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Guo J, Min D, Farrell EK, Zhou Y, Faingold CL, Cotten JF, Feng HJ. Enhancing the action of serotonin by three different mechanisms prevents spontaneous seizure-induced mortality in Dravet mice. Epilepsia 2024; 65:1791-1800. [PMID: 38593237 PMCID: PMC11166528 DOI: 10.1111/epi.17966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is an underestimated complication of epilepsy. Previous studies have demonstrated that enhancement of serotonergic neurotransmission suppresses seizure-induced sudden death in evoked seizure models. However, it is unclear whether elevated serotonin (5-HT) function will prevent spontaneous seizure-induced mortality (SSIM), which is characteristic of human SUDEP. We examined the effects of 5-HT-enhancing agents that act by three different pharmacological mechanisms on SSIM in Dravet mice, which exhibit a high incidence of SUDEP, modeling human Dravet syndrome. METHODS Dravet mice of both sexes were evaluated for spontaneous seizure characterization and changes in SSIM incidence induced by agents that enhance 5-HT-mediated neurotransmission. Fluoxetine (a selective 5-HT reuptake inhibitor), fenfluramine (a 5-HT releaser and agonist), SR 57227 (a specific 5-HT3 receptor agonist), or saline (vehicle) was intraperitoneally administered over an 8-day period in Dravet mice, and the effect of these treatments on SSIM was examined. RESULTS Spontaneous seizures in Dravet mice generally progressed from wild running to tonic seizures with or without SSIM. Fluoxetine at 30 mg/kg, but not at 20 or 5 mg/kg, significantly reduced SSIM compared with the vehicle control. Fenfluramine at 1-10 mg/kg, but not .2 mg/kg, fully protected Dravet mice from SSIM, with all mice surviving. Compared with the vehicle control, SR 57227 at 20 mg/kg, but not at 10 or 5 mg/kg, significantly lowered SSIM. The effect of these drugs on SSIM was independent of sex. SIGNIFICANCE Our data demonstrate that elevating serotonergic function by fluoxetine, fenfluramine, or SR 57227 significantly reduces or eliminates SSIM in Dravet mice in a sex-independent manner. These findings suggest that deficits in serotonergic neurotransmission likely play an important role in the pathogenesis of SSIM, and fluoxetine and fenfluramine, which are US Food and Drug Administration-approved medications, may potentially prevent SUDEP in at-risk patients.
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Affiliation(s)
- Jialing Guo
- National Health Commission Key Laboratory of Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
| | - Daniel Min
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Emory K. Farrell
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Yupeng Zhou
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Carl L. Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Joseph F. Cotten
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
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Okanari K, Teranishi H, Umeda R, Shikano K, Inoue M, Hanada T, Ihara K, Hanada R. Behavioral and neurotransmitter changes on antiepileptic drugs treatment in the zebrafish pentylenetetrazol-induced seizure model. Behav Brain Res 2024; 464:114920. [PMID: 38403178 DOI: 10.1016/j.bbr.2024.114920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Epilepsy, a recurrent neurological disorder involving abnormal neurotransmitter kinetics in the brain, has emerged as a global health concern. The mechanism of epileptic seizures is thought to involve a relative imbalance between excitatory and inhibitory neurotransmitters. Despite the recent advances in clinical and basic research on the pathogenesis of epilepsy, the complex relationship between the neurotransmitter changes and behavior with and without antiepileptic drugs (AEDs) during seizures remains unclear. To investigate the effects of AEDs such as levetiracetam (LEV), carbamazepine (CBZ), and fenfluramine (FFR) on key neurotransmitters in the pentylenetetrazol (PTZ)-induced seizures in adult zebrafish, we examined the changes in glutamic acid, gamma-aminobutyric acid (GABA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), choline, acetylcholine, norepinephrine, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and adenosine. In this study, we observed that 5-HT and DA levels in the brain increased immediately after PTZ-induced seizures. Behavioral tests clearly showed that all of these AEDs suppressed the PTZ-induced seizures. Upon treatment of PTZ-induced seizures with these AEDs, CBZ decreased the glutamic acid and FFR increased the GABA levels; however, no neurotransmitter changes were observed in the brain after LEV administration. Thus, we demonstrated a series of neurotransmitter changes linked to behavioral changes during PTZ-induced epileptic seizures when LEV, CBZ, or FFR were administered. These findings will lead to a more detailed understanding of the pathogenesis of epilepsy associated with behavioral and neurotransmitter changes under AED treatment.
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Affiliation(s)
- Kazuo Okanari
- Department of Pediatrics, Faculty and Medicine, Oita University, Oita, Japan
| | - Hitoshi Teranishi
- Department of Neurophysiology, Faculty and Medicine, Oita University, Oita, Japan
| | - Ryohei Umeda
- Department of Neurophysiology, Faculty and Medicine, Oita University, Oita, Japan
| | - Kenshiro Shikano
- Department of Neurophysiology, Faculty and Medicine, Oita University, Oita, Japan
| | - Masanori Inoue
- Department of Pediatrics, Faculty and Medicine, Oita University, Oita, Japan
| | - Toshikatsu Hanada
- Department of Cell Biology, Faculty and Medicine, Oita University, Oita, Japan
| | - Kenji Ihara
- Department of Pediatrics, Faculty and Medicine, Oita University, Oita, Japan
| | - Reiko Hanada
- Department of Neurophysiology, Faculty and Medicine, Oita University, Oita, Japan.
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3
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Xu Y, Chen D, Liu L. Optimal dose of fenfluramine in adjuvant treatment of drug-resistant epilepsy: evidence from randomized controlled trials. Front Neurol 2024; 15:1371704. [PMID: 38590719 PMCID: PMC10999678 DOI: 10.3389/fneur.2024.1371704] [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: 01/16/2024] [Accepted: 03/08/2024] [Indexed: 04/10/2024] Open
Abstract
Objective Several clinical trials have suggested that fenfluramine (FFA) is effective for the treatment of epilepsy in Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). However, the exploration of its optimal target dose is ongoing. This study aimed to summarize the best evidence to inform this clinical issue. Materials and methods We searched PubMed, Embase (via Ovid), and Web of Science for relevant literature published before December 1st, 2023. Randomized, double-blind, placebo-controlled studies that evaluated the efficacy, safety, and tolerability of FFA in DS and LGS were identified and meta-analysis was performed according to doses. The study was registered with PROSPERO (CRD42023392454). Results Six hundred and twelve patients from four randomized controlled trials were enrolled. The results demonstrated that FFA at 0.2, 0.4, or 0.7 mg/kg/d showed significantly greater efficacy compared to placebo in terms of at least 50% reduction (p < 0.001, p < 0.001, p < 0.001) and at least 75% reduction (p < 0.001, p = 0.007, p < 0.001) in monthly seizure frequency from baseline. Moreover, significantly more patients receiving FFA than placebo were rated as much improved or very much improved in CGI-I by both caregivers/parents and investigators (p < 0.001). The most common treatment-emergent adverse events were decreased appetite, diarrhea, fatigue, and weight loss, with no valvular heart disease or pulmonary hypertension observed in any participant. For dose comparison, 0.7 mg/kg/d group presented higher efficacy on at least 75% reduction in seizure (p = 0.006) but not on at least 50% reduction. Weight loss (p = 0.002), decreased appetite (p = 0.04), and all-cause withdrawal (p = 0.036) were more common in 0.7 mg/kg/d group than 0.2 mg/kg/d. There was no statistical difference in other safety parameters between these two groups. Conclusion The higher range of the licensed dose achieves the optimal balance between efficacy, safety, and tolerability in patients with DS and LGS. Clinical trial registration https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023392454.
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Affiliation(s)
| | | | - Ling Liu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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Mittur A, Madanick R, Langlois M, Boyd B. Effect of Hepatic Impairment on the Pharmacokinetics of Fenfluramine and Norfenfluramine. J Clin Pharmacol 2024. [PMID: 38523492 DOI: 10.1002/jcph.2431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 02/23/2024] [Indexed: 03/26/2024]
Abstract
Fenfluramine (Fintepla®) is approved for the treatment of seizures associated with the rare epileptic encephalopathies Dravet syndrome and Lennox-Gastaut syndrome. Fenfluramine is extensively metabolized; thus, patients with hepatic impairment (HI) might experience changes in exposure to fenfluramine or its metabolites. In this phase 1 study, we investigated the pharmacokinetics (PK) and safety of a single oral dose of 0.35 mg/kg fenfluramine in subjects with mild (n = 8), moderate (n = 8), or severe (n = 7) HI (Child-Pugh A/B/C, respectively) and healthy control subjects (n = 22) matched for sex, age, and BMI. All subjects underwent serial sampling to determine total plasma concentrations of fenfluramine and its active metabolite, norfenfluramine. Hepatic impairment was associated with increases in fenfluramine exposures, mainly area-under-the-curve (AUC). Geometric least squares mean ratios (90% confidence intervals) for fenfluramine AUC0-∞ in mild, moderate, and severe HI versus healthy controls were 1.98 (1.36-2.90), 2.13 (1.43-3.17), and 2.77 (1.82-4.24), respectively. Changes in exposure to norfenfluramine in mild, moderate, and severe HI were minimal compared with normal hepatic function. Exposures to fenfluramine and norfenfluramine in all HI groups were within the ranges that have been characterized in the overall development program, including ranges examined in exposure-response relationships for efficacy and safety in patients, and determined to have an acceptable safety profile. Mild and moderate HI had a modest effect on fenfluramine exposure that was not clinically meaningful, whereas the higher fenfluramine exposure in severe HI may require dose reduction based on general caution in this population. The modest decrease in norfenfluramine exposure is not considered clinically relevant.
