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Wilson C, Hannan AJ, Renoir T. Serotonergic agonism and pharmacologically-induced adolescent stress cause operant-based learning deficits in mice. Neuropharmacology 2024; 244:109801. [PMID: 38040286 DOI: 10.1016/j.neuropharm.2023.109801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/17/2023] [Accepted: 11/26/2023] [Indexed: 12/03/2023]
Abstract
BACKGROUND The interplay between environmental stress and genetic factors is thought to play an important role in the pathogenesis and maintenance of obsessive-compulsive disorder (OCD). However, the relative contribution of these causative antecedents in the manifestation of cognitive inflexibility-a phenotype often seen in obsessive-compulsive (OC)- spectrum disorders-is not fully understood. METHOD In this study, we treated mice with 50 mg/L corticosterone (CORT, a glucocorticoid stress hormone) in their drinking water during adolescence. In adulthood, we assessed anxiety-like behaviour and locomotor activity; along with operant-based discrimination and reversal learning. RU-24969, a selective serotonin receptor 5-HT1A/1B receptor agonist, was used as an acute pharmacological model of OC-like behaviour. RU-24969 (5 mg/kg) was administered prior to each reversal learning testing session. RESULTS We found that acute treatment with 5 mg/kg RU-24969 induced stereotyped hyperlocomotion in vehicle- and CORT-treated mice. Furthermore, pre-treatment with CORT in adolescence produced subtle anxiety-like behaviour in adult mice, and also resulted in an impairment to late-stage discrimination learning and alterations to reversal learning. Finally, acute treatment with 5 mg/kg RU-24969 caused an impairment to early-stage reversal learning. CONCLUSION Whilst we revealed dissociable detrimental effects of adolescent CORT treatment and acute 5-HT1A/1B receptor agonism on discrimination and reversal learning, respectively, we did not find evidence of additive deleterious effects of these two treatments. We therefore suggest that while disrupted serotonergic signalling is likely to be involved in the cognitive phenotype of OC-spectrum disorders, distinct neuropathological pathways may be at play in mediating the role of stress as an antecedent in OCD and related illnesses.
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Affiliation(s)
- Carey Wilson
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, Australia; Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia.
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Najm Al-Halboosi DA, Savchenko O, Heisler LK, Sylantyev S. Modulation of GABA release by 5-HT 1B receptors: An interplay with AMPA-receptors and voltage-gated Ca 2+ channels. Neuropharmacology 2023; 241:109758. [PMID: 37827445 DOI: 10.1016/j.neuropharm.2023.109758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/02/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
Obesity has become a worldwide health challenge and commonly results from the intake of more calories than the body requires. The brain represents the master controller of food intake and as such has been the target of obesity medications. However, key mechanisms of druggable targets remain to be defined. Neurons within the arcuate nucleus of the hypothalamus co-expressing neuropeptide Y (NPY), agouti-related protein (AgRP) and GABA (NAG) are fundamental stimulators of hunger and food intake. NAG neurons also inhibit local satiety-promoting pro-opiomelanocortin (POMC) neurons. Agonists of the 1B subtype of metabotropic serotonin receptor (5-HT1BR) reduce food intake in part through the inhibition of hunger-promoting NAG neurons. We first confirmed that 5-HT1BR activation suppressed intake of a palatable Western diet in a mouse model of common dietary-induced obesity and genetically prone obesity. Next, we combined several electrophysiological approaches to analyse the effect of 5-HT1BRs in NAG neuron cell activity and GABA release. 5-HT1BR activation reduced NAG neuron action potential frequency and neurotransmitter release. We found that 5-HT1BR impact on GABA release from NAG neurons is mediated through voltage-gated Ca2+ channels with a critical input from glutamate receptors of AMPA subtype (AMPARs). As a fundamental outcome, this type of interplay provides an uncommon example of metabotropic action of AMPARs which regulates inhibitory signalling due to modulation of GABA release. As a translational outcome, our results provide a key mechanism through which 5-HT1BR drugs inhibit appetite-stimulating neurons within the brain to suppress food intake. This article is part of the Special Issue on "Ukrainian Neuroscience".
