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Jiruska P, Freestone D, Gnatkovsky V, Wang Y. An update on the seizures beget seizures theory. Epilepsia 2023; 64 Suppl 3:S13-S24. [PMID: 37466948 DOI: 10.1111/epi.17721] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
Seizures beget seizures is a longstanding theory that proposed that seizure activity can impact the structural and functional properties of the brain circuits in ways that contribute to epilepsy progression and the future occurrence of seizures. Originally proposed by Gowers, this theory continues to be quoted in the pathophysiology of epilepsy. We critically review the existing data and observations on the consequences of recurrent seizures on brain networks and highlight a range of factors that speak for and against the theory. The existing literature demonstrates clearly that ictal activity, especially if recurrent, induces molecular, structural, and functional changes including cell loss, connectivity reorganization, changes in neuronal behavior, and metabolic alterations. These changes have the potential to modify the seizure threshold, contribute to disease progression, and recruit wider areas of the epileptic network into epileptic activity. Repeated seizure activity may, thus, act as a pathological positive-feedback mechanism that increases seizure likelihood. On the other hand, the time course of self-limited epilepsies and the presence of seizure remission in two thirds of epilepsy cases and various chronic epilepsy models oppose the theory. Experimental work showed that seizures could induce neural changes that increase the seizure threshold and decrease the risk of a subsequent seizure. Due to the complex nature of epilepsies, it is wrong to consider only seizures as the key factor responsible for disease progression. Epilepsy worsening can be attributed to the various forms of interictal epileptiform activity or underlying disease mechanisms. Although seizure activity can negatively impact brain structure and function, the "seizures beget seizures" theory should not be used dogmatically but with extreme caution.
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Affiliation(s)
- Premysl Jiruska
- Department of Physiology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Yujiang Wang
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Interdisciplinary Computing and Complex BioSystems Group, School of Computing Science, Newcastle University, Newcastle upon Tyne, UK
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2
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Mumtaz F, Rashki A, Imran Khan M, Shadboorestan A, Abdollahi A, Ghazi-Khansari M, Alotaibi G, Dehpour AR. Neuroprotective effect of sumatriptan in pentylenetetrazole-induced seizure is mediated through N-methyl-D-aspartate/nitric oxide and cAMP response element-binding protein signaling pathway. Fundam Clin Pharmacol 2021; 36:250-261. [PMID: 34545607 DOI: 10.1111/fcp.12728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/29/2021] [Accepted: 09/17/2021] [Indexed: 12/12/2022]
Abstract
Seizure occurs as a result of uncontrolled electrical disturbances within the brain. Various biomolecules such as N-methyl-D-aspartate (NMDA), nitric oxide (NO), and cAMP response element-binding protein (CREB) have been implicated in the pathophysiology of seizure. Sumatriptan is a specific 5-Hydroxytryptamine 1B/1D receptor agonist and has neuroprotective effects in various neuropsychiatric disorders. In the current study, we tried to investigate the possible interaction of sumatriptan with NMDA/NO and CREB signaling pathway in PTZ induced seizure. For this purpose, various agonist and antagonist of NMDA such as MK-801 and Ketamine, NO precursor L-ARG, and NOS inhibitors L-NAME and 7-NI were co-administered with sumatriptan in PTZ induced seizure model. The level of nitrite in mice hippocampus was determined by Griess reaction. The gene expression of NR1, NR2A, NR2B, and CREB were quantified by quantitative real time-polymerase chain reaction (qRT-PCR). Furthermore, the involved neuronal nitric oxide synthase (nNOS) protein expression was examined via western blot analysis. Effective dose of sumatriptan (1.2 mg/kg) alone and subeffective dose of sumatriptan (0.3 mg/kg) in combination with NMDA and/or NO antagonist showed significant (P < 0.001) anticonvulsant activity in mice. Furthermore, sumatriptan significantly inhibited the PTZ-induced mRNA expression of NR2A (P < 0.0001), NR2B (P < 0.05), and CREB (P < 0.01). Also, the expression of nNOS protein in PTZ treated group was reversed by sumatriptan (P < 0.01). Hence, current findings suggest that the anticonvulsant effect of sumatriptan was due to down regulation of NMDA/NO and CREB signaling pathway.
