T3) is effective in both augmenting and accelerating the therapeutic response to antidepressant drugs, especially tricyclics, and there is evidence from both human and animal studies that it acts on serotonergic neurotransmission. In this work we examined the effects of T3 alone and together with imipramine on 5-HT levels in the hypothalamus and on 5-HT(1A) and 5-HT(1B) autoreceptor sensitivity, using in vivo microdialysis in the rat. The effects of T3 on postsynaptic 5-HT(1A) receptor activity in the hypothalamus were also determined using a neuroendocrine challenge procedure. T3 administered daily at 20 microg/kg s.c. for 2 weeks reduced the sensitivity of 5-HT(1A) autoreceptors which control 5-HT release, as measured by the effect of 8-OH-DPAT to decrease 5-HT in the hypothalamus, and also the sensitivity of hypothalamic 5-HT(1B) receptors as measured by the effect of the 5-HT(1B) receptor agonist CP 93129 to decrease 5-HT release. Imipramine at 10 mg/kg daily for 4 weeks by osmotic minipump reduced 5-HT(1A) autoreceptor activity, as measured by the effect of 8-OH-DPAT in the hypothalamus, but the combination of T3 and imipramine given for 2 weeks did not affect either 5-HT(1A) or 5-HT(1B) autoreceptor activity. T3 at 20 microg/kg s.c. given daily for 1 week also reduced the sensitivity of postsynaptic 5-HT(1A) receptors in the hypothalamus, as measured by injection of 8-OH-DPAT and determination of the plasma ACTH and corticosterone responses. Animals which received T3 for 7 days showed a dose-dependent reduction in plasma free T4 levels but no change in total T3 levels. We conclude that while T3 alone affects both presynaptic and postsynaptic components of the serotonergic system, these effects may not be responsible for the therapeutic acceleration action seen with a combination of a tricyclic drug and T3.
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MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology
- Adrenocorticotropic Hormone/metabolism
- Analysis of Variance
- Animals
- Antidepressive Agents, Tricyclic/pharmacology
- Autoreceptors/drug effects
- Autoreceptors/metabolism
- Corticosterone/metabolism
- Drug Interactions
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Imipramine/pharmacology
- Male
- Microdialysis
- Microinjections
- Rats
- Rats, Inbred Strains
- Receptor, Serotonin, 5-HT1A/drug effects
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT1B/drug effects
- Receptor, Serotonin, 5-HT1B/metabolism
- Serotonin Receptor Agonists/pharmacology
- Synaptic Transmission/drug effects
- Triiodothyronine/administration & dosage
- Triiodothyronine/physiology
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Affiliation(s)
- Eitan Gur
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, P.O. Box 12000, 91120 Jerusalem, Israel
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17
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Hanoun N, Mocaër E, Boyer PA, Hamon M, Lanfumey L. Differential effects of the novel antidepressant agomelatine (S 20098) versus fluoxetine on 5-HT1A receptors in the rat brain. Neuropharmacology 2004; 47:515-26. [PMID: 15380370 DOI: 10.1016/j.neuropharm.2004.06.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Revised: 05/07/2004] [Accepted: 05/28/2004] [Indexed: 10/26/2022]
Abstract
Agomelatine (S 20098) is a novel antidepressant drug with melatonin receptor agonist and 5-HT(2C) receptor antagonist properties, but actual mechanisms underlying its antidepressant action are unknown. Because functional desensitization of 5-HT(1A) autoreceptors in the dorsal raphe nucleus (DRN) occurs after chronic administration of several classes of antidepressants, we investigated whether this adaptive change could also be induced by agomelatine. Neither acute nor chronic treatment with agomelatine (10 mg/kg i.p. for 14 days or 50 mg/kg i.p. for 21 days) changed the density of 5-HT(1A) receptors and their coupling with G proteins in the DRN and the hippocampus in rats. Moreover, these treatments did not affect the basal electrophysiological characteristics and the responses to 5-HT(1A) receptor stimulation of DRN and hippocampal neurons in brain slices. Parallel experiments with melatonin (10 mg/kg i.p. for 14 days) and fluoxetine (5 mg/kg i.p. for 14 days) as reference compounds showed that the former was unable to affect 5-HT(1A) receptors whereas the latter decreased both the 5-HT(1A) receptor-mediated [(35)S]GTP-gamma-S binding and the potency of ipsapirone, a 5-HT(1A) receptor agonist, to inhibit neuronal firing in the DRN. These data indicate that the antidepressant action of agomelatine is not mediated through the same mechanisms as SSRIs or tricyclics.
