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Bosco F, Guarnieri L, Leo A, Tallarico M, Gallelli L, Rania V, Citraro R, De Sarro G. Audiogenic epileptic DBA/2 mice strain as a model of genetic reflex seizures and SUDEP. Front Neurol 2023; 14:1223074. [PMID: 37681009 PMCID: PMC10481168 DOI: 10.3389/fneur.2023.1223074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/14/2023] [Indexed: 09/09/2023] Open
Abstract
Epilepsy is a chronic neurological disease characterized by abnormal brain activity, which results in repeated spontaneous seizures. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of seizure-related premature death, particularly in drug-resistant epilepsy patients. The etiology of SUDEP is a structural injury to the brain that is not fully understood, but it is frequently associated with poorly controlled and repeated generalized tonic-clonic seizures (GTCSs) that cause cardiorespiratory and autonomic dysfunctions, indicating the involvement of the brainstem. Both respiratory and cardiac abnormalities have been observed in SUDEP, but not much progress has been made in their prevention. Owing to the complexity of SUDEP, experimental animal models have been used to investigate cardiac and/or respiratory dysregulation due to or associated with epileptic seizures that may contribute to death in humans. Numerous rodent models, especially mouse models, have been developed to better understand epilepsy and SUDEP physiopathology. This review synthesizes the current knowledge about dilute brown agouti coat color (DBA/2) mice as a possible SUDEP model because respiratory arrest (RA) and sudden death induced by audiogenic generalized seizures (AGSs) have been observed in these animals. Respiratory/cardiac dysfunction, brainstem arousal system dysfunction, and alteration of the neurotransmitter systems, which are observed in human SUDEP, have also been observed in these mice. In particular, serotonin (5-HT) alteration and adenosine neurotransmission appear to contribute to not only the pathophysiological mechanisms of medication but also seizure-related respiratory dysfunctions in this animal model. These neurotransmitter systems could be the relevant targets for medication development for chronic epilepsy and SUDEP prevention. We reviewed data on AGSs in DBA/2 mice and the relevance of this model of generalized tonic-clonic epilepsy to human SUDEP. Furthermore, the advantages of using this strain prone to AGSs for the identification of possible new therapeutic targets and treatment options have also been assessed.
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Affiliation(s)
- Francesca Bosco
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Lorenza Guarnieri
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Antonio Leo
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Martina Tallarico
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Luca Gallelli
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Vincenzo Rania
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Giovambattista De Sarro
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
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Therapeutic Potential and Limitation of Serotonin Type 7 Receptor Modulation. Int J Mol Sci 2023; 24:ijms24032070. [PMID: 36768393 PMCID: PMC9916679 DOI: 10.3390/ijms24032070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
Although a number of mood-stabilising atypical antipsychotics and antidepressants modulate serotonin type 7 receptor (5-HT7), the detailed contributions of 5-HT7 function to clinical efficacy and pathophysiology have not been fully understood. The mood-stabilising antipsychotic agent, lurasidone, and the serotonin partial agonist reuptake inhibitor, vortioxetine, exhibit higher binding affinity to 5-HT7 than other conventional antipsychotics and antidepressants. To date, the initially expected rapid onset of antidepressant effects-in comparison with conventional antidepressants or mood-stabilising antipsychotics-due to 5-HT7 inhibition has not been observed with lurasidone and vortioxetine; however, several clinical studies suggest that 5-HT7 inhibition likely contributes to quality of life of patients with schizophrenia and mood disorders via the improvement of cognition. Furthermore, recent preclinical studies reported that 5-HT7 inhibition might mitigate antipsychotic-induced weight gain and metabolic complication by blocking other monoamine receptors. Further preclinical studies for the development of 5-HT7 modulation against neurodevelopmental disorders and neurodegenerative diseases have been ongoing. To date, various findings from various preclinical studies indicate the possibility that 5-HT7 modifications can provide two independent strategies. The first is that 5-HT7 inhibition ameliorates the dysfunction of inter-neuronal transmission in mature networks. The other is that activation of 5-HT7 can improve transmission dysfunction due to microstructure abnormality in the neurotransmission network-which could be unaffected by conventional therapeutic agents-via modulating intracellular signalling during the neurodevelopmental stage or via loss of neural networks with aging. This review attempts to describe the current and novel clinical applications of 5-HT7 modulation based on preclinical findings.
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Quintero-Villegas A, Valdés-Ferrer SI. Central nervous system effects of 5-HT 7 receptors: a potential target for neurodegenerative diseases. Mol Med 2022; 28:70. [PMID: 35725396 PMCID: PMC9208181 DOI: 10.1186/s10020-022-00497-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/09/2022] [Indexed: 12/21/2022] Open
Abstract
5-HT7 receptors (5-HT7R) are the most recently identified among the family of serotonin receptors. Their role in health and disease, particularly as mediators of, and druggable targets for, neurodegenerative diseases, is incompletely understood. Unlike other serotonin receptors, for which abundant preclinical and clinical data evaluating their effect on neurodegenerative conditions exist, the available information on the role of the 5-HT7R receptor is limited. In this review, we describe the signaling pathways and cellular mechanisms implicated in the activation of the 5-HT7R; also, we analyze different mechanisms of neurodegeneration and the potential therapeutic implications of pharmacological interventions for 5-HT7R signaling.
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Affiliation(s)
- Alejandro Quintero-Villegas
- Department of Neurology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Sergio Iván Valdés-Ferrer
- Department of Neurology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico. .,Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico. .,Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA.