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Affiliation(s)
| | - Ryan Madanick
- PPD, Thermo Fisher Scientific, Morrisville, North Carolina, USA
| | | | - Brooks Boyd
- UCB Biosciences, Inc, Morrisville, North Carolina, USA
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Fitzgerald LR, Gannon BM, Walther D, Landavazo A, Hiranita T, Blough BE, Baumann MH, Fantegrossi WE. Structure-activity relationships for locomotor stimulant effects and monoamine transporter interactions of substituted amphetamines and cathinones. Neuropharmacology 2024; 245:109827. [PMID: 38154512 PMCID: PMC10842458 DOI: 10.1016/j.neuropharm.2023.109827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/14/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023]
Abstract
Substitutions to the phenethylamine structure give rise to numerous amphetamines and cathinones, contributing to an ever-growing number of abused novel psychoactive substances. Understanding how various substitutions affect the pharmacology of phenethylamines may help lawmakers and scientists predict the effects of newly emerging drugs. Here, we established structure-activity relationships for locomotor stimulant and monoamine transporter effects of 12 phenethylamines with combinations of para-chloro, β-keto, N-methyl, or N-ethyl additions. Automated photobeam analysis was used to evaluate effects of drugs on ambulatory activity in mice, whereas in vitro assays were used to determine activities at transporters for dopamine (DAT), norepinephrine (NET), and 5-HT (SERT) in rat brain synaptosomes. In mouse studies, all compounds stimulated locomotion, except for 4-chloro-N-ethylcathinone. Amphetamines were more potent stimulants than their β-keto counterparts, while para-chloro amphetamines tended to be more efficacious than unsubstituted amphetamines. Para-chloro compounds also produced lethality at doses on the ascending limbs of their locomotor dose-effect functions. The in vitro assays showed that all compounds inhibited uptake at DAT, NET, and SERT, with most compounds also acting as substrates (i.e., releasers) at these sites. Unsubstituted compounds displayed better potency at DAT and NET relative to SERT. Para-chloro substitution or increased N-alkyl chain length augmented relative potency at SERT, while combined para-chloro and N-ethyl substitutions reduced releasing effects at NET and DAT. These results demonstrate orderly SAR for locomotor stimulant effects, monoamine transporter activities, and lethality induced by phenethylamines. Importantly, 4-chloro compounds produce toxicity in mice that suggests serious risk to humans using these drugs in recreational contexts.
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Affiliation(s)
- Lauren R Fitzgerald
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Brenda M Gannon
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Donna Walther
- Designer Drug Research Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Antonio Landavazo
- Center for Drug Discovery, RTI International, Research Triangle Park, NC, 27709, USA
| | - Takato Hiranita
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Bruce E Blough
- Center for Drug Discovery, RTI International, Research Triangle Park, NC, 27709, USA
| | - Michael H Baumann
- Designer Drug Research Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA
| | - William E Fantegrossi
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
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Cheng L, Xia F, Li Z, Shen C, Yang Z, Hou H, Sun S, Feng Y, Yong X, Tian X, Qin H, Yan W, Shao Z. Structure, function and drug discovery of GPCR signaling. MOLECULAR BIOMEDICINE 2023; 4:46. [PMID: 38047990 PMCID: PMC10695916 DOI: 10.1186/s43556-023-00156-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 11/06/2023] [Indexed: 12/05/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are versatile and vital proteins involved in a wide array of physiological processes and responses, such as sensory perception (e.g., vision, taste, and smell), immune response, hormone regulation, and neurotransmission. Their diverse and essential roles in the body make them a significant focus for pharmaceutical research and drug development. Currently, approximately 35% of marketed drugs directly target GPCRs, underscoring their prominence as therapeutic targets. Recent advances in structural biology have substantially deepened our understanding of GPCR activation mechanisms and interactions with G-protein and arrestin signaling pathways. This review offers an in-depth exploration of both traditional and recent methods in GPCR structure analysis. It presents structure-based insights into ligand recognition and receptor activation mechanisms and delves deeper into the mechanisms of canonical and noncanonical signaling pathways downstream of GPCRs. Furthermore, it highlights recent advancements in GPCR-related drug discovery and development. Particular emphasis is placed on GPCR selective drugs, allosteric and biased signaling, polyphamarcology, and antibody drugs. Our goal is to provide researchers with a thorough and updated understanding of GPCR structure determination, signaling pathway investigation, and drug development. This foundation aims to propel forward-thinking therapeutic approaches that target GPCRs, drawing upon the latest insights into GPCR ligand selectivity, activation, and biased signaling mechanisms.
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Affiliation(s)
- Lin Cheng
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610000, China
| | - Fan Xia
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Ziyan Li
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Chenglong Shen
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Zhiqian Yang
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Hanlin Hou
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Suyue Sun
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yuying Feng
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xihao Yong
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xiaowen Tian
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Hongxi Qin
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Wei Yan
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
| | - Zhenhua Shao
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
- Tianfu Jincheng Laboratory, Frontiers Medical Center, Chengdu, 610212, China.
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Dini G, Di Cara G, Ferrara P, Striano P, Verrotti A. Reintroducing Fenfluramine as a Treatment for Seizures: Current Knowledge, Recommendations and Gaps in Understanding. Neuropsychiatr Dis Treat 2023; 19:2013-2025. [PMID: 37790801 PMCID: PMC10543412 DOI: 10.2147/ndt.s417676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023] Open
Abstract
Despite the introduction of new anti-seizure medications in recent years, approximately one-third of the epileptic population continues to experience seizures. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and it has received approval from various regulatory agencies for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome. The potential antiseizure effects of FFA were initially observed in patients with photosensitive epilepsy in the 1980s but it was not rigorously explored as a treatment option until 30 years later. This narrative review aims to provide an overview of the historical progression of FFA's use, starting from initial clinical observations to preclinical studies and, ultimately, successful clinical trials in the field of epilepsy.
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Affiliation(s)
- Gianluca Dini
- Department of Pediatrics, University of Perugia, Perugia, Italy
| | | | - Pietro Ferrara
- Department of Pediatrics, Campus Bio-Medico University, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto “G. Gaslini”, Genoa, Italy
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Sills GJ. Pharmacological diversity amongst approved and emerging antiseizure medications for the treatment of developmental and epileptic encephalopathies. Ther Adv Neurol Disord 2023; 16:17562864231191000. [PMID: 37655228 PMCID: PMC10467199 DOI: 10.1177/17562864231191000] [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: 02/20/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox-Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin.
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Affiliation(s)
- Graeme J. Sills
- School of Life Sciences, University of Glasgow, Room 341, Sir James Black Building, Glasgow G12 8QQ, UK
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Abstract
Fenfluramine (Fintepla®) is an oral anti-seizure medication (ASM) with a novel mechanism of action consisting of activity in the serotonergic system coupled with positive allosteric modulation effects at sigma-1 receptors. Originally approved for use at high doses as an appetite suppressant, it was subsequently withdrawn after being linked to valvular heart disease (VHD) and pulmonary arterial hypertension (PAH), before being investigated for use at low doses as an adjunctive ASM in patients with developmental epileptic encephalopathies, including Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) who have pharmacoresistant seizures. In clinical trials, treatment with adjunctive fenfluramine markedly reduced convulsive seizure frequency in patients with DS that were sustained for up to 3 years, and reduced drop seizure frequency in patients with LGS that were sustained for up to 1 year. Notably, fenfluramine was also associated with clinically meaningful improvements in aspects of everyday executive functioning (EF) not entirely explainable by seizure reduction alone. Furthermore, it was generally well tolerated with, importantly, no reports of VHD or PAH. Thus, adjunctive fenfluramine is a novel and effective treatment for pharmacoresistant seizures associated with DS and LGS that may also improve aspects of everyday EF in some patients.
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Affiliation(s)
- James E Frampton
- Springer Nature, Mairangi Bay, Private Bag 65901, Auckland, 0754, New Zealand.
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Zhu Z, Bolt E, Newmaster K, Osei-Bonsu W, Cohen S, Cuddapah VA, Gupta S, Paudel S, Samanta D, Dang LT, Carney PR, Naik S. SCN1B Genetic Variants: A Review of the Spectrum of Clinical Phenotypes and a Report of Early Myoclonic Encephalopathy. CHILDREN (BASEL, SWITZERLAND) 2022; 9:children9101507. [PMID: 36291443 PMCID: PMC9600564 DOI: 10.3390/children9101507] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
Background: Pathogenic variants in SCN1B, the gene encoding voltage-gated sodium channel b1/b1B subunits are associated with a spectrum of epileptic disorders. This study describes a child with early myoclonic encephalopathy and a compound heterozygous variant in the SCN1B gene (p.Arg85Cys and c.3G>C/p.Met1), along with the child’s clinical response to anti-seizure medications (ASMs) and the ketogenic diet. We reviewed the current clinical literature pertinent to SCN1B-related epilepsy. Methods: We described the evaluation and management of a patient with SCN1B-related developmental and epileptic encephalopathy (DEE). We used the Medline and Pubmed databases to review the various neurological manifestations associated with SCN1B genetic variants, and summarize the functional studies performed on SCN1B variants. Results: We identified 20 families and six individuals (including the index case described herein) reported to have SCN1B-related epilepsy. Individuals with monoallelic pathogenic variants in SCN1B often present with genetic epilepsy with febrile seizures plus (GEFS+), while those with biallelic pathogenic variants may present with developmental and epileptic encephalopathy (DEE). Individuals with DEE present with seizures of various semiologies (commonly myoclonic seizures) and status epilepticus at early infancy and are treated with various antiseizure medications. In our index case, adjunctive fenfluramine was started at 8 months of age at 0.2 mg/kg/day with gradual incremental increases to the final dose of 0.7 mg/kg/day over 5 weeks. Fenfluramine was effective in the treatment of seizures, resulting in a 50% reduction in myoclonic seizures, status epilepticus, and generalized tonic-clonic seizures, as well as a 70−90% reduction in focal seizures, with no significant adverse effects. Following the initiation of fenfluramine at eight months of age, there was also a 50% reduction in the rate of hospitalizations. Conclusions: SCN1B pathogenic variants cause epilepsy and neurodevelopmental impairment with variable expressivity and incomplete penetrance. The severity of disease is associated with the zygosity of the pathogenic variants. Biallelic variants in SCN1B can result in early myoclonic encephalopathy, and adjunctive treatment with fenfluramine may be an effective treatment for SCN1B-related DEE. Further research on the efficacy and safety of using newer ASMs, such as fenfluramine in patients under the age of 2 years is needed.
