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Daniels S, El Mansari M, Blier P. AMPA receptors modulate enhanced dopamine neuronal activity induced by the combined administration of venlafaxine and brexpiprazole. Neuropsychopharmacology 2024:10.1038/s41386-024-01958-4. [PMID: 39147870 DOI: 10.1038/s41386-024-01958-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/29/2024] [Accepted: 08/01/2024] [Indexed: 08/17/2024]
Abstract
Addition of dopamine (DA)/serotonin (5-HT) partial agonists to 5-HT/norepinephrine (NE) reuptake inhibitors are commonly used to enhance the antidepressant response. The simultaneous inhibition of 5-HT and NE transporters with venlafaxine and its combination of brexpiprazole, which blocks the α2-adrenergic autoreceptor on NE terminals, could constitute a superior strategy. Anesthetized rats received venlafaxine and brexpiprazole for 2 and 14 days, then the firing activity of dorsal raphe nucleus 5-HT, locus coeruleus NE, and ventral tegmental area DA neurons were assessed. Net 5-HT and NE neurotransmissions were evaluated by assessing the tonic activation of 5-HT1A, and α1- and α2-adrenergic receptors in the hippocampus. The combination of brexpiprazole with venlafaxine resulted in normalized 5-HT and NE neuron activity, which occurred earlier than that with venlafaxine alone. A significant enhancement of the tonic activation of 5-HT1A receptors and α2-adrenoceptors in the hippocampus was observed following administration of the combination for 14 days. The combination more than doubled the number of DA neurons per electrode descent, after both 2 and 14 days, while this increase was observed only after 14 days of venlafaxine administration. This increase in population activity was prevented by NBQX, an AMPA receptor antagonist. In conclusion, early during administration, the combination of venlafaxine with brexpiprazole normalized firing activity of 5-HT and NE neurons, and increased the population activity of DA neurons through AMPA receptors. In the hippocampus, there was an overall increase in both 5-HT and NE transmissions. These results imply that this strategy could be a rapid-acting approach to treat depression.
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Affiliation(s)
- Stephen Daniels
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, K1Z 7K4, Ottawa, Canada
| | - Mostafa El Mansari
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, K1Z 7K4, Ottawa, Canada.
| | - Pierre Blier
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, K1Z 7K4, Ottawa, Canada
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Grinchii D, Janáková Csatlósová K, Viñas-Noguera M, Dekhtiarenko R, Paliokha R, Lacinová Ľ, Dremencov E, Dubovický M. Effects of pre-gestational exposure to the stressors and perinatal bupropion administration on the firing activity of serotonergic neurons and anxiety-like behavior in rats. Behav Brain Res 2024; 459:114796. [PMID: 38048911 DOI: 10.1016/j.bbr.2023.114796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/22/2023] [Accepted: 11/30/2023] [Indexed: 12/06/2023]
Abstract
Exposure by women to stressors before pregnancy increases their risk of contracting prenatal depression, a condition which typically may require antidepressant treatment. And even though such perinatal antidepressant treatment is generally considered to be safe. For the mother, its effects on the development and functioning of the offspring`s brain remain unknown. In this study, we aimed to investigate the effects of pregestational chronic unpredictable stress (CUS) and perinatal bupropion on the anxiety behavior and firing activity of the dorsal raphe nucleus (DRN) serotonin (5-HT) neurons. Female rats underwent CUS for three weeks before mating. Bupropion was administered to them from gestation day ten until their offspring were weaned. Behavioral (elevated plus maze or EPM test) and neurophysiological (single-unit in vivo electrophysiology) assessments were performed on offspring who reached the age of 48-56 days. We found that maternal CUS and perinatal bupropion, as separate factors on their own, did not change offspring behavior. There was, however, an interaction between their effects on the number of entries to the open arms and time spent in the intersection: maternal CUS tended to decrease these values, and perinatal bupropion tended to diminish CUS effect. Maternal CUS increased the firing activity of 5-HT neurons in males, but not females. Perinatal bupropion did not alter the firing activity of 5-HT neurons but tended to potentiate the maternal CUS-induced increase in 5-HT neuronal firing activity. The CUS-induced increase in firing activity of 5-HT neurons might be a compensatory mechanism that diminishes the negative effects of maternal stress. Perinatal bupropion does not alter the offspring`s anxiety and firing activity of 5-HT, but it does intervene in the effects of maternal stress.