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Sahin B, Ozdemir E, Gumus E, Ergul M, Taskiran AS. The 5-HT7 receptor antagonist SB-269970 alleviates seizure activity and downregulates hippocampal c-Fos expression in pentylenetetrazole-induced kindled rats. Neurol Res 2022; 44:786-796. [DOI: 10.1080/01616412.2022.2064700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Bilal Sahin
- Departments of Physiology, Sivas Cumhuriyet University, School of Medicine, Sivas, Turkey
| | - Ercan Ozdemir
- Departments of Physiology, Sivas Cumhuriyet University, School of Medicine, Sivas, Turkey
| | - Erkan Gumus
- Departments of Histology and Embryology, Aydın Adnan Menderes University, School of Medicine, Aydın, Turkey
| | - Mustafa Ergul
- Departments of Biochemistry, Sivas Cumhuriyet University, School of Pharmacy, Sivas, Turkey
| | - Ahmet Sevki Taskiran
- Departments of Physiology, Sivas Cumhuriyet University, School of Medicine, Sivas, Turkey
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Tupal S, Faingold CL. Serotonin 5-HT 4 receptors play a critical role in the action of fenfluramine to block seizure-induced sudden death in a mouse model of SUDEP. Epilepsy Res 2021; 177:106777. [PMID: 34601387 DOI: 10.1016/j.eplepsyres.2021.106777] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/25/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022]
Abstract
RATIONALE Our previous study showed that the recently approved anticonvulsant drug, fenfluramine, which enhances the release of serotonin (5-hydroxytryptamine, 5-HT) in the brain, prevents seizure-induced respiratory arrest (S-IRA) in the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP). The present study examined the role of 5-HT receptor subtypes in mediating the effect of this agent by combined administration of fenfluramine with selective 5-HT receptor antagonists prior to seizure in DBA/1 mice. METHODS Fenfluramine (15 mg/kg, i.p.) was administered to primed DBA/1 mice, and audiogenic seizure (Sz) was induced 16 h later. Thirty min prior to Sz induction a selective antagonist acting on 5-HT1A, 5-HT2, 5-HT3 5-HT4, 5-HT5A, 5-HT6 or 5-HT7 receptors at a sub-toxic dose was administered, and changes in seizure-induced behaviors were evaluated. Follow-up studies examined the effect of administration of a 5-HT4 receptor agonist, BIMU 8, as well as the effect of co-administration of ineffective doses of fenfluramine and BIMU-8 on Sz behaviors. RESULTS The 5-HT4 antagonist (GR125487) was the only 5-HT receptor antagonist that was able to reverse the action of fenfluramine to block Sz and S-IRA. Treatment with the 5-HT4 receptor agonist (BIMU-8), or co-administration of ineffective doses of BIMU-8 and fenfluramine significantly reduced the incidence of S-IRA and tonic Sz in DBA/1 mice. The antagonists for 5-HT3, 5-HT5A 5-HT6, and 5-HT7 receptors did not significantly affect the action of fenfluramine. However, the 5-HT1A and the 5-HT2 antagonists enhanced the anticonvulsant effects of fenfluramine. CONCLUSIONS These findings suggest that the action of fenfluramine to prevent seizure-induced sudden death in DBA/1 mice is mediated primarily by activation of 5-HT4 receptors. These studies are the first to indicate the therapeutic potential of 5-HT4 receptor agonists either alone or in combination with fenfluramine for preventing SUDEP. Enhancement of the anticonvulsant effect of fenfluramine by 5-HT1A and 5-HT2 antagonists may involve presynaptic actions of these antagonists. Thus, the Sz and S-IRA blocking actions of fenfluramine involve complex interactions with several 5-HT receptor subtypes. These data also provide further support for the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
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Armstrong JL, Casey AB, Saraf TS, Mukherjee M, Booth RG, Canal CE. ( S)-5-(2'-Fluorophenyl)- N, N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine, a Serotonin Receptor Modulator, Possesses Anticonvulsant, Prosocial, and Anxiolytic-like Properties in an Fmr1 Knockout Mouse Model of Fragile X Syndrome and Autism Spectrum Disorder. ACS Pharmacol Transl Sci 2020; 3:509-523. [PMID: 32566916 DOI: 10.1021/acsptsci.9b00101] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Indexed: 12/12/2022]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder characterized by intellectual disabilities and a plethora of neuropsychiatric symptoms. FXS is the leading monogenic cause of autism spectrum disorder (ASD), which is defined clinically by repetitive and/or restrictive patterns of behavior and social communication deficits. Epilepsy and anxiety are also common in FXS and ASD. Serotonergic neurons directly innervate and modulate the activity of neurobiological circuits altered in both disorders, providing a rationale for investigating serotonin receptors (5-HTRs) as targets for FXS and ASD drug discovery. Previously we unveiled an orally active aminotetralin, (S)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine (FPT), that exhibits partial agonist activity at 5-HT1ARs, 5-HT2CRs, and 5-HT7Rs and that reduces repetitive behaviors and increases social approach behavior in wild-type mice. Here we report that in an Fmr1 knockout mouse model of FXS and ASD, FPT is prophylactic for audiogenic seizures. No FPT-treated mice displayed audiogenic seizures, compared to 73% of vehicle-treated mice. FPT also exhibits anxiolytic-like effects in several assays and increases social interactions in both Fmr1 knockout and wild-type mice. Furthermore, FPT increases c-Fos expression in the basolateral amygdala, which is a preclinical effect produced by anxiolytic medications. Receptor pharmacology assays show that FPT binds competitively and possesses rapid association and dissociation kinetics at 5-HT1ARs and 5-HT7Rs, yet has slow association and rapid dissociation kinetics at 5-HT2CRs. Finally, we reassessed and report FPT's affinity and function at 5-HT1ARs, 5-HT2CRs, and 5-HT7Rs. Collectively, these observations provide mounting support for further development of FPT as a pharmacotherapy for common neuropsychiatric symptoms in FXS and ASD.
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Affiliation(s)
- Jessica L Armstrong
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, United States
| | - Austen B Casey
- Center for Drug Discovery, Department of Pharmaceutical Sciences, and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02131, United States
| | - Tanishka S Saraf
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, United States
| | - Munmun Mukherjee
- Center for Drug Discovery, Department of Pharmaceutical Sciences, and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02131, United States
| | - Raymond G Booth
- Center for Drug Discovery, Department of Pharmaceutical Sciences, and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02131, United States
| | - Clinton E Canal
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, United States
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Blattner KM, Canney DJ, Pippin DA, Blass BE. Pharmacology and Therapeutic Potential of the 5-HT 7 Receptor. ACS Chem Neurosci 2019; 10:89-119. [PMID: 30020772 DOI: 10.1021/acschemneuro.8b00283] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
It is well-documented that serotonin (5-HT) exerts its pharmacological effects through a series of 5-HT receptors. The most recently identified member of this family, 5-HT7, was first identified in 1993. Over the course of the last 25 years, this receptor has been the subject of intense investigation, and it has been demonstrated that 5-HT7 plays an important role in a wide range of pharmacological processes. As a result of these findings, modulation of 5-HT7 activity has been the focus of numerous drug discovery and development programs. This review provides an overview of the roles of 5-HT7 in normal physiology and the therapeutic potential of this interesting drug target.
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Affiliation(s)
- Kevin M. Blattner
- Temple University School of Pharmacy, Department of Pharmaceutical Sciences, Moulder Center for Drug Discovery Research, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Daniel J. Canney
- Temple University School of Pharmacy, Department of Pharmaceutical Sciences, Moulder Center for Drug Discovery Research, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Douglas A. Pippin
- Praeventix, LLC, 665 Stockton Drive, Suite 200H, Exton, Pennsylvania 19341, United States
| | - Benjamin E. Blass
- Temple University School of Pharmacy, Department of Pharmaceutical Sciences, Moulder Center for Drug Discovery Research, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States
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Taskiran M, Tasdemir A, Ayyildiz N, Ayyildiz M, Agar E. The effect of serotonin on penicillin-induced epileptiform activity. Int J Neurosci 2019; 129:687-697. [DOI: 10.1080/00207454.2018.1557166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Mehmet Taskiran
- Department of Biology, Faculty of Science, Erciyes University, Kayseri, Turkey
| | - Abdulkadir Tasdemir
- Graduate School of Natural and Applied Sciences, Erciyes University, Kayseri, Turkey
| | - Nusret Ayyildiz
- Department of Biology, Faculty of Science, Erciyes University, Kayseri, Turkey
| | - Mustafa Ayyildiz
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Erdal Agar
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
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Nieoczym D, Socała K, Wlaź P. Evaluation of the role of different neurotransmission systems in the anticonvulsant action of sildenafil in the 6 Hz-induced psychomotor seizure threshold test in mice. Biomed Pharmacother 2018; 107:1674-1681. [PMID: 30257385 DOI: 10.1016/j.biopha.2018.08.163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/28/2018] [Accepted: 08/31/2018] [Indexed: 12/14/2022] Open
Abstract
Sildenafil influences seizure activity in animal seizure models, and its both proconvulsant and anticonvulsant effects were reported. We previously found that this PDE5 inhibitor significantly increased seizure threshold for the 6 Hz-induced psychomotor seizures in mice and therefore we aimed to investigate the influence of some modulators of neurotransmitter receptors, i.e., diazepam (GABA/benzodiazepine receptor agonist), flumazenil (GABA/benzodiazepine receptor antagonist), N-methyl-d-aspartic acid (NMDA glutamate receptor agonist), CGP 37849 (NMDA receptor antagonist), metergoline (serotonin receptor antagonist), 8-cyclopentyl-1,3-dipropylxanthine (adenosine A1 receptor antagonist) and β-funaltrexamine (μ opioid receptor antagonist), on the anticonvulsant effect of sildenafil in this test. Additionally, we estimated influence of the studied compounds and their combinations with sildenafil on the muscular strength (assessed in the grip strength test) and motor coordination (assessed in the chimney test) in mice. Our results indicate that anticonvulsant properties of sildenafil in the 6 Hz test in mice might be related to its interactions with the GABAergic, glutamatergic, serotonergic and adenosinergic neurotransmission. We did not find interactions between sildenafil and μ opioid receptors. Neither the studied ligands nor their combinations with sildenafil impaired muscular strength and motor coordination. In conclusion, sildenafil has complex and extensive influence on neurotransmission and seizure generation in the CNS.
