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5-HT 1A Serotonergic, α-Adrenergic and Opioidergic Receptors Mediate the Analgesic Efficacy of Vortioxetine in Mice. Molecules 2021; 26:molecules26113242. [PMID: 34071269 PMCID: PMC8199248 DOI: 10.3390/molecules26113242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 01/09/2023] Open
Abstract
Vortioxetine is a multimodal antidepressant drug that affects several brain neurochemicals and has the potential to induce various pharmacological effects on the central nervous system. Therefore, we investigated the centrally mediated analgesic efficacy of this drug and the mechanisms underlying this effect. Analgesic activity of vortioxetine (5, 10 and 20 mg/kg, p.o.) was examined by tail-clip, tail-immersion and hot-plate tests. Motor performance of animals was evaluated using Rota-rod device. Time course measurements (30-180 min) showed that vortioxetine (10 and 20 mg/kg) administrations significantly increased the response latency, percent maximum possible effect and area under the curve values in all of the nociceptive tests. These data pointed out the analgesic effect of vortioxetine on central pathways carrying acute thermal and mechanical nociceptive stimuli. Vortioxetine did not alter the motor coordination of mice indicating that the analgesic activity of this drug was specific. In mechanistic studies, pre-treatments with p-chlorophenylalanine (serotonin-synthesis inhibitor), NAN-190 (serotonin 5-HT1A receptor antagonist), α-methyl-para-tyrosine (catecholamine-synthesis inhibitor), phentolamine (non-selective α-adrenoceptor blocker), and naloxone (non-selective opioid receptor blocker) antagonised the vortioxetine-induced analgesia. Obtained findings indicated that vortioxetine-induced analgesia is mediated by 5-HT1A serotonergic, α-adrenergic and opioidergic receptors, and contributions of central serotonergic and catecholaminergic neurotransmissions are critical for this effect.
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Cinar I, Sirin B, Halici Z, Palabiyik-Yucelik SS, Akpinar E, Cadirci E. 5-HT7 receptors as a new target for prostate cancer physiopathology and treatment: an experimental study on PC-3 cells and FFPE tissues. Naunyn Schmiedebergs Arch Pharmacol 2021; 394:1205-1213. [PMID: 33528589 DOI: 10.1007/s00210-021-02051-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Prostate cancer (PCa) is one of the most common types of cancer seen among men worldwide. Previous studies have demonstrated that serotonin regulates cell proliferation, migration, and invasion in vitro; the presence of 5-HT receptors in cancer cells; and the role of serotonin in tumor development. The most recently discovered of these receptors is 5-HT7 but also least characterized receptors of serotonin. The aim of this study is to investigate the existence and possible role of 5-HT7 receptors in healthy and cancerous prostate tissues and also investigate effects of receptor agonists and antagonists on PC-3 cells to evaluate potential therapeutic effects. PC-3 cells were cultured and effects of 5-HT7 receptor agonist (LP-44) and antagonist (SB-269970) were evaluated on these cells. After proliferation analyses, relative expression of apoptotic markers and 5-HT7 receptor mRNA expression levels were determined through real-time PCR. Annexin V-FITC/PI double staining and Hoechst 33258 staining assay methods were applied to determine apoptosis. Additional PCR studies were performed on healthy and cancerous prostate tissue to see existence of receptors in human samples. The viability of PC-3 cells was decreased by SB-269970 after 48 and 72 h of incubation. However, LP-44 increased PC-3 cell proliferation at all time points. In 10-6 M SB-269970 treated PC-3 cells, there was significant increase in the expression of CAS-3 (4-fold), CAS-9 (2.5-fold), BAX (1.9-fold), and Tp-53 (4.8-fold) gene mRNA levels when compared to non-treated control group. Conversely, there was a significant decrease in NF-κB (2.9-fold) and 5-HT7 receptor (3.6-fold) mRNA expression in cells treated with SB-269970 when compared to control. SB-269970 that antagonized 5-HT7 receptors also induced apoptosis in Annexin V-FITC/PI double staining assay and Hoechst 33258 staining assays when compared with other groups. In human samples, 5-HT7 receptor mRNA expression was approximately 200-fold higher than that of heathy ones. In this study, for the first time, the 5-HT7 receptor antagonist SB-269970 has been shown to inhibit proliferation in PC-3 cells and to be associated with an apoptosis-inducing effect. These results suggest blocking 5-HT7 receptors can be a novel therapeutic target for the treatment of prostate cancer.
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Affiliation(s)
- Irfan Cinar
- Department of Pharmacology, Faculty of Medicine, Kastamonu University, 37000, Kastamonu, Turkey
| | - Busra Sirin
- Department of Pharmacology, Faculty of Medicine, Atatürk University, 25240, Erzurum, Turkey
| | - Zekai Halici
- Department of Pharmacology, Faculty of Medicine, Atatürk University, 25240, Erzurum, Turkey.,Clinical Research, Development and Design Application and Research Center, Atatürk University, 25240, Erzurum, Turkey
| | - Saziye Sezin Palabiyik-Yucelik
- Clinical Research, Development and Design Application and Research Center, Atatürk University, 25240, Erzurum, Turkey.,Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Atatürk University, 25240, Erzurum, Turkey
| | - Erol Akpinar
- Department of Pharmacology, Faculty of Medicine, Atatürk University, 25240, Erzurum, Turkey.,Clinical Research, Development and Design Application and Research Center, Atatürk University, 25240, Erzurum, Turkey
| | - Elif Cadirci
- Department of Pharmacology, Faculty of Medicine, Atatürk University, 25240, Erzurum, Turkey. .,Clinical Research, Development and Design Application and Research Center, Atatürk University, 25240, Erzurum, Turkey.
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Czopek A, Partyka A, Bucki A, Pawłowski M, Kołaczkowski M, Siwek A, Głuch-Lutwin M, Koczurkiewicz P, Pękala E, Jaromin A, Tyliszczak B, Wesołowska A, Zagórska A. Impact of N-Alkylamino Substituents on Serotonin Receptor (5-HTR) Affinity and Phosphodiesterase 10A (PDE10A) Inhibition of Isoindole-1,3-dione Derivatives. Molecules 2020; 25:molecules25173868. [PMID: 32854402 PMCID: PMC7504677 DOI: 10.3390/molecules25173868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/22/2020] [Accepted: 08/23/2020] [Indexed: 11/16/2022] Open
Abstract
In this study, a series of compounds derived from 4-methoxy-1H-isoindole-1,3(2H)-dione, potential ligands of phosphodiesterase 10A and serotonin receptors, were investigated as potential antipsychotics. A library of 4-methoxy-1H-isoindole-1,3(2H)-dione derivatives with various amine moieties was synthesized and examined for their phosphodiesterase 10A (PDE10A)-inhibiting properties and their 5-HT1A and 5-HT7 receptor affinities. Based on in vitro studies, the most potent compound, 18 (2-[4-(1H-benzimidazol-2-yl)butyl]-4-methoxy-1H-isoindole-1,3(2H)-dione), was selected and its safety in vitro was evaluated. In order to explain the binding mode of compound 18 in the active site of the PDE10A enzyme and describe the molecular interactions responsible for its inhibition, computer-aided docking studies were performed. The potential antipsychotic properties of compound 18 in a behavioral model of schizophrenia were also investigated.
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Affiliation(s)
- Anna Czopek
- Department of Medicinal Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.B.); (M.P.); (M.K.); (A.Z.)
