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Fernández-Teruel A. From Inhibition of GABA-A Receptor-Mediated Synaptic Transmission by Conventional Antidepressants to Negative Allosteric Modulators of Alpha5-GABA-A Receptors as Putative Fast-Acting Antidepressant Drugs: Closing the Circle? Curr Neuropharmacol 2021; 20:85-89. [PMID: 34736382 PMCID: PMC9199546 DOI: 10.2174/1570159x19666211104144650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 08/18/2021] [Accepted: 10/14/2021] [Indexed: 11/22/2022] Open
Abstract
The present perspective paper shortly and specifically addresses the issues of whether inhibition of GABA-A receptor-mediated synaptic transmission may be involved in antidepressant-like actions and the therapeutic effects of conventional antidepressant (AD) drugs, and whether the recent development of negative allosteric modulators (NAMs) of the alpha5-GABA-A receptor may constitute significant progress in our knowledge on the neurobiology and the treatment of depression.
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Affiliation(s)
- Alberto Fernández-Teruel
- Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193-Bellaterra, Barcelona. Sri Lanka
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2
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Rajkumar R, Dawe GS. OBscure but not OBsolete: Perturbations of the frontal cortex in common between rodent olfactory bulbectomy model and major depression. J Chem Neuroanat 2018; 91:63-100. [DOI: 10.1016/j.jchemneu.2018.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/02/2018] [Accepted: 04/04/2018] [Indexed: 02/08/2023]
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3
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Ghasemi M, Mehranfard N. Mechanisms underlying anticonvulsant and proconvulsant actions of norepinephrine. Neuropharmacology 2018; 137:297-308. [DOI: 10.1016/j.neuropharm.2018.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 01/02/2023]
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4
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Alexander RC. The potential efficacy of GABA B antagonists in depression. Curr Opin Pharmacol 2017; 35:101-104. [PMID: 28807483 DOI: 10.1016/j.coph.2017.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/23/2017] [Indexed: 11/18/2022]
Abstract
Evidence for the potential utility of GABAB antagonists has been assembled from a variety of sources, including clinical experience with the GABAB agonist baclofen, murine genetic GABAB knock-outs, rodent studies of GABAB receptor expression and function following treatment with antidepressant therapies, animal models of depression, and some functional and post mortem data from human subjects. Definitive testing of GABAB antagonists in depression, however, still awaits the development of potent, selective and brain-penetrant compounds for human testing.
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Affiliation(s)
- Robert C Alexander
- Takeda Pharmaceuticals International Co., 40 Landsdowne St., Cambridge, MA 02139, USA.
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5
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Steine IM, Zayats T, Stansberg C, Pallesen S, Mrdalj J, Håvik B, Soulé J, Haavik J, Milde AM, Skrede S, Murison R, Krystal J, Grønli J. Implication of NOTCH1 gene in susceptibility to anxiety and depression among sexual abuse victims. Transl Psychiatry 2016; 6:e977. [PMID: 27959334 PMCID: PMC5290341 DOI: 10.1038/tp.2016.248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 10/17/2016] [Accepted: 10/20/2016] [Indexed: 11/22/2022] Open
Abstract
Sexual abuse contributes to the development of multiple forms of psychopathology, including anxiety and depression, but the extent to which genetics contributes to these disorders among sexual abuse victims remains unclear. In this translational study, we first examined gene expression in the brains of rodents exposed to different early-life conditions (long, brief or no maternal separation). Hypothesizing that genes revealing changes in expression may have relevance for psychiatric symptoms later in life, we examined possible association of those genes with symptoms of anxiety and depression in a human sample of sexual abuse victims. Changes in rodent brain gene expression were evaluated by means of correspondence and significance analyses of microarrays by comparing brains of rodents exposed to different early-life conditions. Tag single-nucleotide polymorphisms (SNPs) of resulting candidate genes were genotyped and tested for their association with symptoms of anxiety and depression (Hospital Anxiety and Depression Scale) in a sample of 361 sexual abuse victims, using multinomial logistic regression. False discovery rate was applied to account for multiple testing in the genetic association study, with q-value of 0.05 accepted as significant. We identified four genes showing differential expression among animals subjected to different early-life conditions as well as having potential relevance to neural development or disorders: Notch1, Gabrr1, Plk5 and Zfp644. In the human sample, significant associations were observed for two NOTCH1 tag SNPs: rs11145770 (OR=2.21, q=0.043) and rs3013302 (OR=2.15, q=0.043). Our overall findings provide preliminary evidence that NOTCH1 may be implicated in the susceptibility to anxiety and depression among sexual abuse victims. The study also underscores the potential importance of animal models for future studies on the health consequences of early-life stress and the mechanisms underlying increased risk for psychiatric disorders.
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Affiliation(s)
- I M Steine
- Department of Psychology, University of California, Berkeley, Berkeley, CA, USA,Department of Clinical Psychology, University of Bergen, Christiesgate 12, 5015 Bergen, Norway. E-mail:
| | - T Zayats
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - C Stansberg
- Dr. Einar Martens Research Group for Biological Psychiatry, Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway,Genomics Core Facility, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - S Pallesen
- Department of Psychosocial Science, University of Bergen, Bergen, Norway,Norwegian Competence Center of Sleep Disorders, Haukeland University Hospital, Bergen, Norway
| | - J Mrdalj
- Norwegian Competence Center of Sleep Disorders, Haukeland University Hospital, Bergen, Norway,Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - B Håvik
- The Norwegian Centre for Mental Disorders Research (NORMENT) and the K.G. Jebsen Centre for Psychosis Research, Department of Clinical Science, Haukeland University Hospital, Bergen, Norway
| | - J Soulé
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway,Department of Biology, University of Bergen, Bergen, Norway
| | - J Haavik
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - A M Milde
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway,Regional Centre for Child and Youth Mental Health and Child Welfare, Bergen, Norway
| | - S Skrede
- The Norwegian Centre for Mental Disorders Research (NORMENT) and the K.G. Jebsen Centre for Psychosis Research, Department of Clinical Science, Haukeland University Hospital, Bergen, Norway
| | - R Murison
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - J Krystal
- Clinical Neuroscience Division, VA National Center for PTSD, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - J Grønli
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway,Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
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6
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Hirose N, Saitoh A, Kamei J. Involvement of glutamatergic N-methyl-d-aspartate receptors in the expression of increased head-dipping behaviors in the hole-board tests of olfactory bulbectomized mice. Behav Brain Res 2016; 312:313-20. [PMID: 27353857 DOI: 10.1016/j.bbr.2016.06.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/21/2016] [Accepted: 06/24/2016] [Indexed: 12/15/2022]
Abstract
Olfactory bulbectomized (OB) mice produce agitated anxiety-like behaviors in the hole-board test, which was expressed by an increase in head-dipping counts and a decrease in head-dipping latencies. However, the associated mechanisms remain unclear. In the present study, MK-801 (10, 100μg/kg), a selective N-methyl-d-aspartate (NMDA) receptor antagonist, significantly and dose-dependently suppressed the increased head-dipping behaviors in OB mice, without affecting sham mice. Similar results were obtained with another selective NMDA receptor antagonist D-AP5 treatment in OB mice. On the other hand, muscimol, a selective aminobutyric acid type A (GABAA) receptor agonist produced no effects on these hyperemotional behaviors in OB mice at a dose (100μg/kg) that produced anxiolytic-like effects in sham mice. Interestingly, glutamine contents and glutamine/glutamate ratios were significantly increased in the amygdala and frontal cortex of OB mice compared to sham mice. Based on these results, we concluded that the glutamatergic NMDA receptors are involved in the expression of increased head-dipping behaviors in the hole-board tests of OB mice. Accordingly, the changes in glutamatergic transmission in frontal cortex and amygdala may play important roles in the expression of these abnormal behaviors in OB mice.