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Affiliation(s)
| | - Olena Savchenko
- National Technical University of Ukraine "Igor Sikorsky KPI", Department of Biotechnology, 37 Beresteiskyi Ave., Kyiv, 03056, Ukraine
| | - Lora K Heisler
- Rowett Institute, University of Aberdeen, Ashgrove Rd. West, Aberdeen, AB25 2ZD, UK
| | - Sergiy Sylantyev
- Rowett Institute, University of Aberdeen, Ashgrove Rd. West, Aberdeen, AB25 2ZD, UK; Odesa National Mechnikov University, Biological Department, 2 Shampansky Ln., Odesa, 65015, Ukraine.
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Desrochers SS, Nautiyal KM. Serotonin 1B receptor effects on response inhibition are independent of inhibitory learning. Neurobiol Learn Mem 2022; 187:107574. [PMID: 34902574 PMCID: PMC8900532 DOI: 10.1016/j.nlm.2021.107574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 11/07/2021] [Accepted: 12/03/2021] [Indexed: 01/03/2023]
Abstract
Impulsivity is defined in terms of deficits in instrumental response inhibition, when the inability to withhold an action produces a negative outcome. However, there are many behavioral and cognitive constructs which theoretically could contribute to disordered impulsivity, including Pavlovian responding, which few studies have considered in this context. In the present set of studies, we examine Pavlovian inhibitory learning and excitatory responding in a mouse model for dysregulated impulsivity, specifically, mice lacking the serotonin 1B receptor (5-HT1BR). Consistent with previous results, we show that these mice display increased impulsivity as measured by premature responding in the operant 5-choice serial reaction time test. In a Pavlovian conditioned inhibition paradigm, they also show a decreased ability to withhold responding, but importantly have an intact ability to learn inhibitory associations. In a Pavlovian appetitive conditioning experiment, 5-HT1BR knockout mice show normal responding under a positive contingency schedule, however, they display increased responding to cues presented on an independent schedule from reinforcement in a zero contingency schedule. Interestingly this difference does not occur when the cues are explicitly unpaired in a negative contingency schedule, nor during a 25% reinforcement schedule. Overall, while our results show that the deficits in operant response inhibition in mice lacking 5-HT1BR are likely not due to Pavlovian inhibitory or excitatory learning, it is relevant to consider associative learning in the context of dysregulated impulsive behavior.
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Affiliation(s)
| | - Katherine M. Nautiyal
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755,To whom correspondence should be addressed: Katherine M. Nautiyal, PhD, 6207 Moore Hall, Hanover, NH 03755, 603-646-2778,
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Tang HX, Lin J, Xu CB, Chen G, Liao YJ, Lei NR, Li J. Minimally modified low-density lipoprotein upregulates mouse mesenteric arterial 5-HT 1B receptor in vivo via activation of the JAK2/STAT3 pathway. Microvasc Res 2021; 139:104260. [PMID: 34624308 DOI: 10.1016/j.mvr.2021.104260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/08/2021] [Accepted: 09/06/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To explore whether minimally modified low-density lipoprotein (mmLDL) upregulates mesenteric arterial 5-hydroxytryptamine 1B (5-HT1B) receptor expression by activating the JAK2/STAT3 signaling pathway. METHODS Mice were randomly divided into the following groups: the normal saline (NS), LDL, mmLDL, mmLDL+galiellactone (GL, a JAK2/STAT3 pathway inhibitor), and mmLDL+DMSO groups. The dose-response curve of mesenteric arterial ring constriction after administration of 5-carboxamidotryptamine (5-CT), an agonist of 5-HT1B, was recorded with a microvascular tensiometer. JAK2, p-JAK2, STAT3, p-STAT3, and 5-HT1B receptor protein expression levels were determined by Western blotting. 5-HT1B receptor mRNA levels were measured by RT-PCR. 5-HT1B receptor protein expression was determined by immunofluorescence. RESULTS Injection of mmLDL into the tail vein significantly increased the contractile dose-response curve after 5-CT stimulation, as the Emax was 82.15 ± 6.15% in the NS group and 171.88 ± 5.78% in the mmLDL group (P < 0.01); significantly elevated 5-HT1B receptor mRNA and protein expression levels; and significantly increased p-JAK2 and p-STAT3 protein expression levels. After intraperitoneal injection of GL, the vasoconstrictive response was significantly reduced compared with that in the mmLDL group, as the Emax was decreased to 97.14 ± 1.20% (P < 0.01); 5-HT1B receptor mRNA and protein expression levels were significantly reduced; STAT3 phosphorylation and p-JAK2 and p-STAT3 protein expression were not significantly changed; and 5-HT1B receptor expression was altered via inhibition of p-STAT3 binding to DNA, which suppressed transcription. CONCLUSIONS mmLDL can upregulate 5-HT1B receptor expression in mouse mesenteric arteries by activating the JAK2/STAT3 signaling pathway.