- Correspondence: ; Tel.: +48-12-620-5450
| | - Anna Partyka
- Department of Clinical Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.P.); (A.W.)
| | - Adam Bucki
- Department of Medicinal Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.B.); (M.P.); (M.K.); (A.Z.)
| | - Maciej Pawłowski
- Department of Medicinal Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.B.); (M.P.); (M.K.); (A.Z.)
| | - Marcin Kołaczkowski
- Department of Medicinal Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.B.); (M.P.); (M.K.); (A.Z.)
| | - Agata Siwek
- Department of Pharmacobiology, Jagiellonian University Collegium Medicum, 9 Medyczna Street, 30-688 Krakow, Poland; (A.S.); (M.G.-L.)
| | - Monika Głuch-Lutwin
- Department of Pharmacobiology, Jagiellonian University Collegium Medicum, 9 Medyczna Street, 30-688 Krakow, Poland; (A.S.); (M.G.-L.)
| | - Paulina Koczurkiewicz
- Department of Pharmaceutical Biochemistry, Jagiellonian University Collegium Medicum, 9 Medyczna Street, 30-688 Krakow, Poland; (P.K.); (E.P.)
| | - Elżbieta Pękala
- Department of Pharmaceutical Biochemistry, Jagiellonian University Collegium Medicum, 9 Medyczna Street, 30-688 Krakow, Poland; (P.K.); (E.P.)
| | - Anna Jaromin
- Department of Lipids and Liposomes, Faculty of Biotechnology, University of Wroclaw, 14a Joliot-Curie, 50-383 Wroclaw, Poland;
| | - Bożena Tyliszczak
- Faculty of Materials Engineering and Physics, Cracow University of Technology, Institute of Materials Science, 24 Warszawska Street, 31-155 Krakow, Poland;
| | - Anna Wesołowska
- Department of Clinical Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.P.); (A.W.)
| | - Agnieszka Zagórska
- Department of Medicinal Chemistry, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland; (A.B.); (M.P.); (M.K.); (A.Z.)
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Hamurtekin Y, Nouilati A, Demirbatir C, Hamurtekin E. The Contribution of Serotonergic Receptors and Nitric Oxide Systems in the Analgesic Effect of Acetaminophen: An Overview of the Last Decade. Turk J Pharm Sci 2020; 17:119-126. [PMID: 32454770 DOI: 10.4274/tjps.galenos.2018.35403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/18/2018] [Indexed: 10/25/2022]
Abstract
Acetaminophen is a widely used analgesic and antipyretic agent. It is also available in over the counter formulations, which has increased its wide use. There have been many studies to date that have aimed to evaluate the mechanism of the analgesic action of acetaminophen. Additional to the inhibition of the cyclooxygenase pathway in the central nervous system, the involvement of opioidergic, cannabinoidergic, dopaminergic, cholinergic, and nitrergic systems as well as the contribution of descending pain inhibitory systems like the bulbospinal serotonergic pathway has been proposed as possible mechanisms of the analgesic action of acetaminophen. In this review, we aimed to collect the data from studies revealing the contribution of the central serotonergic system and the role of central nervous system-located serotonergic receptor subtypes in the analgesic effect of acetaminophen. While doing this, we mainly focused on the research that has been performed in the last ten years and tried to link the previous data with the lately added results. In addition to serotonergic system involvement, we also reviewed the role of nitric oxide in the analgesic action of acetaminophen, especially with the new findings reported over the last decade.
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Affiliation(s)
- Yeşim Hamurtekin
- Eastern Mediterranean University, Faculty of Pharmacy, Department of Pharmacology, Famagusta, North Cyprus Via Mersin 10, Turkey
| | - Ammar Nouilati
- Eastern Mediterranean University, Faculty of Pharmacy, Department of Pharmacology, Famagusta, North Cyprus Via Mersin 10, Turkey
| | - Cansu Demirbatir
- Eastern Mediterranean University, Faculty of Pharmacy, Department of Pharmacology, Famagusta, North Cyprus Via Mersin 10, Turkey
| | - Emre Hamurtekin
- Eastern Mediterranean University, Faculty of Pharmacy, Department of Pharmacology, Famagusta, North Cyprus Via Mersin 10, Turkey
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Zaręba P, Drabczyk AK, Jaśkowska J, Satała G. Chemical puzzles in the search for new, flexible derivatives of lurasidone as antipsychotic drugs. Bioorg Med Chem 2020; 28:115459. [DOI: 10.1016/j.bmc.2020.115459] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/17/2020] [Accepted: 03/16/2020] [Indexed: 10/24/2022]
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Wu MJ, Vinit S, Chen CL, Lee KZ. 5-HT7 Receptor Inhibition Transiently Improves Respiratory Function Following Daily Acute Intermittent Hypercapnic-Hypoxia in Rats With Chronic Midcervical Spinal Cord Contusion. Neurorehabil Neural Repair 2020; 34:333-343. [DOI: 10.1177/1545968320905806] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background. Intermittent hypoxia can induce respiratory neuroplasticity to enhance respiratory motor outputs following hypoxic treatment. This type of respiratory neuroplasticity is primarily mediated by the activation of Gq-protein-coupled 5-HT2 receptors and constrained by Gs-protein-coupled 5-HT7 receptors. Objective. The present study hypothesized that the blockade of 5-HT7 receptors can potentiate the effect of intermittent hypercapnic-hypoxia on respiratory function after cervical spinal cord contusion injury. Methods. The ventilatory behaviors of unanesthetized rats with midcervical spinal cord contusions were measured before, during, and after daily acute intermittent hypercapnic-hypoxia (10 episodes of 5 minutes of hypoxia [10% O2, 4% CO2, 86% N2] with 5 minutes of normoxia intervals for 5 days) at 8 weeks postinjury. On a daily basis, 5 minutes before intermittent hypercapnic-hypoxia, rats received either a 5-HT7 receptor antagonist (SB269970, 4 mg/kg, intraperitoneal) or a vehicle (dimethyl sulfoxide). Results. Treatment with intermittent hypercapnic-hypoxia induced a similar increase in tidal volume between rats that received SB269970 and those that received dimethyl sulfoxide within 60 minutes post-hypoxia on the first day. However, after 2 to 3 days of daily acute intermittent hypercapnic-hypoxia, the baseline tidal volumes of rats treated with SB269970 increased significantly. Conclusions. These results suggest that inhibiting the 5-HT7 receptor can transiently improve daily intermittent hypercapnic-hypoxia–induced tidal volume increase in midcervical spinal contused animals. Therefore, combining pharmacological treatment with rehabilitative intermittent hypercapnic-hypoxia training may be an effective strategy for synergistically enhancing respiratory neuroplasticity to improve respiratory function following chronic cervical spinal cord injury.
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Affiliation(s)
- Ming-Jane Wu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Stéphane Vinit
- Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Chun-Lin Chen
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
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Wu Y, Proch KL, Teran FA, Lechtenberg RJ, Kothari H, Richerson GB. Chemosensitivity of Phox2b-expressing retrotrapezoid neurons is mediated in part by input from 5-HT neurons. J Physiol 2019; 597:2741-2766. [PMID: 30866045 PMCID: PMC6826216 DOI: 10.1113/jp277052] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/07/2019] [Indexed: 01/18/2023] Open
Abstract
KEY POINTS Neurons of the retrotrapezoid nucleus (RTN) and medullary serotonin (5-HT) neurons are both candidates for central CO2 /pH chemoreceptors, but it is not known how interactions between them influence their responses to pH. We found that RTN neurons in brain slices were stimulated by exogenous 5-HT and by heteroexchange release of endogenous 5-HT, and these responses were blocked by antagonists of 5-HT7 receptors. The pH response of RTN neurons in brain slices was markedly reduced by the same antagonists of 5-HT7 receptors. Similar results were obtained in dissociated, primary cell cultures prepared from the ventral medulla, where it was also found that the pH response of RTN neurons was blocked by preventing 5-HT synthesis and enhanced by blocking 5-HT reuptake. Exogenous 5-HT did not enable latent intrinsic RTN chemosensitivity. RTN neurons may play more of a role as relays from other central and peripheral chemoreceptors than as CO2 sensors. ABSTRACT Phox2b-expressing neurons in the retrotrapezoid nucleus (RTN) and serotonin (5-HT) neurons in the medullary raphe have both been proposed to be central respiratory chemoreceptors. How interactions between these two sets of neurons influence their responses to acidosis is not known. Here we recorded from mouse Phox2b+ RTN neurons in brain slices, and found that their response to moderate hypercapnic acidosis (pH 7.4 to ∼7.2) was markedly reduced by antagonists of 5-HT7 receptors. RTN neurons were stimulated in response to heteroexchange release of 5-HT, indicating that RTN neurons are sensitive to endogenous 5-HT. This electrophysiological behaviour was replicated in primary, dissociated cell cultures containing 5-HT and RTN neurons grown together. In addition, pharmacological inhibition of 5-HT synthesis in culture reduced RTN neuron chemosensitivity, and blocking 5-HT reuptake enhanced chemosensitivity. The effect of 5-HT on RTN neuron chemosensitivity was not explained by a mechanism whereby activation of 5-HT7 receptors enables or potentiates intrinsic chemosensitivity of RTN neurons, as exogenous 5-HT did not enhance the pH response. The ventilatory response to inhaled CO2 of mice was markedly decreased in vivo after systemic treatment with ketanserin, an antagonist of 5-HT2 and 5-HT7 receptors. These data indicate that 5-HT and RTN neurons may interact synergistically in a way that enhances the respiratory chemoreceptor response. The primary role of RTN neurons may be as relays and amplifiers of the pH response from 5-HT neurons and other chemoreceptors rather than as pH sensors themselves.