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Affiliation(s)
- Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, PL 20-033, Lublin, Poland.
| | - Katarzyna Socała
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, PL 20-033, Lublin, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, PL 20-033, Lublin, Poland
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Pytka K, Socała K, Rapacz A, Nieoczym D, Pieróg M, Gryboś A, Siwek A, Waszkielewicz A, Wlaź P. HBK-14 and HBK-15, triple 5-HT 1A, 5-HT 7 and 5-HT 3 antagonists with potent antidepressant- and anxiolytic-like properties, increase seizure threshold in various seizure tests in mice. Prog Neuropsychopharmacol Biol Psychiatry 2017; 79:378-385. [PMID: 28729118 DOI: 10.1016/j.pnpbp.2017.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/12/2017] [Accepted: 07/15/2017] [Indexed: 02/02/2023]
Abstract
Most antidepressants lower seizure threshold, which might be due to the modulation of serotonergic neurotransmission. Here, we investigated the effects of two 5-HT1A, 5-HT7 and 5-HT3 antagonists, i.e., 1-(2-(2-(2,6-dimethylphenoxy)ethoxy)ethyl)-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-14) and 1-{2-[2-(2-chloro-6-methylphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-15), with antidepressant- and anxiolytic-like properties, on seizure thresholds in three acute seizure tests, i.e., the intravenous pentylenetetrazole, maximal electroshock seizure threshold (MEST), and 6-Hz corneal stimulation test in mice. We also evaluated their affinity for voltage-gated sodium channels. Our results indicate that HBK-14 increased seizure thresholds in three seizure tests in mice, while HBK-15 was active in the MEST and 6-Hz tests. None of the compounds affected neuromuscular strength or motor coordination at active doses. We showed that both compounds had high affinity for voltage-dependent sodium channels, which combined with the influence on 5-HT1A, 5-HT7 and 5-HT3 receptors, might underlie their anticonvulsant effects. Since most antidepressants lower the seizure threshold, the fact that both compounds with potent antidepressant-like activity, increased or had no influence on seizure threshold is worth investigating.
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Affiliation(s)
- Karolina Pytka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland.
| | - Katarzyna Socała
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
| | - Anna Rapacz
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
| | - Mateusz Pieróg
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
| | - Anna Gryboś
- Department of Pharmacobiology, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Agata Siwek
- Department of Pharmacobiology, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Anna Waszkielewicz
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland
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Svob Strac D, Pivac N, Smolders IJ, Fogel WA, De Deurwaerdere P, Di Giovanni G. Monoaminergic Mechanisms in Epilepsy May Offer Innovative Therapeutic Opportunity for Monoaminergic Multi-Target Drugs. Front Neurosci 2016; 10:492. [PMID: 27891070 PMCID: PMC5102907 DOI: 10.3389/fnins.2016.00492] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 10/13/2016] [Indexed: 12/22/2022] Open
Abstract
A large body of experimental and clinical evidence has strongly suggested that monoamines play an important role in regulating epileptogenesis, seizure susceptibility, convulsions, and comorbid psychiatric disorders commonly seen in people with epilepsy (PWE). However, neither the relative significance of individual monoamines nor their interaction has yet been fully clarified due to the complexity of these neurotransmitter systems. In addition, epilepsy is diverse, with many different seizure types and epilepsy syndromes, and the role played by monoamines may vary from one condition to another. In this review, we will focus on the role of serotonin, dopamine, noradrenaline, histamine, and melatonin in epilepsy. Recent experimental, clinical, and genetic evidence will be reviewed in consideration of the mutual relationship of monoamines with the other putative neurotransmitters. The complexity of epileptic pathogenesis may explain why the currently available drugs, developed according to the classic drug discovery paradigm of “one-molecule-one-target,” have turned out to be effective only in a percentage of PWE. Although, no antiepileptic drugs currently target specifically monoaminergic systems, multi-target directed ligands acting on different monoaminergic proteins, present on both neurons and glia cells, may represent a new approach in the management of seizures, and their generation as well as comorbid neuropsychiatric disorders.
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Affiliation(s)
| | - Nela Pivac
- Division of Molecular Medicine, Rudjer Boskovic Institute Zagreb, Croatia
| | - Ilse J Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel Brussels, Belgium
| | - Wieslawa A Fogel
- Department of Hormone Biochemistry, Medical University of Lodz Lodz, Poland
| | | | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, University of Malta Msida, Malta
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Abstract
The dorsal cochlear nucleus (DCN) is one of the first stations within the central auditory pathway where the basic computations underlying sound localization are initiated and heightened activity in the DCN may underlie central tinnitus. The neurotransmitter serotonin (5-hydroxytryptamine; 5-HT), is associated with many distinct behavioral or cognitive states, and serotonergic fibers are concentrated in the DCN. However, it remains unclear what is the function of this dense input. Using a combination of in vitro electrophysiology and optogenetics in mouse brain slices, we found that 5-HT directly enhances the excitability of fusiform principal cells via activation of two distinct 5-HT receptor subfamilies, 5-HT2A/2CR (5-HT2A/2C receptor) and 5-HT7R (5-HT7 receptor). This excitatory effect results from an augmentation of hyperpolarization-activated cyclic nucleotide-gated channels (Ih or HCN channels). The serotonergic regulation of excitability is G-protein-dependent and involves cAMP and Src kinase signaling pathways. Moreover, optogenetic activation of serotonergic axon terminals increased excitability of fusiform cells. Our findings reveal that 5-HT exerts a potent influence on fusiform cells by altering their intrinsic properties, which may enhance the sensitivity of the DCN to sensory input.
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Ciranna L, Catania MV. 5-HT7 receptors as modulators of neuronal excitability, synaptic transmission and plasticity: physiological role and possible implications in autism spectrum disorders. Front Cell Neurosci 2014; 8:250. [PMID: 25221471 PMCID: PMC4145633 DOI: 10.3389/fncel.2014.00250] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022] Open
Abstract
Serotonin type 7 receptors (5-HT7) are expressed in several brain areas, regulate brain development, synaptic transmission and plasticity, and therefore are involved in various brain functions such as learning and memory. A number of studies suggest that 5-HT7 receptors could be potential pharmacotherapeutic target for cognitive disorders. Several abnormalities of serotonergic system have been described in patients with autism spectrum disorder (ASD), including abnormal activity of 5-HT transporter, altered blood and brain 5-HT levels, reduced 5-HT synthesis and altered expression of 5-HT receptors in the brain. A specific role for 5-HT7 receptors in ASD has not yet been demonstrated but some evidence implicates their possible involvement. We have recently shown that 5-HT7 receptor activation rescues hippocampal synaptic plasticity in a mouse model of Fragile X Syndrome, a monogenic cause of autism. Several other studies have shown that 5-HT7 receptors modulate behavioral flexibility, exploratory behavior, mood disorders and epilepsy, which include core and co-morbid symptoms of ASD. These findings further suggest an involvement of 5-HT7 receptors in ASD. Here, we review the physiological roles of 5-HT7 receptors and their implications in Fragile X Syndrome and other ASD.