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Affiliation(s)
- Naïma Hanoun
- INSERM U288, Neuropsychopharmacologie Moléculaire, Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, 91 Boulevard de l'Hôpital, 75634 Paris Cedex 13, France
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18
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Newman ME, Shalom G, Ran A, Gur E, Van de Kar LD. Chronic fluoxetine-induced desensitization of 5-HT1A and 5-HT1B autoreceptors: regional differences and effects of WAY-100635. Eur J Pharmacol 2004; 486:25-30. [PMID: 14751404 DOI: 10.1016/j.ejphar.2003.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Desensitization of 5-HT(1A) and 5-HT(1B) autoreceptors is thought to be the mechanism underlying the therapeutic effects of fluoxetine and other selective serotonin reuptake inhibitors when these are administered chronically. The blockade of 5-HT(1A) autoreceptors occurring on administration of a selective serotonin reuptake inhibitor together with a 5-HT(1A) autoreceptor antagonist is responsible for the acute increase in 5-hydroxytryptamine (serotonin, 5-HT) levels observed under these circumstances. The effects of repeated administration of selective serotonin reuptake inhibitors together with 5-HT(1A) receptor antagonists have not been widely studied. In this work, we found that the effects of fluoxetine (5 mg/kg, i.p., daily for 12 days) to desensitize 5-HT(1B) autoreceptors in the frontal cortex, as measured by the effect of the locally administered 5-HT(1B) receptor agonist, 3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrolo[3,2-b]pyrid-5-one (CP 93129), and to desensitize 5-HT(1A) autoreceptors as measured by the action of the 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT; 50 microg/kg, s.c.) to reduce 5-HT levels in cortex, were prevented by concomitant administration of the 5-HT(1A) receptor antagonist, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide (WAY-100635; 0.3 mg/kg, s.c.). 5-HT(1B) receptor activity in the hypothalamus, as measured by the effects of locally administered CP 93129, and 5-HT(1A) autoreceptor activity, as determined by the effects of subcutaneous 8-OH-DPAT to reduce 5-HT levels in hypothalamus, were not altered either by fluoxetine alone or by fluoxetine in the presence of WAY-100635. The data suggest that the regulation of extracellular levels of 5-HT in the cortex and hypothalamus is subject to different autoregulatory mechanisms.
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Affiliation(s)
- Michael E Newman
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, PO Box 12000, Jerusalem 91120, Israel.
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19
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Hanley NR, Van de Kar LD. Serotonin and the neuroendocrine regulation of the hypothalamic--pituitary-adrenal axis in health and disease. VITAMINS AND HORMONES 2003; 66:189-255. [PMID: 12852256 DOI: 10.1016/s0083-6729(03)01006-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT)-containing neurons in the midbrain directly innervate corticotropin-releasing hormone (CRH)-containing cells located in paraventricular nucleus of the hypothalamus. Serotonergic inputs into the paraventricular nucleus mediate the release of CRH, leading to the release of adrenocorticotropin, which triggers glucocorticoid secretion from the adrenal cortex. 5-HT1A and 5-HT2A receptors are the main receptors mediating the serotonergic stimulation of the hypothalamic-pituitary-adrenal axis. In turn, both CRH and glucocorticoids have multiple and complex effects on the serotonergic neurons. Therefore, these two systems are interwoven and communicate closely. The intimate relationship between serotonin and the hypothalamic-pituitary-adrenal axis is of great importance in normal physiology such as circadian rhythm and stress, as well as pathophysiological disorders such as depression, anxiety, eating disorders, and chronic fatigue.
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Affiliation(s)
- N R Hanley
- Department of Pharmacology, Center for Serotonin Disorders Research, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
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20
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Dremencov E, Gur E, Lerer B, Newman ME. Effects of chronic antidepressants and electroconvulsive shock on serotonergic neurotransmission in the rat hippocampus. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:729-39. [PMID: 12921903 DOI: 10.1016/s0278-5846(03)00123-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hippocampus may play a critical role in the pathophysiology and treatment of depression. There are two main lines of evidence for this: firstly, many of its functions correspond to those altered in depression, and secondly, many hippocampal functions are regulated by the serotonergic (5-HT) system, which is a common target of antidepressant treatments. Chronic effects of antidepressants and electroconvulsive shock (ECS) have been studied by various methods using electrophysiology, in vivo microdialysis or ex vivo neurochemical measurements. The aim of the current review is to point out possible correlations between these studies based on different methods and to suggest neurochemical mechanisms that result in the observed changes in hippocampal physiology and neurogenesis. These changes in hippocampal neurochemistry are reviewed and compared with the abnormalities associated with stress, corticosterone or depression.
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Affiliation(s)
- Eliyahu Dremencov
- Life Sciences Faculty, Bar-Ilan University, Ramat-Gan 52900, Israel.
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21
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de Groote L, Klompmakers AA, Olivier B, Westenberg HGM. Role of extracellular serotonin levels in the effect of 5-HT1B receptor blockade. Psychopharmacology (Berl) 2003; 167:153-8. [PMID: 12644890 DOI: 10.1007/s00213-002-1371-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Accepted: 11/25/2002] [Indexed: 11/25/2022]
Abstract
The release of serotonin (5-HT) at serotonergic nerve terminals is regulated by 5-HT(1B) autoreceptors. Several studies have reported that the effects of selective 5-HT reuptake inhibitors (SSRIs) on extracellular 5-HT are augmented by 5-HT(1B) receptor antagonists, whereas administration of these antagonists alone do not enhance 5-HT levels. It has been suggested that 5-HT(1B) receptors have low basal endogenous activity and therefore elevated endogenous 5-HT levels are needed to elicit an effect of 5-HT(1B) receptor antagonists. To test this hypothesis, different strategies were used to enhance 5-HT levels in the rat frontal cortex to assess the effects of locally applied NAS-181, a new selective 5-HT(1B) receptor antagonist. Blockade of 5-HT(1B) receptors with NAS-181 dose dependently augmented 5-HT levels when 5-HT levels were enhanced by a SSRI. No additional effect of NAS-181 on 5-HT output was found when 5-HT levels were enhanced by KCl depolarization-induced release or by preventing degradation of 5-HT with the monoamine oxidase inhibitor pargyline. In the presence of fluvoxamine, the increased 5-HT release evoked by KCl depolarization was augmented by NAS-181, supporting the idea that blockade of 5-HT transporters is necessary to measure an effect of 5-HT(1B) receptor blockade. In conclusion, the results provide circumstantial evidence that the effect of a 5-HT(1B) receptor antagonist depends on extracellular 5-HT levels, but strongly suggest that additional 5-HT reuptake inhibition is required to detect any effect of 5-HT(1B) receptor antagonist on 5-HT levels by in vivo microdialysis.