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Affiliation(s)
- Zahra Zhu
- College of Medicine, Penn State University, Hershey, PA 17033, USA
| | - Elizabeth Bolt
- College of Medicine, Penn State University, Hershey, PA 17033, USA
| | - Kyra Newmaster
- College of Medicine, Penn State University, Hershey, PA 17033, USA
| | - Wendy Osei-Bonsu
- College of Medicine, Penn State University, Hershey, PA 17033, USA
| | - Stacey Cohen
- Epilepsy Neurogenetics Initiative, Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Vishnu Anand Cuddapah
- Epilepsy Neurogenetics Initiative, Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Siddharth Gupta
- Kennedy Krieger Institute, Department of Neurology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sita Paudel
- Department of Pediatrics and Neurology, Penn State Health Milton Hershey Medical Center, Hershey, PA 17033, USA
| | - Debopam Samanta
- Division of Pediatric Neurology, Arkansas Children’s Hospital, Little Rock, AR 72202, USA
| | - Louis T. Dang
- Department of Pediatrics, Division of Pediatric Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Paul R. Carney
- Pediatric Neurology Division, University of Missouri Health Care, Columbia, MO 65212, USA
- Correspondence: (P.R.C.); (S.N.)
| | - Sunil Naik
- Department of Pediatrics and Neurology, Penn State Health Milton Hershey Medical Center, Hershey, PA 17033, USA
- Correspondence: (P.R.C.); (S.N.)
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11
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Fenfluramine for the Treatment of Dravet Syndrome and Lennox Gastaut Syndrome: A Review. Curr Treat Options Neurol 2022. [DOI: 10.1007/s11940-022-00741-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Samanta D. Fenfluramine: A Review of Pharmacology, Clinical Efficacy, and Safety in Epilepsy. CHILDREN 2022; 9:children9081159. [PMID: 36010049 PMCID: PMC9406381 DOI: 10.3390/children9081159] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 11/29/2022]
Abstract
Despite the availability of more than 30 antiseizure medications (ASMs), the proportion of patients who remain refractory to ASMs remains static. Refractory seizures are almost universal in patients with epileptic encephalopathies. Since many of these patients are not candidates for curative surgery, there is always a need for newer ASMs with better efficacy and safety profile. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and various regulatory agencies approved it for seizures associated with Dravet and Lennox–Gastaut syndromes. However, there is a limited in-depth critical review of FFA to facilitate its optimal use in a clinical context. This narrative review discusses and summarizes the antiseizure mechanism of action of FFA, clinical pharmacology, and clinical studies related to epilepsy, focusing on efficacy and adverse effects.
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Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, 1 Children's Way, Little Rock, AR 72202, USA
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13
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Abstract
There are numerous potential factors that may affect growth in children with epilepsy, and these must be evaluated in any child with appetite and weight concerns. Antiseizure medications (ASMs) have potential adverse effects, and many may affect appetite, thus impacting normal growth and weight gain. The aim of this review is to focus on the impact of both epilepsy and ASMs on appetite and weight in children. We systematically reviewed studies using Medline assessing the impact of ASMs on appetite and weight in children. Eligible studies included randomized controlled trials and open-label studies (open-label extension and interventional) that targeted or included the pediatric population (0-18 years of age). Each study was classified using the American Academy of Neurology (AAN) Classification of Evidence for Therapeutic Studies, and the level of evidence for impact on appetite and weight in children was graded. ASMs associated with decreased appetite and/or weight loss include fenfluramine, topiramate, zonisamide, felbamate, rufinamide, stiripentol, cannabidiol, brivaracetam and ethosuximide; ASMs with minimal impact on weight and appetite in children include oxcarbazepine, eslicarbazepine, lamotrigine, levetiracetam, lacosamide, carbamazepine, vigabatrin and clobazam. The ASM most robustly associated with increased appetite and/or weight gain is valproic acid; however, both pregabalin and perampanel may also lead to modest weight gain or increased appetite in children. Certain ASMs may impact both appetite and weight, which may lead to increased morbidity of the underlying disease and impaired adherence to the treatment regimen.
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14
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Laureano-Melo R, Dos-Santos RC, da Conceição RR, de Souza JS, da Silva Almeida C, Reis LC, Marinho BG, Giannocco G, Ahmed RG, da Silva Côrtes W. Neonatal D-fenfluramine treatment promotes long-term behavioral changes in adult mice. Int J Dev Neurosci 2022; 82:486-498. [PMID: 35718760 DOI: 10.1002/jdn.10204] [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: 01/03/2022] [Revised: 05/27/2022] [Accepted: 06/01/2022] [Indexed: 11/10/2022] Open
Abstract
Serotonin exerts a significant role in the mammalian central nervous system embryogenesis and brain ontogeny. Therefore, we investigate the effect of neonatal treatment of d-fenfluramine (d-FEN), a serotonin (5-HT) releaser, on the behavioral expression of adult male Swiss mice. For this purpose, we divided pregnant female Swiss mice into two groups (n = 6 each and ~35 g). Their offspring were treated with d-FEN (3 mg/kg, s.c.) from postnatal days (PND) 5 to 20. At PND 21, one male puppy of each litter was euthanized; the midbrain and the hippocampus were dissected for RNA analysis. At PND 70, the male offspring underwent a behavioral assessment in the open field, elevated plus-maze, light-dark box, tail suspension, and rotarod test. The programmed animals had a decrease in 5HT1a, serotonin transporter (SERT), and brain-derived neurotrophic factor (BDNF) expression in the mesencephalic raphe region. Alternatively, there was a reduction only in the tryptophan hydroxylase (TPH2) and BDNF expression in the hippocampus. In the light-dark box test, offspring of the treated group had higher latency to light and less time on the light side than the control. Also, it was observed less time of immobility in the tail suspension test. We also observed low motor skill learning in the rotarod test. These findings suggest that programming with d-FEN during the neonatal period alters a mesencephalic and hippocampal serotonergic system, promoting anxiety, antidepressant behavior, low coordination, and motor learning in adults.
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Affiliation(s)
- Roberto Laureano-Melo
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil.,Behavioral Physiopharmacology Laboratory, Barra Mansa Center University, Rio de Janeiro, Brazil
| | - Raoni Conceição Dos-Santos
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil
| | - Rodrigo Rodrigues da Conceição
- Molecular and Translational Endocrinology Laboratory, Department of Medicine, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Janaina Sena de Souza
- Molecular and Translational Endocrinology Laboratory, Department of Medicine, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Claudio da Silva Almeida
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil
| | - Luís Carlos Reis
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil
| | - Bruno Guimarães Marinho
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil
| | - Gisele Giannocco
- Molecular and Translational Endocrinology Laboratory, Department of Medicine, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Ragab Gaber Ahmed
- Division of Anatomy and Embryology, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Wellington da Silva Côrtes
- Multicenter and Regular Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Universidade Federal Rural do Rio de Janeiro, Seropedica, Brazil
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15
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Simon K, Sheckley H, Anderson CL, Liu Z, Carney PR. A review of fenfluramine for the treatment of Dravet syndrome patients. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 3:100078. [PMID: 34988433 PMCID: PMC8695265 DOI: 10.1016/j.crphar.2021.100078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/06/2021] [Accepted: 12/14/2021] [Indexed: 11/03/2022] Open
Abstract
Introduction Dravet Syndrome (DS) is a rare epileptiform disorder typically presenting within the first year of life of a normally developing infant. It is characterized by several prolonged seizures that are often resistant to current anti-epileptic drug (AED) regimens. This paper outlines the history and clinical trials of the drug fenfluramine, a drug that when used in addition to AED regimens may provide hope to children affected by DS. Body Fenfluramine (3-trifulormethyl-N-ethylamphetamine) is an amphetamine derivative that primarily affects serotonin neurotransmitter levels. It was initially prescribed in the 1960s as an appetite suppressant marketed as a weight loss drug. However, it was removed from the markets due to its association with cardiac valvopathies. It continued to by studied in epilepsy by Gastaut in the 1980s in children with self-induced syncope and irretractable epilepsy. In 2012, Ceulemans et al. studied the use of fenfluramine in patients with DS. Following the success of that retrospective case study, Nabbout et al. and Legae et al. conducted two randomized control trials leading to the FDA approval of fenfluramine under its trade name Fintepla in 2020. Discussion The success of the randomized control trials suggests the addition of fenfluramine to current AED regimens may lead to better control of seizures in patients with DS. The side effects of fenfluramine prove to be manageable and the concern for valvopathies has not been reproducible with low dose fenfluramine.