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Affiliation(s)
- Daniil Grinchii
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Kristína Janáková Csatlósová
- Institute of Experimental Pharmacology and Toxicology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Mireia Viñas-Noguera
- Institute of Experimental Pharmacology and Toxicology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Roman Dekhtiarenko
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Ruslan Paliokha
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Ľubica Lacinová
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Eliyahu Dremencov
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Michal Dubovický
- Institute of Experimental Pharmacology and Toxicology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
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Daniels S, El Mansari M, Hamoudeh R, Blier P. Ketamine promptly normalizes excess norepinephrine and enhances dopamine neuronal activity in Wistar Kyoto rats. Front Pharmacol 2023; 14:1276309. [PMID: 38026921 PMCID: PMC10644068 DOI: 10.3389/fphar.2023.1276309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
Ketamine acts primarily by blocking the N-methyl-D-aspartate (NMDA) receptor at the phencyclidine site. The rapid antidepressant properties of ketamine were demonstrated in the clinic and several behavioral models of depression in rodents. We hypothesized that the normalization of abnormal activity of monoamine neurons in Wistar Kyoto (WKY) rats contributes to the rapid antidepressant effects of ketamine. A single administration of ketamine (10 mg/kg, i. p) or saline was administered to anesthetized WKY rats before in vivo electrophysiological recordings of dorsal raphe nucleus (DRN) serotonin (5-HT), locus coeruleus (LC) norepinephrine (NE) and ventral tegmental area (VTA) dopamine (DA) neuronal activity. Pyramidal neurons from the medial prefrontal cortex (mPFC) were also recorded before and after a ketamine injection. In the VTA, ketamine elicited a significant increase in the population activity of DA neurons. This enhancement was consistent with findings in other depression-like models in which such a decreased population activity was observed. In the LC, ketamine normalized increased NE neuron burst activity found in WKY rats. In the DRN, ketamine did not significantly reverse 5-HT neuronal activity in WKY rats, which is dampened compared to Wistar rats. Ketamine did not significantly alter the neuronal activity of mPFC pyramidal neurons. These findings demonstrate that ketamine normalized NE neuronal activity and enhanced DA neuronal activity in WKY rats, which may contribute to its rapid antidepressant effect.
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Affiliation(s)
| | - Mostafa El Mansari
- Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada
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Jiang JL, El Mansari M, Blier P. Triple reuptake inhibition of serotonin, norepinephrine, and dopamine increases the tonic activation of α 2-adrenoceptors in the rat hippocampus and dopamine levels in the nucleus accumbens. Prog Neuropsychopharmacol Biol Psychiatry 2020; 103:109987. [PMID: 32474007 DOI: 10.1016/j.pnpbp.2020.109987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/03/2023]
Abstract
Clinical studies have shown the therapeutic efficacy of an increase in dopamine (DA) transmission in treatment of major depressive disorder (MDD). In the present study, we investigated whether blockade of DA transporters in addition to serotonin (5-HT) and norepinephrine (NE) produced additional adaptations of monoaminergic systems. In vivo electrophysiological recordings were carried out in male anesthetized rats. Vehicle, the 5-HT reuptake inhibitor escitalopram, the NE/DA reuptake blocker nomifensine and their combination (triple reuptake inhibition; TRI) were delivered for 2 or 14 days. Firing activity of NE, 5-HT and DA neurons was assessed. Tonic activation of 5-HT1A receptors and α1- and α2-adrenoceptors was determined in the hippocampus and extracellular DA levels in the nucleus accumbens (NAc). Unlike escitalopram, nomifensine and TRI administration increased the tonic activation of α2-adrenoceptors in the hippocampus despite decreasing NE neuronal firing activity after 2 and 14 days of administration. The firing activity of 5-HT neurons was increased after prolonged nomifensine and TRI regimens, while addition of nomifensine to escitalopram prevented the early 2-day suppression of firing by 5-HT reuptake inhibition. The tonic activation of 5-HT1A receptors was enhanced only with escitalopram. Whereas escitalopram and nomifensine decreased firing activity of DA neurons after a 2-day administration, their combination normalized it to baseline level after 14 days; this was accompanied by a robust increase in extracellular DA levels in the NAc. In summary, these results indicate that TRI increases NE and DA but not 5-HT transmission, suggesting a differential efficacy profile in MDD patients.
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Affiliation(s)
- Jojo L Jiang
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada
| | - Mostafa El Mansari
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada.
| | - Pierre Blier
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada
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El Mansari M, Ebrahimzadeh M, Hamati R, Iro CM, Farkas B, Kiss B, Adham N, Blier P. Long-term administration of cariprazine increases locus coeruleus noradrenergic neurons activity and serotonin 1A receptor neurotransmission in the hippocampus. J Psychopharmacol 2020; 34:1143-1154. [PMID: 32684081 DOI: 10.1177/0269881120936891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Cariprazine, the novel dopamine (DA) D3-preferring D3/D2 and serotonin (5-HT)1A receptor partial agonist, has activity as an adjunctive therapy in major depressive disorder (MDD). AIMS This study aims to investigate the effects of chronic cariprazine administration in combination with the selective serotonin reuptake inhibitor escitalopram on the activity of monoaminergic systems. METHODS Rats received cariprazine alone and in adjunct to escitalopram for 2 and 14 days and the firing activity of dorsal raphe nucleus 5-HT, locus coeruleus norepinephrine (NE) and ventral tegmental area DA neurons was assessed. 5-HT and NE neurotransmission in hippocampus pyramidal neurons was evaluated by assessing tonic activation of their 5-HT1A, and α1- and α2-adrenergic receptors, using their selective antagonists. RESULTS Two and 14-day cariprazine regimens increased the firing rate of NE, but not 5-HT and DA neurons. Addition of cariprazine to escitalopram reversed the inhibitory effect of escitalopram on NE but not 5-HT and DA neurons. In the hippocampus, there was an increase in neurotransmission at 5-HT1A receptors in cariprazine-treated rats, but no change in overall NE transmission by either regimen. CONCLUSION Cariprazine increased NE neuronal firing and reversed the escitalopram-induced inhibition of these neurons. Despite a lack of effect on 5-HT neuronal firing activity, there was an increase in tonic activation of hippocampus 5-HT1A receptors by cariprazine alone but not with the combination. These effects provide a possible rationale for the clinical efficacy of cariprazine as an adjunctive strategy in patients with MDD.