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Affiliation(s)
- Lucia Ciranna
- Department of Biomedical Sciences, University of Catania Catania, Italy
| | - Maria Vincenza Catania
- Institute of Neurological Sciences, the National Research Council of Italy (CNR) Catania, Italy ; Laboratory of Neurobiology, IRCCS Oasi Maria SS Troina, Italy
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Wang X, Fang Y, Liang J, Yan M, Hu R, Pan X. 5-HT7 Receptors Are Involved in Neurogenic Dural Vasodilatation in an Experimental Model of Migraine. J Mol Neurosci 2014; 54:164-70. [DOI: 10.1007/s12031-014-0268-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/17/2014] [Indexed: 11/24/2022]
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15
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Chitta A, Sivan SK, Manga V. 3D QSAR based design of novel oxindole derivative as 5HT7 inhibitors. J Recept Signal Transduct Res 2014; 34:185-94. [PMID: 24456291 DOI: 10.3109/10799893.2013.869601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To understand the structural requirements of 5-hydroxytryptamine (5HT7) receptor inhibitors and to design new ligands against 5HT7 receptor with enhanced inhibitory potency, a three-dimensional quantitative structure-activity relationship study with comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) for a data set of 56 molecules consisting of oxindole, tetrahydronaphthalene, aryl ketone substituted arylpiperazinealkylamide derivatives was performed. Derived model showed good statistical reliability in terms of predicting 5HT7 inhibitory activity of the molecules, based on molecular property fields like steric, electrostatic, hydrophobic, hydrogen bond donor and hydrogen bond acceptor fields. This is evident from statistical parameters like conventional r2 and a cross validated (q2) values of 0.985, 0.743 for CoMFA and 0.970, 0.608 for CoMSIA, respectively. Predictive ability of the models to determine 5HT7 antagonistic activity is validated using a test set of 16 molecules that were not included in the training set. Predictive r2 obtained for the test set was 0.560 and 0.619 for CoMFA and CoMSIA, respectively. Steric, electrostatic fields majorly contributed toward activity which forms the basis for design of new molecules. Absorption, distribution, metabolism and elimination (ADME) calculation using QikProp 2.5 (Schrodinger 2010, Portland, OR) reveals that the molecules confer to Lipinski's rule of five in majority of the cases.
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Affiliation(s)
- Aparna Chitta
- Molecular Modeling and Medicinal Chemistry Group, Department of Chemistry, Nizam College, Osmania University , Basheerbagh, Hyderabad , India
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16
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The role of different serotonin receptor subtypes in seizure susceptibility. Exp Brain Res 2013; 232:347-67. [PMID: 24232860 DOI: 10.1007/s00221-013-3757-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 10/27/2013] [Indexed: 10/26/2022]
Abstract
5-Hydroxytryptamine (5-HT) has the most diverse set of receptors in comparison with any other neurotransmitter or hormone in the body. To date, seven families of 5-HT receptors have been characterized. A great number of studies have been published regarding the role of 5-HT and its receptors in seizures. However, with a few exceptions, the net effect of activating or inhibiting each 5-HT receptor subtype on the development or severity of seizures remains controversial. Additionally, the results of studies, which have used knockout animals to investigate the role of 5-HT receptors in seizures, have sometimes been contradictory to those which have used pharmacological tools. The present study aims to review the available data regarding the influence of each receptor subtype on seizure development and, when possible, reconcile between the apparently different results obtained in these studies.
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Hamid H, Kanner AM. Should antidepressant drugs of the selective serotonin reuptake inhibitor family be tested as antiepileptic drugs? Epilepsy Behav 2013; 26:261-5. [PMID: 23395350 DOI: 10.1016/j.yebeh.2012.10.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 10/17/2012] [Indexed: 01/11/2023]
Abstract
For a long time, there has been a misconception that all antidepressant drugs have proconvulsant effects. Yet, antidepressants of the selective serotonin reuptake inhibitor (SSRI) family not only have been shown to be safe when used in patients with epilepsy (PWE) but also have been found to possess antiepileptic properties in animal models of epilepsy. In humans randomized to SSRIs vs. placebo for the treatment of major depressive episodes, the incidence of epileptic seizures was significantly lower among those treated with the antidepressants. These data raise the question of whether there is enough evidence that would support a randomized placebo-controlled trial to test antiepileptic effect of SSRIs in PWE. This article reviews the preclinical and clinical data to address this question.
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Affiliation(s)
- Hamada Hamid
- Department of Neurology, Yale University School of Medicine, USA
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18
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Involvement of 5-HT7 receptors in the pathogenesis of temporal lobe epilepsy. Eur J Pharmacol 2012; 685:52-8. [DOI: 10.1016/j.ejphar.2012.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 11/21/2022]
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19
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Igelström KM. Preclinical antiepileptic actions of selective serotonin reuptake inhibitors--implications for clinical trial design. Epilepsia 2012; 53:596-605. [PMID: 22416943 DOI: 10.1111/j.1528-1167.2012.03427.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) can reduce seizure frequency in humans, but no large-scale clinical trials have been done to test the utility of SSRIs as potential antiepileptic drugs. This may be caused in part by a small number of reports on seizures triggered by SSRI treatment. The preclinical literature on SSRIs is somewhat conflicting, which is likely to contribute to the hesitance in accepting SSRIs as possible anticonvulsant drug therapy. A careful review of preclinical studies reveals that SSRIs appear to have region-specific and seizure subtype-specific effects, with models of chronic partial epilepsy being more likely to respond than models of acute generalized seizures. Moreover, this preclinical profile is similar to that of clinical antiepileptic drugs. These observations suggest that SSRIs are promising antiepileptic agents, and that clinical trials may benefit from defining patient groups according to the underlying pathology.
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Affiliation(s)
- Kajsa M Igelström
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
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20
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Saulin A, Savli M, Lanzenberger R. Serotonin and molecular neuroimaging in humans using PET. Amino Acids 2011; 42:2039-57. [PMID: 21947614 DOI: 10.1007/s00726-011-1078-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 02/07/2023]
Abstract
The serotonergic system is one of the most important modulatory neurotransmitter systems in the human brain. It plays a central role in major physiological processes and is implicated in a number of psychiatric disorders. Along with the dopaminergic system, it is also one of the phylogenetically oldest human neurotransmitter systems and one of the most diverse, with 14 different receptors identified up to this day, many of whose function remains to be understood. The system's functioning is even more diverse than the number of its receptors, since each is implicated in a number of different processes. This review aims at illustrating the distribution and summarizing the main functions of the serotonin (5-hydroxytryptamin, 5-HT) receptors as well as the serotonin transporter (SERT, 5-HTT), the vesicular monoamine transporter 2, monoamine oxidase type A and 5-HT synthesis in the human brain. Recent advances in in vivo quantification of these different receptors and enzymes that are part of the serotonergic system using positron emission tomography are described.
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Affiliation(s)
- Anne Saulin
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Matthys A, Haegeman G, Van Craenenbroeck K, Vanhoenacker P. Role of the 5-HT7 receptor in the central nervous system: from current status to future perspectives. Mol Neurobiol 2011; 43:228-53. [PMID: 21424680 DOI: 10.1007/s12035-011-8175-3] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 03/01/2011] [Indexed: 12/11/2022]
Abstract
Pharmacological and genetic tools targeting the 5-hydroxytryptamine (5-HT)7 receptor in preclinical animal models have implicated this receptor in diverse (patho)physiological processes of the central nervous system (CNS). Some data obtained with 5-HT7 receptor knockout mice, selective antagonists, and, to a lesser extent, agonists, however, are quite contradictory. In this review, we not only discuss in detail the role of the 5-HT7 receptor in the CNS but also propose some hypothetical models, which could explain the observed inconsistencies. These models are based on two novel concepts within the field of G protein-coupled receptors (GPCR), namely biphasic signaling and G protein-independent signaling, which both have been shown to be mediated by GPCR dimerization. This led us to suggest that the 5-HT7 receptor could reside in different dimeric contexts and initiate different signaling pathways, depending on the neuronal circuitry and/or brain region. In conclusion, we highlight GPCR dimerization and G protein-independent signaling as two promising future directions in 5-HT7 receptor research, which ultimately might lead to the development of more efficient dimer- and/or pathway-specific therapeutics.