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Affiliation(s)
- Kayla Simon
- Department of Child Health, University of Missouri, Columbia, MO, 65201, USA
| | - Hunter Sheckley
- Department of Child Health, University of Missouri, Columbia, MO, 65201, USA
| | - Christopher L Anderson
- Department of Child Health, University of Missouri, Columbia, MO, 65201, USA.,Department of Neurology, University of Missouri, Columbia, MO, 65201, USA
| | - Zhao Liu
- Department of Child Health, University of Missouri, Columbia, MO, 65201, USA.,Department of Neurology, University of Missouri, Columbia, MO, 65201, USA
| | - Paul R Carney
- Department of Child Health, University of Missouri, Columbia, MO, 65201, USA.,Department of Neurology, University of Missouri, Columbia, MO, 65201, USA.,Department of Biomedical Engineering, University of Missouri, Columbia, MO, 65201, USA
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16
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Lou S, Cui S. Drug treatment of epilepsy: From serendipitous discovery to evolutionary mechanisms. Curr Med Chem 2021; 29:3366-3391. [PMID: 34514980 DOI: 10.2174/0929867328666210910124727] [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: 05/07/2021] [Revised: 07/17/2021] [Accepted: 07/21/2021] [Indexed: 11/22/2022]
Abstract
Epilepsy is a chronic brain disorder caused by abnormal firing of neurons. Up to now, using antiepileptic drugs is the main method of epilepsy treatment. The development of antiepileptic drugs lasted for centuries. In general, most agents entering clinical practice act on the balance mechanisms of brain "excitability-inhibition". More specifically, they target voltage-gated ion channels, GABAergic transmission and glutamatergic transmission. In recent years, some novel drugs representing new mechanisms of action have been discovered. Although there are about 30 available drugs in the market, it is still in urgent need of discovering more effective and safer drugs. The development of new antiepileptic drugs is into a new era: from serendipitous discovery to evolutionary mechanism-based design. This article presents an overview of drug treatment of epilepsy, including a series of traditional and novel drugs.
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Affiliation(s)
- Shengying Lou
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
| | - Sunliang Cui
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
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17
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Odi R, Invernizzi RW, Gallily T, Bialer M, Perucca E. Fenfluramine repurposing from weight loss to epilepsy: What we do and do not know. Pharmacol Ther 2021; 226:107866. [PMID: 33895186 DOI: 10.1016/j.pharmthera.2021.107866] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/26/2021] [Accepted: 04/12/2021] [Indexed: 12/21/2022]
Abstract
In 2020, racemic-fenfluramine was approved in the U.S. and Europe for the treatment of seizures associated with Dravet syndrome, through a restricted/controlled access program aimed at minimizing safety risks. Fenfluramine had been used extensively in the past as an appetite suppressant, but it was withdrawn from the market in 1997 when it was found to cause cardiac valvulopathy. Available evidence indicates that appetite suppression and cardiac valvulopathy are mediated by different serotonergic mechanisms. In particular, appetite suppression can be ascribed mainly to the enantiomers d-fenfluramine and d-norfenfluramine, the primary metabolite of d-fenfluramine, whereas cardiac valvulopathy can be ascribed mainly to d-norfenfluramine. Because of early observations of markedly improved seizure control in some forms of epilepsy, fenfluramine remained available in Belgium through a Royal Decree after 1997 for use in a clinical trial in patients with Dravet syndrome at average dosages lower than those generally prescribed for appetite suppression. More recently, double-blind placebo-controlled trials established its efficacy in the treatment of convulsive seizures associated with Dravet syndrome and of drop seizures associated with Lennox-Gastaut syndrome, at doses up to 0.7 mg/kg/day (maximum 26 mg/day). Although no cardiovascular toxicity has been associated with the use of fenfluramine in epilepsy, the number of patients exposed to date has been limited and only few patients had duration of exposure longer than 3 years. This article analyzes available evidence on the mechanisms involved in fenfluramine-induced appetite suppression, antiseizure effects and cardiovascular toxicity. Despite evidence that stimulation of 5-HT2B receptors (the main mechanism leading to cardiac valvulopathy) is not required for antiseizure activity, there are many critical gaps in understanding fenfluramine's properties which are relevant to its use in epilepsy. Particular emphasis is placed on the remarkable lack of publicly accessible information about the comparative activity of the individual enantiomers of fenfluramine and norfenfluramine in experimental models of seizures and epilepsy, and on receptors systems considered to be involved in antiseizure effects. Preliminary data suggest that l-fenfluramine retains prominent antiseizure effects in a genetic zebrafish model of Dravet syndrome. If these findings are confirmed and extended to other seizure/epilepsy models, there would be an incentive for a chiral switch from racemic-fenfluramine to l-fenfluramine, which could minimize the risk of cardiovascular toxicity and reduce the incidence of adverse effects such as loss of appetite and weight loss.
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Affiliation(s)
- Reem Odi
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Tamar Gallily
- Yissum Technology Transfer Company of the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel; David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Emilio Perucca
- Division of Clinical and Experimental Pharmacology, Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy
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18
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Johannessen Landmark C, Potschka H, Auvin S, Wilmshurst JM, Johannessen SI, Kasteleijn-Nolst Trenité D, Wirrell EC. The role of new medical treatments for the management of developmental and epileptic encephalopathies: Novel concepts and results. Epilepsia 2021; 62:857-873. [PMID: 33638459 DOI: 10.1111/epi.16849] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/28/2021] [Accepted: 01/30/2021] [Indexed: 12/20/2022]
Abstract
Developmental and epileptic encephalopathies (DEEs) are among the most challenging of all epilepsies to manage, given the exceedingly frequent and often severe seizure types, pharmacoresistance to conventional antiseizure medications, and numerous comorbidities. During the past decade, efforts have focused on development of new treatment options for DEEs, with several recently approved in the United States or Europe, including cannabidiol as an orphan drug in Dravet and Lennox-Gastaut syndromes and everolimus as a possible antiepileptogenic and precision drug for tuberous sclerosis complex, with its impact on the mammalian target of rapamycin pathway. Furthermore, fenfluramine, an old drug, was repurposed as a novel therapy in the treatment of Dravet syndrome. The evolution of new insights into pathophysiological processes of various DEEs provides possibilities to investigate novel and repurposed drugs and to place them into the context of their role in future management of these patients. The purpose of this review is to provide an overview of these new medical treatment options for the DEEs and to discuss the clinical implications of these results for improved treatment.
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Affiliation(s)
- Cecilie Johannessen Landmark
- Program for Pharmacy, Department of Life Sciences and Health, Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway.,National Center for Epilepsy, Oslo University Hospital, Oslo, Norway.,Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Stéphane Auvin
- Pediatric Neurology Department, Robert Debré Hospital, Public Hospital Network of Paris, Paris, France.,Mixed Unit of Research NeuroDiderot U1141, University of Paris, Paris, France
| | - Jo M Wilmshurst
- Paediatric Neurology Department, Red Cross War Memorial Children's Hospital, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Svein I Johannessen
- National Center for Epilepsy, Oslo University Hospital, Oslo, Norway.,Section for Clinical Pharmacology, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | | | - Elaine C Wirrell
- Divisions of Child and Adolescent Neurology and Epilepsy, Mayo Clinic, Rochester, Minnesota, USA
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19
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Sullivan J, Scheffer IE, Lagae L, Nabbout R, Pringsheim M, Talwar D, Polster T, Galer B, Lock M, Agarwal A, Gammaitoni A, Morrison G, Farfel G. Fenfluramine HCl (Fintepla ® ) provides long-term clinically meaningful reduction in seizure frequency: Analysis of an ongoing open-label extension study. Epilepsia 2020; 61:2396-2404. [PMID: 33078386 PMCID: PMC7756901 DOI: 10.1111/epi.16722] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Fenfluramine has been shown to provide clinically meaningful and statistically significant reductions in convulsive seizure frequency in children and adolescents (aged 2-18 years) with Dravet syndrome in two randomized, placebo-controlled clinical trials. The objective of this analysis was to assess longer-term safety and efficacy of fenfluramine in patients who completed one of the double-blind studies and entered an open-label extension (OLE) study. METHODS Patients enrolling in the OLE study initiated fenfluramine at 0.2 mg/kg/d regardless of their treatment assignment in the double-blind study. After 4 weeks, the fenfluramine dose could be titrated based on efficacy and tolerability to maximum of 0.7 mg/kg/d (absolute maximum 27 mg/d) or maximum of 0.4 mg/kg/d (absolute maximum 17 mg/d) in patients receiving concomitant stiripentol. The number and type of seizures were recorded daily in an electronic diary, and safety, including echocardiography, was assessed at Months 1, 2, and 3, and at 3-month intervals thereafter. RESULTS A total of 232 patients were enrolled as of March 13, 2018. During this analysis period, patients were treated for a median 256 days (range = 46-634 days). Over the entire OLE analysis period, the median decrease in convulsive seizure frequency compared to baseline in the double-blind studies was -66.8% (range = -100% to 234.9%; P < .001). The median reduction in seizure frequency was similar in patients <6 (-75.7%) and ≥6 years old (-64.7%). The most commonly reported adverse events included pyrexia (21.6%), nasopharyngitis (19.4%), and decreased appetite (-15.9%). No valvular heart disease (VHD) or pulmonary arterial hypertension (PAH) was observed. SIGNIFICANCE Study results demonstrate that fenfluramine provides clinically meaningful (≥50%) seizure frequency reduction over an extended period in patients with Dravet syndrome. No patient developed VHD or PAH, and fenfluramine was generally well tolerated.