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Affiliation(s)
- Mostafa El Mansari
- Mood Disorders Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Mohammad Ebrahimzadeh
- Mood Disorders Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Rami Hamati
- Mood Disorders Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Chidibere M Iro
- Mood Disorders Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | | | - Béla Kiss
- Gedeon Richter Plc, Budapest, Hungary
| | | | - Pierre Blier
- Mood Disorders Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
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Sadighparvar S, Tale F, Shahabi P, Naderi S, Ghaderi Pakdel F. The Response of Ventral Tegmental Area Dopaminergic Neurons to Bupropion: Excitation or Inhibition? Basic Clin Neurosci 2020; 10:281-304. [PMID: 32231766 PMCID: PMC7101519 DOI: 10.32598/bcn.9.10.250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/05/2017] [Accepted: 04/21/2018] [Indexed: 11/25/2022] Open
Abstract
Introduction: Antidepressants can modulate brain monoamines by acting on pre-synaptic and postsynaptic receptors. Autoreceptors can reduce the monoamines effect on the somatodendritic or pre-synaptic regions despite its postsynaptic counter effects. The direct effect of some antidepressants is related to its temporal and spatial bioavailability in the vicinity of these receptors (still a matter of controversies). This research evaluated the direct effect of acute bupropion on the Ventral Tegmental Area (VTA) dopaminergic neuronal firing rate. Methods: Male Wistar rats were divided into intracerebroventricular and microiontophoretic groups with 14 subgroups (n=5 in each subgroup). Amounts of 1, 0.5, 0.1, 0.01, 0.001, and 0.0001 mol of bupropion (5 μL/3 min) were microinfused to the first group and then the ejected amounts of bupropion at -500, -300, -150, -50 nA of electrical currents (1 mol, pH=4.5, 5 min) were applied to the second group. The control and sham subgroups were studied in each group, too. The units with stable firing rates were extracted, and the effect of bupropion was evaluated statistically with a P value less than 0.05 as the level of significance. Results: The highest amount of bupropion in the intracerebroventricular application could excite 42% of the neurons and inhibit 56% of them, but the highest amount of microiontophoretic application of bupropion could inhibit 97.5% of the neurons. The neuronal response to bupropion was dose-dependent in all treated groups. Conclusion: The dual effects of intracerebroventricular bupropion on the VTA dopaminergic neurons but solo inhibitory effect of its microiontophoretic application reflect the intra-VTA and extra-VTA heterogenic cellular and molecular control over the dopaminergic outflow that can be mediated by different receptors. The dopamine autoreceptors on the VTA dopaminergic neurons have complex modulatory effects on the dopaminergic response.
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Affiliation(s)
- Shirin Sadighparvar
- Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran.,Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Fereshteh Tale
- Department of Physiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Parviz Shahabi
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Somayyeh Naderi
- Reproductive Health Research Center, Urmia University of Medical Sciences, Urmia, Iran
| | - Firouz Ghaderi Pakdel
- Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran.,Reproductive Health Research Center, Urmia University of Medical Sciences, Urmia, Iran
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Montalbano A, Mlinar B, Bonfiglio F, Polenzani L, Magnani M, Corradetti R. Dual inhibitory action of trazodone on dorsal raphe serotonergic neurons through 5-HT1A receptor partial agonism and α1-adrenoceptor antagonism. PLoS One 2019; 14:e0222855. [PMID: 31557210 PMCID: PMC6763016 DOI: 10.1371/journal.pone.0222855] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/09/2019] [Indexed: 11/19/2022] Open
Abstract
Trazodone is an antidepressant drug with considerable affinity for 5-HT1A receptors and α1-adrenoceptors for which the drug is competitive agonist and antagonist, respectively. In this study, we used cell-attached or whole-cell patch-clamp recordings to characterize the effects of trazodone at somatodendritic 5-HT1A receptors (5-HT1AARs) and α1-adrenoceptors of serotonergic neurons in rodent dorsal raphe slices. To reveal the effects of trazodone at α1-adrenoceptors, the baseline firing of 5-HT neurons was facilitated by applying the selective α1-adrenoceptor agonist phenylephrine at various concentrations. In the absence of phenylephrine, trazodone (1–10 μM) concentration-dependently silenced neurons through activation of 5-HT1AARs. The effect was fully antagonized by the selective 5-HT1A receptor antagonist Way-100635. With 5-HT1A receptors blocked by Way-100635, trazodone (1–10 μM) concentration-dependently inhibited neuron firing facilitated by 1 μM phenylephrine. Parallel rightward shift of dose-response curves for trazodone recorded in higher phenylephrine concentrations (10–100 μM) indicated competitive antagonism at α1-adrenoceptors. Both effects of trazodone were also observed in slices from Tph2-/- mice that lack synthesis of brain serotonin, showing that the activation of 5-HT1AARs was not mediated by endogenous serotonin. In whole-cell recordings, trazodone activated 5-HT1AAR-coupled G protein-activated inwardly-rectifying (GIRK) channel conductance with weak partial agonist efficacy (~35%) compared to that of the full agonist 5-CT. Collectively our data show that trazodone, at concentrations relevant to its clinical effects, exerts weak partial agonism at 5-HT1AARs and disfacilitation of firing through α1-adrenoceptor antagonism. These two actions converge in inhibiting dorsal raphe serotonergic neuron activity, albeit with varying contribution depending on the intensity of α1-adrenoceptor stimulation.