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Affiliation(s)
- Lotte de Groote
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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22
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Fernández-Guasti A, Ulloa RE, Nicolini H. Age differences in the sensitivity to clomipramine in an animal model of obsessive-compulsive disorder. Psychopharmacology (Berl) 2003; 166:195-201. [PMID: 12589517 DOI: 10.1007/s00213-002-1301-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2001] [Accepted: 10/05/2002] [Indexed: 10/20/2022]
Abstract
RATIONALE Subtypes of obsessive-compulsive disorder (OCD) related to age could determine differential response to treatment. OBJECTIVES To explore possible age differences in the effect of clomipramine in an animal model of OCD. METHODS The deficits on spontaneous alternation produced by 8-OH-DPAT and the preventing actions of clomipramine, desipramine and WAY 100635 were compared between young and adult rats. RESULTS No age differences were found in spontaneous alternation. The 5-HT(1A) agonist, 8-OH-DPAT (0.031, 0.125, 0.5 and 2.0 mg/kg, -15 min) produced perseveration in young and adult rats. However, young rats were sensitive to a lower dose of 8-OH-DPAT. Clomipramine (10 mg/kg per three administrations) completely prevented the action of 8-OH-DPAT (0.5 mg/kg) in adult rats. However, this treatment as well as higher doses (15 mg/kg 3 administrations) or injected for longer periods (10 mg/kg 5 administrations) produced weak protective effects (versus 0.125 mg/kg 8-OH-DPAT) or had no action (versus 0.5 mg/kg 8-OH-DPAT) in young animals. WAY 100 635 (0.5 mg/kg) blocked the action of 8-OH-DPAT (0.5 mg/kg) in both young and adult rats. Desipramine (10 mg/kg/3 administrations) lacked of a preventive effect on the 8-OH-DPAT (0.5 mg/kg) action. This result indicated that the 5-HT(1A) receptor is involved in the deficits on spontaneous alternation produced by 8-OH-DPAT. CONCLUSIONS The present data shows important age differences in the effect of clomipramine in a model of OCD. Such differences could be relevant for the age variations in the response to treatment in clinical practice.
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Affiliation(s)
- A Fernández-Guasti
- Departamento de Farmacobiología, Centro de Investigación y Estudios Avanzados, Calz. De los Tenorios 235, Col. Granjas Coapa, 14330, México D.F., México.
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23
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Castro ME, Diaz A, del Olmo E, Pazos A. Chronic fluoxetine induces opposite changes in G protein coupling at pre and postsynaptic 5-HT1A receptors in rat brain. Neuropharmacology 2003; 44:93-101. [PMID: 12559126 DOI: 10.1016/s0028-3908(02)00340-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chronic treatment with the antidepressant fluoxetine may lead to changes in the properties of pre- and postsynaptic 5-HT(1A) receptors due to modifications in the receptor-G protein coupling process. We have evaluated, in rats, the effect of chronic fluoxetine (10 mg/kg/day) at brain 5-HT(1A) receptors using different techniques. The density of 5-HT(1A) receptors was unchanged in fluoxetine-treated rats vs. vehicle group. Stimulation of [(35)S]GTPgammaS binding induced by (+/-)8-OH-DPAT was significantly attenuated in dorsal raphe nucleus after fluoxetine (+3.7 vs. +31.2% in vehicle). The inhibition of dorsal raphe firing by (+/-)8-OH-DPAT (ED(50) in vehicle = 2.1 microg/kg, i.v.) was also attenuated in rats treated with fluoxetine (ED(50)=4.7 microg/kg). In contrast, a significant increase on (+/-)8-OH-DPAT-induced stimulation of [(35)S]GTPgammaS binding was observed in CA(1) (+53.4 vs.+20.2% in vehicle) and dentate gyrus (+105.7 vs. +52.6% in vehicle) but not in entorhinal cortex. Our data demonstrate that fluoxetine-induced desensitization of 5-HT(1A) autoreceptors occurs at G protein level. Moreover, a relevant finding is the region-specific hypersensitivity of postsynaptic 5-HT(1A) receptors, in the hippocampus but not in entorhinal cortex, following chronic fluoxetine. These differential adaptive changes in brain 5-HT(1A) receptors could underlie the mechanism of action of antidepressants and also contribute to their clinical effects.