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Affiliation(s)
- Faiza Mumtaz
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,International Campus of Tehran University of Medical Sciences, Tehran, Iran
| | - Asma Rashki
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Muhammad Imran Khan
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Amir Shadboorestan
- Department of Toxicology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Alireza Abdollahi
- Department of Pathology, Imam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Ghazi-Khansari
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghallab Alotaibi
- Department of Pharmaceutical Sciences, College of Pharmacy, Al-Dawadmi Campus, Shaqra University, Shaqra, Kingdom of Saudi Arabia
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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3
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Mumtaz F, Shafaroodi H, Nezamoleslami S, Zubair M, Sheibani M, Nikoui V, Ghazi-Khansari M, Dehpour AR. Involvement of nNOS, and α1, α2, β1, and β2 Subunits of Soluble Guanylyl Cyclase Genes Expression in Anticonvulsant Effect of Sumatriptan on Pentylenetetrazole-Induced Seizure in Mice. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2021; 19:181-192. [PMID: 33841534 PMCID: PMC8019868 DOI: 10.22037/ijpr.2020.112594.13844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Epileptic seizure is phenomenon of abnormal synchronous neuronal discharge of a set of neurons in brain as a result of neuronal excitation. Evidence shows the nitric oxide (NO) involvement in neuronal excitability. Moreover, the role of cyclic guanosine monophosphate (cGMP) activation in seizure pathogenesis is well-established. Sumatriptan is a selective agonist of 5-Hydroxytryptamine1B/D auto-receptor, has been reassessed for its neuroprotection. This study was aimed to explore the anticonvulsant effect of sumatriptan through possible involvement of NO-cGMP pathway in mice. For this purpose, the protective effect of sumatriptan on PTZ-induced clonic seizure threshold (CST) was measured using NO-cGMP pathway inhibitors including N(G)-nitro-L-arginine (L-NNA, 1, 5, and 10 mg/kg), 7-nitroindazole (7-NI, 30, 45, and 60 mg/kg), aminoguanidine (AG, 30, 50, and 100 mg/kg), methylene blue (MB, 0.1, 0.5, and 1 mg/kg) and sildenafil (5, 10, and 20 mg/kg). The involvement of nitrergic system was further confirmed by measurement of nitrite levels by Griess reaction. The gene expression of neuronal nitric oxide synthase (nNOS) and subunits of soluble guanylyl cyclase (sGC) was studied using qRT-PCR analysis. Acute administration of sumatriptan (1.2 and 0.3 mg/kg) in combination with subeffective doses of NOS, sGC, and phosphodiesterase 5 inhibitors significantly reversed the PTZ-induced CST (P ≤ 0.001). The nitrite level in prefrontal cortex was significantly attenuated by sumatriptan (P ≤ 0.01). Furthermore, sumatriptan downregulated the PTZ-induced mRNA expression of nNOS (P ≤ 0.01), α1 (P ≤ 0.001), α2 (P ≤ 0.05), and β1 (P ≤ 0.05) genes in cerebral cortex of mice. In conclusion, the anticonvulsant activity of sumatriptan at least, in part, is mediated through inhibiting NO-cGMP pathway.
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Affiliation(s)
- Faiza Mumtaz
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamed Shafaroodi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sadaf Nezamoleslami
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Muhammad Zubair
- Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, PR China
| | - Mohammad Sheibani
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Vahid Nikoui
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Ghazi-Khansari
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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4
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Vieira ÉLM, da Silva MCM, Gonçalves AP, Martins GL, Teixeira AL, de Oliveira ACP, Reis HJ. Serotonin and dopamine receptors profile on peripheral immune cells from patients with temporal lobe epilepsy. J Neuroimmunol 2021; 354:577534. [PMID: 33713941 DOI: 10.1016/j.jneuroim.2021.577534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/27/2021] [Accepted: 02/27/2021] [Indexed: 01/11/2023]
Abstract
The role of inflammation and immune cells has been demonstrated in neurological diseases, including epilepsy. Leukocytes, as well as inflammatory mediators, contribute to abnormal processes that lead to a reduction in seizure threshold and synaptic reorganization. In this sense, identifying different phenotypes of circulating immune cells is essential to understanding the role of these cells in epilepsy. Immune cells can express a variety of surface markers, including neurotransmitter receptors, such as serotonin and dopamine. Alteration in these receptors expression patterns may affect the level of inflammatory mediators and the pathophysiology of epilepsy. Therefore, in the current study, we evaluated the expression of dopamine and serotonin receptors on white blood cells from patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Blood samples from 17 patients with TLE-HS and 21 controls were collected. PBMC were isolated and stained ex vivo for flow cytometry. We evaluated the expression of serotonin (5-HT1A, 5-HT1B, 5-HT2, 5-HT2B, 5-HT2C, 5-HT3, 5-HT4), and dopamine receptors (D1, D2, D3, D4, and D5) on the cell surface of lymphocytes and innate immune cells (monocytes and granulocytes). Our results demonstrated that innate cells and lymphocytes from patients with TLE-HS showed high mean fluorescent intensity (MFI) for 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 compared to controls. No difference was observed for 5-HT2B. For dopamine receptors, the expression of D1, D2, D4, and D5 receptors was higher on innate cells from patients with TLE-HS when compared to controls for the MFI. Regarding lymphocytes population, D2 expression was increased in patients with TLE-HS. In conclusion, there are alterations in the expression of serotonin and dopamine receptors on immune blood cells of patients with TLE-HS. Although the biological significance of these findings still needs to be further investigated, these changes may contribute to the understanding of TLE-HS pathophysiology.