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Affiliation(s)
- Alberto Montalbano
- NEUROFARBA—Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Università di Firenze, Firenze, Italia
| | - Boris Mlinar
- NEUROFARBA—Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Università di Firenze, Firenze, Italia
| | - Francesco Bonfiglio
- NEUROFARBA—Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Università di Firenze, Firenze, Italia
| | - Lorenzo Polenzani
- Angelini RR&D (Research, Regulatory & Development), Angelini S.p.A, S.Palomba-Pomezia (Roma), Italia
| | - Maurizio Magnani
- Angelini RR&D (Research, Regulatory & Development), Angelini S.p.A, S.Palomba-Pomezia (Roma), Italia
| | - Renato Corradetti
- NEUROFARBA—Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Università di Firenze, Firenze, Italia
- * E-mail:
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Fitzgerald PJ, Watson BO. In vivo electrophysiological recordings of the effects of antidepressant drugs. Exp Brain Res 2019; 237:1593-1614. [PMID: 31079238 PMCID: PMC6584243 DOI: 10.1007/s00221-019-05556-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/06/2019] [Indexed: 12/11/2022]
Abstract
Antidepressant drugs are a standard biological treatment for various neuropsychiatric disorders, yet relatively little is known about their electrophysiologic and synaptic effects on mood systems that set moment-to-moment emotional tone. In vivo electrical recording of local field potentials (LFPs) and single neuron spiking has been crucial for elucidating important details of neural processing and control in many other systems, and yet electrical approaches have not been broadly applied to the actions of antidepressants on mood-related circuits. Here we review the literature encompassing electrophysiologic effects of antidepressants in animals, including studies that examine older drugs, and extending to more recently synthesized novel compounds, as well as rapidly acting antidepressants. The existing studies on neuromodulator-based drugs have focused on recording in the brainstem nuclei, with much less known about their effects on prefrontal or sensory cortex. Studies on neuromodulatory drugs have moreover focused on single unit firing patterns with less emphasis on LFPs, whereas the rapidly acting antidepressant literature shows the opposite trend. In a synthesis of this information, we hypothesize that all classes of antidepressants could have common final effects on limbic circuitry. Whereas NMDA receptor blockade may induce a high powered gamma oscillatory state via direct and fast alteration of glutamatergic systems in mood-related circuits, neuromodulatory antidepressants may induce similar effects over slower timescales, corresponding with the timecourse of response in patients, while resetting synaptic excitatory versus inhibitory signaling to a normal level. Thus, gamma signaling may provide a biomarker (or “neural readout”) of the therapeutic effects of all classes of antidepressants.
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Affiliation(s)
- Paul J Fitzgerald
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, 48109-5720, USA.
| | - Brendon O Watson
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, 48109-5720, USA.
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Ebrahimzadeh M, El Mansari M, Blier P. Synergistic effect of aripiprazole and escitalopram in increasing serotonin but not norepinephrine neurotransmission in the rat hippocampus. Neuropharmacology 2019; 146:12-18. [DOI: 10.1016/j.neuropharm.2018.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 10/31/2018] [Accepted: 11/05/2018] [Indexed: 12/28/2022]
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Volle J, Bregman T, Scott B, Diwan M, Raymond R, Fletcher PJ, Nobrega JN, Hamani C. Deep brain stimulation and fluoxetine exert different long-term changes in the serotonergic system. Neuropharmacology 2018; 135:63-72. [PMID: 29505786 DOI: 10.1016/j.neuropharm.2018.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 02/23/2018] [Accepted: 03/01/2018] [Indexed: 01/19/2023]
Abstract
Both selective serotonin reuptake inhibitors (SSRIs) and ventromedial prefrontal cortex (vmPFC) deep brain stimulation (DBS) modulate serotonergic activity. We compared the acute (1 day) and long-term (12 days) effects of vmPFC stimulation and fluoxetine on serotonin (5-HT) release and receptor expression in rats. Samples to measure serotonin levels were collected from the hippocampus using microdialysis. Serotonin transporter (SERT), 5-HT1A and 5-HT1B mRNA were measured using in situ hybridization. [3H]8-OH-DPAT and [125I]cyanopindolol autoradiography were used to measure 5-HT1A and 5-HT1B binding. Our results show that after fluoxetine injections serotonin levels were approximately 150% higher than at baseline. Twelve days later, pre-injection 5-HT extracellular concentration was substantially higher than on day 1. In contrast, serotonin levels following DBS were only 50% higher than at baseline. While pre-stimulation 5-HT on day 12 was significantly higher than on treatment day 1, no stimulation-induced 5-HT peak was recorded. SERT expression in the dorsal raphe was increased after acute fluoxetine and decreased following a single day of DBS. Neither fluoxetine nor DBS administered acutely substantially changed 5-HT1A or 5-HT1B binding. Chronic fluoxetine treatment, however, was associated with a decrease in [3H]8-OH-DPAT prefrontal cortex and hippocampus expression. In contrast, chronic DBS induced a significant increase in [125I]cyanopindolol binding in the prefrontal cortex, globus pallidus, substantia nigra and raphe nuclei. mRNA expression of 5-HT1A and 5-HT1B in raphe nuclei was not altered by either treatment. These results suggest that fluoxetine and DBS modulate activity of the serotonergic system but likely exert their effects through different mechanisms.