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Affiliation(s)
- Hong-Xia Tang
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China
| | - Jie Lin
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China
| | - Cang-Bao Xu
- Shanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Gen Chen
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China
| | - Ya-Jie Liao
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China
| | - Ning-Ren Lei
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China
| | - Jie Li
- The First People's Hospital of Chenzhou, Hengyang Medical School, University of South China, Hu'nan, China.
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Lavoie B, Roberts JA, Haag MM, Spohn SN, Margolis KG, Sharkey KA, Lian JB, Mawe GM. Gut-derived serotonin contributes to bone deficits in colitis. Pharmacol Res 2018; 140:75-84. [PMID: 30030171 PMCID: PMC6336528 DOI: 10.1016/j.phrs.2018.07.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/14/2018] [Accepted: 07/16/2018] [Indexed: 02/07/2023]
Abstract
Osteoporosis and bone fractures occur at higher frequency in patients with inflammatory bowel disease (IBD), and decreased bone mass is observed in animal models of colitis. Another consistent feature of colitis is increased serotonin (5-HT) availability in the intestinal mucosa. Since gut-derived 5-HT can decrease bone mass, via activation of 5-HT1B receptors on pre-osteoblasts, we tested the hypothesis that 5-HT contributes to bone loss in colitis. Colitis was chronically induced in mice by adding dextran sodium sulfate (DSS) to their drinking water for 21 days. At day 21, circulating 5-HT levels were elevated in DSS-inflamed mice. Micro-computed tomography of femurs showed a decrease in trabecular bone volume fraction, formation, and surface area, due largely to decreased trabecular numbers in DSS-treated mice. The colitis-induced loss of trabecular bone was significantly suppressed in mice treated with the 5-HT synthesis inhibitor, p-chloro-DL-phenylalanine (PCPA; 300 mg/kg/day IP daily), and in mice treated with the 5-HT1B receptor antagonist GR55562 (1 mg/Kg/day SC daily). The 5-HT reuptake transporter (SERT) is critical for moving 5-HT from the interstitial space into enterocytes and from serum into platelets. Mice lacking SERT exhibited significant deficits in trabecular bone mass that are similar to those observed in DSS-inflamed mice, and these deficits were not extensively worsened by DSS-induced colitis in the SERT-/- mice. Taken together, findings from both the DSS and SERT-/- mouse models support a contributing role for 5-HT as a significant factor in bone loss induced by colitis.
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Affiliation(s)
- B Lavoie
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA.
| | - J A Roberts
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
| | - M M Haag
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
| | - S N Spohn
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
| | - K G Margolis
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - K A Sharkey
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - J B Lian
- Department of Biochemistry, The University of Vermont, Burlington, VT, USA
| | - G M Mawe
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
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Lindberg A, Nag S, Schou M, Takano A, Matsumoto J, Amini N, Elmore CS, Farde L, Pike VW, Halldin C. [ 11C]AZ10419096 - a full antagonist PET radioligand for imaging brain 5-HT 1B receptors. Nucl Med Biol 2017; 54:34-40. [PMID: 28950161 DOI: 10.1016/j.nucmedbio.2017.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/05/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The serotonergic system is widely present in all regions of the central nervous system (CNS) and plays a key modulatory role in many of its functions. Positron emission tomography (PET) is used to study several serotonin receptors in CNS in vivo. The G-protein coupled receptor 5-HT1B is mostly present in the occipital cortex and in midbrain and is linked to several psychiatric disorders. There is evidence that agonist PET radioligands for neuroreceptors are more sensitive to endogenous neurotransmitters than antagonists. Our previously developed 5-HT1B receptor PET radioligand, [11C]AZ10419369, is now considered a partial agonist. In this work we are aiming to develop a full antagonist PET radioligand for imaging brain 5-HT1B