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Affiliation(s)
| | - Maria Carolina Machado da Silva
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Ana Paula Gonçalves
- Programa de Neurociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Gabriela Lopes Martins
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Antônio Lúcio Teixeira
- Instituto de Ensino e Pesquisa, Santa Casa BH, Belo Horizonte 30260-070, Brazil; Neuropsychiatry Program and Immuno-Psychiatry Lab, Department of Psychiatry and Behavioral Sciences, UT Health Houston, 1941 East Road, Houston, TX 77054, USA
| | - Antônio Carlos Pinheiro de Oliveira
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; Programa de Neurociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil.
| | - Helton José Reis
- Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; Programa de Neurociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil.
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5
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Deidda G, Crunelli V, Di Giovanni G. 5-HT/GABA interaction in epilepsy. PROGRESS IN BRAIN RESEARCH 2021; 259:265-286. [PMID: 33541679 DOI: 10.1016/bs.pbr.2021.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Epilepsy is a neurological condition characterized by synchronous neuronal oscillations (seizures) in the electroencephalogram. Seizures are classified in focal or generalized (depending on the brain territory interested during seizures), and in convulsive and/or not convulsive (depending on the presence or not of involuntary movements). The current pharmacological treatments are mainly based on GABA modulation although different neurotransmitters are also involved in epilepsy, including serotonin. However despite much extensive progress in the understanding of epilepsy mechanisms, still, a percentage of people with epilepsy are pharmaco-resistant calling for the need for new therapeutic targets. Here we review preclinical and human evidence showing that serotonin modulates epilepsy that this likely happens via a major modulation/interaction with GABA.
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Affiliation(s)
- Gabriele Deidda
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.
| | - Vincenzo Crunelli
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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6
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Gooshe M, Ghasemi K, Rohani MM, Tafakhori A, Amiri S, Aghamollaii V, Ahmadi M, Dehpour AR. Biphasic effect of sumatriptan on PTZ-induced seizures in mice: Modulation by 5-HT1B/D receptors and NOS/NO pathway. Eur J Pharmacol 2018; 824:140-147. [DOI: 10.1016/j.ejphar.2018.01.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/14/2018] [Accepted: 01/19/2018] [Indexed: 11/17/2022]
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7
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Mosińska P, Socała K, Nieoczym D, Laudon M, Storr M, Fichna J, Wlaź P. Anticonvulsant activity of melatonin, but not melatonin receptor agonists Neu-P11 and Neu-P67, in mice. Behav Brain Res 2016; 307:199-207. [DOI: 10.1016/j.bbr.2016.03.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/03/2016] [Accepted: 03/21/2016] [Indexed: 11/26/2022]
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8
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Sapa J, Zygmunt M, Kulig K, Malawska B, Dudek M, Filipek B, Bednarski M, Kusak A, Nowak G. Evaluation of anticonvulsant activity of novel pyrrolidin-2-one derivatives. Pharmacol Rep 2014; 66:708-11. [DOI: 10.1016/j.pharep.2014.02.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 02/11/2014] [Accepted: 02/14/2014] [Indexed: 11/25/2022]
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9
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Singh E, Pillai KK, Mehndiratta M. Characterization of a Lamotrigine-Resistant Kindled Model of Epilepsy in Mice: Evaluation of Drug Resistance Mechanisms. Basic Clin Pharmacol Toxicol 2014; 115:373-8. [DOI: 10.1111/bcpt.12238] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/10/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Ekta Singh
- Department of Pharmacology; Faculty of Pharmacy; Jamia Hamdard (Hamdard University); New Delhi India
| | - Krishna K. Pillai
- Department of Pharmacology; Faculty of Pharmacy; Jamia Hamdard (Hamdard University); New Delhi India
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10
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Vinuela-Fernandez I, Sun L, Jerina H, Curtis J, Allchorne A, Gooding H, Rosie R, Holland P, Tas B, Mitchell R, Fleetwood-Walker S. The TRPM8 channel forms a complex with the 5-HT(1B) receptor and phospholipase D that amplifies its reversal of pain hypersensitivity. Neuropharmacology 2013; 79:136-51. [PMID: 24269608 DOI: 10.1016/j.neuropharm.2013.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/07/2013] [Accepted: 11/11/2013] [Indexed: 12/25/2022]
Abstract