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Affiliation(s)
- M Elena Castro
- Department of Physiology and Pharmacology, School of Medicine, Cardenal Herrera Oria s/n, University of Cantabria, 39011 Santander, Cantabria, Spain
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24
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Gur E, Dremencov E, Garcia F, Van de Kar LD, Lerer B, Newman ME. Functional effects of chronic electroconvulsive shock on serotonergic 5-HT(1A) and 5-HT(1B) receptor activity in rat hippocampus and hypothalamus. Brain Res 2002; 952:52-60. [PMID: 12363404 DOI: 10.1016/s0006-8993(02)03193-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aims of this work were to determine the influence of chronic electroconvulsive shock (ECS) on presynaptic 5-HT(1A) receptor function, postsynaptic 5-HT(1A) receptor function in hippocampus and hypothalamus, and presynaptic 5-HT(1B) receptor function in hippocampus and hypothalamus. This represents part of an on-going study of the effects of ECS on serotonergic receptor activity in selected brain areas which may be relevant to the effects of electroconvulsive therapy (ECT) in humans. Chronic ECS reduced the ability of the 5-HT(1A) receptor agonist 8-hydroxy-2(di-n-propylamino)tetraline (8-OH-DPAT) (0.2 mg/kg s.c.) to decrease 5-HT levels in hypothalamus as shown by in vivo microdialysis, indicative of a reduction in sensitivity of presynaptic 5-HT(1A) autoreceptors. The ability of the 5-HT(1B) receptor antagonist GR 127935 (5 mg/kg s.c.) to increase 5-HT levels in both hippocampus and hypothalamus was unaffected by chronic ECS. 8-OH-DPAT (0.2 mg/kg s.c.) increased cyclic AMP levels in hippocampus measured by in vivo microdialysis approximately 2-fold. The degree of stimulation of cyclic AMP formation was not altered by chronic ECS. However the cyclic AMP response to forskolin (50 micro M) administered via the microdialysis probe, which was approximately 4-fold of basal in sham-treated rats, was almost completely abolished in ECS-treated rats. Since this indicates that either adenylate cyclase catalytic unit activity or Gs protein activity is reduced in the hippocampus after chronic ECS, the lack of change in 8-OH-DPAT-induced cyclic AMP formation may be taken as possible evidence of an increase in sensitivity of postsynaptic 5-HT(1A) receptors in the hippocampus by chronic ECS. Chronic ECS increased basal plasma levels of corticosterone, ACTH and oxytocin. The ACTH response to s.c. injections of 0.2 mg/kg or 0.5 mg/kg 8-OH-DPAT was reduced by chronic ECS. Postsynaptic 5-HT(1A) receptor activity in the hypothalamus, in contrast to the hippocampus, thus appears to be desensitized after chronic ECS. We conclude that chronic ECS has regionally specific effects on both pre- and post-synaptic 5-HT(1A) receptors, but, in contrast to some antidepressant drugs, does not affect presynaptic 5-HT(1B) receptor activity.
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Affiliation(s)
- Eitan Gur
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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25
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Dremencov E, Gur E, Lerer B, Newman ME. Effects of chronic antidepressants and electroconvulsive shock on serotonergic neurotransmission in the rat hypothalamus. Prog Neuropsychopharmacol Biol Psychiatry 2002; 26:1029-34. [PMID: 12452522 DOI: 10.1016/s0278-5846(02)00227-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The hypothalamus may play a critical role in the pathophysiology and treatment of depression. There are two main lines of evidence for this: firstly, many of its functions correspond to those altered in depression; and secondly, many hypothalamic functions are regulated by the serotonergic system, which is a common target of antidepressant treatments. In keeping with observations from other laboratories, we have found that chronic antidepressants and electroconvulsive shock increase serotonergic neurotransmission in the rat hypothalamus by inducing desensitization of presynaptic autoreceptors. We have also found that chronic hypercorticosolemia, which constitutes a model of depression, has an opposite effect. We postulate that presynaptic autoregulation of serotonergic neurotransmission in the hypothalamus may play a critical role in the pathophysiology and treatment of depression.
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Affiliation(s)
- Eliyahu Dremencov
- Life Sciences Faculty, Bar-Ilan University, Ramat Gan 52900, Israel.