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Affiliation(s)
- Joseph Sullivan
- Benioff Children's Hospital, University of California San Francisco, San Francisco, CA, USA
| | - Ingrid E Scheffer
- Austin Health and Royal Children's Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Lieven Lagae
- Department of Paediatric Neurology, University of Leuven, Leuven, Belgium
| | - Rima Nabbout
- Service de Neurologie Pédiatrique Centre de Référence Épilepsies Rares (CReER), Hôpital Universitaire Necker - Enfants Malades, Paris, France
| | - Milka Pringsheim
- Department of Pediatric Cardiology, German Heart Centre Munich, Munich, Germany.,Pediatric Neurology, Schön Klinik Vogtareuth, Vogtareuth, Germany
| | - Dinesh Talwar
- Center for Neurosciences, University of Arizona Health Sciences Center, Tucson, AZ, USA
| | - Tilman Polster
- Department of Pediatric Epileptology, Bethel Epilepsy Center, Mara Hospital, Bielefeld, Germany
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20
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Balagura G, Cacciatore M, Grasso EA, Striano P, Verrotti A. Fenfluramine for the Treatment of Dravet Syndrome and Lennox-Gastaut Syndrome. CNS Drugs 2020; 34:1001-1007. [PMID: 32875491 DOI: 10.1007/s40263-020-00755-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The last 50 years has seen the introduction of a great number of antiepileptic drugs, relieving the burden of seizures for many patients. However, some conditions remain a challenge for epileptologists, especially Dravet syndrome and Lennox-Gastaut syndrome, which are severe epileptic and developmental encephalopathies characterized by multiple seizure types and electroencephalographic abnormalities that are often unresponsive to combinations of antiepileptic drugs. The re-purposing of an old drug such as fenfluramine could provide an indispensable tool for clinicians, especially because only a few drugs have been tested in relatively homogeneous populations, like Dravet syndrome. It could also provide insights into precision medicine approaches to the treatment of epileptic syndromes. We searched for relevant papers within MEDLINE, EMBASE, and the Clinical Trial Database, considering publications through July 2020. Pre-clinical studies show a mechanism of action for fenfluramine that goes beyond its pro-serotoninergic activity and that is at the intersection of several pathways involved in excitation/inhibition balance. From the ongoing clinical trial data, it is evident that fenfluramine is proving to be a promising antiepileptic drug with very favorable pharmacokinetics and with a good overall safety profile when used at a lower dosage (0.2-0.7 mg/kg/day), despite its previously link to major cardiac adverse events that prompted its withdrawal from the market in 1997. Here, we review the experimental and clinical evidence of the efficacy of fenfluramine, including the latest results from ongoing clinical trials, and critically discuss the future potential of fenfluramine in terms of safety and precision medicine. Available data from the literature suggest a very good efficacy for both epileptic syndromes with a reduction in seizure burden and a longer seizure-free interval. We note the higher prevalence of evidence in patients with Dravet syndrome. Fenfluramine has been used in association with both first- and second-line medications, while its use in monotherapy still needs to be assessed.
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Affiliation(s)
- Ganna Balagura
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Marta Cacciatore
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Eleonora A Grasso
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Alberto Verrotti
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.
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21
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Mustac T, Yuabov A, Macanian J, Aminov S, Fazylov D, Lulu EB, Nashed M, Albakry A, Jean-Philippe-Morisset B, Bodnar RJ. Acute d-fenfluramine, but not fluoxetine decreases sweet intake in BALB/c, C57BL/6 and SWR inbred mouse strains. Physiol Behav 2020; 224:113029. [PMID: 32590091 DOI: 10.1016/j.physbeh.2020.113029] [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: 02/24/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 11/29/2022]
Abstract
Dopamine, opioid and muscarinic receptor antagonists differentially reduce sucrose and saccharin intakes across inbred mouse strains. Whereas these systems stimulate sweet intake, serotonin signaling inhibits food intake. The present study examined whether fluoxetine (0.1-10 mg/kg) or d-fenfluramine (0.1-6 mg/kg) differentially inhibited sucrose or saccharin intake in BALB/c, C57BL/6 and SWR mice. Fluoxetine marginally altered sucrose intake in all strains. d-fenfluramine significantly, but quite similarly reduced (ID40) sucrose and saccharin intake in BALB/c (5.7 vs. 5.8 mg/kg), C57BL/6 (4.4 vs. 4.3 mg/kg) and SWR (4.6 vs. 5.6 mg/kg) mice, suggesting serotonin-induced inhibition of orosensory mechanisms in all three inbred mouse strains.
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Affiliation(s)
- Tatjana Mustac
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Asnat Yuabov
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Jason Macanian
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Sonya Aminov
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - David Fazylov
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Eden Ben Lulu
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Mirna Nashed
- Department of Psychology, Queens College, City University of New York (CUNY)
| | - Ahmed Albakry
- Department of Psychology, Queens College, City University of New York (CUNY)
| | | | - Richard J Bodnar
- Department of Psychology, Queens College, City University of New York (CUNY); CUNY Neuroscience Collaborative and Psychology Doctoral Program, CUNY Graduate Center, New York, NY, USA.
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22
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Yen JY, Lin HC, Lin PC, Liu TL, Long CY, Ko CH. Leptin and ghrelin concentrations and eating behaviors during the early and late luteal phase in women with premenstrual dysphoric disorder. Psychoneuroendocrinology 2020; 118:104713. [PMID: 32460195 DOI: 10.1016/j.psyneuen.2020.104713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/01/2020] [Accepted: 05/06/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVES In this study, we evaluated the changes in leptin and ghrelin concentrations, eating behavior, depression, and impulsivity and their correlations within the luteal phase among women with premenstrual dysphoric disorder (PMDD). METHODS In 63 women with PMDD and 53 healthy controls, we prospectively evaluated serum levels of leptin and ghrelin, Body Mass Index(BMI), and self-reported sweet cravings, cognitive restraint, uncontrolled eating, emotional eating, depression, and impulsivity during the early luteal (EL) and late luteal (LL) phases. RESULTS Compared with the controls, the women with PMDD had higher BMI, higher leptin concentrations in the EL and LL phase, and leptin concentrations increased from the EL to the LL phase. However, there is no significant difference in ghrelin. Women with PMDD increased sweet cravings and uncontrolled eating from EL to LL phase. No significant correlation was observed between the EL-LL changes in leptin or ghrelin concentrations and those in eating behaviors. Both depression and impulsivity correlated with sweet craving and uncontrolled eating. Depression mediated the association between PMDD and uncontrolled eating. The BMI of women with PMDD positively correlated with their EL-LL change in leptin, and LL depression levels and emotional eating. CONCLUSION Young women with PMDD had higher leptin concentrations and BMI in the luteal phase. The LL leptin level was not the primary factor responsible for the increased uncontrolled eating of PMDD. Whether the increased eating and depression in the LL phase contribute to the risk of obesity or hyperleptinemia among women with PMDD need to be evaluated in the future.
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Affiliation(s)
- Ju-Yu Yen
- Department of Psychiatry, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Psychiatry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Huang-Chi Lin
- Department of Psychiatry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Pai-Cheng Lin
- Department of Psychiatry, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tai-Ling Liu
- Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Cheng-Yu Long
- Department of Obstetrics and Gynecology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chih-Hung Ko
- Department of Psychiatry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Department of Psychiatry, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Research Center for Substance Addiction and Behavior Addiction, Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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A phase I, randomized, open-label, single-dose, 3-period crossover study to evaluate the drug-drug interaction between ZX008 (fenfluramine HCl oral solution) and a regimen of stiripentol, clobazam, and valproate in healthy subjects
. Int J Clin Pharmacol Ther 2019; 57:11-19. [PMID: 30336805 PMCID: PMC6298132 DOI: 10.5414/cp203276] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2018] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Phase I, open-label, randomized, single-dose, 3-period crossover study assessing pharmacokinetics (PK) and safety of ZX008, a liquid oral formulation of fenfluramine (FFA) under development for adjunctive treatment of Dravet syndrome and Lennox-Gastaut syndrome, administered with and without a combined antiepileptic drug (AED) regimen of stiripentol (STP), valproate (VPA), and clobazam (CLB) (STP regimen). MATERIALS AND METHODS 26 healthy adults were administered the following treatments: ZX008 0.8 mg/kg; STP 3,500 mg, CLB 20 mg, VPA 25 mg/kg (max. 1,500 mg); and ZX008 0.8 mg/kg + STP regimen. Dose periods were 17 days apart. Blood samples were obtained for 72 hours after drug administration and used to calculate non-compartmental PK parameters. RESULTS Statistical bioequivalence-type analysis demonstrated ZX008 had no significant impact on the PK of any drug in the STP regimen, while the STP regimen moderately affected FFA PK. The 3-drug combination increased the geometric mean Cmax, AUC0-t, and AUC0-inf of FFA while reducing the Cmax and AUC0-t of its major metabolite, norfenfluramine (norFFA). Adverse events (AEs) were mild to moderate and resolved spontaneously. ZX008 + STP regimen co-administration to healthy adult subjects modestly impacted the number but not severity of AEs. CONCLUSION Results show that the STP regimen had a moderate impact on FFA and norFFA PK and ZX008 had no significant impact on the 3 STP regimen drugs. ZX008 would not be expected to alter the clinical response of patients to this regimen by means of an effect on PK. When administering these drugs together, a downward dose adjustment of ZX008 may be warranted.