Effective relief from chronic hypersensitive pain states remains an unmet need. Here we report the discovery that the TRPM8 ion channel, co-operating with the 5-HT(1B) receptor (5-HT(1B)R) in a subset of sensory afferents, exerts an influence at the spinal cord level to suppress central hypersensitivity in pain processing throughout the central nervous system. Using cell line models, ex vivo rat neural tissue and in vivo pain models, we assessed functional Ca(2+) fluorometric responses, protein:protein interactions, immuno-localisation and reflex pain behaviours, with pharmacological and molecular interventions. We report 5-HT(1B)R expression in many TRPM8-containing afferents and direct interaction of these proteins in a novel multi-protein signalling complex, which includes phospholipase D1 (PLD1). We provide evidence that the 5-HT(1B)R activates PLD1 to subsequently activate PIP 5-kinase and generate PIP2, an allosteric enhancer of TRPM8, achieving a several-fold increase in potency of TRPM8 activation. The enhanced activation responses of synaptoneurosomes prepared from spinal cord and cortical regions of animals with a chronic inflammatory pain state are inhibited by TRPM8 activators that were applied in vivo topically to the skin, an effect potentiated by co-administered 5-HT(1B)R agonists and attenuated by 5-HT(1B)R antagonists, while 5-HT(1B)R agents alone had no detectable effect. Corresponding results are seen when assessing reflex behaviours in inflammatory and neuropathic pain models. Control experiments with alternative receptor/TRP channel combinations reveal no such synergy. Identification of this novel receptor/effector/channel complex and its impact on nociceptive processing give new insights into possible strategies for enhanced analgesia in chronic pain.
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Affiliation(s)
- Ignacio Vinuela-Fernandez
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Liting Sun
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Helen Jerina
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - John Curtis
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Andrew Allchorne
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Hayley Gooding
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Roberta Rosie
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Pamela Holland
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Basak Tas
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
| | - Rory Mitchell
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom.
| | - Sue Fleetwood-Walker
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom.
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11
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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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12
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Bian ZX, Qin HY, Tian SL, Qi SD. Combined effect of early life stress and acute stress on colonic sensory and motor responses through serotonin pathways: differences between proximal and distal colon in rats. Stress 2011; 14:448-58. [PMID: 21438781 DOI: 10.3109/10253890.2011.558604] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Clinically, adults who have experienced stresses in childhood present with episodes of serious symptoms of irritable bowel syndrome that are associated with acute stress, but the mechanism is not well understood. This study aimed to investigate the colonic sensory/motor responses to acute water avoidance stress (WAS) in male adult rats subjected to neonatal maternal separation (NMS), and the underlying mechanism of sensory/motor responses. Effects of the combined acute and early life stress on visceral sensation, colonic motility, and the tissue and luminal content of serotonin (5-hydroxytryptamine, 5-HT) in the proximal and distal colon were evaluated using the abdominal withdrawal reflex test, faecal pellet output measurement and capillary electrophoresis analysis, respectively. Results showed that WAS significantly increased not only visceral sensitivity but also colonic motility in NMS rats compared to the normal rats. These alterations were accompanied by significant increase in 5-HT content in the proximal but not the distal colonic tissues; these alterations were also associated with increased density of enterochromaffin (EC) cells in the proximal segment. In contrast, the faecal content of 5-HT increased similarly in both segments. Consecutive administration of parachlorophenylalanine to NMS rats was more potent at 500 mg kg⁻¹ day⁻¹ than at 150 mg kg⁻¹ day⁻¹ in suppressing colonic sensory/motor responses to WAS, corresponding to the greater reduction of the tissue and faecal content of 5-HT and of EC cell density in the colon. These data indicate that combined early life stress and acute stress effectively induce visceral hyperalgesia and motility disorder through 5-HT pathways in the colon of rats, and the proximal and distal colon have different responses towards the combined stressors.