receptors, and evaluate its sensitivity to increased endogenous serotonin concentration. MATERIALS [11C]AZ10419096 was synthesized by rapid methylation of the prepared corresponding N-desmethyl precursor with [11C]methyl triflate. Five PET measurements were performed in cynomolgus monkeys, consisting of two at baseline, one after treatment of a monkey with a 5-HT1B antagonist, AR-A000002, and two in which fenfluramine was administered during scanning to induce endogenous serotonin release. RESULTS AND DISCUSSION [11C]AZ10419096 was synthesized in high yield and purity within 30 min, including purification, formulation and sterile filtration. The baseline PET measurements demonstrated [11C]AZ10419096 to have favorable radioligand characteristics, including high specific binding in brain regions that have high 5-HT1B density, such as occipital cortex and globus pallidus, as well as subsequent rapid elimination from brain and a minor abundance of lipophilic radiometabolites in plasma. AR-A00002 completely blocked radioligand receptor-specific binding. Fenfluramine produced a distinct displacement of radioligand consistent with an expected increase of synaptic endogenous serotonin concentration. CONCLUSIONS [11C]AZ10419096, a full 5-HT1B antagonist PET radioligand, demonstrates high specific binding in monkey brain that is sensitive to competition from a known 5-HT1B antagonist as well as to putatively increased endogenous serotonin levels.
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Affiliation(s)
- Anton Lindberg
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden.
| | - Sangram Nag
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Magnus Schou
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden; AstraZeneca, Personalised Healthcare and Biomarkers, AstraZeneca PET Science Centre, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Akihiro Takano
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Junya Matsumoto
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Nahid Amini
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Charles S Elmore
- Isotope chemistry, Early Chemical Development, Pharmaceutical Sciences Innovative Medicines and Early Development, AstraZeneca, Mölndal, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden; AstraZeneca, Personalised Healthcare and Biomarkers, AstraZeneca PET Science Centre, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
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Araldi D, Ferrari LF, Green P, Levine JD. Marked sexual dimorphism in 5-HT 1 receptors mediating pronociceptive effects of sumatriptan. Neuroscience 2016; 344:394-405. [PMID: 28040566 DOI: 10.1016/j.neuroscience.2016.12.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/17/2016] [Accepted: 12/18/2016] [Indexed: 11/28/2022]
Abstract
Amongst the side effects of triptans, a substantial percentage of patients experience injection site pain and tenderness, the underlying mechanism of which is unknown. We found that the dose range from 10fg to 1000ng (intradermal) of sumatriptan induced a complex dose-dependent mechanical hyperalgesia in male rats, with distinct peaks, at 1pg and 10ng, but no hyperalgesia at 1ng. In contrast, in females, there was 1 broad peak. The highest dose (1000ng) did not produce hyperalgesia in either sex. We evaluated the receptors mediating sumatriptan hyperalgesia (1pg, 1 and 10ng). In males, the injection of an antagonist for the serotonin (5-HT) receptor subtype 1B (5-HT1B), but not 5-HT1D, markedly inhibited sumatriptan (1pg)-induced hyperalgesia, at 10ng a 5-HT1D receptor antagonist completely eliminated hyperalgesia. In contrast, in females, the 5-HT1D, but not 5-HT1B, receptor antagonist completely blocked sumatriptan (1pg and 10ng) hyperalgesia and both 5-HT1B and 5-HT1D receptor antagonists attenuated hyperalgesia (1ng) in females, which is GPR30 estrogen receptor dependent. While selective 5-HT1D or 5-HT1B, agonists produce robust hyperalgesia in female and male rats, respectively, when co-injected the hyperalgesia induced in both sexes was attenuated. Mechanical hyperalgesia induced by sumatriptan (1pg and 10ng) is dependent on the G-protein αi subunit and protein kinase A (PKA), in IB4-positive and negative nociceptors. Understanding the mechanisms responsible for the complex dose dependence for triptan hyperalgesia may provide useful information for the design of anti-migraine drugs with improved therapeutic profiles.