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Affiliation(s)
- Yuanming Wu
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
| | - Katherine L. Proch
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
| | - Frida A. Teran
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIA52242USA
| | | | - Harsh Kothari
- Department of PediatricsUniversity of IowaIowa CityIA52242USA
| | - George B. Richerson
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
- Department of Molecular Physiology & BiophysicsUniversity of IowaIowa CityIA52242USA
- Neurology ServiceVeterans Affairs Medical CenterIowa CityIA52242USA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIA52242USA
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Odagaki Y, Kinoshita M, Ota T. Functional activation of Gα q/11 protein via α 1 -adrenoceptor in rat cerebral cortical membranes. Clin Exp Pharmacol Physiol 2019; 46:567-574. [PMID: 30869808 DOI: 10.1111/1440-1681.13084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/21/2019] [Accepted: 03/09/2019] [Indexed: 11/26/2022]
Abstract
Although it is recognized that α1 -adrenoceptors are coupled to diverse intracellular signalling pathways, its primary transduction mechanisms are evoked by activating phospholipase C in the cell membrane through Gαq/11 , resulting in production of inositol 1,4,5-trisphosphate and diacylglycerol. However, there have been few studies that indicate directly the involvement of Gαq/11 proteins in this signalling pathway in the central nervous system. In the current study, we tried to pharmacologically characterize (-)-adrenaline-stimulated [35 S]GTPγS binding to Gαq/11 in rat brain membranes. Functional activation of Gαq/11 coupled to α1 -adrenoceptor was investigated by using [35 S]GTPγS binding/immunoprecipitation assay in the membranes prepared from rat cerebral cortex, hippocampus, and striatum. The specific [35 S]GTPγS binding to Gαq/11 was stimulated by (-)-adrenaline in a concentration-dependent and saturable manner in rat cerebral cortical membranes. In hippocampal or striatal membranes, the stimulatory effects of (-)-adrenaline were scarce. The effect of (-)-adrenaline was potently inhibited by prazosin, a potent and selective α1 -adrenoceptor antagonist, but not by yohimbine, a selective α2 -adrenoceptor antagonist. The response was mimicked by cirazoline, but not by R(-)-phenylephrine. Although oxymetazoline also stimulated the specific [35 S]GTPγS binding to Gαq/11 as an apparent "super-agonist", detailed pharmacological characterization revealed that its agonistic properties in this experimental system were derived from off-target effects on 5-HT2A receptors, but not via α1 -adrenoceptors. In conclusion, functional coupling of α1 -adrenoceptors to Gαq/11 proteins are detectable in rat brain membranes by means of [35 S]GTPγS binding/immunoprecipitation assay. It is necessary to interpret the experimental data with caution when oxymetazoline is included as an agonist at α1 -adrenoceptors.
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Affiliation(s)
- Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan
| | - Masakazu Kinoshita
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan
| | - Toshio Ota
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan
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Wöhr M, van Gaalen MM. Pharmacological Studies on the Role of Serotonin in Regulating Socioemotional Ultrasonic Vocalizations in Rats. HANDBOOK OF ULTRASONIC VOCALIZATION - A WINDOW INTO THE EMOTIONAL BRAIN 2018. [DOI: 10.1016/b978-0-12-809600-0.00028-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Bannister K, Lockwood S, Goncalves L, Patel R, Dickenson AH. An investigation into the inhibitory function of serotonin in diffuse noxious inhibitory controls in the neuropathic rat. Eur J Pain 2016; 21:750-760. [PMID: 27891703 DOI: 10.1002/ejp.979] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND Following neuropathy α2-adrenoceptor-mediated diffuse noxious inhibitory controls (DNIC), whereby a noxious conditioning stimulus inhibits the activity of spinal wide dynamic range (WDR) neurons, are abolished, and spinal 5-HT7 receptor densities are increased. Here, we manipulate spinal 5-HT content in spinal nerve ligated (SNL) animals and investigate which 5-HT receptor mediated actions predominate. METHODS Using in vivo electrophysiology we recorded WDR neuronal responses to von frey filaments applied to the hind paw before, and concurrent to, a noxious ear pinch (the conditioning stimulus) in isoflurane-anaesthetised rats. The expression of DNIC was quantified as a reduction in WDR neuronal firing in the presence of conditioning stimulus and was investigated in SNL rats following spinal application of (1) selective serotonin reuptake inhibitors (SSRIs) citalopram or fluoxetine, or dual application of (2) SSRI plus 5-HT7 receptor antagonist SB269970, or (3) SSRI plus α2 adrenoceptor antagonist atipamezole. RESULTS DNIC were revealed in SNL animals following spinal application of SSRI, but this effect was abolished upon joint application of SSRI plus SB269970 or atipamezole. CONCLUSIONS We propose that in SNL animals the inhibitory actions (quantified as the presence of DNIC) of excess spinal 5-HT (presumed present following application of SSRI) were mediated via 5-HT7 receptors. The anti-nociception depends upon an underlying tonic noradrenergic inhibitory tone via the α2-adrenoceptor. SIGNIFICANCE Following neuropathy enhanced spinal serotonin availability switches the predominant spinal 5-HT receptor-mediated actions but also alters noradrenergic signalling. We highlight the therapeutic complexity of SSRIs and monoamine modulators for the treatment of neuropathic pain.
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Affiliation(s)
- K Bannister
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - S Lockwood
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - L Goncalves
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - R Patel
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - A H Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
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Zhou QG, Lee D, Ro EJ, Suh H. Regional-specific effect of fluoxetine on rapidly dividing progenitors along the dorsoventral axis of the hippocampus. Sci Rep 2016; 6:35572. [PMID: 27759049 PMCID: PMC5069667 DOI: 10.1038/srep35572] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 10/03/2016] [Indexed: 01/08/2023] Open
Abstract
Hippocampus-dependent cognitive and emotional function appears to be regionally dissociated along the dorsoventral (DV) axis of the hippocampus. Recent observations that adult hippocampal neurogenesis plays a critical role in both cognition and emotion raised an interesting question whether adult neurogenesis within specific subregions of the hippocampus contributes to these distinct functions. We examined the regional-specific and cell type-specific effects of fluoxetine, which requires adult hippocampal neurogenesis to function as an antidepressant, on the proliferation of hippocampal neural stem cells (NSCs). Fluoxetine specifically increased proliferation of NSCs located in the ventral region of the hippocampus while the mitotic index of NSCs in the dorsal portion of the hippocampus remained unaltered. Moreover, within the ventral hippocampus, type II NSC and neuroblast populations specifically responded to fluoxetine, showing increased proliferation; however, proliferation of type I NSCs was unchanged in response to fluoxetine. Activation or inhibition of serotonin receptor 1A (5-HTR1A) recapitulated or abolished the effect of fluoxetine on proliferation of type II NSCs and neuroblast populations in the ventral hippocampus. Our study showed that the effect of fluoxetine on proliferation is dependent upon the type and the position of the NSCs along the DV axis of the hippocampus.