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Affiliation(s)
- Zhao-Xiang Bian
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, People's Republic of China.
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13
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Stefulj J, Bordukalo-Niksic T, Hecimovic H, Demarin V, Jernej B. Epilepsy and serotonin (5HT): variations of 5HT-related genes in temporal lobe epilepsy. Neurosci Lett 2010; 478:29-31. [PMID: 20435093 DOI: 10.1016/j.neulet.2010.04.060] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 04/22/2010] [Accepted: 04/25/2010] [Indexed: 01/12/2023]
Abstract
Several lines of evidence point to the role of serotonin (5HT) neurotransmission in the epileptogenesis. The present preliminary study investigated possible association of the temporal lobe epilepsy (TLE) with the polymorphisms in several 5HT-related genes, including serotonin transporter (5HTT), monoamine oxidase A (MAO-A) and serotonin receptors 5HT-1A, 5HT-1B and 5HT-2C. All participants (101 TLE patients and 170 healthy controls) were unrelated individuals of Croatian origin. 5HT-1B allele 861G was found to be slightly overrepresented in the patient group (p=0.0385). No significant differences between groups were observed for the other tested polymorphisms. Within the limitations imposed by the size of our sample, negative findings suggest that the respective loci do not make considerable contribution to the etiopathogenesis of TLE. Further examination of 5HT-1B gene, which yielded positive result at a trend level, is possibly warranted.
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Affiliation(s)
- Jasminka Stefulj
- Laboratory of Neurochemistry and Molecular Neurobiology, Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka cesta 54, HR-10000 Zagreb, Croatia
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14
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Peddie C, Davies H, Colyer F, Stewart M, Rodríguez J. Dendritic colocalisation of serotonin1B receptors and the glutamate NMDA receptor subunit NR1 within the hippocampal dentate gyrus: An ultrastructural study. J Chem Neuroanat 2008; 36:17-26. [DOI: 10.1016/j.jchemneu.2008.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/08/2008] [Accepted: 05/06/2008] [Indexed: 10/22/2022]
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15
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Ward SE, Eddershaw PJ, Scott CM, Gordon LJ, Lovell PJ, Moore SH, Smith PW, Starr KR, Thewlis KM, Watson JM. Discovery of potent, orally bioavailable, selective 5-HT1A/B/D receptor antagonists. J Med Chem 2008; 51:2887-90. [PMID: 18433113 DOI: 10.1021/jm8001444] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
5-HT1 receptor antagonists have been discovered with good selectivity over the 5-HT transporter. This is the first report of highly potent, selective ligands for the 5-HT1A/B/D receptors with low intrinsic activity, which represent a useful set of molecules for further understanding the roles of the 5-HT1 receptor subtypes and providing new approaches for the treatment of depression.
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Affiliation(s)
- Simon E Ward
- Psychiatry Centre of Excellence for Drug Discovery and Molecular Discovery Research, GlaxoSmithKline, Essex, UK.