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Affiliation(s)
- Anne Matthys
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Department of Physiology, Ghent University (UGent), Ghent, Belgium
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Leopoldo M, Lacivita E, Berardi F, Perrone R, Hedlund PB. Serotonin 5-HT7 receptor agents: Structure-activity relationships and potential therapeutic applications in central nervous system disorders. Pharmacol Ther 2010; 129:120-48. [PMID: 20923682 DOI: 10.1016/j.pharmthera.2010.08.013] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 08/26/2010] [Indexed: 12/19/2022]
Abstract
Since its discovery in the 1940s in serum, the mammalian intestinal mucosa, and in the central nervous system, serotonin (5-HT) has been shown to be involved in virtually all cognitive and behavioral human functions, and alterations in its neurochemistry have been implicated in the etiology of a plethora of neuropsychiatric disorders. The cloning of 5-HT receptor subtypes has been of importance in enabling them to be classified as specific protein molecules encoded by specific genes. The 5-HT(7) receptor is the most recently classified member of the serotonin receptor family. Since its identification, it has been the subject of intense research efforts driven by its presence in functionally relevant regions of the brain. The availability of some selective antagonists and agonists, in combination with genetically modified mice lacking the 5-HT(7) receptor, has allowed for a better understanding of the pathophysiological role of this receptor. This paper reviews data on localization and pharmacological properties of the 5-HT(7) receptor, and summarizes the results of structure-activity relationship studies aimed at the discovery of selective 5-HT(7) receptor ligands. Additionally, an overview of the potential therapeutic applications of 5-HT(7) receptor agonists and antagonists in central nervous system disorders is presented.
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Affiliation(s)
- Marcello Leopoldo
- Dipartimento Farmaco-Chimico, Università degli Studi di Bari "A. Moro", via Orabona, 4, 70125 Bari, Italy.
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Wang X, Fang Y, Liang J, Yin Z, Miao J, Luo N. Selective Inhibition of 5-HT7Receptor Reduces CGRP Release in an Experimental Model for Migraine. Headache 2010; 50:579-87. [DOI: 10.1111/j.1526-4610.2010.01632.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The 5-HT7 receptor and disorders of the nervous system: an overview. Psychopharmacology (Berl) 2009; 206:345-54. [PMID: 19649616 PMCID: PMC2841472 DOI: 10.1007/s00213-009-1626-0] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 07/14/2009] [Indexed: 12/20/2022]
Abstract
RATIONALE The 5-HT(7) receptor is a more recently discovered G-protein-coupled receptor for serotonin. The functions and possible clinical relevance of this receptor are not yet fully understood. OBJECTIVE The present paper reviews to what extent the use of animal models of human psychiatric and neurological disorders have implicated the 5-HT(7) receptor in such disorders. The studies have used a combination of pharmacological and genetic tools targeting the receptor to evaluate effects on behavior. RESULTS Models of anxiety and schizophrenia have yielded mixed results with no clear role for the 5-HT(7) receptor described in these disorders. Some data are available for epilepsy, migraine, and pain but it is still very early to draw any definitive conclusions. There is a considerable amount of evidence supporting a role for the 5-HT(7) receptor in depression. Both blockade and inactivation of the receptor have resulted in an antidepressant-like profile in models of depression. Supporting evidence has also been obtained in sleep studies. Especially interesting are the augmented effects achieved by combining antidepressants and 5-HT(7) receptor antagonists. The antidepressant effect of amisulpride has been shown to most likely be mediated by the 5-HT(7) receptor. CONCLUSIONS The use of pharmacological and genetic tools in preclinical animal models strongly supports a role for the 5-HT(7) receptor in depression. Indirect evidence exists showing that 5-HT(7) receptor antagonism is clinically useful in the treatment of depression. Available data also indicate a possible involvement of the 5-HT(7) receptor in anxiety, epilepsy, pain, and schizophrenia.
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Mirski MA, Ziai WC, Chiang J, Hinich M, Sherman D. Anticonvulsant serotonergic and deep brain stimulation in anterior thalamus. Seizure 2009; 18:64-70. [DOI: 10.1016/j.seizure.2008.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Accepted: 06/20/2008] [Indexed: 11/15/2022] Open
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Rocha L, Lorigados-Pedre L, Orozco-Suárez S, Morales-Chacón L, Alonso-Vanegas M, García-Maeso I, Villeda-Hernández J, Osorio-Rico L, Estupiñán B, Quintana C. Autoradiography reveals selective changes in serotonin binding in neocortex of patients with temporal lobe epilepsy. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1208-18. [PMID: 17513030 DOI: 10.1016/j.pnpbp.2007.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/18/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
The main goal of the present study was to evaluate binding to serotonin in the neocortex surrounding the epileptic focus of patients with mesial temporal lobe epilepsy (MTLE). Binding to 5-HT, 5-HT(1A), 5-HT(4), 5-HT(7) receptors and serotonin transporter (5-HTT) in T1-T2 gyri of 15 patients with MTLE and their correlations with clinical data, neuronal count and volume were determined. Autopsy material acquired from subjects without epilepsy (n=6) was used as control. The neocortex from MTLE patients demonstrated decreased cell count in layers III-IV (21%). No significant changes were detected on the neuronal volume. Autoradiography experiments showed the following results: reduced 5-HT and 5-HT(1A) binding in layers I-II (24% and 92%, respectively); enhanced 5-HT(4) binding in layers V-VI (32%); no significant changes in 5-HT(7) binding; reduced 5-HTT binding in all layers (I-II, 90.3%; III-IV, 90.3%, V-VI, 86.9%). Significant correlations were found between binding to 5-HT(4) and 5-HT(7) receptors and age of seizure onset, duration of epilepsy and duration of antiepileptic treatment. The present results support an impaired serotoninergic transmission in the neocortex surrounding the epileptic focus of patients with MTLE, a situation that could be involved in the initiation and propagation of seizure activity.
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Affiliation(s)
- Luisa Rocha
- Departamento de Farmacobiología, Sede Sur del Centro de Investigación y de Estudios Avanzados, Calz. Tenorios 235, Col. Granjas Coapa, C.P. 14330, México, DF, Mexico.
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27
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Witkin JM, Baez M, Yu J, Barton ME, Shannon HE. Constitutive deletion of the serotonin-7 (5-HT7) receptor decreases electrical and chemical seizure thresholds. Epilepsy Res 2007; 75:39-45. [PMID: 17485199 DOI: 10.1016/j.eplepsyres.2007.03.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 03/05/2007] [Accepted: 03/28/2007] [Indexed: 12/01/2022]
Abstract
The localization of serotonin-7 (5-HT(7)) receptors and the biological activity of ligands have suggested that 5-HT(7) receptors might be involved in pain, migraine, epilepsy, anxiety, depression, memory, and sleep. In the present study, the potential involvement of 5-HT(7) receptors in epilepsy and other seizure disorders was assessed by comparing the seizures produced by three types of electrical stimulation and three chemical convulsants in 5-HT(7) receptor-deficient (knockout, KO) mice to those seizures observed in wild-type (WT) mice. Thresholds for producing electroshock-induced clonic seizures did not differ between KO versus WT mice. However, thresholds for producing electroshock-induced tonic seizures were significantly lower in KO than in WT mice. Seizures produced by pentylenetetrazole (PTZ, a GABA(A) receptor antagonist), N-methyl-d-aspartate (NMDA, an agonist at NMDA-type glutamate receptors), and cocaine (an inhibitor of monoamine uptake) were also studied. PTZ was more potent in inducing seizures in 5-HT(7) KO mice than in wild-type mice. Likewise, cocaine was more potent in inducing seizures in 5-HT(7) KO than in WT mice; moreover, death resulted from cocaine administration in 5-HT(7) KO mice but not in WT mice. There was a similar trend for NMDA that did not reach statistical significance. The present findings point to the potential for a generalized reduction in seizure threshold with constitutive deletion of the 5-HT(7) receptor gene. Since seizures have not been reported with pharmacological blockade of the receptor, the findings suggest that adaptive changes may play a role in the low seizure thresholds in these mice. In addition, the data suggest that the lower thresholds for seizures produced by diverse mechanisms should be taken into account when interpreting other aspects of the phenotype and behavioral pharmacology of this mouse.