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Affiliation(s)
- Qi-Gang Zhou
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Institution of Stem Cells and Neuroregeneration, Department of Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing, P.R. China
| | - Daehoon Lee
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Eun Jeoung Ro
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Hoonkyo Suh
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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Odagaki Y, Kinoshita M, Ota T. Comparative analysis of pharmacological properties of xanomeline and N-desmethylclozapine in rat brain membranes. J Psychopharmacol 2016; 30:896-912. [PMID: 27464743 DOI: 10.1177/0269881116658989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND 3(3-Hexyloxy-1,2,5-thiadiazol-4-yl)-1,2,5,6-tetrahydro-1-methylpyridine (xanomeline) and N-desmethylclozapine are of special interest as promising antipsychotics with better efficacy, especially for negative symptoms and/or cognitive/affective impairment. METHODS The guanosine-5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) binding experiments were performed using (1) conventional filtration technique, (2) antibody-capture scintillation proximity assay, and (3) immunoprecipitation method, in brain membranes prepared from rat cerebral cortex, hippocampus, and striatum. RESULTS Xanomeline had agonistic activity at the M1 muscarinic acetylcholine receptor (mAChR) in all brain regions, as well as at the 5-HT1A receptor in the cerebral cortex and hippocampus. On the other hand, N-desmethylclozapine exhibited slight agonistic effects on the M1 mAChR, and agonistic properties at the 5-HT1A receptor in the cerebral cortex and hippocampus. This compound also behaved as an agonist at the δ-opioid receptor in the cerebral cortex and striatum. In addition, the stimulatory effects of N-desmethylclozapine on [(35)S]GTPγS binding to Gαi/o were partially mediated through mAChRs (most likely M4 mAChR subtype), at least in striatum. CONCLUSIONS The agonistic effects on the mAChRs (particularly M1 subtype, and also probably M4 subtype), the 5-HT1A receptor and the δ-opioid receptor expressed in native brain tissues, some of which are common to both compounds and others specific to either, likely shape the unique beneficial effectiveness of both compounds in the treatment for schizophrenic patients. These characteristics provide us with a clue to develop newer antipsychotics, beyond the framework of dopamine D2 receptor antagonism, that are effective not only on positive symptoms but also on negative symptoms and/or cognitive/affective impairment.
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Affiliation(s)
- Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Masakazu Kinoshita
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Toshio Ota
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
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Novel N-acyl-carbazole derivatives as 5-HT7R antagonists. Eur J Med Chem 2016; 110:302-10. [PMID: 26852005 DOI: 10.1016/j.ejmech.2016.01.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 02/06/2023]
Abstract
To discover a novel 5-HT7R antagonist for treatment of depression, we designed N-acyl-carbazole derivatives which were synthesized and biologically evaluated against 5-HT7R. Among total 30 compounds synthesized, four compounds 27-30 showed good binding affinities with Ki values of <100 nM. The compound 28, 1-(9H-carbazol-9-yl)-6-(4-(2-methoxyphenyl)piperazin-1-yl)hexan-1-one, showed good selectivity over other serotonin receptor subtypes and turned out to be a novel selective 5-HT7R antagonist following functional assays. The compound 28 showed moderate activity on hERG channel and good stability in microsomal stability test. The compound 28 exhibited a good pharmacokinetic profile with 67.8% oral bioavailability and good penetration to the brain. The compound 28 was also tested in in vivo depression animal model and showed antidepressant effect in the forced swimming test. Therefore, the selective 5-HT7R antagonist 28 can be considered as a good lead for discovery of novel 5-HT7R antagonists as antidepressants.
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Garay RP, Bourin M, de Paillette E, Samalin L, Hameg A, Llorca PM. Potential serotonergic agents for the treatment of schizophrenia. Expert Opin Investig Drugs 2015; 25:159-70. [DOI: 10.1517/13543784.2016.1121995] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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15
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Effects of the selective 5-HT7 receptor antagonist SB-269970 on premature responding in the five-choice serial reaction time test in rats. Behav Brain Res 2015; 289:149-56. [PMID: 25930219 DOI: 10.1016/j.bbr.2015.04.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 04/13/2015] [Accepted: 04/16/2015] [Indexed: 01/17/2023]
Abstract
The antagonists of serotonin 5-HT7 receptors have been demonstrated to ameliorate cognitive impairments in pharmacological animal models of schizophrenia that involve blockade of N-methyl-D-aspartate receptors (NMDARs). The administration of NMDAR antagonists evokes a broad range of cognitive deficits, including a loss of impulse control. The involvement of 5-HT7 receptors in the modulation of impulsivity has been recently suggested but has not been studied in great detail. The aim of the present study was to examine the effect of a selective 5-HT7 receptor antagonist SB-269970 on a measure of impulsive action, i.e., premature responding on the five-choice serial reaction time task (5-CSRTT) in rats. The antagonist of 5-HT2A receptor M100,907 was used as a positive control. The efficacies of both compounds were assessed in conditions of increased impulsivity that were produced by the administration of the NMDAR antagonist MK-801 or/and non-drug stimuli, i.e., using variable inter-trial intervals (vITIs). To examine the general ability of SB-269970 to counteract the MK-801-induced impairments, a discrete paired-trial delayed alternation task in a T-maze was employed. MK-801 significantly increased the number of premature responses in 5-CSRTT, and this effect was abolished by the administration of M100,907 (0.5 mg/kg) and SB-269970 (1 mg/kg). In addition, M100,907, but not SB-269970, reduced premature responding in the prolonged ITI trials. Both M100,907 and SB-269970 attenuated MK-801-induced working memory impairment in a T-maze. The present study demonstrated the efficacy of SB-269970 against MK-801-induced premature responding in the 5-CSRTT. This anti-impulsive action may offer additional benefits to the cognitive-enhancing effects of pharmacological blockade of 5-HT7 receptors.
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Huot P, Fox SH, Brotchie JM. Monoamine reuptake inhibitors in Parkinson's disease. PARKINSON'S DISEASE 2015; 2015:609428. [PMID: 25810948 PMCID: PMC4355567 DOI: 10.1155/2015/609428] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/26/2014] [Indexed: 12/13/2022]
Abstract
The motor manifestations of Parkinson's disease (PD) are secondary to a dopamine deficiency in the striatum. However, the degenerative process in PD is not limited to the dopaminergic system and also affects serotonergic and noradrenergic neurons. Because they can increase monoamine levels throughout the brain, monoamine reuptake inhibitors (MAUIs) represent potential therapeutic agents in PD. However, they are seldom used in clinical practice other than as antidepressants and wake-promoting agents. This review article summarises all of the available literature on use of 50 MAUIs in PD. The compounds are divided according to their relative potency for each of the monoamine transporters. Despite wide discrepancy in the methodology of the studies reviewed, the following conclusions can be drawn: (1) selective serotonin transporter (SERT), selective noradrenaline transporter (NET), and dual SERT/NET inhibitors are effective against PD depression; (2) selective dopamine transporter (DAT) and dual DAT/NET inhibitors exert an anti-Parkinsonian effect when administered as monotherapy but do not enhance the anti-Parkinsonian actions of L-3,4-dihydroxyphenylalanine (L-DOPA); (3) dual DAT/SERT inhibitors might enhance the anti-Parkinsonian actions of L-DOPA without worsening dyskinesia; (4) triple DAT/NET/SERT inhibitors might exert an anti-Parkinsonian action as monotherapy and might enhance the anti-Parkinsonian effects of L-DOPA, though at the expense of worsening dyskinesia.