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Affiliation(s)
- Julien Volle
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Tatiana Bregman
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Brian Scott
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Mustansir Diwan
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Roger Raymond
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Paul J Fletcher
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Biopsychology Section, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - José N Nobrega
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Clement Hamani
- Behavioural Neurobiology Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Harqauil Neuromodulation Centre, Hurvitz Brain Science Program, Sunnybrook Research Institute, University of Toronto, 2075 Bayview Ave, Toronto, ON, M4N 3M5, Canada.
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11
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Partial inhibition of catecholamine activity and enhanced responsiveness to NMDA after sustained administration of vortioxetine. Neuropharmacology 2018; 128:425-432. [DOI: 10.1016/j.neuropharm.2017.10.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/26/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
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Long-term administration of the antidepressant vilazodone modulates rat brain monoaminergic systems. Neuropharmacology 2015; 99:696-704. [DOI: 10.1016/j.neuropharm.2015.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/26/2015] [Accepted: 09/05/2015] [Indexed: 11/23/2022]
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El Mansari M, Manta S, Oosterhof C, El Iskandrani KS, Chenu F, Shim S, Blier P. Restoration of serotonin neuronal firing following long-term administration of bupropion but not paroxetine in olfactory bulbectomized rats. Int J Neuropsychopharmacol 2015; 18:pyu050. [PMID: 25522394 PMCID: PMC4360219 DOI: 10.1093/ijnp/pyu050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Olfactory bulbectomized rats generally manifest many of the neurochemical, physiological, and behavioral features of major depressive disorder in humans. Another interesting feature of this model is that it responds to chronic but not acute antidepressant treatments, including selective serotonin reuptake inhibitors. The purpose of the present study was first to characterize the firing activity of dorsal raphe serotonin neurons in olfactory bulbectomized rats and then examine the effects of 2 antidepressants, bupropion and paroxetine. METHODS Olfactory bulbectomy was performed by aspirating olfactory bulbs in anesthetized rats. Vehicle and drugs were delivered for 2 and 14 days via subcutaneously implanted minipumps. In vivo electrophysiological recordings were carried out in male anesthetized Sprague-Dawley rats. RESULTS Following ablation of olfactory bulbs, the firing rate of serotonin neurons was decreased by 36%, leaving those of norepinephrine and dopamine neurons unchanged. In olfactory bulbectomized rats, bupropion (30 mg/kg/d) restored the firing rate of serotonin neurons to the control level following 2- and 14-day administration and also induced an increase in the tonic activation of serotonin(1A) receptors; paroxetine (10 mg/kg/d) did not result in a return to normal of the attenuated firing of serotonin neurons in olfactory bulbectomized rats. In the hippocampus, although at a higher dose of WAY 100635 than that required in bupropion-treated animals, paroxetine administration also resulted in an increase in the tonic activation of serotonin(1A) receptors. CONCLUSIONS The present results indicate that unlike paroxetine, bupropion administration normalized serotonin neuronal activity and increased tonic activation of the serotonin(1A) receptors in hippocampus.
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Affiliation(s)
- Mostafa El Mansari
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
| | - Stella Manta
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Chris Oosterhof
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | | | - Franck Chenu
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Stacey Shim
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Pierre Blier
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
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Jaworska N, Protzner A. Electrocortical features of depression and their clinical utility in assessing antidepressant treatment outcome. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2013; 58:509-14. [PMID: 24099498 DOI: 10.1177/070674371305800905] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Major depressive disorder (MDD) is primarily characterized by decreased affect and accompanying behavioural consequences, but it is also associated with cognitive dysfunction. Assessment of electroencephalographic (EEG) activity and associated event-related potentials (ERPs; derived from averaged EEG activity in response to a stimulus) in the context of MDD has provided insights into the electrocortical abnormalities associated with the disorder. Importantly, EEG and ERPs also have emerged as candidates for predicting and optimizing antidepressant (AD) treatment outcome. This is critical in light of relatively low remission rates or a limited response to initial AD interventions. In contrast to other neuroimaging approaches, EEG and ERPs may be superior for predicting and monitoring AD response, as electrocortical measures are relatively inexpensive, easy to use, and have excellent temporal (that is, millisecond) resolution, enabling fine-grained assessment of basic cognitive and emotive processes. This review aims to highlight the most consistently noted EEG and ERP features in MDD, which may one day assist with diagnostic confirmation, as well as the potential clinical utility of specific electrocortical measures in aiding with response prediction.