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Affiliation(s)
- Jeffrey M Witkin
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA.
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Pericić D, Svob Strac D. The role of 5-HT7 receptors in the control of seizures. Brain Res 2007; 1141:48-55. [PMID: 17276417 DOI: 10.1016/j.brainres.2007.01.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 12/22/2006] [Accepted: 01/05/2007] [Indexed: 11/20/2022]
Abstract
Serotonin exerts its effects via at least 14 different receptor subtypes, but the role of only a few of them has been studied in relation to the control of seizures. A negative role of 5-HT(7) receptors has recently been proposed. To evaluate further in unstressed and stressed animals the possible role of this receptor subtype in the control of brain excitability, we treated mice with antagonists and agonists of these receptors prior to exposure to swim stress and the intravenous infusion of picrotoxin, a non-competitive GABA(A) receptor antagonist. In accordance with the previous studies, swim stress increased the doses of picrotoxin producing two convulsant signs (running/bouncing clonus, tonic hindlimb extension) and death, i.e., swim stress increased the seizure threshold for picrotoxin. SB-269970 (10-30 mg/kg ip), a selective antagonist of 5-HT(7) receptors, and ritanserin (1 mg/kg ip), a nonselective 5-HT (2/7) antagonist, failed to affect, while 5-carboxamidotryptamine (5-CT), a potent 5-HT (1/7) receptor agonist, increased in unstressed and swim-stressed mice the doses of picrotoxin producing convulsions and death. The anticonvulsant effect obtained with 5-CT 0.5 mg/kg was not greater than that obtained with 0.1 mg/kg. The 5-CT (0.1 mg/kg ip)-induced increase of the seizure threshold for picrotoxin in stressed mice was abolished with SB-269970 (10 mg/kg), but not with WAY-100635 (0.3 mg/kg), a selective antagonist of 5-HT(1A) receptors, suggesting that the anticonvulsant effect of 5-CT against convulsions produced by picrotoxin was achieved via 5-HT(7) receptors. The results suggest a positive role of 5-HT(7) receptors in the control of seizures.
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Affiliation(s)
- Danka Pericić
- Laboratory for Molecular Neuropharmacology, Division of Molecular Medicine, Ruder Bosković Institute, P.O. Box 180, 10002 Zagreb, Croatia.
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Abstract
In recent years, there has been increasing evidence that serotonergic neurotransmission modulates a wide variety of experimentally induced seizures. Generally, agents that elevate extracellular serotonin (5-HT) levels, such as 5-hydroxytryptophan and serotonin reuptake blockers, inhibit both focal and generalized seizures, although exceptions have been described, too. Conversely, depletion of brain 5-HT lowers the threshold to audiogenically, chemically and electrically evoked convulsions. Furthermore, it has been shown that several anti-epileptic drugs increase endogenous extracellular 5-HT concentration. 5-HT receptors are expressed in almost all networks involved in epilepsies. Currently, the role of at least 5-HT(1A), 5-HT(2C), 5-HT(3) and 5-HT(7) receptor subtypes in epileptogenesis and/or propagation has been described. Mutant mice lacking 5-HT(1A) or 5-HT(2C) receptors show increased seizure activity and/or lower threshold. In general, hyperpolarization of glutamatergic neurons by 5-HT(1A) receptors and depolarization of GABAergic neurons by 5-HT(2C) receptors as well as antagonists of 5-HT(3) and 5-HT(7) receptors decrease the excitability in most, but not all, networks involved in epilepsies. Imaging data and analysis of resected tissue of epileptic patients, and studies in animal models all provide evidence that endogenous 5-HT, the activity of its receptors, and pharmaceuticals with serotonin agonist and/or antagonist properties play a significant role in the pathogenesis of epilepsies.
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Affiliation(s)
- Gyorgy Bagdy
- Laboratory of Neurochemistry and Experimental Medicine, National Institute of Psychiatry and Neurology, Budapest, Hungary.
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Paillet-Loilier M, Fabis F, Lepailleur A, Bureau R, Butt-Gueulle S, Dauphin F, Delarue C, Vaudry H, Rault S. Phenylpyrroles, a new chemolibrary virtual screening class of 5-HT7 receptor ligands. Bioorg Med Chem Lett 2005; 15:3753-7. [PMID: 16002287 DOI: 10.1016/j.bmcl.2005.05.059] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 05/16/2005] [Accepted: 05/17/2005] [Indexed: 11/18/2022]
Abstract
Virtual screening studies have identified a series of phenylpyrroles as novel 5-HT7 receptor ligands. The synthesis and the affinity for the 5-HT7 receptor of these phenylpyrroles are described. Some of these compounds exhibited high affinity for the 5-HT7 receptors.
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Affiliation(s)
- Magalie Paillet-Loilier
- Centre d'Etudes et de Recherche sur le Médicament de Normandie, Université de Caen, UFR des Sciences Pharmaceutiques, 5, rue Vaubénard 14032 Caen Cedex, France
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Slassi A, Isaac M, Xin T. Recent progress in 5-HT7receptors: potential treatment of central and peripheral nervous system diseases. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.14.7.1009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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32
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Palea S, Lluel P, Barras M, Duquenne C, Galzin AM, Arbilla S. Involvement of 5-hydroxytryptamine (HT)7 receptors in the 5-HT excitatory effects on the rat urinary bladder. BJU Int 2004; 94:1125-31. [PMID: 15541139 DOI: 10.1111/j.1464-410x.2004.05114.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate the in vitro and in vivo effects of 5-hydroxytryptamine (5-HT) on the rat urinary bladder and to characterize the receptors involved in mediating these pharmacological effects by using selective antagonists. MATERIALS AND METHODS Female Wistar rats (250-350 g) were used for all studies. In vitro, detrusor muscle strips were mounted between two platinum electrodes in organ baths filled with a modified Krebs' solution bubbled with 95% O(2) and 5% CO(2) at 37 degrees C. After equilibration and a contraction to 80 mmol/L KCl, strips were exposed to electrical field stimulation for 30 min and incubated with the antagonist or vehicle for a further 30 min, then a 5-HT concentration-response curve (CRC) was obtained. In vivo, rats were anaesthetized with pentobarbital, and the ureters and urethra ligated, the bladder catheterized and infused with saline. 5-HT (3-100 microg/kg intravenous) dose-dependently increased intravesical pressure (IVP). After administering 5-HT at 30 microg/kg three times at 10 min intervals (controls), one dose of antagonist was perfused for 5 min and, after a further 5 min, 30 microg/kg 5-HT was tested again. This cycle was repeated four times using increasing doses of the antagonist to be tested. RESULTS In vitro, 5-HT (0.01-100 micromol/L) induced a concentration-dependent enhancement of the neurogenic response, with a mean (sd) pEC(50) of 6.36 (0.15) and E(max) of 41.1 (4.6)% KCl (eight rats). In unstimulated tissues, 5-HT induced no contractile effect. Selective 5-HT(4), 5-HT(3) and 5-HT(1A) receptor antagonists had no effect on the 5-HT potentiating effects. The potentiating effect of 5-HT was antagonized by mesulergine at 0.3 micromol/L, R(+)lisuride at 0.3 micromol/L and the selective 5-HT(7) receptor antagonist SB-258741 at 0.3 micromol/L. In vivo, in anaesthetized rats, IVP increases induced by repeated doses of 30 microg/kg 5-HT were reproducible. R(+)lisuride (3-100 microg/kg) dose-dependently inhibited the 5-HT-induced increase of IVP. At the maximum dose tested, R(+)lisuride almost totally inhibited the 5-HT effect. CONCLUSIONS In rat isolated detrusor muscle the 5-HT(7) receptor antagonists SB-258741, R(+)lisuride and mesulergine blocked the 5-HT potentiating effect with the expected potency. Moreover, in anaesthetized rats, R(+)lisuride abolished 5-HT effects on IVP at doses that antagonize physiological effects known to be mediated by 5-HT(7) receptor activation in several animal species. These results suggest the involvement of 5-HT(7) receptors in the modulation of rat bladder contraction both in vitro and in vivo.