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Affiliation(s)
- Philippe Huot
- Toronto Western Research Institute, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
- Division of Neurology, Movement Disorder Clinic, Toronto Western Hospital, University Health Network, University of Toronto, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
- Department of Pharmacology and Division of Neurology, Faculty of Medicine, Université de Montréal and Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada
| | - Susan H. Fox
- Toronto Western Research Institute, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
- Division of Neurology, Movement Disorder Clinic, Toronto Western Hospital, University Health Network, University of Toronto, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
| | - Jonathan M. Brotchie
- Toronto Western Research Institute, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
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Tzirogiannis KN, Kourentzi KT, Zyga S, Papalimneou V, Tsironi M, Grypioti AD, Protopsaltis I, Panidis D, Panoutsopoulos GI. Effect of 5-HT7 receptor blockade on liver regeneration after 60-70% partial hepatectomy. BMC Gastroenterol 2014; 14:201. [PMID: 25433672 PMCID: PMC4267430 DOI: 10.1186/s12876-014-0201-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 11/11/2014] [Indexed: 01/05/2023] Open
Abstract
Background Serotonin exhibits a vast repertoire of actions including cell
proliferation and differentiation. The effect of serotonin, as an incomplete
mitogen, on liver regeneration has recently been unveiled and is mediated through
5-HT2 receptor. The aim of the present study was to
investigate the effect of 5-HT7 receptor blockade on liver
regeneration after partial hepatectomy. Methods Male Wistar rats were subjected to 60-70% partial hepatectomy.
5-HT7 receptor blockade was applied by intraperitoneal
administration of SB-269970 hydrochloride two hours prior to and sixteen hours
after partial hepatectomy and by intraperitoneal administration of SB-258719
sixteen hours after partial hepatectomy. Animals were sacrificed at different time
points until 72 h after partial hepatectomy. Liver regeneration was evaluated by
[3H]-thymidine incorporation into hepatic DNA, the
mitotic index in hematoxylin-eosin (HE) sections and by immunochemical detection
of Ki67 nuclear antigen. Reversion of 5-HT7 blockade was
performed by intraperitoneal administration of AS-19. Serum and liver tissue
lipids were also quantified. Results Liver regeneration peaked at 24 h
([3H]-thymidine incorporation into hepatic DNA and
mitotic index by immunochemical detection of Ki67) and at 32 h (mitotic index in
HE sections) in the control group of rats. 5-HT7 receptor
blockade had no effect on liver regeneration when applied 2 h prior to partial
hepatectomy. Liver regeneration was greatly attenuated when blockade of
5-HT7 receptor was applied (by SB-258719 and SB-269970)
at 16 h after partial hepatectomy and peaked at 32 h
([3H]-thymidine incorporation into hepatic DNA and
mitotic index by immunochemical detection of Ki67) and 40 h (mitotic index in HE
sections) after partial hepatectomy. AS-19 administration totally reversed the
observed attenuation of liver regeneration. Conclusions In conclusion, 5-HT7 receptor is a novel type
of serotonin receptor implicated in hepatocyte proliferation.
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Affiliation(s)
| | - Kalliopi T Kourentzi
- Department of Experimental Pharmacology, Medical School, Athens University, Athens, 11527, Greece.
| | - Sofia Zyga
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, 23100, Greece.
| | | | - Maria Tsironi
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, 23100, Greece.
| | - Agni D Grypioti
- Department of Experimental Pharmacology, Medical School, Athens University, Athens, 11527, Greece.
| | - Ioannis Protopsaltis
- Department of Internal Medicine, Tzanio General Hospital of Piraeus, Piraeus, 18537, Greece.
| | - Dimitrios Panidis
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, 23100, Greece.
| | - Georgios I Panoutsopoulos
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Orthias Artemidos and Plateon, Sparta, 23100, Greece.
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Kim Y, Tae J, Lee K, Rhim H, Choo IH, Cho H, Park WK, Keum G, Choo H. Novel N-biphenyl-2-ylmethyl 2-methoxyphenylpiperazinylalkanamides as 5-HT7R antagonists for the treatment of depression. Bioorg Med Chem 2014; 22:4587-96. [PMID: 25127461 DOI: 10.1016/j.bmc.2014.07.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 12/26/2022]
Abstract
5-HT7 receptor (5-HT7R) is a promising target for the treatment of depression and neuropathic pain. 5-HT7R antagonists exhibited antidepressant effects, while the agonists produced strong anti-hyperalgesic effects. In our efforts to discover selective 5-HT7R antagonists or agonists, N-biphenylylmethyl 2-methoxyphenylpiperazinylalkanamides 1 were designed, synthesized, and biologically evaluated against 5-HT7R. Among the synthesized compounds, N-2'-chlorobiphenylylmethyl 2-methoxyphenylpiperazinylpentanamide 1-8 showed the best binding affinity with a Ki value of 8.69nM and it was verified as a novel antagonist according to functional assays. The compound 1-8 was very selective over 5-HT1DR, 5-HT2AR, 5-HT3R, 5-HT5AR and 5-HT6R and moderately selective over 5-HT1AR, 5-HT1BR and 5-HT2CR. The novel 5-HT7R antagonist 1-8 exhibited an antidepressant effect at a dose of 25mg/kg in the forced swimming test in mice and showed a U-shaped dose-response curve which typically appears in 5-HT7R antagonists such as SB-269970 and lurasidone.
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Affiliation(s)
- Youngjae Kim
- Center for Neuro-Medicine, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Chemistry, Yonsei University, Seodaemun-gu, Seoul 120-749, Republic of Korea
| | - Jinsung Tae
- Department of Chemistry, Yonsei University, Seodaemun-gu, Seoul 120-749, Republic of Korea
| | - Kangho Lee
- Center for Neuroscience, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Neuroscience, University of Science and Technology, Yuseong-gu, Daejeon 305-350, Republic of Korea
| | - Hyewhon Rhim
- Center for Neuroscience, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Neuroscience, University of Science and Technology, Yuseong-gu, Daejeon 305-350, Republic of Korea
| | - Il Han Choo
- School of Medicine, Chosun University, Dong-gu, Kwangju 501-759, Republic of Korea
| | - Heeyeong Cho
- Pharmacology Research Center, Korea Research Institute of Chemical Technology, Yuseong-gu, Daejeon 305-343, Republic of Korea
| | - Woo-Kyu Park
- Pharmacology Research Center, Korea Research Institute of Chemical Technology, Yuseong-gu, Daejeon 305-343, Republic of Korea
| | - Gyochang Keum
- Center for Neuro-Medicine, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Biological Chemistry, University of Science and Technology, Yuseong-gu, Daejeon 305-350, Republic of Korea.
| | - Hyunah Choo
- Center for Neuro-Medicine, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Biological Chemistry, University of Science and Technology, Yuseong-gu, Daejeon 305-350, Republic of Korea.
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Vleugels R, Lenaerts C, Vanden Broeck J, Verlinden H. Signalling properties and pharmacology of a 5-HT7 -type serotonin receptor from Tribolium castaneum. INSECT MOLECULAR BIOLOGY 2014; 23:230-243. [PMID: 24330075 DOI: 10.1111/imb.12076] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the last decade, genome sequence data and gene structure information on invertebrate receptors has been greatly expanded by large sequencing projects and cloning studies. This information is of great value for the identification of receptors; however, functional and pharmacological data are necessary for an accurate receptor classification and for practical applications. In insects, an important group of neurotransmitter and neurohormone receptors, for which ample sequence information is available but pharmacological information is missing, are the biogenic amine G protein-coupled receptors (GPCRs). In the present study, we investigated the sequence information, pharmacology and signalling properties of a 5-HT7 -type serotonin receptor from the red flour beetle, Tribolium castaneum (Trica5-HT7 ). The receptor encoding cDNA shows considerable sequence similarity with cognate 5-HT7 receptors and phylogenetic analysis also clusters the receptor within this 5-HT receptor group. Real-time reverse transcription PCR demonstrated high expression levels in the brain, indicating the possible importance of this receptor in neural processes. Trica5-HT7 was dose-dependently activated by 5-HT, which induced elevated intracellular cyclic AMP levels but had no effect on calcium signalling. The synthetic agonists, α-methyl 5-HT, 5-methoxytryptamine, 5-carboxamidotryptamine and 8-hydroxy-2-(dipropylamino)tetralin hydrobromide, showed a response, although with a much lower potency and efficacy than 5-HT. Ketanserin and methiothepin were the most potent antagonists. Both showed characteristics of competitive inhibition on Trica5-HT7 . The signalling pathway and pharmacological profile offer important information that will facilitate functional and comparative studies of 5-HT receptors in insects and other invertebrates. The pharmacology of invertebrate 5-HT receptors differs considerably from that of vertebrates. The present study may therefore contribute to establishing a more reliable classification of invertebrate 5-HT receptors.