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Affiliation(s)
- Noritaka Hirose
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Akiyoshi Saitoh
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
| | - Junzo Kamei
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
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Bruzos-Cidón C, Llamosas N, Ugedo L, Torrecilla M. Dysfunctional inhibitory mechanisms in locus coeruleus neurons of the wistar kyoto rat. Int J Neuropsychopharmacol 2015; 18:pyu122. [PMID: 25586927 PMCID: PMC4540101 DOI: 10.1093/ijnp/pyu122] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/30/2014] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The noradrenergic nucleus locus coeruleus (LC) has functional relevance in several psychopathologies such as stress, anxiety, and depression. In addition to glutamatergic and GABAergic synaptic inputs, the activation of somatodendritic α2-adrenoceptors is the main responsible for LC activity regulation. The Wistar Kyoto (WKY) rat exhibits depressive- and anxiety-like behaviors and hyperresponse to stressors. Thus, the goal of the present study was to investigate in vitro the sensitivity of α2-adrenoceptors, as well as the glutamatergic and GABAergic synaptic activity on LC neurons of the WKY strain. METHODS For that purpose patch-clamp whole-cell recordings were done in LC slices. RESULTS The α2-adrenoceptors of LC neurons from WKY rats were less sensitive to the effect induced by the agonist UK 14 304 as compared to that recorded in the Wistar (Wis) control strain. In addition, the GABAergic input to LC neurons of WKY rats was significantly modified compared to that in Wis rats, since the amplitude of spontaneous GABAergic postsynaptic currents was reduced and the half-width increased. On the contrary, no significant alterations were detected regarding glutamatergic input to LC neurons between rat strains. CONCLUSIONS These results point out that in WKY rats the inhibitory control exerted by α2-adrenoceptors and GABAergic input onto LC neurons is dysregulated. Overall, this study supports in this animal model the hypothesis that claims an imbalance between the glutamatergic-GABAergic systems as a key factor in the pathophysiology of depression.
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Affiliation(s)
| | | | | | - M Torrecilla
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU, 48940 Leioa, Spain (Drs Bruzos-Cidón, Ugedo, and Torrecilla, and Llamosas).
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Wabno J, Hess G. Repeated administration of imipramine modifies GABAergic transmission in rat frontal cortex. J Neural Transm (Vienna) 2012. [PMID: 23180303 PMCID: PMC3631518 DOI: 10.1007/s00702-012-0919-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alterations in the functions of brain gamma-aminobutyric acid (GABA) inhibitory system and a distortion in the balance between excitatory and inhibitory synaptic transmission have been hypothesized to be possible causes of mood disorders. Experimental evidence points to modifications of GABAergic transmission as a result of prolonged treatment with antidepressant drugs, however, the influence of the tricyclic antidepressant imipramine on inhibitory synaptic transmission in the rat cerebral cortex has not yet been investigated. Therefore, in the present study the effects of single and repeated administration of imipramine were evaluated ex vivo in slices of the rat frontal cortex using electrophysiological approach. In slices prepared 2 days after the last drug administration from animals receiving imipramine for 14 days (dose 10 mg/kg p.o., twice daily) the mean frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) recorded from layer II/III pyramidal neurons was decreased, while the mean amplitude of sIPSCs was increased. These effects were absent in slices obtained from rats which received imipramine once. Application of N,N′-dibenzhydrylethane-1,2-diamine dihydrochloride (AMN 082), a selective mGluR7 allosteric agonist, to the slice incubation medium resulted in a decrease in the mean frequency of sIPSCs in preparations obtained from repeated imipramine-treated animals, in contrast to slices originating from control rats where no AMN 082-induced effects were observed. Repeated imipramine treatment reduced protein density levels of the three tested GABAA receptor subunits: α1, β2 and γ2. These data indicate that repeated treatment of normal rats with imipramine results in a modification of the release mechanism of GABA from presynaptic terminals and its modulation by mGluR7 receptors as well as in an alteration in GABAA receptor subunit protein levels in the rat cerebral cortex.