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26
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De Groote L, Olivier B, Westenberg HGM. The effects of selective serotonin reuptake inhibitors on extracellular 5-HT levels in the hippocampus of 5-HT(1B) receptor knockout mice. Eur J Pharmacol 2002; 439:93-100. [PMID: 11937097 DOI: 10.1016/s0014-2999(02)01417-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of two selective serotonin reuptake inhibitors on 5-hydroxy-tryptamine (5-HT) in the hippocampus were studied in wildtype and in 5-HT(1B) receptor knockout mice using in vivo microdialysis. Basal 5-HT levels in the hippocampus were not different between the two genotypes. The functional absence of 5-HT(1B) receptors was examined in the knockout mice by local infusion of the 5-HT(1B) receptor agonist, 1,4-Dihydro-3-(1,2,3,6-tetrahydro-4-pyridinyl)-5H-pyrrolo[3,2-b]pyridin-5-one (CP93129) into the hippocampus. CP93129 (1 microM) decreased 5-HT levels in wildtype mice, but not in 5-HT(1B) knockout mice. Systemic administration of the selective 5-HT reuptake inhibitor paroxetine (5 mg/kg, i.p.) increased extracellular 5-HT levels. The increase of 5-HT in 5-HT(1B) knockout mice was almost twofold higher than in wildtype mice. Systemic administration of selective 5-HT reuptake inhibitors stimulates both terminal 5-HT(1B) autoreceptors and somatodendritic 5-HT(1A) autoreceptors. Therefore, the selective 5-HT reuptake inhibitor, fluvoxamine, was applied locally into the hippocampus to investigate the role of the terminal 5-HT(1B) autoreceptors. Local administration of 0.3 microM fluvoxamine resulted in comparable increases in extracellular 5-HT in both genotypes, whereas 1.0 microM fluvoxamine produced a twofold greater increase in 5-HT levels in 5-HT(1B) knockout as compared to wildtype mice. In conclusion, the differences in hippocampal 5-HT output between wildtype and 5-HT(1B) knockout mice after local or systemic administration of selective 5-HT reuptake inhibitors show that 5-HT(1B) autoreceptors play a significant role in the inhibition of 5-HT release at serotonergic nerve terminals. In addition, the different dose-response to fluvoxamine suggests that 5-HT(1B) knockout mice have possible adaptations of 5-HT transporters in order to compensate for the loss of the terminal 5-HT(1B) autoreceptor.
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Affiliation(s)
- Lotte De Groote
- Department of Psychiatry, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
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27
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Butterweck V, Böckers T, Korte B, Wittkowski W, Winterhoff H. Long-term effects of St. John's wort and hypericin on monoamine levels in rat hypothalamus and hippocampus. Brain Res 2002; 930:21-9. [PMID: 11879791 DOI: 10.1016/s0006-8993(01)03394-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypericum perforatum L. (St. John's wort) is one of the leading psychotherapeutic phytomedicines and, because of this, great effort has been devoted to clarifying its mechanism of action. Chronic effects of St. John's wort and hypericin, one of its major active compounds, on regional brain amine metabolism have not been reported yet. We used a high-performance liquid chromatography system to examine the effects of short-term (2 weeks) and long-term (8 weeks) administration of imipramine, Hypericum extract or hypericin on regional levels of serotonin (5-HT), norepinephrine, dopamine and their metabolites in the rat brain. We focused our interest on the hypothalamus and hippocampus, as these brain regions are thought to be involved in antidepressant drug action. Imipramine (15 mg/kg, p.o.), Hypericum extract (500 mg/kg, p.o.), and hypericin (0.2 mg/kg, p.o.) given daily for 8 weeks significantly increased 5-HT levels in the hypothalamus (P<0.05). The 5-HT turnover was significantly lowered in both brain regions after 8 weeks of daily treatment with the Hypericum extract (both P<0.05). Consistent changes in catecholamine levels were only detected in hypothalamic tissues after long-term treatment. Comparable to imipramine, Hypericum extract as well as hypericin significantly decreased 3,4-dihydroxyphenylacetic acid and homovanillic acid levels in the hypothalamus (P<0.01). Our data clearly show that long-term, but not short-term administration of St. John's wort and its active constituent hypericin modify levels of neurotransmitters in brain regions involved in the pathophysiology of depression.
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Affiliation(s)
- Veronika Butterweck
- Institute of Pharmacology and Toxicology, Domagkstrasse 12, 48149 Muenster, Germany.
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28
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Gur E, Dremencov E, Van De Kar LD, Lerer B, Newman ME. Effects of chronically administered venlafaxine on 5-HT receptor activity in rat hippocampus and hypothalamus. Eur J Pharmacol 2002; 436:57-65. [PMID: 11834247 DOI: 10.1016/s0014-2999(01)01578-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The effects of chronic administration of the mixed serotonin [5-hydroxytryptamine (5-HT)]/norepinephrine re-uptake inhibitor venlafaxine (5 mg/kg daily by osmotic minipump for 28 days) on the sensitivity of somatodendritic 5-HT(1A) autoreceptors on serotonergic neurons innervating the hypothalamus, and on 5-HT(1B) autoreceptors in both hypothalamus and hippocampus, were determined using in vivo microdialysis in freely moving rats. Venlafaxine induced a reduction in sensitivity of 5-HT(1B) autoreceptors in hypothalamus, but did not affect the sensitivity of 5-HT(1A) autoreceptors, or of 5-HT(1B) autoreceptors in hippocampus. The corticosterone and oxytocin responses to the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.05 or 0.2 mg/kg), a measure of postsynaptic 5-HT(1A) receptor activity in the hypothalamus, were reduced in animals administered 5 or 10 mg/kg venlafaxine daily by intraperitoneal injection for 21 days. This desensitization of post-synaptic 5- HT(1A) receptors in the hypothalamus may be a consequence of increased 5-HT levels induced by desensitization of the presynaptic 5-HT(1B) receptors. These results taken together with those of previous studies suggest that the hypothalamus might be an important site of drug action, and that venlafaxine has an overall mechanism similar to that of selective serotonin re-uptake inhibitors.