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Affiliation(s)
- Natalia Jaworska
- Postdoctoral Fellow, Department of Psychiatry, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta
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15
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Jaworska N, Blondeau C, Tessier P, Norris S, Fusee W, Blier P, Knott V. Response prediction to antidepressants using scalp and source-localized loudness dependence of auditory evoked potential (LDAEP) slopes. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:100-7. [PMID: 23360662 PMCID: PMC3654010 DOI: 10.1016/j.pnpbp.2013.01.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/12/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
The loudness-dependence of the auditory evoked potential (LDAEP) slope may be inversely related to serotonin (5-HT) neurotransmission. Thus, steep LDAEPs tend to predict a positive response to selective serotonin reuptake inhibitor (SSRI) antidepressants, which augment 5-HT. However, LDAEPs also predict outcome to antidepressants indirectly altering 5-HT (e.g. bupropion). Hence, the LDAEP's predicative specificity and sensitivity to antidepressant response/outcome remains elusive. Scalp N1, P2 and N1/P2 LDAEP slopes and standardized low resolution brain electromagnetic tomography (sLORETA)-localized N1 and P2 LDAEP slopes were assessed in depressed individuals (N=51) at baseline, 1 and 12 weeks post-treatment with one of three antidepressant regimens [escitalopram (ESC)+bupropion (BUP), ESC or BUP]. Clinical response was greatest with ESC+BUP at week 1. Treatment responders had steep N1 sLORETA-LDAEP baseline slopes while non-responders had shallow ones. P2 sLORETA-LDAEP slope increases at 1 week existed in responders; decreases were noted in non-responders. Exploratory analyses indicated that more BUP and ESC responders versus non-responders had steep baseline N1 sLORETA-LDAEP slopes. Additionally, slight decreases in scalp P2 LDAEP by week 1 existed for ESC treatment, while slope increases existed with ESC+BUP treatment. Only baseline N1 sLORETA-LDAEP discriminated treatment responders/non-responders. This work confirms that certain LDAEP measures are associated with treatment outcome and appear to be differentially modulated with varying antidepressant drug regimens, though this should be confirmed using larger samples.
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Affiliation(s)
- Natalia Jaworska
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
| | - Claude Blondeau
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Pierre Tessier
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Sandhaya Norris
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Wendy Fusee
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
| | - Pierre Blier
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
,Departments of Psychiatry & Cellular and Molecular Medicine, University of Ottawa
| | - Verner Knott
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada
,Department of Psychology, University of Ottawa, Ottawa, ON, Canada
,Departments of Psychiatry & Cellular and Molecular Medicine, University of Ottawa
,Department of Psychology/Behavioural Neuroscience, Carleton University, Ottawa, ON, Canada
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16
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Yang H, Thompson A, McIntosh BJ, Altieri SC, Andrews AM. Physiologically relevant changes in serotonin resolved by fast microdialysis. ACS Chem Neurosci 2013; 4:790-8. [PMID: 23614776 PMCID: PMC3656759 DOI: 10.1021/cn400072f] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 04/03/2013] [Indexed: 01/17/2023] Open
Abstract
Online microdialysis is a sampling and detection method that enables continuous interrogation of extracellular molecules in freely moving subjects under behaviorally relevant conditions. A majority of recent publications using brain microdialysis in rodents report sample collection times of 20-30 min. These long sampling times are due, in part, to limitations in the detection sensitivity of high performance liquid chromatography (HPLC). By optimizing separation and detection conditions, we decreased the retention time of serotonin to 2.5 min and the detection threshold to 0.8 fmol. Sampling times were consequently reduced from 20 to 3 min per sample for online detection of serotonin (and dopamine) in brain dialysates using a commercial HPLC system. We developed a strategy to collect and to analyze dialysate samples continuously from two animals in tandem using the same instrument. Improvements in temporal resolution enabled elucidation of rapid changes in extracellular serotonin levels associated with mild stress and circadian rhythms. These dynamics would be difficult or impossible to differentiate using conventional microdialysis sampling rates.
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Affiliation(s)
- Hongyan Yang
- Semel Institute for Neuroscience & Human
Behavior and Hatos Center for Neuropharmacology, David Geffen School
of Medicine, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California, Los Angeles,
California, United States
| | - Andrew
B. Thompson
- Semel Institute for Neuroscience & Human
Behavior and Hatos Center for Neuropharmacology, David Geffen School
of Medicine, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California, Los Angeles,
California, United States
| | | | - Stefanie C. Altieri
- Semel Institute for Neuroscience & Human
Behavior and Hatos Center for Neuropharmacology, David Geffen School
of Medicine, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California, Los Angeles,
California, United States
| | - Anne M. Andrews
- Semel Institute for Neuroscience & Human
Behavior and Hatos Center for Neuropharmacology, David Geffen School
of Medicine, Department of Chemistry and Biochemistry, and California NanoSystems Institute, University of California, Los Angeles,
California, United States
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Chenu F, El Mansari M, Blier P. Electrophysiological effects of repeated administration of agomelatine on the dopamine, norepinephrine, and serotonin systems in the rat brain. Neuropsychopharmacology 2013; 38:275-84. [PMID: 22871919 PMCID: PMC3527117 DOI: 10.1038/npp.2012.140] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Agomelatine is a melatonergic MT1/MT2 agonist and a serotonin (5-HT) 5-HT(2C) antagonist. The effects of 2-day and 14-day administration of agomelatine were investigated on the activity of ventral tegmental area (VTA) dopamine (DA), locus coeruleus (LC) norepinephrine (NE), and dorsal raphe nucleus (DRN) 5-HT neurons using in vivo electrophysiology in rats. The 5-HT(1A) transmission was assessed at hippocampus CA3 pyramidal neurons. After a 2-day regimen of agomelatine (40 mg/kg/day, i.p.), an increase in the number of spontaneously active VTA-DA neurons (p<0.001) and in the firing rate of LC-NE neurons (p<0.001) was observed. After 14 days, the administration of agomelatine induced an increase in: (1) the number of spontaneously active DA neurons (p<0.05), (2) the bursting activity of DA neurons (bursts/min, p<0.01 and percentage of spikes occurring in bursts, p<0.05), (3) the firing rate of DRN-5-HT neurons (p<0.05), and (4) the tonic activation of postsynaptic 5-HT(1A) receptors located in the hippocampus. The increase in 5-HT firing rate was D2 dependent, as it was antagonized by the D2 receptor antagonist paliperidone. The enhancement of NE firing was restored by the 5-HT(2A) receptor antagonist MDL-100,907 after the 14-day regimen. All the effects of agomelatine were antagonized by a single administration of the melatonergic antagonist S22153 (except for the increase in the percentage of spikes occurring in burst for DA neurons). The present results suggest that (1) agomelatine exerts direct (2 days) and indirect (14 days) modulations of monoaminergic neuronal activity and (2) the melatonergic agonistic activity of agomelatine contributes to the enhancement of DA and 5-HT neurotransmission.