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Affiliation(s)
- Joanna Wabno
- Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland
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Paroxetine pretreatment does not change the effects induced in the rat cortical beta-adrenergic receptor system by repetitive transcranial magnetic stimulation and electroconvulsive shock. Int J Neuropsychopharmacol 2010; 13:737-46. [PMID: 19698191 DOI: 10.1017/s1461145709990459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a clinically effective antidepressant treatment, but meta-analysis suggests that its efficacy is marginal. We investigated whether the administration of rTMS together with paroxetine would enhance its effects on the beta-adrenergic system of the rat. We compared our results with the effects of electroconvulsive shock therapy (ECS). The experiment was performed for 12 d on male Wistar rats that received a physical treatment of either rTMS (B=1.4 T, f=10 Hz, 300 s) or ECS (I=130 mA, f=50 Hz, t=500 ms), preceded by sterile water or paroxetine (10 mg/kg i.p. 30 min earlier). All rats were decapitated 24 h after the final treatment. Cyclic AMP (cAMP) was measured in cortical slices prelabelled with [3H]adenine and stimulated with noradrenaline. beta-adrenoceptor parameters (Bmax and KD) were assessed in the P2 fraction of cortical homogenates using [3H]CGP 12177 as a ligand. ECS resulted in down-regulation of both the cAMP response and beta-adrenoceptor density, while rTMS depressed only the responsiveness of the cAMP-generating system. Paroxetine, which was only effective in dampening the cAMP response, did not change the effects of either physical treatment. The data suggest that any possible interaction between paroxetine and rTMS or ECS does not involve the beta-adrenergic mechanisms.
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10
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Cryan JF, Slattery DA. GABAB Receptors and Depression: Current Status. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:427-51. [DOI: 10.1016/s1054-3589(10)58016-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Lei Y, Yaroslavsky I, Tejani-Butt SM. Strain differences in the distribution of N-methyl-d-aspartate and gamma (gamma)-aminobutyric acid-A receptors in rat brain. Life Sci 2009; 85:794-9. [PMID: 19874829 DOI: 10.1016/j.lfs.2009.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 10/12/2009] [Accepted: 10/17/2009] [Indexed: 11/16/2022]
Abstract
AIMS Previous studies have shown that the Wistar-Kyoto (WKY) rat strain exhibits depressive symptoms such as anhedonia, psychomotor retardation, ambivalence and negative memory bias following exposure to stress. Given the involvement of excitatory glutamate and inhibitory gamma (gamma)-aminobutyric acid (GABA) signaling pathways in influencing depressive behavior, the present study investigated strain differences in the distribution of central N-methyl-d-aspartate (NMDA) and GABA(A) receptor sites in WKY compared to their inbred counterpart, Wistar (WIS) rats. MAIN METHODS Quantitative autoradiographic analysis was used to map the binding and distribution of NMDA and GABA(A) receptors in various brain regions in WKY and WIS rats. KEY FINDINGS Results indicated a significant difference between the two strains. Lower NMDA receptor binding was found in the anterior cingulate cortex, caudate putmen, nucleus accumbens, CA1 region of the hippocampus and the substantia nigra pars reticulata in WKY compared to WIS rats. Conversely, higher GABA(A) receptor binding was found in the amygdala, caudate putmen, dentate gyrus, CA2 and CA3 fields of the hippocampus, periaqueductal grey and substantia nigra pars reticulata in WKY compared to WIS rats. SIGNIFICANCE Given that these two rat strains differ in their behavioural, endocrine and neurochemical profile, the observed strain differences in NMDA and GABA(A) receptor binding suggest that these two neurotransmitter systems may be involved in the depressive and stress-sensitive phenotype of the WKY rat strain.
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Affiliation(s)
- Yanlin Lei
- Department of Pharmaceutical Sciences, University of the Sciences in Philadelphia, Philadelphia, PA 19104, USA
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12
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Abstract
This review assesses the parallel data on the role of gamma-aminobutyric acid (GABA) in depression and anxiety. We review historical and new data from both animal and human experimentation which have helped define the key role for this transmitter in both these mental pathologies. By exploring the overlap in these conditions in terms of GABAergic neurochemistry, neurogenetics, brain circuitry, and pharmacology, we develop a theory that the two conditions are intrinsically interrelated. The role of GABAergic agents in demonstrating this interrelationship and in pointing the way to future research is discussed.
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Affiliation(s)
- Allan V Kalueff
- Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, Maryland, USA
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13
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Ahern TH, Javors MA, Eagles DA, Martillotti J, Mitchell HA, Liles LC, Weinshenker D. The effects of chronic norepinephrine transporter inactivation on seizure susceptibility in mice. Neuropsychopharmacology 2006; 31:730-8. [PMID: 16052243 DOI: 10.1038/sj.npp.1300847] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epilepsy and depression are comorbid disorders, but the mechanisms underlying their relationship have not been identified. Traditionally, many antidepressants have been thought to increase seizure incidence, although this remains controversial, and it is unclear which medications should be used to treat individuals suffering from both epilepsy and depression. Since the neurotransmitter norepinephrine (NE) has both antidepressant and anticonvulsant properties, we speculated that NE transporter (NET) inhibitor antidepressants might be therapeutic candidates for comorbid individuals. To test this idea, we assessed the effects of chronic administration (via osmotic minipump) of the selective NET inhibitor reboxetine on flurothyl-induced seizures in mice. We found that reboxetine had both proconvulsant and anticonvulsant properties; it lowered both seizure threshold and maximal seizure severity. NET knockout (NET KO) mice essentially phenocopied the effects of reboxetine on flurothyl-induced seizures, and the trends were extended to pentylenetetrazole and maximal electroshock seizures (MES). Furthermore, reboxetine had no further effect in NET KO mice, demonstrating the specificity of reboxetine for the NET. We next tested the chronic and acute effects of other classes of antidepressants (desipramine, imipramine, sertraline, bupropion, and venlafaxine) on seizure susceptibility. Only venlafaxine was devoid of proconvulsant activity, and retained some anticonvulsant activity. These results suggest that chronic antidepressant drug treatment has both proconvulsant and anticonvulsant effects, and that venlafaxine is a good candidate for the treatment of epilepsy and depression comorbidity.