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Affiliation(s)
- Eitan Gur
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, PO Box 12000, 91120, Jerusalem, Israel
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Haleem DJ, Saify ZS, Siddiqui S, Batool F, Haleem MA. Pre- and postsynaptic responses to 1-(1-naphthylpiperazine) following adaptation to stress in rats. Prog Neuropsychopharmacol Biol Psychiatry 2002; 26:149-56. [PMID: 11853106 DOI: 10.1016/s0278-5846(01)00240-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In view of a role of pre- and postsynaptic serotonin (5-hydroxytryptamine; 5-HT) receptors in adaptation to stress, effects of 1-(1-naphthylpiperazine) (1-NP) were compared in unrestrained and repeatedly restrained adapted rats. In the first part of the study, effects of various doses (1.0-15 mg/kg ip) of 1-NP were monitored on brain 5-HT metabolism (presynaptic response) and on the activity (postsynaptic response) of rats in an activity cage to which the rats were habituated before the drug administration. The drug injected at doses of 2.5-15.0 mg/kg increased motor activity and decreased brain 5-hydroxyindoleacetic acid (5-HIAA) concentration in a dose-dependent manner. In the second part of the study, rats were restrained on wire grids 2 h/day for 5 days. First-day episode of 2-h restraint decreased 24-h cumulative food intake, water intake and growth rate. The decreases attenuated following second-, third- and fourth-day episodes of 2-h restraint were not observed following fifth-day episode of 2-h restraint stress, suggesting adaptation to the stress schedule has occurred. Serotonergic and motor responses to 1-NP in unrestrained and repeatedly restrained adapted rats were compared by injecting the drug at a dose of 5 mg/kg, a dose that above results suggested would not produce maximal effects on 5-HT metabolism or motor activity. Administration of 1-NP at a dose of 5 mg/kg increased motor activity and decreased brain 5-HIAA concentration in unrestrained and repeatedly restrained adapted rats. Increases of motor activity were much greater in repeatedly restrained adapted than unrestrained rats. Decreases of 5-HIAA concentration were comparable in the two groups. The results are discussed in the context of an increase in the effectiveness of postsynaptic 5-HT-1A and 5-HT-1B receptors and a decrease in the effectiveness of presynaptic 5-HT-1A (somatodendritic) and 5-HT-1B (terminal) receptors following adaptation to stress. It is suggested that these changes of receptor responsiveness might help coping with stress demand to produce adaptation to stress.
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Affiliation(s)
- Darakhshan J Haleem
- Neurochemistry and Biochemical Neuropharmacology Research Laboratory, Department of Biochemistry, University of Karachi, Pakistan
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30
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Pullar IA, Boot JR, Carney SL, Cohen ML, Colvin EM, Conway RG, Hardy CH, Lucaites VL, Nelson DL, Schenck KW, Tomlinson R, Wedley S. In vitro activity of LY393558, an inhibitor of the 5-hydroxytryptamine transporter with 5-HT(1B/1D/2) receptor antagonist properties. Eur J Pharmacol 2001; 432:9-17. [PMID: 11734182 DOI: 10.1016/s0014-2999(01)01468-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1-[2-[4-(6-fluoro-1H-indol-3-yl)-3,6-dihydro-1(2H)-pyridinyl]ethyl]-3-isopropyl-6-(methylsulphonyl)-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide (LY393558) is a potent inhibitor of [3H]5-hydroxytryptamine ([3H]5-HT) uptake into rat cortical synaptosomes (pIC(50)=8.48+/-0.12). It produces a dextral shift of the 5-HT dose-response curves for the binding of GTPgamma[35S] to human 5-HT(1B) (pK(b)=9.05+/-0.14) and 5-HT(1D) (pK(b)=8.98+/-0.07) receptors and inhibits the contractile response of the rabbit saphenous vein to the 5-HT(1B/D) receptor agonist, sumatriptan (pK(b)=8.4+/-0.2). In addition, it is an antagonist at the 5-HT(2A) (pK(i)=7.29+/-0.19) and 5-HT(2B) (pK(i)=7.35+/-0.11) receptors. Presynaptic autoreceptor antagonist activity was demonstrated by its ability to potentiate the K(+)-induced outflow of [3H]5-HT from guinea pig cortical slices (pEC(50)=7.74+/-0.05 nM) in which the 5-HT transporter had been inhibited by a maximally effective concentration of paroxetine. It is concluded that LY393558 should be an effective antidepressant with the potential to produce an earlier onset of efficacy than selective serotonin uptake inhibitors.
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MESH Headings
- Animals
- Binding, Competitive
- Carrier Proteins/antagonists & inhibitors
- Carrier Proteins/metabolism
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Cyclic S-Oxides/metabolism
- Cyclic S-Oxides/pharmacology
- Dose-Response Relationship, Drug
- Drug Synergism
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Humans
- In Vitro Techniques
- Male
- Membrane Glycoproteins/antagonists & inhibitors
- Membrane Glycoproteins/metabolism
- Membrane Transport Proteins
- Mice
- Nerve Tissue Proteins
- Norepinephrine/pharmacokinetics
- Potassium/pharmacology
- Rabbits
- Receptor, Serotonin, 5-HT1B
- Receptor, Serotonin, 5-HT1D
- Receptor, Serotonin, 5-HT2A
- Receptor, Serotonin, 5-HT2B
- Receptor, Serotonin, 5-HT2C
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/metabolism
- Saphenous Vein/drug effects
- Saphenous Vein/physiology
- Serotonin/metabolism
- Serotonin/pharmacokinetics
- Serotonin Antagonists/metabolism
- Serotonin Antagonists/pharmacology
- Serotonin Plasma Membrane Transport Proteins
- Serotonin Receptor Agonists/pharmacology
- Sulfur Radioisotopes
- Sumatriptan/pharmacology
- Thiadiazines/metabolism
- Thiadiazines/pharmacology
- Tritium
- Vasoconstriction/drug effects
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Affiliation(s)
- I A Pullar
- Eli Lilly and Company, Lilly Research Centre Ltd., Erl Wood Manor, Windlesham, GU20 6PH, Surrey, UK.