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Hughes ZA, Starr KR, Scott CM, Newson MJ, Sharp T, Watson JM, Hagan JJ, Dawson LA. Simultaneous blockade of 5-HT1A/B receptors and 5-HT transporters results in acute increases in extracellular 5-HT in both rats and guinea pigs: in vivo characterization of the novel 5-HT1A/B receptor antagonist/5-HT transport inhibitor SB-649915-B. Psychopharmacology (Berl) 2007; 192:121-33. [PMID: 17265079 DOI: 10.1007/s00213-006-0691-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 12/21/2006] [Indexed: 11/26/2022]
Abstract
RATIONALE The delay in onset and treatment resistance of subpopulations of depressed patients to conventional serotonin reuptake inhibitors has lead to new drug development strategies to produce agents with improved antidepressant efficacy. OBJECTIVES We report the in vivo characterization of the novel 5-HT(1A/1B) autoreceptor antagonist/5-HT transporter inhibitor (6-[(1-{2-[(2-methyl-5-quinolinyl)oxy]ethyl}-4-piperidinyl)methyl]-2H-1,4-benzoxazin-3(4H)-one), SB-649915-B. MATERIALS AND METHODS Ex vivo binding was used to ascertain 5-HT(1A) receptor and serotonin transporter occupancy. 8-OH-DPAT-induced hyperlocomotion and SKF-99101-induced elevation of seizure threshold were used as markers of central blockade of 5-HT(1A) and 5-HT(1B) receptors, respectively. In vivo electrophysiology in the rat dorsal raphe and microdialysis in freely moving guinea pigs and rats were used to evaluate the functional outcome of SB-649915-B. RESULTS SB-649915-B (1-10 mg/kg p.o.) produced a dose-related inhibition of 5-HT(1A) receptor radioligand binding and inhibited ex vivo [(3)H]5-HT uptake in both guinea pig and rat cortex. SB-649915-B (0.1-10 mg/kg p.o.) reversed both 8-OH-DPAT-induced hyperlocomotor activity and SKF-99101-induced elevation of seizure threshold in the rat, demonstrating in vivo blockade of both 5-HT(1A) and 5-HT(1B) receptors, respectively. SB-649915-B (0.1-3 mg/kg i.v.) produced no change in raphe 5-HT neuronal cell firing per se but attenuated the inhibitory effect of 8-OH-DPAT. Acute administration of SB-649915-B resulted in increases (approximately two- to threefold) in extracellular 5-HT in the cortex of rats and the dentate gyrus and cortex of guinea pigs. CONCLUSIONS Based on these data, one may speculate that the 5-HT autoreceptor antagonist/5-HT transport inhibitor SB-649915-B will have therapeutic efficacy in the treatment of affective disorders with the potential for a faster onset of action compared to current selective serotonin reuptake inhibitors.
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Affiliation(s)
- Zoë A Hughes
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline, New Frontiers Science Park (North), Harlow, Essex, CM19 5AW, UK
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Evaluation of the mGlu8 receptor as a putative therapeutic target in schizophrenia. Brain Res 2007; 1152:215-27. [PMID: 17434465 DOI: 10.1016/j.brainres.2007.03.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 03/09/2007] [Accepted: 03/10/2007] [Indexed: 11/29/2022]
Abstract
Aberrant glutamatergic neurotransmission may underlie the pathogenesis of schizophrenia and metabotropic glutamate receptors (mGluRs) have been implicated in the disease. We have established the localization of the group III mGluR subtype, mGluR8, in the human body and investigated the biological effects of the selective mGluR8 agonist (S)-3,4-dicarboxyphenylglycine ((S)-3,4-DCPG) in schizophrenia-related animal models. The mGlu8 receptor has a widespread CNS distribution with expression observed in key brain regions associated with schizophrenia pathogenesis including the hippocampus. (S)-3,4-DCPG inhibited synaptic transmission and increased paired-pulse facilitation in rat hippocampal slices supporting the role of mGluR8 as a presynaptic autoreceptor. Using the rat Maximal Electroshock Seizure Threshold (MEST) test, (S)-3,4-DCPG (30 mg/kg, i.p.) reduced seizure activity confirming the compound to be centrally active following systemic administration. (S)-3,4-DCPG did not reverse (locomotor) hyperactivity induced by acute administration of phenylcyclidine (PCP, 1-32 mg/kg, i.p.) or amphetamine (3-30 mg/kg, i.p.) in Sprague-Dawley rats. However, 10 nmol (i.c.v.) (S)-3.4-DCPG did reverse amphetamine-induced hyperactivity in mice although it also inhibited spontaneous locomotor activity at this dose. In addition, mGluR8 null mutant mouse behavioral phenotyping revealed an anxiety-related phenotype but no deficit in sensorimotor gating. These data provide a potential role for mGluR8 in anxiety and suggest that mGluR8 may not be a therapeutic target for schizophrenia.