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Affiliation(s)
- Dioneia Araldi
- Department of Oral & Maxillofacial Surgery, University of California at San Francisco, San Francisco, CA 94143-0440, United States; Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143-0440, United States
| | - Luiz F Ferrari
- Department of Oral & Maxillofacial Surgery, University of California at San Francisco, San Francisco, CA 94143-0440, United States; Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143-0440, United States
| | - Paul Green
- Department of Oral & Maxillofacial Surgery, University of California at San Francisco, San Francisco, CA 94143-0440, United States; Department of Preventative & Restorative, University of California at San Francisco, San Francisco, CA 94143-0440, United States; Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143-0440, United States
| | - Jon D Levine
- Department of Oral & Maxillofacial Surgery, University of California at San Francisco, San Francisco, CA 94143-0440, United States; Division of Neuroscience, University of California at San Francisco, San Francisco, CA 94143-0440, United States.
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Ishola IO, Agbaje EO, Akinleye MO, Ibeh CO, Adeyemi OO. Antidepressant-like effect of the hydroethanolic leaf extract of Alchornea cordifolia (Schumach. & Thonn.) Mull. Arg. (Euphorbiaceae) in mice: involvement of monoaminergic system. J Ethnopharmacol 2014; 158 Pt A:364-372. [PMID: 25448506 DOI: 10.1016/j.jep.2014.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/12/2014] [Accepted: 10/08/2014] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The leaf of Alchornea cordifolia (Euphorbiaceae) is used in traditional African medicine in the treatment of various neurological and psychiatric disorders including depression. Previous studies have shown its potent antidepressant-like effect in the forced swimming test (FST). Hence, this study sought to investigate the involvement of monoaminergic systems in the antidepressant-like effect elicited by hydroethanolic leaf extract of Alchornea cordifolia (HeAC) in the FST. MATERIALS AND METHODS HeAC (25-400mg/kg, p.o.) was administered 1h before the FST. To investigate the contribution of monoaminergic systems to antidepressant-like effect, receptors antagonists were injected 15min before oral administration of HeAC (200mg/kg) to mice and 1h thereafter, subjected to FST. RESULTS HeAC (200 and 400mg/kg, p.o.) produced dose dependent and significant (P<0.001) antidepressant-like effect, in the FST, without accompanying changes in spontaneous locomotor activities in the open-field test. The anti-immobility effect of HeAC (200mg/kg) in the FST was prevented by pretreatment of mice with SCH 23390 (0.05mg/kg, s.c., a dopamine D1 receptor antagonist), sulpiride (50mg/kg, i.p., a dopamine D2 receptor antagonist), prazosin (1mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1mg/kg, i.p., an α2-adrenoceptor antagonist), and GR 127993 (5-HT1B receptor antagonist). Similarly, 3 days intraperitoneal injection of p-chlorophenylalanine (pCPA, 150mg/kg, i.p., an inhibitor of serotonin synthesis) prevented the antidepressant-like effect elicited by HeAC. The combination of subeffective doses of imipramine (5mg/kg, p.o.) or fluoxetine (5mg/kg, p.o.), with HeAC (25mg/kg, p.o., subeffective dose) produced a synergistic antidepressant-like effect in the FST. CONCLUSION The hydroethanolic extract of Alchornea cordifolia possesses antidepressant-like effect mediated through interaction with dopamine (D1 and D2), noradrenergic (α1 and α2 adrenoceptors), and serotonergic (5HT1B receptors) systems. Also, the potentiation of the anti-immobility effect of conventional antidepressants (fluoxetine and imipramine) by Alchornea cordifolia suggest potential therapeutic effect in depression.
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Affiliation(s)
- Ismail O Ishola
- Department of Pharmacology, Therapeutics, and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003 Surulere, Lagos, Nigeria
| | - Esther O Agbaje
- Department of Pharmacology, Therapeutics, and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003 Surulere, Lagos, Nigeria.