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Mitchell SN, Greenslade RG, Cooper J. LY393558, a 5-hydroxytryptamine reuptake inhibitor and 5-HT(1B/1D) receptor antagonist: effects on extracellular levels of 5-hydroxytryptamine in the guinea pig and rat. Eur J Pharmacol 2001; 432:19-27. [PMID: 11734183 DOI: 10.1016/s0014-2999(01)01469-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The stimulation of terminal 5-HT(1B/1D) autoreceptors limits the effects of selective serotonin reuptake inhibitors on extracellular levels of 5-hydroxytryptamine (5-HT, serotonin) in vivo. Microdialysis studies show that acute oral administration of LY393558-a 5-HT reuptake inhibitor and antagonist at both the human 5-HT(1B) and 5-HT(1D) receptor-in the dose range 1-20 mg/kg, increases extracellular levels of 5-HT in both the guinea pig hypothalamus and rat frontal cortex. In both species, the levels of 5-HT that were attained were higher than following an acute, maximally effective dose of fluoxetine (20 mg/kg orally), reaching approximately 1500% in the guinea pig hypothalamus and 700% in the rat frontal cortex. In both species, the response to LY393558 (10 mg/kg p.o.) was impulse dependent, being absent in the presence of tetrodotoxin delivered at 1 microM via the microdialysis probe. The sensitivity to tetrodotoxin contrasted with the effects seen with DL-fenfluramine. Studies in rats showed that the microdialysate 5-HT concentration achieved in the frontal cortex after an acute challenge with LY393558 (5 mg/kg p.o.) was significantly greater than following a chronic regime of fluoxetine treatment (10 mg/kg/day orally for 21 days). Moreover, in rats chronically treated with LY393558 (5 mg/kg/day orally for 21 days), the mean basal concentration, 24 h after the final pretreatment dose, was of the same magnitude as that following chronic fluoxetine. However, in contrast to the response seen in fluoxetine-pretreated animals, a challenge dose of LY393558 still elicited a further increase in extracellular 5-HT in LY393558-pretreated animals. LY393558 is a potent 5-HT reuptake inhibitor and 5-HT(1B/1D) receptor antagonist. Microdialysis studies show that acute oral administration increases extracellular levels of 5-HT, by an impulse-dependent mechanism, above those produced by a maximally effective dose of fluoxetine, and in rats to levels only achieved following chronic fluoxetine treatment. Its neurochemical profile in vivo suggests that it may be a more effective antidepressant with the potential for producing an earlier onset of clinical activity than selective serotonin reuptake inhibitors.
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Affiliation(s)
- S N Mitchell
- Eli Lilly and Company Ltd., Lilly Research Centre, Erl Wood Manor, Windlesham, Surrey GU20 6PH, UK.
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Butterweck V, Winterhoff H, Herkenham M. St John's wort, hypericin, and imipramine: a comparative analysis of mRNA levels in brain areas involved in HPA axis control following short-term and long-term administration in normal and stressed rats. Mol Psychiatry 2001; 6:547-64. [PMID: 11526469 DOI: 10.1038/sj.mp.4000937] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2000] [Revised: 03/29/2001] [Accepted: 04/03/2001] [Indexed: 11/08/2022]
Abstract
Clinical studies demonstrate that the antidepressant efficacy of St John's wort (Hypericum) is comparable to that of tricyclic antidepressants such as imipramine. Onset of efficacy of these drugs occurs after several weeks of treatment. Therefore, we used in situhybridization histochemistry to examine in rats the effects of short-term (2 weeks) and long-term (8 weeks) administration of imipramine, Hypericum extract, and hypericin (an active constituent of St John's wort) on the expression of genes that may be involved in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Imipramine (15 mg kg(-1)), Hypericum (500 mg kg(-1)), and hypericin (0.2 mg kg(-1)) given daily by gavage for 8 weeks but not for 2 weeks significantly decreased levels of corticotropin-releasing hormone (CRH) mRNA by 16-22% in the hypothalamic paraventricular nucleus (PVN) and serotonin 5-HT(1A) receptor mRNA by 11-17% in the hippocampus. Only imipramine decreased tyrosine hydroxylase (TH) mRNA levels in the locus coeruleus (by 23%), and only at 8 weeks. The similar delayed effects of the three compounds on gene transcription suggests a shared action on the centers that control HPA axis activity. A second study was performed to assess the effects of long-term imipramine and Hypericum administration on stress-induced changes in gene transcription in stress-responsive circuits. Repeated immobilization stress (2 h daily for 7 days) increased mRNA levels of CRH in the PVN, proopiomelanocortin (POMC) in the anterior pituitary, glutamic acid decarboxylase (GAD 65/67) in the bed nucleus of the stria terminalis (BST), cyclic AMP response element binding protein (CREB) in the hippocampus, and TH in the locus coeruleus. It decreased mRNA levels of 5-HT(1A) and brain-derived neurotrophic factor (BDNF) in the hippocampus. Long-term pre-treatment with either imipramine or Hypericum reduced to control levels the stress-induced increases in gene transcription of GAD in the BST, CREB in the hippocampus, and POMC in the pituitary. The stress-induced increases in mRNA levels of CRH in the PVN and TH in the locus coeruleus were reduced by imipramine but not by Hypericum. The stress-induced decreases in BDNF and 5-HT(1A)mRNA levels were not prevented by either drug. Taken together, these data show: (1) that Hypericum and hypericin have delayed effects on HPA axis control centers similar to those of imipramine; and (2) that select stress-induced changes in gene transcription in particular brain areas can be prevented by long-term treatment with either the prototypic tricyclic antidepressant imipramine or the herbiceutical St John's wort. However, imipramine appears to be more effective in blocking stress effects on the HPA axis than the plant extract.