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Eschbach K, Knupp KG. Stiripentol for the treatment of seizures in Dravet syndrome. Expert Rev Clin Pharmacol 2019; 12:379-388. [DOI: 10.1080/17512433.2019.1605904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Krista Eschbach
- University of Colorado Denver Anschutz School of Medicine, Children’s Hospital Colorado, Aurora, CO, USA
| | - Kelly G Knupp
- University of Colorado Denver Anschutz School of Medicine, Children’s Hospital Colorado, Aurora, CO, USA
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25
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Vavers E, Zvejniece L, Maurice T, Dambrova M. Allosteric Modulators of Sigma-1 Receptor: A Review. Front Pharmacol 2019; 10:223. [PMID: 30941035 PMCID: PMC6433746 DOI: 10.3389/fphar.2019.00223] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/22/2019] [Indexed: 11/13/2022] Open
Abstract
Allosteric modulators of sigma-1 receptor (Sig1R) are described as compounds that can increase the activity of some Sig1R ligands that compete with (+)-pentazocine, one of the classic prototypical ligands that binds to the orthosteric Sig1R binding site. Sig1R is an endoplasmic reticulum membrane protein that, in addition to its promiscuous high-affinity ligand binding, has been shown to have chaperone activity. Different experimental approaches have been used to describe and validate the activity of allosteric modulators of Sig1R. Sig1R-modulatory activity was first found for phenytoin, an anticonvulsant drug that primarily acts by blocking the voltage-gated sodium channels. Accumulating evidence suggests that allosteric Sig1R modulators affect processes involved in the pathophysiology of depression, memory and cognition disorders as well as convulsions. This review will focus on the description of selective and non-selective allosteric modulators of Sig1R, including molecular structure properties and pharmacological activity both in vitro and in vivo, with the aim of providing the latest overview from compound discovery approaches to eventual clinical applications. In this review, the possible mechanisms of action will be discussed, and future challenges in the development of novel compounds will be addressed.
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Affiliation(s)
- Edijs Vavers
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Liga Zvejniece
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Tangui Maurice
- MMDN, University of Montpellier, INSERM, EPHE, UMR-S1198, Montpellier, France
| | - Maija Dambrova
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia
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26
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Polster T. Individualized treatment approaches: Fenfluramine, a novel antiepileptic medication for the treatment of seizures in Dravet syndrome. Epilepsy Behav 2019; 91:99-102. [PMID: 30269941 DOI: 10.1016/j.yebeh.2018.08.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 01/02/2023]
Abstract
Dravet syndrome is a rare and severe encephalopathy that first presents in infancy with seizures refractory to conventional antiepileptic drugs. Forty-five percent of patients report four or more tonic-clonic seizures per month despite multidrug regimens. Fenfluramine, an amphetamine derivative, was initially developed as an appetite suppressant with a serotonergic mechanism of action. Clinical observation of a potential antiepileptic activity in a small homogeneous cohort of patients combined with a genetic workup of these patients led to the hypothesis of fenfluramine as a treatment for seizures in Dravet syndrome. This concept was successfully evaluated in a zebrafish model and led to a Phase 3 trial of fenfluramine to treat seizures in children with Dravet syndrome. Preliminary results of the trial suggest that fenfluramine may be a highly effective, well-tolerated treatment for patients with Dravet syndrome. This short review summarizes the history of use of fenfluramine from the initial clinical observations followed by preclinical studies and subsequent successful clinical trial. This article is part of the Special Issue "Individualized Epilepsy Management: Medicines, Surgery and Beyond."
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Affiliation(s)
- Tilman Polster
- Paediatric Epileptology, Mara Hospital, Bethel Epilepsy Centre, Bielefeld, Germany.
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27
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Lagae L, Schoonjans AS, Gammaitoni AR, Galer BS, Ceulemans B. A pilot, open-label study of the effectiveness and tolerability of low-dose ZX008 (fenfluramine HCl) in Lennox-Gastaut syndrome. Epilepsia 2018; 59:1881-1888. [DOI: 10.1111/epi.14540] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Lieven Lagae
- Department of Development and Regeneration; Division of Pediatric Neurology; University of Leuven; Leuven Belgium
| | - An-Sofie Schoonjans
- Division of Pediatric Neurology; Antwerp University Hospital; University of Antwerp; Edegem Belgium
| | | | | | - Berten Ceulemans
- Division of Pediatric Neurology; Antwerp University Hospital; University of Antwerp; Edegem Belgium
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28
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Gammaitoni A, Smith S, Boyd B. The Lack of Effect of Food on the Pharmacokinetics of ZX008 (Fenfluramine Oral Solution): Results of a Single-dose, Two-period Crossover Study. Clin Ther 2018; 40:1338-1346. [PMID: 29941151 DOI: 10.1016/j.clinthera.2018.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/01/2018] [Accepted: 05/20/2018] [Indexed: 11/30/2022]
Abstract
PURPOSE Fenfluramine is being developed as a low-dose adjunctive treatment for seizures in patients with Dravet syndrome and other epileptic encephalopathies, including Lennox-Gastaut syndrome. Most patients with Dravet syndrome receive multiple antiepileptic drugs, making it challenging for caregivers to track correct administration times. The present Phase I study was conducted to determine the effect of food on the pharmacokinetic properties of fenfluramine. METHODS Healthy nonsmoking subjects aged 18 to 50 years were enrolled in an open-label, crossover, Phase I pharmacokinetic and safety profile study and received 2 single 0.8-mg/kg doses of ZX008 (fenfluramine hydrochloride oral solution), 1 after a 10-hour overnight fast and the other 30 minutes after the start of consumption of a high-fat breakfast, in a randomly assigned order. A washout period of at least 9 days separated the 2 treatment periods. Venous blood samples were taken before each dose and periodically for 72 hours after each dose for determination of concentrations of fenfluramine and its active metabolite norfenfluramine. Plasma pharmacokinetic parameters were estimated for each subject by noncompartmental analysis. FINDINGS In the 13 subjects completing both treatment periods, food had no effect on the rate or extent of absorption and bioavailability of fenfluramine as assessed by fed vs fasted adjusted geometric mean observed plasma Cmax (59.1 vs 56.7 ng/mL; NS) and AUC0-∞ (1640 vs 1600 ng · h/mL; NS). Additionally, there was no impact of food on systemic exposure of norfenfluramine. Seven subjects reported at least 1 treatment-emergent adverse event; all treatment-emergent adverse events were mild in severity. IMPLICATIONS The bioequivalence and tolerability of single 0.8-mg/kg oral doses of ZX008 in the fed and fasted states support ZX008 administration without regard to meals.
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Rodríguez-Muñoz M, Sánchez-Blázquez P, Garzón J. Fenfluramine diminishes NMDA receptor-mediated seizures via its mixed activity at serotonin 5HT2A and type 1 sigma receptors. Oncotarget 2018; 9:23373-23389. [PMID: 29805740 PMCID: PMC5955088 DOI: 10.18632/oncotarget.25169] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/03/2018] [Indexed: 10/27/2022] Open
Abstract
Fenfluramine exhibits antiepileptic properties and thus diminishes epileptiform discharges in experimental animal models of Dravet syndrome. Fenfluramine is metabolized into norfenfluramine in vivo, which shows greater affinity and agonist activity at serotonin 5HT2 receptors (5HT2R) than fenfluramine. In this study, we found that fenfluramine and norfenfluramine disrupted the regulatory association of the sigma 1 receptor (σ1R) with NR1 subunits of glutamate N-methyl-D-aspartate receptors (NMDAR), an effect that was also produced by σ1R antagonists such as S1RA and prevented by σ1R agonists such as PPCC. The antagonists removed σ1R bound to NMDAR NR1 subunits enabling calcium-regulated calmodulin (CaM) to bind to those subunits. As a result, CaM may inhibit calcium permeation through NMDARs. The serotoninergic activity of fenfluramine at 5HT2AR, and likely also at 5HT2CR, collaborated with its activity at σ1Rs to prevent the convulsive syndrome promoted by NMDAR overactivation. Notably, fenfluramine enhanced the inhibitory coupling of G protein-coupled receptors such as 5HT1AR and cannabinoid type 1 receptor with NMDARs, thus allowing the more effective restrain of NMDAR activity. Thus, fenfluramine circumvents the negative side effects of direct NMDAR antagonists and may improve the quality of life of subjects affected by such proconvulsant dysfunctions.
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Affiliation(s)
- María Rodríguez-Muñoz
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Pilar Sánchez-Blázquez
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Javier Garzón
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
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Schoonjans AS, Marchau F, Paelinck BP, Lagae L, Gammaitoni A, Pringsheim M, Keane MG, Ceulemans B. Cardiovascular safety of low-dose fenfluramine in Dravet syndrome: a review of its benefit-risk profile in a new patient population. Curr Med Res Opin 2017; 33:1773-1781. [PMID: 28704161 DOI: 10.1080/03007995.2017.1355781] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Dravet syndrome (DS) is a rare, treatment-resistant epilepsy syndrome for which current treatment regimens are often ineffective. Fenfluramine is currently in development for treatment of DS, based on reports in the 1980s and 1990s of its anti-epileptic activity in pediatric patients with intractable epilepsy. However, fenfluramine was withdrawn from global markets in 1997 following reports of its association with pulmonary hypertension and heart valve disease in adult patients treated for obesity. This review was conducted to assess cardiac safety of fenfluramine when used at lower doses for treatment of DS. METHODS Pubmed was searched for clinical studies of fenfluramine in obese adults who reported incidence of heart valve disease. These data were reviewed against published results from Belgian patients with DS who have been treated with low-dose fenfluramine for up to 28 years. RESULTS Nine controlled studies of fenfluramine and related compounds (dexfenfluramine and/or phentermine) which assessed incidence and severity of cardiac valve disease in 3,268 treated patients and 2,017 control subjects have been reported. Mild or greater aortic valve regurgitation was found in 9.6% of treated patients compared with 3.9% of control subjects, and moderate or greater mitral valve regurgitation was found in 3.1% of treated patients and 2.5% of control subjects. Nineteen DS patients have been treated for up to 28 years with 10-20 mg/day fenfluramine, with no clinical signs or symptoms of cardiac valve disease or pulmonary hypertension. Slight and clinically unimportant changes in valve structure have been seen on echocardiography in five patients at some time during the observation period. CONCLUSIONS A different benefit-risk relationship appears to be emerging when fenfluramine is used at low doses for extended periods in young patients with DS. Continued cardiac assessments during ongoing Phase 3 clinical trials will provide additional safety information for this potential new and effective treatment.