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Affiliation(s)
- Franck Chenu
- Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada
| | - Mostafa El Mansari
- Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada
| | - Pierre Blier
- Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada,Institute of Mental Health Research (IMHR), 1145 Carling Avenue, University of Ottawa, Room 6412, Ottawa K1Z 7K4, ON, Canada, Tel: +1 613 722 6521 (ext 6944), Fax: +1 613 761 3610, E-mail:
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18
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Ghanbari R, El Mansari M, Blier P. Enhancement of serotonergic and noradrenergic neurotransmission in the rat hippocampus by sustained administration of bupropion. Psychopharmacology (Berl) 2011; 217:61-73. [PMID: 21445565 DOI: 10.1007/s00213-011-2260-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/06/2011] [Indexed: 12/31/2022]
Abstract
RATIONALE Previous studies reported that bupropion, an effective antidepressant, exerts modulatory actions on serotonin (5-HT) and norepinephrine (NE) neurons. OBJECTIVES This study examined effects of bupropion administration on 5-HT and NE neurotransmission in hippocampus. METHODS Electrophysiological recordings were obtained from anesthetized Sprague-Dawley rats. Subcutaneously implanted minipumps delivered saline or bupropion (30 mg/kg/day) for 2 and 14 days. RESULTS Although sustained bupropion administration did not alter the sensitivity of 5-HT(1A) and α₂-adrenergic receptors, the tonic activation of postsynaptic 5-HT(1A) receptors by endogenous 5-HT was enhanced in 14-day bupropion-treated rats to a greater extent than in the 2-day and control rats, as revealed by the greater disinhibitory action of the 5-HT(1A) antagonist WAY-100635 on hippocampus pyramidal neurons. The function of terminal 5-HT(1B) autoreceptors was not changed as determined by the unaltered effectiveness of different frequencies of stimulation of the ascending 5-HT fibers. The function of α₂-adrenergic receptors on 5-HT terminals was, however, diminished, as indicated by the lesser effect of the α₂-adrenoceptor agonist clonidine. Tonic activation of postsynaptic α₂- and α₁-adrenoceptors by endogenous NE was also increased in 14-day bupropion-treated rats, as indicated by the greater effect of the α₂- and α₁-adrenoceptor antagonists idazoxan and prazosin, respectively, on pyramidal firing. The function of terminal α₂-adrenergic autoreceptors was attenuated since increasing frequency of stimulation of the ascending NE pathway produced a lesser degree of suppression of pyramidal neurons in rats administered bupropion than the control. CONCLUSION Enhancement of 5-HT and NE transmissions in hippocampus by prolonged bupropion may account for its effectiveness in major depression.
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MESH Headings
- Action Potentials/drug effects
- Animals
- Antidepressive Agents, Second-Generation/administration & dosage
- Antidepressive Agents, Second-Generation/pharmacology
- Bupropion/administration & dosage
- Bupropion/pharmacology
- CA3 Region, Hippocampal/drug effects
- CA3 Region, Hippocampal/metabolism
- Electric Stimulation
- Infusion Pumps, Implantable
- Iontophoresis
- Male
- Neurons
- Norepinephrine/metabolism
- Pyramidal Cells/drug effects
- Pyramidal Cells/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/metabolism
- Synaptic Transmission/drug effects
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Affiliation(s)
- Ramez Ghanbari
- Institute of Mental Health Research, University of Ottawa, Room 6411, 1145 Carling Avenue, Ottawa, K1Z7K4 ON, Canada
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Hache G, Coudore F, Gardier AM, Guiard BP. Monoaminergic Antidepressants in the Relief of Pain: Potential Therapeutic Utility of Triple Reuptake Inhibitors (TRIs). Pharmaceuticals (Basel) 2011. [PMCID: PMC4053958 DOI: 10.3390/ph4020285] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Over 75% of depressed patients suffer from painful symptoms predicting a greater severity and a less favorable outcome of depression. Imaging, anatomical and functional studies have demonstrated the existence of common brain structures, neuronal pathways and neurotransmitters in depression and pain. In particular, the ascending serotonergic and noradrenergic pathways originating from the raphe nuclei and the locus coeruleus; respectively, send projections to the limbic system. Such pathways control many of the psychological functions that are disturbed in depression and in the perception of pain. On the other hand, the descending pathways, from monoaminergic nuclei to the spinal cord, are specifically implicated in the inhibition of nociception providing rationale for the use of serotonin (5-HT) and/or norepinephrine (NE) reuptake inhibitors (SSRIs, NRIs, SNRIs), in the relief of pain. Compelling evidence suggests that dopamine (DA) is also involved in the pathophysiology and treatment of depression. Indeed, recent insights have demonstrated a central role for DA in analgesia through an action at both the spinal and suprasinal levels including brain regions such as the periaqueductal grey (PAG), the thalamus, the basal ganglia and the limbic system. In this context, dopaminergic antidepressants (i.e., containing dopaminergic activity), such as bupropion, nomifensine and more recently triple reuptake inhibitors (TRIs), might represent new promising therapeutic tools in the treatment of painful symptoms with depression. Nevertheless, whether the addition of the dopaminergic component produces more robust effects than single- or dual-acting agents, has yet to be demonstrated. This article reviews the main pathways regulating pain transmission in relation with the monoaminergic systems. It then focuses on the current knowledge regarding the in vivo pharmacological properties and mechanism of action of monoaminergic antidepressants including SSRIs, NRIs, SNRIs and TRIs. Finally, a synthesis of the preclinical studies supporting the efficacy of these antidepressants in analgesia is also addressed in order to highlight the relative contribution of 5-HT, NE and DA to nociception.