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Affiliation(s)
- Todd H Ahern
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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Schechter LE, Ring RH, Beyer CE, Hughes ZA, Khawaja X, Malberg JE, Rosenzweig-Lipson S. Innovative approaches for the development of antidepressant drugs: current and future strategies. NeuroRx 2006; 2:590-611. [PMID: 16489368 PMCID: PMC1201318 DOI: 10.1602/neurorx.2.4.590] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Depression is a highly debilitating disorder that has been estimated to affect up to 21% of the world population. Despite the advances in the treatment of depression with selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs), there continue to be many unmet clinical needs with respect to both efficacy and side effects. These needs range from efficacy in treatment resistant patients, to improved onset, to reductions in side effects such as emesis or sexual dysfunction. To address these needs, there are numerous combination therapies and novel targets that have been identified that may demonstrate improvements in one or more areas. There is tremendous diversity in the types of targets and approaches being taken. At one end of a spectrum is combination therapies that maintain the benefits associated with SSRIs but attempt to either improve efficacy or reduce side effects by adding additional mechanisms (5-HT1A, 5-HT1B, 5-HT1D, 5-HT2C, alpha-2A). At the other end of the spectrum are more novel targets, such as neurotrophins (BDNF, IGF), based on recent findings that antidepressants induce neurogenesis. In between, there are many approaches that range from directly targeting serotonin receptors (5-HT2C, 5-HT6) to targeting the multiplicity of potential mechanisms associated with excitatory (glutamate, NMDA, mGluR2, mGluR5) or inhibitory amino acid systems (GABA) or peptidergic systems (neurokinin 1, corticotropin-releasing factor 1, melanin-concentrating hormone 1, V1b). The present review addresses the most exciting approaches and reviews the localization, neurochemical and behavioral data that provide the supporting rationale for each of these targets or target combinations.
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Affiliation(s)
- Lee E Schechter
- Discovery Neuroscience, Wyeth Research, CN 8000, Princeton, New Jersey 08543, USA.
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15
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Slattery DA, Cryan JF. The role of GABAB receptors in depression and antidepressant-related behavioural responses. Drug Dev Res 2006. [DOI: 10.1002/ddr.20110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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16
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Bajbouj M, Luborzewski A, Danker-Hopfe H, Lang UE. Motor cortical excitability in depressive patients after electroconvulsive therapy and repetitive transcranial magnetic stimulation. J ECT 2005; 21:243-5. [PMID: 16301886 DOI: 10.1097/01.yct.0000180039.12176.9c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex are brain stimulation techniques that are used as therapeutic interventions in major depression. However, the exact therapeutic mode of action needs further clarification. In this case report, we describe the impact of these stimulation techniques on motor cortical excitability, as revealed by transcranial magnetic stimulation-elicited motor-evoked potentials in 2 patients who received consecutively both rTMS and ECT. Both patients showed a decrease in motor cortical excitability after response to antidepressant brain stimulation, whereas parameters of motor cortical excitability remained unchanged after the first non-successful intervention. These results suggest that both ECT and rTMS may have an impact on parameters of motor cortical neuronal excitability. Furthermore, measurement of motor cortical excitability may be a useful tool for investigating and monitoring inhibitory brain effects of different antidepressant stimulation techniques.
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Affiliation(s)
- Malek Bajbouj
- Department of Psychiatry, Charité-University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany.
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Abstract
Bilateral olfactory bulbectomy results in changes in behavior, and in the endocrine, immune and neurotransmitter systems, that simulates many of those seen in patients with major depression. The olfactory system in the rat forms a part of the limbic region in which the amygdala and hippocampus contribute to the emotional and memory components of behavior. However, the loss of olfaction alone, which results from bulbectomy, is not the major factor that contributes to the behavioral abnormalities as peripherally induced anosmia does not cause the same behavioral changes. Thus it would appear that bulbectomy causes a major dysfunction of the cortical-hippocampal-amygdala circuit that underlies the behavioral and other changes. These neuroanatomical areas also seem to be dysfunctional in the patient with major depression. Chronic, but not acute, administration of antidepressants largely corrects most the behavioral, endocrine, immune and neurotransmitter changes that occur following bulbectomy. Thus the olfactory bulbectomized rat is not only a model for detecting antidepressant activity but also one for exploring the inter-relationships between these systems that are also dysfunctional in patients with major depression.
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Affiliation(s)
- Cai Song
- Department of Biomedical Science, AVC, University of Prince Edward Island and National Institute of Nutrisciences and Health, Charlottetown, Canada.
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18
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A review of the relevance and validity of olfactory bulbectomy as a model of depression. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1566-2772(03)00087-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Harro J, Oreland L. Depression as a spreading adjustment disorder of monoaminergic neurons: a case for primary implication of the locus coeruleus. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2001; 38:79-128. [PMID: 11750928 DOI: 10.1016/s0165-0173(01)00082-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A model for the pathophysiology of depression is discussed in the context of other existing theories. The classic monoamine theory of depression suggests that a deficit in monoamine neurotransmitters in the synaptic cleft is the primary cause of depression. More recent elaborations of the classic theory also implicitly include this postulate, other theories of depression frequently prefer to depart from the monoamine-based model altogether. We suggest that the primary defect emerges in the regulation of firing rates in brainstem monoaminergic neurons, which brings about a decrease in the tonic release of neurotransmitters in their projection areas, an increase in postsynaptic sensitivity, and concomitantly, exaggerated responses to acute increases in the presynaptic firing rate and transmitter release. It is proposed that the initial defect involves, in particular, the noradrenergic innervation from the locus coeruleus (LC). Dysregulation of the LC projection activities may lead in turn to dysregulation of serotonergic and dopaminergic neurotransmission. Failure of the LC function could explain the basic impairments in the processing of novel information, intensive processing of irrational beliefs, and anxiety. Concomitant impairments in the serotonergic neurotransmission may contribute to the mood changes and reduction in the mesotelencephalic dopaminergic activity to loss of motivation, and anhedonia. Dysregulation of CRF and other neuropeptides such as neuropeptide Y, galanin and substance P may reinforce the LC dysfunction and thus further weaken the adaptivity to stressful stimuli.
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Affiliation(s)
- J Harro
- Department of Psychology, University of Tartu, Tiigi 78, EE-50410 Tartu, Estonia.
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20
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Jenkins JA, Williams P, Kramer GL, Davis LL, Petty F. The influence of gender and the estrous cycle on learned helplessness in the rat. Biol Psychol 2001; 58:147-58. [PMID: 11600242 DOI: 10.1016/s0301-0511(01)00111-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although the etiology of clinical depression is unknown, women are more likely to suffer from major depressive disorder than men. In addition, in some women, there is a clear association between depression and specific phases of the menstrual cycle. Surprisingly little research has examined gender differences and the influences of the estrous cycle in this and other animal behavioral models of clinical depression. Learned helplessness is a valid animal model of stress-induced behavioral depression in which prior exposure to inescapable stress produces deficits in escape testing. Learned helplessness was studied in rats using an inescapable tail shock stress followed by a shuttle box test to determine escape latencies. Animals with mean escape latencies of >or=20 s after shuttle-box testing are defined as learned helpless. Males and normal cycling female rats in the estrus and diestrus II phases were studied. Female rats in the diestrus II phase had significantly higher escape latencies and exhibited a more helpless behavior than female rats in the estrus phase. Male rat escape latencies were intermediate between the two female phases. These results suggest a role for gonadal hormones in the development of stress-induced behavioral depression or 'learned helplessness.'