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Affiliation(s)
- An-Sofie Schoonjans
- a Department of Paediatric Neurology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Fabienne Marchau
- b Department of Paediatric Cardiology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Bernard P Paelinck
- c Department of Cardiology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Lieven Lagae
- d Department of Development and Regeneration , Section of Paediatric Neurology, University Hospitals Gasthuisberg , Leuven , Belgium
| | | | - Milka Pringsheim
- f Department of Pediatric Cardiology , German Heart Centre Munich , Munich , Germany
- g Pediatric Neurology, Schön Klinik Vogtareuth , Vogtareuth , Germany
| | | | - Berten Ceulemans
- a Department of Paediatric Neurology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
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Bialer M, Johannessen SI, Levy RH, Perucca E, Tomson T, White HS. Progress report on new antiepileptic drugs: A summary of the Thirteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIII). Epilepsia 2017; 58:181-221. [PMID: 28111749 DOI: 10.1111/epi.13634] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 01/05/2023]
Abstract
The Thirteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIII) took place in Madrid, Spain, on June 26-29, 2016, and was attended by >200 delegates from 31 countries. The present Progress Report provides an update on experimental and clinical results for drugs presented at the Conference. Compounds for which summary data are presented include an AED approved in 2016 (brivaracetam), 12 drugs in phase I-III clinical development (adenosine, allopregnanolone, bumetanide, cannabidiol, cannabidivarin, 2-deoxy-d-glucose, everolimus, fenfluramine, huperzine A, minocycline, SAGE-217, and valnoctamide) and 6 compounds or classes of compounds for which only preclinical data are available (bumetanide derivatives, sec-butylpropylacetamide, FV-082, 1OP-2198, NAX 810-2, and SAGE-689). Overall, the results presented at the Conference show that considerable efforts are ongoing into discovery and development of AEDs with potentially improved therapeutic profiles compared with existing agents. Many of the drugs discussed in this report show innovative mechanisms of action and many have shown promising results in patients with pharmacoresistant epilepsies, including previously neglected rare and severe epilepsy syndromes.
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Affiliation(s)
- Meir Bialer
- Faculty of Medicine, School of Pharmacy and David R. Bloom Center for Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Svein I Johannessen
- The National Center for Epilepsy, Sandvika, Norway.,Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - René H Levy
- Department of Pharmaceutics and Neurological Surgery, University of Washington, Seattle, Washington, U.S.A
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy.,C. Mondino National Neurological Institute, Pavia, Italy
| | - Torbjörn Tomson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - H Steve White
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, U.S.A
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Balestrini S, Sisodiya SM. Pharmacogenomics in epilepsy. Neurosci Lett 2017; 667:27-39. [PMID: 28082152 PMCID: PMC5846849 DOI: 10.1016/j.neulet.2017.01.014] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 12/12/2022]
Abstract
Genetic variation can influence response to antiepileptic drug (AED) treatment through various effector processes. Metabolism of many AEDs is mediated by the cytochrome P450 (CYP) family; some of the CYPs have allelic variants that may affect serum AED concentrations. ‘Precision medicine’ focuses on the identification of an underlying genetic aetiology allowing personalised therapeutic choices. Certain human leukocyte antigen, HLA, alleles are associated with an increased risk of idiosyncratic adverse drug reactions. New results are emerging from large-scale multinational efforts, likely imminently to add knowledge of value from a pharmacogenetic perspective.
There is high variability in the response to antiepileptic treatment across people with epilepsy. Genetic factors significantly contribute to such variability. Recent advances in the genetics and neurobiology of the epilepsies are establishing the basis for a new era in the treatment of epilepsy, focused on each individual and their specific epilepsy. Variation in response to antiepileptic drug treatment may arise from genetic variation in a range of gene categories, including genes affecting drug pharmacokinetics, and drug pharmacodynamics, but also genes held to actually cause the epilepsy itself. From a purely pharmacogenetic perspective, there are few robust genetic findings with established evidence in epilepsy. Many findings are still controversial with anecdotal or less secure evidence and need further validation, e.g. variation in genes for transporter systems and antiepileptic drug targets. The increasing use of genetic sequencing and the results of large-scale collaborative projects may soon expand the established evidence. Precision medicine treatments represent a growing area of interest, focussing on reversing or circumventing the pathophysiological effects of specific gene mutations. This could lead to a dramatic improvement of the effectiveness and safety of epilepsy treatments, by targeting the biological mechanisms responsible for epilepsy in each specific individual. Whilst much has been written about epilepsy pharmacogenetics, there does now seem to be building momentum that promises to deliver results of use in clinic.
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Affiliation(s)
- Simona Balestrini
- NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, and Epilepsy Society, Chalfont-St-Peter, Bucks, United Kingdom; Neuroscience Department, Polytechnic University of Marche, Ancona, Italy
| | - Sanjay M Sisodiya
- NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, and Epilepsy Society, Chalfont-St-Peter, Bucks, United Kingdom.
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Reif PS, Tsai MH, Helbig I, Rosenow F, Klein KM. Precision medicine in genetic epilepsies: break of dawn? Expert Rev Neurother 2016; 17:381-392. [DOI: 10.1080/14737175.2017.1253476] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Philipp Sebastian Reif
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe-University Frankfurt, Frankfurt, Germany
| | - Meng-Han Tsai
- Division of Brain Function & Epilepsy, Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ingo Helbig
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neuropediatrics, Christian-Albrechts-University of Kiel and University Medical Center Schleswig-Holstein, Kiel, Germany
- Departments of Brain and Cognitive Sciences, Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Felix Rosenow
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe-University Frankfurt, Frankfurt, Germany
- Epilepsy Center Hessen, Department of Neurology, University Hospitals Giessen & Marburg, and Philipps-University Marburg, Marburg, Germany
| | - Karl Martin Klein
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe-University Frankfurt, Frankfurt, Germany
- Epilepsy Center Hessen, Department of Neurology, University Hospitals Giessen & Marburg, and Philipps-University Marburg, Marburg, Germany
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Ceulemans B, Schoonjans AS, Marchau F, Paelinck BP, Lagae L. Five-year extended follow-up status of 10 patients with Dravet syndrome treated with fenfluramine. Epilepsia 2016; 57:e129-34. [PMID: 27197941 DOI: 10.1111/epi.13407] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2016] [Indexed: 11/28/2022]
Abstract
Dravet syndrome (DS) is a rare and therapy-resistant epilepsy syndrome. A retrospective analysis of add-on fenfluramine treatment in 12 patients with DS was published in 2012 and provided evidence of a meaningful long-term response. Herein we present the results of a subsequent 5-year prospective observation of this original cohort. Ten patients with a mean current age of 24 years were followed prospectively from 2010 until 2014. The mean current dose of fenfluramine was 0.27 mg/kg/day, with a mean treatment duration of 16.1 years. Seizure frequency was derived from a seizure diary. Cardiac examinations and assessments of clinical effectiveness and adverse events were performed at least annually. Three patients were seizure-free for the entire 5 years, and an additional four patients experienced seizure-free intervals of at least 2 years. Fenfluramine was generally well-tolerated. Two patients had mild (stable) valve thickening on the last echocardiography that was deemed clinically insignificant. No patient had any clinical or echocardiographic signs of pulmonary hypertension. These findings support the long-term control of convulsive seizures by low-dose fenfluramine while being well tolerated in this cohort of patients with DS. After up to 27 years of treatment, no patient has developed any clinical signs or symptoms of cardiac valvulopathy or pulmonary hypertension.
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Affiliation(s)
- Berten Ceulemans
- Department of Neurology-Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - An-Sofie Schoonjans
- Department of Neurology-Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Fabienne Marchau
- Department of Pediatric Cardiology, Antwerp University Hospital, Edegem, Belgium
| | - Bernard P Paelinck
- Department of Cardiology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Lieven Lagae
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospitals Gasthuisberg, Leuven, Belgium
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Schoonjans AS, Lagae L, Ceulemans B. Low-dose fenfluramine in the treatment of neurologic disorders: experience in Dravet syndrome. Ther Adv Neurol Disord 2015; 8:328-38. [PMID: 26600876 DOI: 10.1177/1756285615607726] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this paper, we review the experience with fenfluramine in epileptic and other paroxysmal disorders. Since the best available data are from the treatment of Dravet syndrome, we will focus primarily on this condition. Originally fenfluramine was launched as an anorectic agent. As early as 1985, seizure reduction in children could be demonstrated in a few cases with photosensitive, self-induced epilepsy. Hereafter, a small study was launched in patients with self-induced epilepsy. Results showed a significant seizure reduction, and review of the patient data showed that 5 of the 12 patients had Dravet syndrome. During that observation period, fenfluramine was withdrawn from the market because of cardiovascular side effects associated with prescribing higher doses in combination with phentermine for weight loss. In March 2002, a Belgian Royal Decree was issued permitting further study of fenfluramine in pediatric patients with intractable epilepsy. In 2011 under the Royal Decree, a prospective study of patients with Dravet syndrome treated with low-dose fenfluramine was initiated and is currently ongoing. The initial results are promising in terms of reduction of seizure frequency and overall tolerability.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Neurology-Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Belgium
| | - Lieven Lagae
- Department of Pediatric Neurology, University Hospitals Gasthuisberg, Leuven, Belgium
| | - Berten Ceulemans
- Department of Neurology-Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium
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Dinday MT, Baraban SC. Large-Scale Phenotype-Based Antiepileptic Drug Screening in a Zebrafish Model of Dravet Syndrome. eNeuro 2015; 2:ENEURO.0068-15.2015. [PMID: 26465006 PMCID: PMC4596025 DOI: 10.1523/eneuro.0068-15.2015] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 07/28/2015] [Accepted: 08/04/2015] [Indexed: 11/23/2022] Open
Abstract
Mutations in a voltage-gated sodium channel (SCN1A) result in Dravet Syndrome (DS), a catastrophic childhood epilepsy. Zebrafish with a mutation in scn1Lab recapitulate salient phenotypes associated with DS, including seizures, early fatality, and resistance to antiepileptic drugs. To discover new drug candidates for the treatment of DS, we screened a chemical library of ∼1000 compounds and identified 4 compounds that rescued the behavioral seizure component, including 1 compound (dimethadione) that suppressed associated electrographic seizure activity. Fenfluramine, but not huperzine A, also showed antiepileptic activity in our zebrafish assays. The effectiveness of compounds that block neuronal calcium current (dimethadione) or enhance serotonin signaling (fenfluramine) in our zebrafish model suggests that these may be important therapeutic targets in patients with DS. Over 150 compounds resulting in fatality were also identified. We conclude that the combination of behavioral and electrophysiological assays provide a convenient, sensitive, and rapid basis for phenotype-based drug screening in zebrafish mimicking a genetic form of epilepsy.