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Affiliation(s)
- R Vleugels
- Laboratory for Molecular Developmental Physiology and Signal Transduction, Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Leuven, Belgium
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Modulation of 5-HT7 receptor: effect on object recognition performances in mice. Psychopharmacology (Berl) 2014; 231:393-400. [PMID: 23995300 DOI: 10.1007/s00213-013-3247-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 08/07/2013] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Recent data suggest that 5-HT7 receptors (5-HT7R) are involved in memory processes and, particularly, those related to novelty-induced arousal, even though this remains so far speculative and controversial. In order to assess the role of 5-HT7R in episodic-like memory, mice were administered 5-carboxamidotryptamine (5-CT, a 5-HT1A/1B/1D/7R agonist) and/or SB-269970 (a selective 5-HT7R antagonist) immediately after the acquisition session of the novel object recognition test. MATERIALS AND METHODS The object recognition test was performed in order to assess the effects of modulation of 5-HT7R during consolidation phase on episodic-like memory performances in mice. A protocol including 3 days of familiarisation to the apparatus has been realised in order to decrease the effect of novelty-induced arousal. RESULTS With a 2-h delay, SB-269970 (3 and 10 mg/kg, administered subcutaneously) impaired the discrimination of the novel object. With a 4-h delay, while control mice were not able to discriminate the novel object, mice treated with 5-CT (1 mg/kg) showed a significant discrimination. This promnesic effect with a long delay is effectively mediated by 5-HT7R activation since it was blocked by SB-269970 (10 mg/kg), but not by WAY-100135 (10 mg/kg) or by GR-127935 (10 mg/kg). CONCLUSION These data suggest that 5-HT7R tonically modulates cognitive processes involved in consolidation performances in object recognition. Therefore, 5-HT7R could be a promising target to treat memory dysfunctions (especially episodically related deficits) related to normal or pathological ageing.
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Johnston KD, Lu Z, Rudd JA. Looking beyond 5-HT(3) receptors: a review of the wider role of serotonin in the pharmacology of nausea and vomiting. Eur J Pharmacol 2013; 722:13-25. [PMID: 24189639 DOI: 10.1016/j.ejphar.2013.10.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/09/2013] [Accepted: 10/09/2013] [Indexed: 12/18/2022]
Abstract
The concept that 5-hydroxytryptamine (5-HT; serotonin) is involved in the emetic reflex was revealed using drugs that interfere with its synthesis, storage, release and metabolism ahead of the discovery of selective tools to modulate specific subtypes of receptors. This review comprehensively examines the fundamental role of serotonin in emesis control and highlights data indicating association of 5-HT1-4 receptors in the emetic reflex, whilst leaving open the possibility that 5-HT5-7 receptors may also be involved. The fact that each receptor subtype may mediate both emetic and anti-emetic effects is discussed in detail for the first time. These discussions are made in light of known species differences in emesis control, which has sometimes affected the perception of the translational value of data in regard to the development of novel anti-emetic for use in man.
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Affiliation(s)
- Kevin D Johnston
- Department of Anesthesia, School of Medicine, The University of Leeds, Leeds, West Yorkshire, England
| | - Zengbing Lu
- Emesis Research Group, Neuro-degeneration, Development and Repair, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - John A Rudd
- Emesis Research Group, Neuro-degeneration, Development and Repair, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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22
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Systematic identification of proteins that elicit drug side effects. Mol Syst Biol 2013; 9:663. [PMID: 23632385 PMCID: PMC3693830 DOI: 10.1038/msb.2013.10] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/17/2013] [Indexed: 01/02/2023] Open
Abstract
Side effect similarities of drugs have recently been employed to predict new drug targets, and networks of side effects and targets have been used to better understand the mechanism of action of drugs. Here, we report a large-scale analysis to systematically predict and characterize proteins that cause drug side effects. We integrated phenotypic data obtained during clinical trials with known drug-target relations to identify overrepresented protein-side effect combinations. Using independent data, we confirm that most of these overrepresentations point to proteins which, when perturbed, cause side effects. Of 1428 side effects studied, 732 were predicted to be predominantly caused by individual proteins, at least 137 of them backed by existing pharmacological or phenotypic data. We prove this concept in vivo by confirming our prediction that activation of the serotonin 7 receptor (HTR7) is responsible for hyperesthesia in mice, which, in turn, can be prevented by a drug that selectively inhibits HTR7. Taken together, we show that a large fraction of complex drug side effects are mediated by individual proteins and create a reference for such relations.
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Kim J, Kim Y, Tae J, Yeom M, Moon B, Huang XP, Roth BL, Lee K, Rhim H, Choo IH, Chong Y, Keum G, Nam G, Choo H. Aryl Biphenyl-3-ylmethylpiperazines as 5-HT7Receptor Antagonists. ChemMedChem 2013; 8:1855-64. [DOI: 10.1002/cmdc.201300240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/05/2013] [Indexed: 01/07/2023]
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Zeni ALB, Zomkowski ADE, Maraschin M, Tasca CI, Rodrigues ALS. Evidence of the involvement of the monoaminergic systems in the antidepressant-like effect of Aloysia gratissima. JOURNAL OF ETHNOPHARMACOLOGY 2013; 148:914-920. [PMID: 23747494 DOI: 10.1016/j.jep.2013.05.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/23/2013] [Accepted: 05/20/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aloysia gratissima (Verbenaceae) is an aromatic plant distributed in South America and, employed in folk medicine for the treatment of nervous systems illness, including depression. The neuroprotective and antidepressant-like activities of the aqueous extract of Aloysia gratissima (AE) administered orally has already been demonstrated.In this study the involvement of monoaminergic systems in the antidepressant-like effect of the AE was investigated. MATERIALS AND METHODS The implication of the monoaminergic systems in the antidepressant-like activity of Aloysia gratissima was evaluated using different pharmacological antagonists that were administered previously to the acute oral administration of AE (10 mg/kg). The antidepressant-like effect was assessed in the TST and locomotor activity was evaluated in the open-field test in mice. RESULTS The anti-immobility effect elicited by AE in the TST was prevented by the pre-treatment of mice with the antagonists, NAN-190 (5-HT(1A) receptor), ketanserin (5-HT(2A/2C) receptor), prazosin (α1-adrenoceptor), yohimbine (α2-adrenoceptor), SCH23390 (dopamine D1 receptor), or sulpiride (dopamine D2 receptor). CONCLUSIONS These results indicate that the antidepressant-like effect of AE in the TST is dependent on its interaction with the serotonergic (5-HT(1A) and 5-HT(2A/2C)), noradrenergic (α1 and α2-adrenoceptors) and dopaminergic (D1 and D2 receptors) systems, suggesting that this specie might act as a new potential resource for developing antidepressants to treat depressive disorders.
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Affiliation(s)
- Ana Lúcia B Zeni
- Departamento de Ciências Naturais, Centro de Ciências Exatas e Naturais, Universidade Regional de Blumenau, Campus I, 89012-900 SC, Brazil.