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Watson JM, Dawson LA. Characterization of the potent 5-HT(1A/B) receptor antagonist and serotonin reuptake inhibitor SB-649915: preclinical evidence for hastened onset of antidepressant/anxiolytic efficacy. CNS DRUG REVIEWS 2007; 13:206-23. [PMID: 17627673 PMCID: PMC6726354 DOI: 10.1111/j.1527-3458.2007.00012.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An increase in brain serotonin (5-HT) levels is thought to be a key mechanism of action responsible for generating antidepressant efficacy. It has been proven that selective serotonin reuptake inhibitors are effective antidepressants, but the delay to therapeutic onset of these agents is thought to be due to the time required for 5-HT1A, and possibly 5-HT1B, autoreceptors to desensitize. Therefore, an agent incorporating 5-HT reuptake inhibition coupled with 5-HT1A and/or 5-HT1B autoreceptor antagonism may provide a fast-acting clinical agent. The current studies review the profile of SB-649915 (6-[(1-{2-[(2-methylquinolin-5-yl)oxy]ethyl}piperidin-4-yl)methyl]-2H-1,4-benzoxazin-3(4H)-one), a novel compound with high affinity for human (h) 5-HT1A and 5-HT1B receptors (pKi values of 8.6 and 8.0, respectively) as well as the (h) 5-HT transporter (SERT) (pKi value of 9.3). SB-649915 behaved as an antagonist at both 5-HT1A and 5-HT1B receptors in vitro and in vivo, reversing 5-HT, (+)8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and SKF99101-induced functional/behavioral responses. Furthermore, it inhibited [3H]5-HT reuptake in rat cortical synaptosomes, in vitro and ex vivo. In electrophysiological studies SB-649915 had no effect on rat dorsal raphe neuronal cell firing per se, but reversed 8-OH-DPAT-induced inhibition of firing both in vitro and in vivo. In addition, in a microdialysis study, it produced an acute increase in extracellular 5-HT in forebrain structures of the rat. Finally, SB-649915 demonstrated acute anxiolytic activity in both rodent and non-human primate and reduced the latency to onset of anxiolytic behavior, compared to paroxetine, in the rat social interaction paradigm. In summary, SB-649915 is a novel, potent 5-HT1A/1B autoreceptor antagonist, and 5-HT reuptake inhibitor. This particular pharmacological profile provides a novel mechanism that could offer fast-acting antidepressant activity.
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Affiliation(s)
- Jeannette M Watson
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline, New Frontiers Science Park, Harlow, Essex, UK.
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Wesołowska A, Nikiforuk A, Chojnacka-Wójcik E. Anticonvulsant effect of the selective 5-HT1B receptor agonist CP 94253 in mice. Eur J Pharmacol 2006; 541:57-63. [PMID: 16765343 DOI: 10.1016/j.ejphar.2006.04.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 04/27/2006] [Accepted: 04/28/2006] [Indexed: 11/25/2022]
Abstract
The effect of the selective 5-hydroxytryptamine1B (5-HT1B) receptor agonist 5-propoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-pyrrolo[3,2-b]pyridine (CP 94253) and the 5-HT1A/1B/1D receptor agonist 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridyl)-1H-indole (RU 24969) in maximal electroshock- and pentylenetetrazol-induced seizures in mice was examined. CP 94253 (10-40 mg/kg) afforded no protection against maximal electroshock-evoked convulsions, but produced anticonvulsant action in the pentylenetetrazol-induced seizures (ED50 = 29 mg/kg). The anticonvulsant effect of CP 94253 was abolished by the selective 5-HT1B receptor antagonist N-[3-(2-dimethylamino)ethoxy-4-methoxyphenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)-(1,1'-biphenyl)-4-carboxamide (SB 216641; 20 mg/kg) but it was maintained following the p-chlorophenylalanine (p-CPA; 3 x 300 mg/kg)-induced 5-HT depletion. Interestingly, CP 94253 potentiated the anticonvulsant activity of diazepam in the pentylenetetrazol test; on the other hand, the benzodiazepine receptor antagonist, flumazenil (10 mg/kg), did not modify the anticonvulsant effect of CP 94253. RU 24969 (5 mg/kg) evoked no effect in the maximal electroshock model, but it produced anticonvulsant activity in the pentylenetetrazol assay, the latter effect being attenuated by the selective 5-HT1A receptor antagonist N-(2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl)-N-(2-pyridyl)-cyclohexanecarboxamide (WAY 100635; 0.3 mg/kg) and SB 216641 (10-20 mg/kg). The obtained results suggest that CP 94253 exerts anticonvulsant activity on pentylenetetrazol-induced seizures in mice, as a consequence of stimulation of 5-HT1B receptors (probably located postsynaptically and/or as heteroreceptors); the antiseizure activity of RU 24969 seems to depend on the stimulation of both 5-HT1A and 5-HT1B receptors.