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Affiliation(s)
- Guillaume Hache
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: 011-331-46-83-53-61
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Electrophysiological studies in the rat brain on the basis for aripiprazole augmentation of antidepressants in major depressive disorder. Psychopharmacology (Berl) 2009; 206:335-44. [PMID: 19641901 DOI: 10.1007/s00213-009-1611-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 07/02/2009] [Indexed: 12/28/2022]
Abstract
RATIONALE Aripiprazole (ARI) is an atypical antipsychotic approved by the Food and Drug Administration for use in major depressive disorder as an adjunct to antidepressants. However, the precise mechanisms responsible for the effectiveness of ARI augmentation are not fully understood. OBJECTIVES The current study was aimed at examining the effects of ARI administration alone and in combination with the selective serotonin reuptake inhibitors (SSRI) escitalopram (ESC) on the firing of serotonin (5-HT), norepinephrine (NE), and dopamine (DA) neurons. METHODS Electrophysiological experiments were carried out in anesthetized Sprague-Dawley rats. ESC was delivered via subcutaneously implanted osmotic minipumps at a dose of 10 mg/kg/day. ARI was subcutaneously injected daily at a dose of 2 mg/kg/day. Both drugs were administered for 2 and 14 days alone and in combination. Control rats received physiological saline in analogous regimens. RESULTS Two-day ESC administration resulted in a significant decrease in the firing rate of 5-HT, NE, and DA neurons. Following 14 days of ESC administration, 5-HT firing returned to the baseline. The firing rate of NE and DA neurons remained significantly decreased. ARI administered for 2 or 14 days significantly increased the firing rate of 5-HT neurons by 36% and 48%, respectively, but not those of DA and NE neurons. Desensitization of somatodendritic 5-HT autoreceptors was observed after 2 days of ARI administration. The combination of the two drugs reversed the inhibitory action of ESC on the firing rate of 5-HT, NE, and DA neurons. CONCLUSION The present study showed that addition of ARI to an SSRI regimen reverses the inhibitory action of the SSRI on monoaminergic neuronal firing.
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Ghanbari R, El Mansari M, Shahid M, Blier P. Electrophysiological characterization of the effects of asenapine at 5-HT(1A), 5-HT(2A), alpha(2)-adrenergic and D(2) receptors in the rat brain. Eur Neuropsychopharmacol 2009; 19:177-87. [PMID: 19116183 DOI: 10.1016/j.euroneuro.2008.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/23/2008] [Accepted: 11/04/2008] [Indexed: 10/21/2022]
Abstract
Asenapine is a psychopharmacologic agent being developed for schizophrenia and bipolar disorder. This study electrophysiologically characterized the in vivo effects of asenapine at dorsal raphe nucleus (DRN) and hippocampus serotonin-1A (5-HT(1A)), ventral tegmental area D(2), locus coeruleus 5-HT(2A,) and alpha(2)-adrenergic receptors in anesthetized rats. Asenapine displayed potent antagonistic activity at alpha(2)-adrenoceptors (ED(50), 85+/-2 microg/kg), 5-HT(2A) (ED(50), 75+/-2 microg/kg) and D(2) receptors (ED(50), 40+/-2 microg/kg) as evidenced by its reversal of clonidine-, DOI-, and apomorphine-induced inhibition of norepinephrine and dopamine neurons. In contrast, asenapine acted as a partial agonist at 5-HT(1A) receptors in DRN and hippocampus, as indicated by blockade of its inhibitory effect on neuronal firing by the 5-HT(1A) antagonist WAY 100635 and the partial inhibition of the suppressant action of 5-HT when co-applied by microiontophoresis. These results confirm that asenapine displays potent antagonistic activity at 5-HT(2A), D(2), alpha(2)-adrenergic receptors and provide evidence to support its 5-HT(1A) partial agonistic activity.
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Affiliation(s)
- Ramez Ghanbari
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z7K4, Canada.
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