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Cappelli A, Manini M, Valenti S, Castriconi F, Giuliani G, Anzini M, Brogi S, Butini S, Gemma S, Campiani G, Giorgi G, Mennuni L, Lanza M, Giordani A, Caselli G, Letari O, Makovec F. Synthesis and structure–activity relationship studies in serotonin 5-HT1A receptor agonists based on fused pyrrolidone scaffolds. Eur J Med Chem 2013; 63:85-94. [DOI: 10.1016/j.ejmech.2013.01.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/14/2013] [Accepted: 01/17/2013] [Indexed: 11/25/2022]
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Galdino PM, Nascimento MVM, Florentino IF, Lino RC, Fajemiroye JO, Chaibub BA, de Paula JR, de Lima TCM, Costa EA. The anxiolytic-like effect of an essential oil derived from Spiranthera odoratissima A. St. Hil. leaves and its major component, β-caryophyllene, in male mice. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:276-84. [PMID: 22542869 DOI: 10.1016/j.pnpbp.2012.04.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 04/10/2012] [Accepted: 04/14/2012] [Indexed: 01/22/2023]
Abstract
Spiranthera odoratissima A. St. Hil. (manacá) is used in folk medicine to treat renal and hepatic diseases, stomachache, headaches and rheumatism. A central nervous system (CNS) depressant effect of the hexane fraction from the ethanolic extract of this plant has been described. β-caryophyllene, the main component of this essential oil, is a sesquiterpene compound with anti-inflammatory properties that has been found in essential oils derived from several medicinal plants. This work is aimed to evaluate the pharmacological activity of the essential oil obtained from S. odoratissima leaves (EO) and its major component on the murine CNS; we aimed to evaluate a possible anxiolytic-like effect and the underlying mechanisms involved. In an open field test, EO (500 mg/kg) and β-caryophyllene (50, 100 and 200 mg/kg) increased the crossing frequency (P<0.05) and, EO (250 and 500 mg/kg) and β-caryophyllene (200 mg/kg) increased the time spent in the center (P<0.05) without altering total crossings of the open field. EO and β-caryophyllene did not alter the number of falls in the rota-rod test (P>0.05). In the pentobarbital-induced sleep test, EO (500 mg/kg) and β-caryophyllene (200 and 400 mg/kg) decreased the latency to sleep (P<0.05), and EO (125, 250 and 500 mg/kg) (P<0.001) and β-caryophyllene (200 and 400 mg/kg) (P<0.05 and P<0.001) increased the sleep time. In anxiety tests, EO (500 mg/kg) and β-caryophyllene (100 and 200 mg/kg) increased head-dipping behavior (P<0.05) in the hole-board test, entries (P<0.05) into and time spent (P<0.05) on the open arms of the elevated plus maze (EPM), and number of transitions (P<0.05) and time spent in the light compartment (P<0.05) of a light-dark box (LDB). We further investigated the mechanism of action underlying the anxiolytic-like effect of EO and β-caryophyllene by pre-treating animals with antagonists of benzodiazepine (flumazenil) and 5-HT(1A) (NAN-190) receptors prior to evaluation using EPM and LDB. The anxiolytic-like effects of EO were significantly reduced by pre-treatment with NAN-190 (P<0.05) but not flumazenil (P>0.05). The anxiolytic-like effects of β-caryophyllene were not blocked by either NAN-190 or flumazenil (P>0.05). In conclusion, these results suggest that the essential oil derived from S. odoratissima produces an anxiolytic-like effect without altering motor performance and that this effect is mediated by 5-HT(1A) but not via benzodiazepine receptors. In addition, the major component, β-caryophyllene, also has an anxiolytic-like effect that may contribute to the effects of EO, but this effect does not seem to be mediated via 5-HT(1A) or benzodiazepine receptors.
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Affiliation(s)
- Pablinny Moreira Galdino
- Laboratório de Farmacologia de Produtos Naturais, Instituto de Ciências Fisiológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil.
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Chambers JD, Bornstein JC, Thomas EA. Multiple neural oscillators and muscle feedback are required for the intestinal fed state motor program. PLoS One 2011; 6:e19597. [PMID: 21573176 PMCID: PMC3088688 DOI: 10.1371/journal.pone.0019597] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 04/12/2011] [Indexed: 12/14/2022] Open
Abstract
After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40-60 s and separated by quiescent episodes lasting 40-200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle.
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Affiliation(s)
- Jordan D. Chambers
- Department of Physiology, The University of Melbourne, Parkville, Australia
| | - Joel C. Bornstein
- Department of Physiology, The University of Melbourne, Parkville, Australia
- * E-mail:
| | - Evan A. Thomas
- Department of Physiology, The University of Melbourne, Parkville, Australia
- Florey Neuroscience Institutes, Parkville, Australia
- Centre for Neuroscience, The University of Melbourne, Parkville, Australia
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Huo FQ, Huang FS, Lv BC, Chen T, Feng J, Qu CL, Tang JS, Li YQ. Activation of serotonin 1A receptors in ventrolateral orbital cortex depresses persistent nociception: A presynaptic inhibition mechanism. Neurochem Int 2010; 57:749-55. [DOI: 10.1016/j.neuint.2010.08.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/24/2010] [Accepted: 08/11/2010] [Indexed: 11/30/2022]
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Dickson EJ, Heredia DJ, Smith TK. Critical role of 5-HT1A, 5-HT3, and 5-HT7 receptor subtypes in the initiation, generation, and propagation of the murine colonic migrating motor complex. Am J Physiol Gastrointest Liver Physiol 2010; 299:G144-57. [PMID: 20413719 PMCID: PMC2904117 DOI: 10.1152/ajpgi.00496.2009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The colonic migrating motor complex (CMMC) is necessary for fecal pellet propulsion in the murine colon. We have previously shown that 5-hydroxytryptamine (5-HT) released from enterochromaffin cells activates 5-HT(3) receptors on the mucosal processes of myenteric Dogiel type II neurons to initiate the events underlying the CMMC. Our aims were to further investigate the roles of 5-HT(1A), 5-HT(3), and 5-HT(7) receptor subtypes in generating and propagating the CMMC using intracellular microelectrodes or tension recordings from the circular muscle (CM) in preparations with and without the mucosa. Spontaneous CMMCs were recorded from the CM in isolated murine colons but not in preparations without the mucosa. In mucosaless preparations, ondansetron (3 microM; 5-HT(3) antagonist) plus hexamethonium (100 microM) completely blocked spontaneous inhibitory junction potentials, depolarized the CM. Ondansetron blocked the preceding hyperpolarization associated with a CMMC. Spontaneous CMMCs and CMMCs evoked by spritzing 5-HT (10 and 100 microM) or nerve stimulation in preparations without the mucosa were blocked by SB 258719 or SB 269970 (1-5 microM; 5-HT(7) antagonists). Both NAN-190 and (S)-WAY100135 (1-5 microM; 5-HT(1A) antagonists) blocked spontaneous CMMCs and neurally evoked CMMCs in preparations without the mucosa. Both NAN-190 and (S)-WAY100135 caused an atropine-sensitive depolarization of the CM. The precursor of 5-HT, 5-hydroxytryptophan (5-HTP) (10 microM), and 5-carboxamidotryptamine (5-CT) (5 microM; 5-HT(1/5/7) agonist) increased the frequency of spontaneous CMMCs. 5-HTP and 5-CT also induced CMMCs in preparations with and without the mucosa, which were blocked by SB 258719. 5-HT(1A), 5-HT(3), and 5-HT(7) receptors, most likely on Dogiel Type II/AH neurons, are important in initiating, generating, and propagating the CMMC. Tonic inhibition of the CM appears to be driven by ongoing activity in descending serotonergic interneurons; by activating 5-HT(7) receptors on AH neurons these interneurons also contribute to the generation of the CMMC.