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Affiliation(s)
- Anna Wesołowska
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, Kraków, PL 31-343, Poland
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Obniska J, Kołaczkowski M, Bojarski AJ, Duszyńska B. Synthesis, anticonvulsant activity and 5-HT1A, 5-HT2A receptor affinity of new N-[(4-arylpiperazin-1-yl)-alkyl] derivatives of 2-azaspiro[4.4]nonane and [4.5]decane-1,3-dione. Eur J Med Chem 2006; 41:874-81. [PMID: 16600439 DOI: 10.1016/j.ejmech.2006.03.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/03/2006] [Accepted: 03/06/2006] [Indexed: 11/17/2022]
Abstract
The synthesis, physicochemical and pharmacological properties of new N-[(4-arylpiperazin-1-yl)-alkyl]-2-azaspiro[4.4]nonane- (8a-c, 10a-d) and [4.5]decane-1,3-dione (9a-c, 11a-d) derivatives were described. The antiepileptic effects of those compounds were examined by a maximal electroshock (MES) and a pentylenetetrazole (sc. PTZ) tests, and their neurotoxicity was determined using a rota-rod test. Compounds 8c, 9c, 10c, d, 11c, d with a CF(3) group at the 3-position of the 4-arylpiperazine fragment exhibited anti-seizure properties in the MES model; in contrast, their 2-CH(3) and 2-OCH(3) analogues were inactive in both the tests used. Moreover, since the investigated compounds belong to the class of long-chain arylpiperazines, their serotonin 5-HT(1A) and 5-HT(2A) receptor affinity was determined. The relationship between the length of alkylene spacer and 5-HT(1A)/5-HT(2A) receptor activity was observed. Compounds with an ethylene and a propylene bridge (10a-d and 11a-d) were 3-80-fold more potent (K(i) ranged from 3.1 to 94 nM for 5-HT(1A) and 32-465 nM for 5-HT(2A)) than their methylene analogues (8a-c and 9a-c; K(i) ranged from 81 to 370 nM for 5-HT(1A) and 126-1370 nM for 5-HT(2A)). The highest 5-HT(1A) receptor affinity was displayed by 2-OCH(3) and 3-CF(3) phenyl derivatives (10b, 11b: K(i)=6.8 and 5.7 nM, respectively, and 10c, 11c: K(i)=6.0 and 3.1 nM, respectively), while in the case of 5-HT(2A) receptor the highest affinity was observed for the 3-CF(3) phenyl derivatives 10c, d, 11c, d (K(i) ranged from 32 to 86 nM).
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Affiliation(s)
- J Obniska
- Department of Pharmaceutical Chemistry, Jagiellonian University Medical College, Kraków, Poland.
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Heightman TD, Gaster LM, Pardoe SL, Pilleux JP, Hadley MS, Middlemiss DN, Price GW, Roberts C, Scott CM, Watson JM, Gordon LJ, Holland VA, Powles J, Riley GJ, Stean TO, Trail BK, Upton N, Austin NE, Ayrton AD, Coleman T, Cutler L. 8-Piperazinyl-2,3-dihydropyrrolo[3,2-g]isoquinolines: potent, selective, orally bioavailable 5-HT1 receptor ligands. Bioorg Med Chem Lett 2005; 15:4370-4. [PMID: 16039851 DOI: 10.1016/j.bmcl.2005.06.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 06/09/2005] [Accepted: 06/09/2005] [Indexed: 11/23/2022]
Abstract
The novel 8-piperazinyl-2,3-dihydropyrroloisoquinoline template was synthesized in nine steps. The template was N-substituted to give a series of compounds showing binding to human cloned 5-HT1A, 5-HT1B and 5-HT1D receptors with pKi's greater than 9 and selectivities up to 1000-fold against other serotonin, dopamine and adrenergic receptors. Several compounds were shown to possess weak partial agonist activity in cloned receptors, which translated to antagonism in in vitro studies.
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Affiliation(s)
- Tom D Heightman
- High Throughput Chemistry, Discovery Research, GlaxoSmithKline, New Frontiers Science Park, Third Avenue, Harlow Essex CM19 5AW, UK.
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