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Affiliation(s)
- Stefano Palea
- Sanofi-Synthélabo Recherche, Rueil-Malmaison, France.
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33
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Graf M, Jakus R, Kantor S, Levay G, Bagdy G. Selective 5-HT1A and 5-HT7 antagonists decrease epileptic activity in the WAG/Rij rat model of absence epilepsy. Neurosci Lett 2004; 359:45-8. [PMID: 15050708 DOI: 10.1016/j.neulet.2004.01.072] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Revised: 01/27/2004] [Accepted: 01/27/2004] [Indexed: 11/18/2022]
Abstract
Recent studies have provided evidence that activation of 5-HT1A receptors increases epileptic activity in the WAG/Rij rat model of absence epilepsy, and additional data have suggested the involvement of 5-HT7 receptors as well. Therefore, we have tested the effects of the selective 5-HT1A receptor antagonist WAY-100635 and the selective 5-HT7 receptor antagonist SB-258719 on spontaneous epileptic activity. In general, both compounds reduced epileptic activity compared to vehicle. Significant decreases were found in the number of paroxysms and the cumulative and average duration of spike-wave discharges (SWDs), although the time courses of these effects induced by the two compounds were clearly different. These results provide evidence that activation of 5-HT1A and 5-HT7 receptors plays a significant role in regulating SWD activity in this animal model of absence epilepsy.
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Affiliation(s)
- Marton Graf
- Laboratory of Neurochemistry and Experimental Medicine, National Institute of Psychiatry and Neurology, Huvosvolgyi ut 116, H-1021, Budapest, Hungary
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34
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Martín-Cora FJ, Pazos A. Autoradiographic distribution of 5-HT7 receptors in the human brain using [3H]mesulergine: comparison to other mammalian species. Br J Pharmacol 2003; 141:92-104. [PMID: 14656806 PMCID: PMC1574165 DOI: 10.1038/sj.bjp.0705576] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The main aim of this investigation was to delineate the distribution of the 5-HT(7) receptor in human brain. Autoradiographic studies in guinea-pig and rat brain were also carried out in order to revisit and compare the anatomical distribution of 5-HT(7) receptors in different mammalian species. 2. Binding studies were performed in rat frontal cortex membranes using 10 nm [(3)H]mesulergine in the presence of raclopride (10 microm) and DOI (0.8 microm). Under these conditions, a binding site with pharmacological characteristics consistent with those of the 5-HT(7) receptors was identified (rank order of binding affinity values: 5-CT>5-HT>5-MeOT>mesulergine approximately methiothepin>8-OH-DPAT=spiperone approximately (+)-butaclamol>>imipramine approximately (+/-)-pindolol>>ondansetron approximately clonidine approximately prazosin). 3. The autoradiographic studies revealed that the anatomical distribution of 5-HT(7) receptors throughout the human brain was heterogenous. High densities were found over the caudate and putamen nuclei, the pyramidal layer of the CA2 field of the hippocampus, the centromedial thalamic nucleus, and the dorsal raphe nucleus. The inner layer of the frontal cortex, the dentate gyrus of the hippocampus, the subthalamic nucleus and superior colliculus, among others, presented intermediate concentrations of 5-HT(7) receptors. A similar brain anatomical distribution of 5-HT(7) receptors was observed in all three mammalian species studied. 4. By using [(3)H]mesulergine, we have mapped for the first time the anatomical distribution of 5-HT(7) receptors in the human brain, overcoming the limitations previously found in radiometric studies with other radioligands, and also revisiting the distribution in guinea-pig and rat brain.
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Affiliation(s)
- Francisco J Martín-Cora
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Cardenal Herrera Oria, Santander 39011, Cantabria, Spain
| | - Angel Pazos
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Cardenal Herrera Oria, Santander 39011, Cantabria, Spain
- Author for correspondence:
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35
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Alanine A, Bourson A, Büttelmann B, Gill R, Heitz MP, Mutel V, Pinard E, Trube G, Wyler R. 1-Benzyloxy-4,5-dihydro-1H-imidazol-2-yl-amines, a novel class of NR1/2B subtype selective NMDA receptor antagonists. Bioorg Med Chem Lett 2003; 13:3155-9. [PMID: 12951084 DOI: 10.1016/s0960-894x(03)00713-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Screening of the Roche compound depository led to the identification of (1-benzyloxy-4,5-dihydro-1H-imidazol-2-yl)-butyl amine 4, a structurally novel NR1/2B subtype selective NMDA receptor antagonist. The structure-activity relationships developed in this series resulted in the discovery of a novel class of potent and selective NMDA receptor blockers displaying activity in vivo.
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Affiliation(s)
- Alexander Alanine
- Pharma Division, Discovery Chemistry, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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36
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Affiliation(s)
- Richard A Glennon
- Department of Medicinal Chemistry, School of Pharmacy, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298-0540, USA.
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37
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Büttelmann B, Alanine A, Bourson A, Gill R, Heitz MP, Mutel V, Pinard E, Trube G, Wyler R. 4-(3,4-dihydro-1H-isoquinolin-2yl)-pyridines and 4-(3,4-dihydro-1H-isoquinolin-2-yl)-quinolines as potent NR1/2B subtype selective NMDA receptor antagonists. Bioorg Med Chem Lett 2003; 13:1759-62. [PMID: 12729659 DOI: 10.1016/s0960-894x(03)00232-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A series of 4-(3,4-dihydro-1H-isoquinolin-2yl)-pyridines and analogous quinolines was prepared and evaluated as NR1/2B subtype selective NMDA receptor antagonists. 2-Hydroxyalkylamino substitution combines high affinity with selectivity (vs alpha1 and M1 receptors) and activity in vivo.
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Affiliation(s)
- Bernd Büttelmann
- Pharma Division, Discovery Chemistry, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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38
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Büttelmann B, Alanine A, Bourson A, Gill R, Heitz MP, Mutel V, Pinard E, Trube G, Wyler R. 2-(3,4-Dihydro-1H-isoquinolin-2yl)-pyridines as a novel class of NR1/2B subtype selective NMDA receptor antagonists. Bioorg Med Chem Lett 2003; 13:829-32. [PMID: 12617901 DOI: 10.1016/s0960-894x(03)00007-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recently, we disclosed 4-aminoquinolines as structurally novel NR1/2B subtype selective NMDA receptor antagonists. We would now like to report our findings on structurally related pyridine analogues. The SAR developed in this series resulted in the discovery of high affinity antagonists which are selective (vs alpha1 and M1 receptors) and active in vivo.