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Affiliation(s)
- J A Jenkins
- Department of Psychiatry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX, USA.
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21
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Robichaud M, Beauchemin V, Lavoie N, Dennis T, Debonnel G. Effects of bilateral olfactory bulbectomy on N-methyl-D-aspartate receptor function: autoradiographic and behavioral studies in the rat. Synapse 2001; 42:95-103. [PMID: 11574946 DOI: 10.1002/syn.1105] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Rat bilateral olfactory bulbectomy (OBX) serves as a useful model in the study of depression and the mechanisms of action of antidepressant treatments. Considering the evidence of NMDA receptors involvement in depression, the present study was undertaken in order to investigate the time-course effects of OBX on the NMDA receptor function. Following bilateral olfactory bulbectomy, rats display an increase in locomotor activity and changes in other types of behavior in a novel environment. Autoradiographic experiments using the noncompetitive NMDA antagonist [(125)I]-iodo-MK-801 as the labeling agent showed that this increase in behavioral activities corresponds to a decrease in [(125)I]-iodo-MK-801 binding in a number of brain regions. In most regions, this reduction reached significance by the third week following OBX. However, in some cortical areas-a nucleus of the thalamus (AV) and one of the amygdala (LA)-this reduction was already significant in the first or second week following OBX and lasted throughout the 4 weeks of the study. We also compared the behavioral modifications induced by a challenge injection of MK-801 (0.2 mg/kg i.p.) in OBX and sham-operated rats. This challenge is known to induce hyperlocomotion and a number of stereotypies in naive rats. These effects were drastically reduced in OBX as compared to sham-operated rats. These data are consistent with the above-mentioned decrease in cerebral binding of MK-801 to NMDA receptors.
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Affiliation(s)
- M Robichaud
- McGill University, Department of Psychiatry, 1033 Pine Avenue West, Montréal, Québec, Canada H3A 1A1
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22
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Molina-Hernández M, Téllez-Alcántara NP. Antidepressant-like actions of pregnancy, and progesterone in Wistar rats forced to swim. Psychoneuroendocrinology 2001; 26:479-91. [PMID: 11337132 DOI: 10.1016/s0306-4530(01)00007-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In rats, some behavioral changes occurring during pregnancy related to the presence of progesterone may be analyzed in the forced swimming task (FST), which is designed to test the antidepressant profile of drugs. The present study was aimed to analyze in pregnant rats, in rats after delivery, or in rats after receiving progesterone those behavioral changes displayed in the FST. We hypothesize that pregnancy and progesterone will produce antidepressant-like effects in rats forced to swim. Therefore, pregnant rats (14th, 17th, and 20th days), or rats after delivery (3rd, and 7th days) were tested in the FST. Ovariectomized rats receiving saline (0.9%; i.p.), clomipramine (1.25 mg/kg; i.p.), or desipramine (2.14 mg/kg; i.p.) for 28 days were also tested in the FST. In a second series of experiments, ovariectomized rats receiving vehicle or progesterone (0.5 mg/kg; or 2.0 mg/kg; sc.) were tested in the FST. Locomotion was evaluated in the open field test. Results showed that in the FST: 1) pregnancy (P < 0.05), or progesterone (P < 0.05), or desipramine (P < 0.05), reduced immobility by increasing climbing; 2) clomipramine (P < 0.05) reduced immobility by increasing swimming; 3) rats tested after delivery displayed similar behavior than control rats. A lower locomotion was observed only at the end of pregnancy. In conclusion, results suggest that during pregnancy, a reproductive process characterized by its high levels of progesterone, antidepressant-like effects can be found.
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Affiliation(s)
- M Molina-Hernández
- Laboratorio de Conducta, Instituto de Investigaciones Psicológicas, Universidad Veracruzana, PO Box 361, 91000 Xalapa, Veracruz, Mexico.
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23
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Matsubara M, Suzuki S, Miura K, Terashima M, Sugita S, Kimura H, Hatsuda S, Mori T, Murakami H, Hayashi T, Ohta T, Ohara M. Electrophysiologic analysis of antidepressant drug effects on the GABA(A) receptor complex based upon antagonist-induced encephalographic power spectrum changes. Neuropsychobiology 2001; 42:149-57. [PMID: 11015033 DOI: 10.1159/000026685] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To better understand antidepressant drug effects on the GABA(A) receptor complex (the GABA(A) receptor, chloride ionophore and benzodiazepine receptor), we investigated how antidepressants influenced power spectrum changes induced by pentylenetetrazol (PTZ), a chloride ionophore antagonist, in the rat hippocampal electroencephalogram (EEG). In control recording, PTZ (27.5 mg/kg i. p.) increased EEG power at frequencies under 12 Hz up to five times. After rats were pretreated with imipramine, fluoxetine or trazodone for 7 days (10 mg/kg i.p., twice a day), PTZ could not increase EEG power to more than three times the power before injection; this effect was not observed after pretreatment for 3 days. These three antidepressants inhibit serotonin uptake, while two other antidepressants, desipramine and nortriptyline, that inhibit norepinephrine uptake failed to counter the PTZ effect. We concluded that antidepressants with serotonergic effects enhanced the function of the GABA(A) receptor complex.
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Affiliation(s)
- M Matsubara
- Department of Neuropsychiatry, Aichi Medical College, Aichi, Japan
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24
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Abstract
The therapeutic effects of valproate in psychiatric conditions are most substantially recognized in bipolar disorder. However, this well-tolerated medication may be beneficial in the treatment of other mental illnesses. In this article, the authors comprehensively review studies of valproate as treatment for psychiatric conditions, including bipolar, depressive, anxiety, and psychotic disorders; alcohol withdrawal and dependence; tardive dyskinesia; agitation associated with dementia; and borderline personality disorder. Valproate shows the most promising efficacy in treating mood and anxiety disorders, with possible efficacy in the treatment of agitation and impulsive aggression, and less convincing therapeutic response in treating psychosis and alcohol withdrawal or dependence. The authors conclude with a brief summary of its mechanism of action and therapeutic spectrum.