| | - Moshood O Akinleye
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Lagos, Lagos, Nigeria
| | - Chris O Ibeh
- Department of Pharmacology, Therapeutics, and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003 Surulere, Lagos, Nigeria
| | - Olufunmilayo O Adeyemi
- Department of Pharmacology, Therapeutics, and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003 Surulere, Lagos, Nigeria
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Montañez S, Munn JL, Owens WA, Horton RE, Daws LC. 5-HT1B receptor modulation of the serotonin transporter in vivo: studies using KO mice. Neurochem Int 2013; 73:127-31. [PMID: 24246466 DOI: 10.1016/j.neuint.2013.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/01/2013] [Accepted: 11/05/2013] [Indexed: 11/28/2022]
Abstract
The serotonin transporter (SERT) controls the strength and duration of serotonergic neurotransmission by the high-affinity uptake of serotonin (5-HT) from extracellular fluid. SERT is a key target for many psychotherapeutic and abused drugs, therefore understanding how SERT activity and expression are regulated is of fundamental importance. A growing literature suggests that SERT activity is under regulatory control of the 5-HT1B autoreceptor. The present studies made use of mice with a constitutive reduction (5-HT1B+/-) or knockout of 5-HT1B receptors (5-HT1B-/-), as well as mice with a constitutive knockout of SERT (SERT-/-) to further explore the relationship between SERT activity and 5-HT1B receptor expression. High-speed chronoamperometry was used to measure clearance of 5-HT from CA3 region of hippocampus in vivo. Serotonin clearance rate, over a range of 5-HT concentrations, did not differ among 5-HT1B receptor genotypes, nor did [(3)H]cyanoimipramine binding to SERT in this brain region, suggesting that SERT activity is not affected by constitutive reduction or loss of 5-HT1B receptors; alternatively, it might be that other transport mechanisms for 5-HT compensate for loss of 5-HT1B receptors. Consistent with previous reports, we found that the 5-HT1B receptor antagonist, cyanopindolol, inhibited 5-HT clearance in wild-type mice. However, this effect of cyanopindolol was lost in 5-HT1B-/- mice and diminished in 5-HT1B+/- mice, indicating that the 5-HT1B receptor is necessary for cyanopindolol to inhibit 5-HT clearance. Likewise, cyanopindolol was without effect on 5-HT clearance in SERT-/- mice, demonstrating a requirement for the presence of both SERT and 5-HT1B receptors in order for cyanopindolol to inhibit 5-HT clearance in CA3 region of hippocampus. Our findings are consistent with SERT being under the regulatory control of 5-HT1B autoreceptors. Future studies to identify signaling pathways involved may help elucidate novel therapeutic targets for the treatment of psychiatric disorders, particularly those linked to gene variants of the 5-HT1B receptor.
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Affiliation(s)
- Sylvia Montañez
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA
| | - Jaclyn L Munn
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA
| | - W Anthony Owens
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA
| | - Rebecca E Horton
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA
| | - Lynette C Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA; Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7764, San Antonio, TX 78229-3900, USA.
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Wang H, Chen XY, Chen WF, Xue Y, Wei L, Chen L. Anticataleptic effects of 5-HT(1B) receptors in the globus pallidus. Neurosci Res 2013; 77:162-9. [PMID: 24045116 DOI: 10.1016/j.neures.2013.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 08/09/2013] [Accepted: 09/03/2013] [Indexed: 11/18/2022]
Abstract
The globus pallidus occupies an important position in the indirect pathway of the basal ganglia. Being a monoamine neurotransmitter, 5-HT is involved in mediating many physiological functions and pathophysiological processes in several movement disorders. Morphological studies have revealed that the globus pallidus receives serotonergic innervation arising from the raphe nuclei, mainly the dorsal raphe nucleus. A high level of 5-HT and 5-HT(1B) receptors were detected in the globus pallidus. In the present study, bilateral microinjection of 5-HT or 5-HT(1B) receptor agonist, CP-93129, into the globus pallidus significantly alleviated the symptoms of rigidity caused by haloperidol. To further elucidate 5-HT(1B) receptor-induced anticatalepsy, in vivo extracellular recordings were performed to examine the effects of 5-HT(1B) receptor activation on the firing activity of the globus pallidus neurons under the presence of haloperidol. Micro-pressure ejection of 5-HT or CP-93129 increased the spontaneous firing rate of the pallidal neurons. Furthermore, by using immunohistochemistry, positive staining of 5-HT(1B) receptor was observed in the globus pallidus neurons. Taken together, the present findings provide evidence that activation of 5-HT(1B) receptor may exert anticataleptic effects by increasing the activity of pallidal neurons.
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Affiliation(s)
- Hua Wang
- Department of Physiology, Qingdao University, Qingdao 266071, China; Department of Physiology, Binzhou Medical University, Yantai 264003, China
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