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Affiliation(s)
- Bernd Büttelmann
- Pharma Division, Discovery Chemistry, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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39
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Pinard E, Alanine A, Bourson A, Büttelmann B, Heitz M, Mutela Ramanjit Gill V, Trube G, Wyler R. 4-Aminoquinolines as a novel class of NR1/2B subtype selective NMDA receptor antagonists. Bioorg Med Chem Lett 2002; 12:2615-9. [PMID: 12182873 DOI: 10.1016/s0960-894x(02)00470-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Screening of the Roche compound library led to the identification of 4-aminoquinoline 4 as structurally novel NR1/2B subtype selective NMDA receptor antagonist. The SAR which was developed in this series resulted in the discovery of highly potent and in vivo active blockers.
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Affiliation(s)
- Emmanuel Pinard
- Pharma Division, Discovery Chemistry, F. Hoffmann-La Roche Ltd., CH-4070, Basel, Switzerland.
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40
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Terrón JA. Is the 5-HT(7) receptor involved in the pathogenesis and prophylactic treatment of migraine? Eur J Pharmacol 2002; 439:1-11. [PMID: 11937086 DOI: 10.1016/s0014-2999(02)01436-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The mechanisms underlying the pathogenesis of migraine and their possible association with serotonin (5-hydroxytryptamine; 5-HT) have not yet been elucidated. One of the major obstacles in achieving this goal is the lack of information on the mechanisms by which the monoamine could possibly trigger and/or modulate the basic pathophysiological features of the condition, that is, cranial vasodilatation and neurogenic inflammation. This information should provide a useful theoretical framework to insight the nature of the postulated fundamental triggering mechanism in the brain that ultimately results in head pain. Novel avenues for research and drug development may be envisaged upon the recent observations showing that 5-HT is actually able to produce vasodilatation of intra- and extra-cranial blood vessels through a mechanism pharmacologically resembling the 5-HT(7) receptor type, and that the messenger RNA (mRNA) encoding for this receptor is highly expressed in cranial vessels. Other lines of evidence have suggested that the 5-HT(7) receptor may play an excitatory role in neuronal systems and that it may be involved in hyperalgesic pain and neurogenic inflammation. On the basis of these observations, it is proposed that the 5-HT(7) receptor may well represent a link between the abnormal phenomena of 5-HT processing and neurotransmission that are observed in migraine patients, and the vascular and neurogenic alterations that account for migraine headache. This view is supported by the fact that most of the migraine prophylactic 5-HT receptor antagonists display relatively high affinity for the 5-HT(7) receptor, which significantly correlates with their pharmaceutically active oral doses.
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Affiliation(s)
- José A Terrón
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apdo. Postal 14-740, Zacatenco 07000, México D.F., Mexico.
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41
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Abstract
Recently, a series of 5-HT7 receptor antagonists have been developed (24,29,36,68). Among them SB-258741, R-(+)-1-(toluene-3-sulfonyl)-2-[2-(4-methylpiperidin-1-yl)ethyl]-pyrrolidine, (compound "13" in 36,37) was one of the most potent and specific compounds. Due to a lack of specific ligands the pharmacology of 5-HT7 receptor antagonists is still relatively unexplored. It has been suggested, however, that 5-HT7 receptor ligands could be useful in the therapy of various disorders such as sleep disorders, schizophrenia, depression, migraine, epilepsy, pain, or memory impairment. Many of these conceivable indications are not supported by pharmacological data. It is, therefore, of particular interest to review the data generated from studies of one of these most potent and specific 5-HT7 receptor antagonists, SB-258741, with a goal of testing the validity of the proposed clinical indications. In this review, the author describes pharmacology of this compound in order to define its potential clinical use. The available safety pharmacology data are discussed in an attempt to predict potential side effects of specific 5-HT7 receptor antagonists.
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Affiliation(s)
- Bruno Pouzet
- H. Luncbeck A/S, Department of Psychopharmacology, Ottiliavej 7-9, Dk-2500 Valby, Denmark.
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42
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Gill CH, Soffin EM, Hagan JJ, Davies CH. 5-HT7 receptors modulate synchronized network activity in rat hippocampus. Neuropharmacology 2002; 42:82-92. [PMID: 11750918 DOI: 10.1016/s0028-3908(01)00149-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the CA3 region of rat hippocampal slices gamma-amino-butyric acid (GABA)(A/B) receptor antagonists induce low frequency bursting activity that was either inhibited (in 21% of slices) or increased by the selective 5-HT receptor agonists 5-carboxy-tryptamine (0.1-1 microM) and 8-hydroxydipropylaminotetralin (8-OH-DPAT). The selective 5-HT1A receptor antagonist N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexane carboxamide (WAY 100635) reversed the depression of bursting activity whereas the 5-HT7 receptor antagonist, (R)-3-(2-(2-(4-methylpiperidin-1-yl)-ethyl)pyrrolidine-1-sulfonyl)phenol (SB-269970; 1-10 microM), but not the 5-HT1A, 4 or 6 receptor antagonists WAY100635 (10 microM), SB-204070 (10 microM) and SB-271046 (10 microM), reversed the increase in bursting activity. The apparent -log10 K(D) value (8.4) for the effect of SB-269970 was consistent with a selective action at 5-HT7 receptors. Accompanying the 5-CT-induced increase in bursting frequency there was a shortening of the burst event waveform and a reduction in the after-hyperpolarization following each bursting event both of which were inhibited by SB-269970. These effects appeared to result predominantly from a direct 5-HT(7) receptor-mediated inhibition of a Ca2+ activated K+ channel.
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Affiliation(s)
- Catherine H Gill
- Department of Neuroscience Research, SmithKline Beecham Pharmaceuticals, New Frontiers Science Park North, Third Avenue, CM19 5AW, Harlow, UK
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43
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Pinard E, Alanine A, Bourson A, Büttelmann B, Gill R, Heitz M, Jaeschke G, Mutel V, Trube G, Wyler R. Discovery of (R)-1-[2-hydroxy-3-(4-hydroxy-phenyl)-propyl]-4-(4-methyl-benzyl)-piperidin-4-ol: a novel NR1/2B subtype selective NMDA receptor antagonist. Bioorg Med Chem Lett 2001; 11:2173-6. [PMID: 11514163 DOI: 10.1016/s0960-894x(01)00392-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Starting from Ro-25-6981 as a lead compound, highly potent and selective NR1/2B subtype selective NMDA receptor antagonists, with low activity at alpha(1) adrenergic receptors were developed.
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Affiliation(s)
- E Pinard
- Pharma Division, Discovery Chemistry, F. Hoffmann-La Roche Ltd., CH-4070, Basel, Switzerland.
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44
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Abstract
Tinnitus is a debilitating condition from which some 0.5-1% of the population of the Western world suffer sufficiently badly as to interfere with their normal working and leisure life. There is no satisfactory treatment at the present time and the uncertainty surrounding the mechanism of its generation makes it difficult to devise an effective cure. After much debate, the consensus of opinion amongst researchers regarding its site of origin is that it is primarily a central nervous system pathology although there certainly exists a class of patients whose tinnitus is peripherally based. In this paper, we provide some speculative ideas on how an initial auditory insult can be translated into central neurological substrates that represent tinnitus. Plastic changes arising from sensory deprivation trigger a change in synaptology and neurotransmission with a consequent change in receptor configuration. From neuroanatomical considerations and analogies with other clinical conditions, we postulate the involvement of serotonin (5-HT) in these plastic changes and consider the evidence available from the use of serotonergic drugs in different conditions. A possible relationship between 5-HT and lidocaine is also discussed.
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Affiliation(s)
- J J Simpson
- Department of Pharmacology, Division of Neuroscience, Medical School, University of Birmingham, Vincent Drive, B15 2TT, Birmingham, UK.
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