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Affiliation(s)
- L L Davis
- Veteran's Affairs Medical Center, Tuscaloosa, Alabama 35404, USA.
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25
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Fernández-Guasti A, Martínez-Mota L, Estrada-Camarena E, Contreras CM, López-Rubalcava C. Chronic treatment with desipramine induces an estrous cycle-dependent anxiolytic-like action in the burying behavior, but not in the elevated plus-maze test. Pharmacol Biochem Behav 1999; 63:13-20. [PMID: 10340518 DOI: 10.1016/s0091-3057(98)00231-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effect of chronic desipramine (DMI, 2.5 mg/kg x 21-26 days) treatment in female rats in two anxiety paradigms was assessed: the burying behavior (BB) and the elevated plus-maze (EPM) tests. In the BB test DMI produced a significant decrease in burying in ovariectomized rats, an effect considered as anxiolytic-like. In cycling females, DMI also reduced the cumulative BB most notably in proestrus rats. However, in diestrus rats no anxiolytic-like actions were observed. In addition, DMI increased BB latencies in proestrus and estrus rats. In the EPM test, DMI produced anxiolytic-like actions only in ovariectomized rats, while no significant actions were found in cycling females. Finally, the chronic treatment with DMI produced a general reduction in the ambulatory behavior of rats in all estrous cycle phases. Results are discussed on the basis of the differences between both anxiety paradigms and the probable relationship between the steroids secreted during proestrus and chronic DMI treatment.
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26
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McGrath C, Norman TR. (+)-S-20499 -- a potential antidepressant? A behavioural and neurochemical investigation in the olfactory bulbectomised rat. Eur Neuropsychopharmacol 1999; 9:21-7. [PMID: 10082224 DOI: 10.1016/s0924-977x(97)00103-x] [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: 10/18/2022]
Abstract
The study was designed to assess the potential antidepressant properties of the 5-HT1A receptor agonist, (+)-S-20499 (10 mg kg(-1) i.p.) in the olfactory bulbectomised (OB) rat. Following 2 weeks of treatment, the rats were tested in the elevated plus maze and the "open field". A characteristic hyperactive response was evident in the OB animals in the "open field" which was reversed following chronic treatment with (+)-S-20499. In the elevated plus maze an increase in the number of open arm entries and the time spent on the open arms was observed, although this failed to reach significance. A significant decrease in beta1 receptor affinity was evident following olfactory bulbectomy which was normalised by (+)-S-20499. (+)-S-20499 also significantly reduced the density of 5-HT2 receptors in the sham operated (SO) animals. These studies demonstrate the usefulness of the OB rat as a screening test for compounds with novel putative mechanisms of action, and highlights the potential antidepressant properties of (+)-S-20499.
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Affiliation(s)
- C McGrath
- Department of Psychiatry, Austin and Repatriation Medical Centre, Heidelberg, Vic, Australia.
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27
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McGrath C, Burrows GD, Norman TR. Neurochemical effects of the enantiomers of mirtazapine in normal rats. Eur J Pharmacol 1998; 356:121-6. [PMID: 9774241 DOI: 10.1016/s0014-2999(98)00509-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The present study was designed to examine the neurochemical effects of (+/-)-mirtazapine (10 mg kg(-1) i.p.) and its enantiomers in rats. Male Sprague-Dawley rats received either (+)-mirtazapine, (-)-mirtazapine, (+/-)-mirtazapine or vehicle, by intraperitoneal injection for two weeks. Maximum change in temperature from baseline, following a single dose of the 5-HT1A receptor agonist 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (0.15 mg kg(-1) s.c.), was used to assess the function of the 5-HT1A receptors. Chronic drug treatment potentiated this response, with (+/-)-mirtazapine > (-)-mirtazapine > (+)-mirtazapine. Receptor changes were also observed with a slight decrease in beta1-adrenoceptor density, although this failed to reach significance. A significant decrease in beta1-adrenoceptor affinity was observed following (-)-mirtazapine treatment. All drugs tested significantly reduced the density of the 5-HT2 receptors. Results of the present study suggest that in so far as alterations in these receptor populations are important for the therapeutic action of antidepressants, neither of the enantiomers appear to be more active than the racemic mixture.
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Affiliation(s)
- C McGrath
- Department of Psychiatry, Austin and Repatriation Medical Centre, Heidelberg, Victoria, Australia.
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28
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Ichikawa J, Kuroki T, Meltzer HY. Differential effects of chronic imipramine and fluoxetine on basal and amphetamine-induced extracellular dopamine levels in rat nucleus accumbens. Eur J Pharmacol 1998; 350:159-64. [PMID: 9696403 DOI: 10.1016/s0014-2999(98)00247-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of chronic treatment with the tricyclic antidepressant drug, imipramine (10 mg/kg per day), the selective serotonin (5-HT) reuptake inhibitor, fluoxetine hydrochloride (10 mg/kg per day), and vehicle, in drinking water for 24-28 days followed by 3-5 days withdrawal, on extracellular dopamine levels was studied in rat nucleus accumbens by in vivo microdialysis. Basal extracellular dopamine levels in the nucleus accumbens were increased after chronic imipramine (12.7 +/- 1.5 fmol/20 microl per 30 min, P = 0.019), and moderately decreased after chronic fluoxetine (6.5 +/- 0.6, P = 0.047), as compared to the vehicle controls (9.1 +/- 0.7), determined by one-way analysis of variance (ANOVA). Repeated measure ANOVA indicated that the D-amphetamine sulfate (0.5 mg/kg, s.c.)-induced increase in extracellular dopamine levels in the nucleus accumbens was potentiated after chronic imipramine (P = 0.002), but unchanged after chronic fluoxetine (P = 0.83). The difference in the effect of amphetamine could be influenced by the significant differences in basal levels. However, these results were also confirmed by analysis of the net area under the curve (net-AUC) for a 180-min period (six samples): for chronic imipramine (337 +/- 45 fmol/180 min, P = 0.005) and chronic fluoxetine (249 +/- 38, P = 0.57), as compared to the vehicle controls (178 +/- 29), determined by one-way ANOVA. We suggest that the effect of treatment with these agents on mesolimbic dopamine is unlikely to be involved in their shared antidepressant action, but may be relevant to other aspects of the therapeutic profile of these two drugs, e.g. the switch into mania which is more common after treatment with imipramine than fluoxetine and exacerbation of positive symptoms in patients with schizophrenia or schizoaffective disorder.