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MESH Headings
- Adrenal Glands/drug effects
- Adrenal Glands/physiology
- Adrenocorticotropic Hormone/blood
- Animals
- Anthracenes
- Antidepressive Agents/administration & dosage
- Antidepressive Agents/pharmacology
- Arginine Vasopressin/genetics
- Brain/drug effects
- Brain/metabolism
- Brain-Derived Neurotrophic Factor/genetics
- Corticosterone/blood
- Corticotropin-Releasing Hormone/genetics
- Cyclic AMP Response Element-Binding Protein/genetics
- Drug Administration Schedule
- Glutamate Decarboxylase/genetics
- Hippocampus/drug effects
- Hippocampus/metabolism
- Hypericum
- Hypothalamo-Hypophyseal System/drug effects
- Hypothalamo-Hypophyseal System/metabolism
- Imipramine/administration & dosage
- Imipramine/pharmacology
- In Situ Hybridization
- Isoenzymes/genetics
- Locus Coeruleus/drug effects
- Locus Coeruleus/metabolism
- Male
- Paraventricular Hypothalamic Nucleus/drug effects
- Paraventricular Hypothalamic Nucleus/metabolism
- Perylene/administration & dosage
- Perylene/analogs & derivatives
- Perylene/pharmacology
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- Plants, Medicinal
- Pro-Opiomelanocortin/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Serotonin/genetics
- Receptors, Serotonin, 5-HT1
- Reference Values
- Restraint, Physical
- Stress, Psychological/genetics
- Stress, Psychological/metabolism
- Transcription, Genetic/drug effects
- Tyrosine 3-Monooxygenase/genetics
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Affiliation(s)
- V Butterweck
- Institute of Pharmacology and Toxicology, Domagkstrasse 12, 48149 Munster, Germany
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Gur E, Dremencov E, Lerer B, Newman ME. Functional effects of corticosterone on 5-HT(1A) and 5-HT(1B) receptor activity in rat brain: in vivo microdialysis studies. Eur J Pharmacol 2001; 411:115-122. [PMID: 11137865 DOI: 10.1016/s0014-2999(00)00911-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucocorticoid hormones are known to be elevated in depression, and to interact with serotonin 5-HT(1A) receptors at both the presynaptic and postsynaptic levels. Since one of the presumed mechanisms of action of antidepressant drugs is induction of changes in sensitivity of 5-HT(1A) and also 5-HT(1B) receptors, the effects of repeated administration of corticosterone (50 mg/kg s.c. b.i.d. for 10 days) on activities of these receptors were determined using in vivo microdialysis in freely moving rats. Presynaptic 5-HT(1A) receptor activity, as measured by the effect of a challenge dose (0.2 mg/kg s.c.) of the 5-HT(1A) agonist 8-hydroxy-2 (di-n-propylamino) tetralin (8-OH-DPAT) to reduce 5-HT levels in the hypothalamus, was not affected by corticosterone administration. Presynaptic 5-HT(1B) receptor activity, as measured by the effect of the 5-HT(1B) receptor antagonist (N-[4-methoxy-3-(4-methyl-1-piperizinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazole-3-yl)[1,1'-biphenyl]-carboxamide (GR 127935) (5 mg/kg s.c.) to increase 5-HT levels, was increased in hypothalamus but not hippocampus of corticosterone-treated rats. Postsynaptic 5-HT(1A) receptor activity, as measured by the effect of 8-OH-DPAT to increase cyclic AMP levels in the hippocampus, was not affected by corticosterone administration. The decrease in presynaptic 5-HT(1B) receptor activity after chronic administration of antidepressant drugs complements the increases in 5-HT(1B) receptor number observed in animal models of depression.
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Affiliation(s)
- E Gur
- Biological Psychiatry Laboratory, Department of Psychiatry, Hadassah-Hebrew University Medical Center, PO Box 12000, 91120, Jerusalem, Israel
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