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Affiliation(s)
- Eamonn J. Dickson
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Dante J. Heredia
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Terence K. Smith
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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Bornstein JC, Marks KA, Foong JPP, Gwynne RM, Wang ZH. Nitric oxide enhances inhibitory synaptic transmission and neuronal excitability in Guinea-pig submucous plexus. Front Neurosci 2010; 4:30. [PMID: 20589236 PMCID: PMC2904599 DOI: 10.3389/fnins.2010.00030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 04/23/2010] [Indexed: 11/19/2022] Open
Abstract
Varicosities immunoreactive for nitric oxide synthase (NOS) make synaptic connections with submucosal neurons in the guinea-pig small intestine, but the effects of nitric oxide (NO) on these neurons are unknown. We used intracellular recording to characterize effects of sodium nitroprusside (SNP, NO donor) and nitro-l-arginine (NOLA, NOS inhibitor), on inhibitory synaptic potentials (IPSPs), slow excitatory synaptic potentials (EPSPs) and action potential firing in submucosal neurons of guinea-pig ileum in vitro. Recordings were made from neurons with the characteristic IPSPs of non-cholinergic secretomotor neurons. SNP (100 μM) markedly enhanced IPSPs evoked by single stimuli applied to intermodal strands and IPSPs evoked by trains of 2–10 pulses (30 Hz). Both noradrenergic (idazoxan-sensitive) and non-adrenergic (idazoxan-insensitive) IPSPs were affected. SNP enhanced hyperpolarizations evoked by locally applied noradrenaline or somatostatin. SNP did not affect slow EPSPs evoked by single stimuli, but depressed slow EPSPs evoked by stimulus trains. NOLA (100 μM) depressed IPSPs evoked by one to three stimulus pulses and enhanced slow EPSPs evoked by trains of two to three stimuli (30 Hz). SNP also increased the number of action potentials and the duration of firing evoked by prolonged (500 or 1000 ms) depolarizing current pulses, but NOLA had no consistent effect on action potential firing. We conclude that neurally released NO acts post-synaptically to enhance IPSPs and depress slow EPSPs, but may enhance the intrinsic excitability of these neurons. Thus, NOS neurons may locally regulate several secretomotor pathways ending on common neurons.
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Affiliation(s)
- Joel C Bornstein
- Department of Physiology, University of Melbourne Melbourne, VIC, Australia
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Foong JPP, Parry LJ, Gwynne RM, Bornstein JC. 5-HT(1A), SST(1), and SST(2) receptors mediate inhibitory postsynaptic potentials in the submucous plexus of the guinea pig ileum. Am J Physiol Gastrointest Liver Physiol 2010; 298:G384-94. [PMID: 20007849 PMCID: PMC2838515 DOI: 10.1152/ajpgi.00438.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vasoactive intestinal peptide (VIP) immunoreactive neurons are important secretomotor neurons in the submucous plexus. They are the only submucosal neurons to receive inhibitory inputs and exhibit both noradrenergic and nonadrenergic inhibitory synaptic potentials (IPSPs). The former are mediated by alpha(2)-adrenoceptors, but the receptors mediating the latter have not been identified. We used standard intracellular recording, RT-PCR, and confocal microscopy to test whether 5-HT(1A), SST(1), and/or SST(2) receptors mediate nonadrenergic IPSPs in VIP submucosal neurons in guinea pig ileum in vitro. The specific 5-HT(1A) receptor antagonist WAY 100135 (1 microM) reduced the amplitude of IPSPs, an effect that persisted in the presence of the alpha(2)-adrenoceptor antagonist idazoxan (2 microM), suggesting that 5-HT might mediate a component of the IPSPs. Confocal microscopy revealed that there were many 5-HT-immunoreactive varicosities in close contact with VIP neurons. The specific SSTR(2) antagonist CYN 154806 (100 nM) and a specific SSTR(1) antagonist SRA 880 (3 microM) each reduced the amplitude of nonadrenergic IPSPs and hyperpolarizations evoked by somatostatin. In contrast with the other antagonists, CYN 154806 also reduced the durations of nonadrenergic IPSPs. Effects of WAY 100135 and CYN 154806 were additive. RT-PCR revealed gene transcripts for 5-HT(1A), SST(1), and SST(2) receptors in stripped submucous plexus preparations consistent with the pharmacological data. Although the involvement of other neurotransmitters or receptors cannot be excluded, we conclude that 5-HT(1A), SST(1), and SST(2) receptors mediate nonadrenergic IPSPs in the noncholinergic (VIP) secretomotor neurons. This study thus provides the tools to identify functions of enteric neural pathways that inhibit secretomotor reflexes.
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Affiliation(s)
| | - Laura J. Parry
- 2Zoology, University of Melbourne, Parkville, Victoria, Australia
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Foong JPP, Bornstein JC. mGluR(1) Receptors Contribute to Non-Purinergic Slow Excitatory Transmission to Submucosal VIP Neurons of Guinea-Pig Ileum. Front Neurosci 2009; 3:46. [PMID: 20582273 PMCID: PMC2695390 DOI: 10.3389/neuro.21.001.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/14/2009] [Indexed: 11/23/2022] Open
Abstract
Vasoactive intestinal peptide (VIP) immunoreactive secretomotor neurons in the submucous plexus are involved in mediating bacterial toxin-induced hypersecretion leading to diarrhoea. VIP neurons become hyperexcitable after the mucosa is exposed to cholera toxin, which suggests that the manipulation of the excitability of these neurons may be therapeutic. This study used standard intracellular recording methods to systematically characterize slow excitatory postsynaptic potentials (EPSPs) evoked in submucosal VIP neurons by different stimulus regimes (1, 3 and 15 pulse 30 Hz stimulation), together with their associated input resistances and pharmacology. All slow EPSPs were associated with a significant increase in input resistance compared to baseline values. Slow EPSPs evoked by a single stimulus were confirmed to be purinergic, however, slow EPSPs evoked by 15 pulse trains were non-purinergic and those evoked by 3 pulse trains were mixed. NK1 or NK3 receptor antagonists did not affect slow EPSPs. The group I mGluR receptor antagonist, PHCCC reduced the amplitude of purinergic and non-purinergic slow EPSPs. Blocking mGluR1 receptors depressed the overall response to 3 and 15 pulse trains, but this effect was inconsistent, while blockade of mGluR5 receptors had no effect on the non-purinergic slow EPSPs. Thus, although other receptors are almost certainly involved, our data indicate that there are at least two pharmacologically distinct types of slow EPSPs in the VIP secretomotor neurons: one mediated by P2Y receptors and the other in part by mGluR1 receptors.
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Gál A, Ducza E, Minorics R, Klukovits A, Gálik M, Falkay G, Gáspár R. The roles of alpha2-adrenoceptor subtypes in the control of cervical resistance in the late-pregnant rat. Eur J Pharmacol 2009; 615:193-200. [PMID: 19450576 DOI: 10.1016/j.ejphar.2009.04.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 04/22/2009] [Accepted: 04/29/2009] [Indexed: 11/26/2022]
Abstract
The roles of the alpha(2)-adrenoceptor subtypes in the regulation of cervical resistance have previously not been investigated. The aim of the present study was to identify these receptors in the late-pregnant cervix and determine their functions in vitro in the rat. The expressions of the alpha(2)-adrenoceptor subtypes were determined by means of RT-PCR and Western blotting techniques. The changes in cervical resistance due to subtype-selective antagonists were investigated in stretching tests. The cyclic AMP immunoassay technique was used to detect the level of cyclic AMP following stimulation of the alpha(2)-adrenoceptors with or without pertussis toxin. On pregnancy days 18, 20, 21 and 22, the RT-PCR and Western blotting studies revealed the expressions of all three alpha(2)-adrenoceptor subtype mRNAs and proteins. On days 18 and 20, noradrenaline increased and decreased the resistance, respectively. Its effect was blocked by each of the antagonists used, except ARC 239 on both days. On day 21, noradrenaline again increased the resistance, this effect being maintained only in the presence of spiroxatrine. Noradrenaline was ineffective on day 22. These results were supported by the changes in cyclic AMP levels. Pertussis toxin pretreatment eliminated the changes in the cyclic AMP level on days 18 and 21. We presume that the alpha(2A)- and alpha(2C)-adrenoceptors play predominant roles in the regulation of cervical resistance on days 18-21. Depending on the day of pregnancy, stimulation of these alpha(2)-adrenoceptors could even result in opposite effects. This fluctuation can be explained by the changes in the G(i)/G(s)-coupling of the alpha(2A)- and alpha(2C)-adrenoceptors.
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Affiliation(s)
- Adrienn Gál
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, H-6720 Szeged, Eötvös u. 6, Hungary.
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