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Affiliation(s)
- J Ichikawa
- Department of Psychiatry, Vanderbilt University School of Medicine, Psychiatry Hospital at Vanderbilt, Nashville, TN 37212, USA
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29
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Kelly JP, Wrynn AS, Leonard BE. The olfactory bulbectomized rat as a model of depression: an update. Pharmacol Ther 1997; 74:299-316. [PMID: 9352586 DOI: 10.1016/s0163-7258(97)00004-1] [Citation(s) in RCA: 490] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The olfactory bulbectomized (OB) rat has been proposed as an animal model of depression. The following behavioural changes have been observed following bilateral olfactory bulbectomy: hyperactivity in an enclosed arena, such as the open-field; enhanced nocturnal hyperactivity in a 24-hr home cage activity monitor; deficits in memory, as shown by passive avoidance behaviour and in the Morris maze and the 8-arm radial maze; increased open arm entries in the elevated plus-maze; and changes in food motivated and conditioned taste aversion behaviour. Alterations in the noradrenergic, serotonergic, cholinergic, gamma-aminobutyric acid (GABA)ergic and glutamatergic neurotransmitter systems are also associated with olfactory bulbectomy. The variety of immune changes following olfactory bulbectomy includes reduced neutrophil phagocytosis, lymphocyte mitogenesis, lymphocyte number and negative acute phase proteins, increased leucocyte adhesiveness/aggregation, monocyte phagocytosis, neutrophil number and positive acute phase proteins. An enhanced nocturnal secretion of corticosterone is observed in OB rats, which is normally suppressed by dexamethasone. The most commonly employed behavioural indicator of antidepressant activity is attenuation of the OB-related hyperactivity in the open-field. However, many of the other behavioural, neurotransmitter and immune changes have been shown to be attenuated by chronic (but not acute) antidepressant treatment. Tricyclic antidepressants (amitriptyline, desipramine), atypical agents (mianserin), selective serotonin reuptake inhibitors (paroxetine, sertraline, fluvoxamine), reversible inhibitors of monoamine oxidase A (moclobemide), as well as putative antidepressants such as 5-hydroxytryptamine1A agonists (zalospirone, ipsapirone), noncompetitive N-methyl-D-aspartate antagonists (MK-801) and triazolobenzodiazepines (alprazolam, adinazolam), have demonstrated antidepressant-like activity in this model. As many of the changes exhibited by the OB rat are qualitatively similar to those observed in depressed patients, it may be concluded that the OB rat is a model of depression and not just a means whereby putative antidepressants may be tested.
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Affiliation(s)
- J P Kelly
- Department of Pharmacology, University College, Galway, Ireland
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30
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Davis LL, Trivedi M, Choate A, Kramer GL, Petty F. Growth hormone response to the GABAB agonist baclofen in major depressive disorder. Psychoneuroendocrinology 1997; 22:129-40. [PMID: 9203224 DOI: 10.1016/s0306-4530(96)00048-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Growth hormone (GH) response to the gamma-aminobutyric acid B receptor agonist, baclofen, was measured in 16 male patients with major depressive disorder and in 16 age-matched healthy male controls. No significant differences were found in the GH response to baclofen between the depressed patients and controls. On repeat testing, the GH response to baclofen showed significant retest reliability in both groups. There was no significant correlation between serum baclofen levels and the GH response to baclofen. Age significantly correlated with GH response, with older subjects having lower GH response to baclofen. These data do not suggest that a blunted GH response to baclofen. represents a specific neuroendocrine feature of major depression.
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Affiliation(s)
- L L Davis
- Veterans Affairs Medical Center, Dallas, TX 75216, USA.
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31
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Nakagawa Y, Ishima T, Ishibashi Y, Tsuji M, Takashima T. Involvement of GABAB receptor systems in experimental depression: baclofen but not bicuculline exacerbates helplessness in rats. Brain Res 1996; 741:240-5. [PMID: 9001728 DOI: 10.1016/s0006-8993(96)00929-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
There are two gamma-aminobutyric acid (GABA) hypotheses of the antidepressants action: an increase in GABAA neurotransmission or a decrease in GABAB neurotransmission may contribute to action of antidepressants. In this study, involvement of GABAA and GABAB receptor systems was examined in the learned helplessness paradigm in rats. Rats were injected with bicuculline or baclofen for 14 days. On day 14, the rats were subjected to 15 inescapable shocks. On day 15, they underwent the 40-trial escape test. Baclofen exacerbated the escape failures in the rats subjected to the inescapable shocks, although baclofen had no effects in the animals without shock pre-treatment. Bicuculline failed to influence the escape failures in the rats with the 15-shock pre-treatment. These results suggest that the long-term increase in GABAB neurotransmission but not the long-term attenuation of GABAA neurotransmission may be related to helplessness in rats.
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Affiliation(s)
- Y Nakagawa
- Tsukuba Research Laboratories, Experimental Biomedical Research Inc. (Jisseiken), Ibaraki, Japan
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32
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Nakagawa Y, Ishima T, Ishibashi Y, Tsuji M, Takashima T. Involvement of GABAB receptor systems in action of antidepressants. II: Baclofen attenuates the effect of desipramine whereas muscimol has no effect in learned helplessness paradigm in rats. Brain Res 1996; 728:225-30. [PMID: 8864486 DOI: 10.1016/0006-8993(96)00413-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Involvement of GABAergic systems in action of antidepressants was examined in the learned helplessness paradigm in rats. Rats were treated with desipramine, baclofen or muscimol for 14 days. On day 14, the rats were subjected to 90 inescapable shocks. On day 15, the rats received the 40-trial escape test. The inescapable shocks induced the subsequent increase in escape failures in the escape test. Desipramine dose-dependently improved the increased escape failures induced by the inescapable shocks. Baclofen attenuated the escape failures-improving effect of desipramine, although baclofen had no effects on the increased escape failures when it was injected alone. Muscimol at any dose failed to influence the increased escape failures. Therefore, it is suggested that the long-term decrease in GABAB neurotransmission may be involved in the action of antidepressants. Our present results do not support the hypothesis that activation of GABAA receptors may contribute to the action of antidepressants.
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Affiliation(s)
- Y Nakagawa
- Tsukuba Research Laboratories, Experimental Biomedical Research Inc. (Jisseiken), Ibaraki, Japan
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33
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Petersen B, Mørk A. Chronic treatment with citalopram induces noradrenaline receptor hypoactivity. A microdialysis study. Eur J Pharmacol 1996; 300:67-70. [PMID: 8741166 DOI: 10.1016/0014-2999(95)00874-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To investigate whether chronic citalopram administration influences the cyclic AMP (cAMP) synthesis in vivo, microdialysis was used to assess citalopram-induced alterations in extracellular concentrations of cAMP in the dorsal hippocampus of freely moving rats. Citalopram administration for 4 weeks (40 mg/kg p.o. daily) did not affect the baseline levels of cAMP but decreased the noradrenaline-induced enhancement of cAMP levels. No change in forskolin-induced enhancement of cAMP levels was observed. Citalopram in situ did not exert any effect on the cAMP levels. These data support the hypothesis that chronic administration of antidepressants alters the function of noradrenergic receptors.
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Affiliation(s)
- B Petersen
- Department of Pharmacology, University of Copenhagen, Denmark
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34
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Gurguis GN, Kramer G, Petty F. Indices of brain beta-adrenergic receptor signal transduction in the learned helplessness animal model of depression. J Psychiatr Res 1996; 30:135-46. [PMID: 8816307 DOI: 10.1016/0022-3956(95)00045-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Both stress response and antidepressant drug action may be mediated by beta-adrenergic receptors (beta AR). Since learned helplessness is a stress-induced animal model of depression, beta AR are relevant to investigate in this model. To date, studies have measured changes in total receptor density (RT), but have not examined more detailed aspects of signal transduction mechanisms such as coupling of the receptor to GS protein. We have investigated brain beta AR coupling in the frontal cortex, hippocampus and hypothalamus of rats exposed to inescapable shock and then tested for learned helplessness, and in both tested and naive controls using [125I]-iodocyanopindolol (ICYP) as the ligand. Both antagonist-saturation and agonist-displacement experiments were conducted, and the specificity for the beta AR was optimized by excluding ICYP binding to 5HT1B receptors. The percentage receptor density in the high-conformational state (%RH) and the ratio of agonist (isoproterenol) dissociation constant from the receptor in the low-/high-conformational states (KL/KH) were used as indices of coupling to GS protein. No significant differences were found between rats developing learned helplessness and non-helpless rats after inescapable stress in any parameter measured in any brain region. In the frontal cortex, exposure to inescapable shock induced beta AR uncoupling from GS protein as suggested by a low KL/KH ratio both in helpless and non-helpless rats but not in either control group. In the hypothalamus, there were trends for higher RL, RT and KL/KH ratio in helpless rats and stressed controls compared to naive controls. These findings suggest that beta AR binding parameters in frontal cortex, hippocampus or hypothalamus did not differentiate between helpless and non-helpless rats. Changes in beta AR coupling observed in these brain regions may reflect effects of stress, which appeared to be region-specific, rather than stress-induced behavioral depression.
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Affiliation(s)
- G N Gurguis
- Veterans Affairs Medical Center, Dallas, TX 75216, USA
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35
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Nakagawa Y, Ishima T, Ishibashi Y, Yoshii T, Takashima T. Involvement of GABA(B) receptor systems in action of antidepressants: baclofen but not bicuculline attenuates the effects of antidepressants on the forced swim test in rats. Brain Res 1996; 709:215-20. [PMID: 8833757 DOI: 10.1016/0006-8993(95)01273-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Involvement of GABAergic systems in action of antidepressants was examined in the forced swim test in rats. Rats were forced to swim in a cylinder for 15 min on day 1 and for 5 min on day 2. Desipramine, mianserin and buspirone, administered after the 15-min swim session on day 1 and before the 5-min swim test on day 2, dose-dependently decreased the duration of immobility in the swim test on day 2. Baclofen attenuated the decreased duration of immobility induced by desipramine, mianserin and buspirone in the swim test, although baclofen did not affect the duration of immobility when it was injected alone. Muscimol dose-dependently decreased the duration of immobility in the swim test on day 2. Bicuculline antagonized the decreased duration of immobility induced by muscimol. However, bicuculline failed to antagonize the decreased duration of immobility induced by desipramine, mianserin and buspirone. These results suggest that GABA(B) but not GABA(A) receptor systems may be involved in action of antidepressants.
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Affiliation(s)
- Y Nakagawa
- Tsukuba Research Laboratories, Experimental Biomedical Research Inc. (Jisseiken), Ibaraki Japan
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36
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Dennis T, Beauchemin V, Lavoie N. Antidepressants reverse the olfactory bulbectomy-induced decreases in splenic peripheral-type benzodiazepine receptors in rats. Eur J Pharmacol 1995; 272:279-88. [PMID: 7713172 DOI: 10.1016/0014-2999(94)00654-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The present study investigated the effects of 21-day administration of clorgyline (1 mg/kg/day), desipramine (10 mg/kg/day) or paroxetine (10 mg/kg/day) on peripheral-type benzodiazepine receptors in rat peripheral tissues following bilateral olfactory bulbectomy. Thymus and spleen weights decreased as a result of bulbectomy. Subsequent antidepressant drug administration had no further effects on the weights of thymus glands but increased those of spleens. In thymus glands, higher densities of peripheral-type benzodiazepine receptors were observed in medulla than in cortex; no significant variations were observed following bulbectomy or antidepressant drug administration. In spleen, higher densities were observed in white pulp than in red pulp. The bulbectomy-induced decreases in binding densities observed in both regions were reversed following administration of antidepressants. Adrenal peripheral-type benzodiazepine receptors were not altered by bulbectomy or subsequent treatment with clorgyline or desipramine while paroxetine upregulated these receptors. No changes in kidney peripheral-type benzodiazepine receptors were observed. The present study confirms that cell lines of the rat immune system possess high densities of peripheral-type benzodiazepine receptor binding sites and further support the contention that, following olfactory bulbectomy, rats may present an antidepressant-reversible immunitary dysfunction.
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Affiliation(s)
- T Dennis
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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