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Affiliation(s)
- Matthew T. Dinday
- Department of Neurological Surgery, Epilepsy Research Laboratory, University of California San Francisco, San Francisco, California 94143
| | - Scott C. Baraban
- Department of Neurological Surgery, Epilepsy Research Laboratory, University of California San Francisco, San Francisco, California 94143
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, California 94143
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Selvaraj S, Arnone D, Cappai A, Howes O. Alterations in the serotonin system in schizophrenia: a systematic review and meta-analysis of postmortem and molecular imaging studies. Neurosci Biobehav Rev 2014; 45:233-45. [PMID: 24971825 DOI: 10.1016/j.neubiorev.2014.06.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 05/13/2014] [Accepted: 06/16/2014] [Indexed: 02/04/2023]
Abstract
Serotonergic dysfunction is thought to contribute to the pathophysiology of schizophrenia but the evidence has not been systematically synthesised before. We therefore systematically reviewed postmortem and in vivo molecular imaging studies of serotonin function in schizophrenia. We identified fifty relevant studies investigating eight different serotonin receptor systems in a total of 684 patients and 675 controls. Meta-analysis of postmortem studies found an elevation in prefrontal 5-HT1A receptors with a moderate to large effect size (N=8, 85 patients and 94 controls, SMD=0.60; CI: 0.17-1.03; p=0.007) and a reduction with a large effect size in prefrontal 5-HT2A receptors (N=8, 168 patients and 163 controls, SMD=-0.73; CI: -1.33, -0.12; p=0.019) in schizophrenia vs healthy controls. The evidence for alterations in serotonin transporter availability or other serotonin receptors (5-HT1B; 5-HT1D; 5-HT3; 5-HT4; 5-HT7) is limited. There are fewer studies investigating 5-HT receptors in schizophrenia with neuroimaging. Findings indicated possible 5-HT alterations at psychosis onset, although due to the limited number it was not possible to combine studies in a meta-analysis. Further in vivo studies, particularly in drug naive patients using radiotracers that can index high affinity states, will help determine if the postmortem findings are primary or secondary to other factors.
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Affiliation(s)
- Sudhakar Selvaraj
- Medical Research Council, Clinical Sciences Centre, Institute of Clinical Sciences, Hammersmith Hospital Campus, Imperial College London, London W12 0NN, UK; Department of Psychiatry and Behavioural Sciences, The University of Texas Health Science Centre at Houston, Houston, TX, USA.
| | - Danilo Arnone
- Centre for Affective Disorders, Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Alessandra Cappai
- Medical Research Council, Clinical Sciences Centre, Institute of Clinical Sciences, Hammersmith Hospital Campus, Imperial College London, London W12 0NN, UK; Forensic Outreach Service & Inreach Team HMP Wandsworth, South West London & St George's NHS Mental Health Trust, Springfield Hospital, Glenburnie Road, London SW17 7DJ, UK
| | - Oliver Howes
- Medical Research Council, Clinical Sciences Centre, Institute of Clinical Sciences, Hammersmith Hospital Campus, Imperial College London, London W12 0NN, UK; Department of Psychosis Studies, Institute of Psychiatry, King's College London, London SE5 8AF, UK
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Abstract
The solute carrier 6 (SLC6) family of the human genome comprises transporters for neurotransmitters, amino acids, osmolytes and energy metabolites. Members of this family play critical roles in neurotransmission, cellular and whole body homeostasis. Malfunction or altered expression of these transporters is associated with a variety of diseases. Pharmacological inhibition of the neurotransmitter transporters in this family is an important strategy in the management of neurological and psychiatric disorders. This review provides an overview of the biochemical and pharmacological properties of the SLC6 family transporters.
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Affiliation(s)
- Stefan Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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Mikail HG, Dalla C, Kokras N, Kafetzopoulos V, Papadopoulou-Daifoti Z. Sertraline behavioral response associates closer and dose-dependently with cortical rather than hippocampal serotonergic activity in the rat forced swim stress. Physiol Behav 2012; 107:201-6. [DOI: 10.1016/j.physbeh.2012.06.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 06/01/2012] [Accepted: 06/26/2012] [Indexed: 12/16/2022]
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Giuliano F, Clèment P. Pharmacology for the Treatment of Premature Ejaculation. Pharmacol Rev 2012; 64:621-44. [DOI: 10.1124/pr.111.004952] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Fletcher PJ, Tampakeras M, Sinyard J, Slassi A, Isaac M, Higgins GA. Characterizing the effects of 5-HT2C receptor ligands on motor activity and feeding behaviour in 5-HT2C receptor knockout mice. Neuropharmacology 2009; 57:259-67. [DOI: 10.1016/j.neuropharm.2009.05.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 11/28/2022]
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Mice overexpressing the 5-hydroxytryptamine transporter show no alterations in feeding behaviour and increased non-feeding responses to fenfluramine. Psychopharmacology (Berl) 2008; 200:291-300. [PMID: 18560807 DOI: 10.1007/s00213-008-1206-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Accepted: 05/14/2008] [Indexed: 11/26/2022]
Abstract
RATIONALE The 5-HT transporter (5-HTT) is implicated in the regulation of appetite. Expression of the 5-HTT varies in the human population, and this variation may determine both individual differences in feeding and abnormal feeding behaviours such as eating disorders. OBJECTIVES The effects of 5-HTT expression on feeding and satiety were examined in a transgenic mouse model of 5-HTT overexpression. MATERIALS AND METHODS We measured free-feeding food intake and observed the behavioural satiety sequence (BSS) after food deprivation in mice at baseline and after administration of the anorectic drug fenfluramine. RESULTS 5-HTT overexpressing mice were both lighter and shorter than their wildtype littermates. Despite this size difference, food intake by transgenic and wildtype mice did not differ. There was no effect of genotype on the BSS or on food intake during the test at baseline. Increasing doses of fenfluramine reduced food intake in a similar manner in both transgenic and wildtype mice. After 0.3 and 1 mg/kg fenfluramine, the temporal pattern of the BSS was the same for both groups, whereas 3 and 10 mg/kg fenfluramine disrupted the BSS. In transgenic mice, this disruption was evident at the 3 mg/kg dose, while in wildtypes, it emerged only at the 10-mg/kg dose. CONCLUSION These data suggest that overexpression of the 5-HTT does not lead to alterations in feeding or satiety in food-deprived mice but does increase the occurrence of other non-feeding behaviours in response to the 5-HT releasing agent fenfluramine.
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Giuliano F. 5-hydroxytryptamine in premature ejaculation: opportunities for therapeutic intervention. Trends Neurosci 2007; 30:79-84. [PMID: 17169440 DOI: 10.1016/j.tins.2006.12.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 10/24/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
Ejaculation, although mediated by a spinal ejaculation generator, is subject to descending supraspinal modulation from several brain regions. 5-Hydroxytryptamine (5-HT or serotonin) is involved in ejaculatory control, with its ejaculation-retarding effects likely to be attributable to activation of 5-HT1B and 5-HT2C receptors, both spinally and supraspinally. By contrast, stimulation of 5-HT1A receptors precipitates ejaculation. Selective serotonin reuptake inhibitors (SSRIs), which are used for treatment of psychiatric disorders, can delay ejaculation in humans and are widely used 'off-label' for treatment of premature ejaculation. SSRIs require 1-2 weeks' chronic dosing to be effective, similar to their use for treatment of depression. However, a new short-acting SSRI is effective 'on demand' and might represent the first of a new generation of therapies targeted to premature ejaculation.
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Affiliation(s)
- François Giuliano
- AP-HP, Neuro-Uro-Andrology Unit, Department of Physical Medicine and Rehabilitation, Raymond Poincaré Hospital, 104 Bd Raymond Poincaré, 92380 Garches, France.
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Fletcher PJ, Sinyard J, Higgins GA. The effects of the 5-HT(2C) receptor antagonist SB242084 on locomotor activity induced by selective, or mixed, indirect serotonergic and dopaminergic agonists. Psychopharmacology (Berl) 2006; 187:515-25. [PMID: 16832658 DOI: 10.1007/s00213-006-0453-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Accepted: 05/20/2006] [Indexed: 11/26/2022]
Abstract
RATIONALE The 5-HT(2C) receptor modulates mesolimbic dopamine (DA) function and the expression of DA-dependent behaviors, including stimulant-induced hyperactivity. The 5-HT(2C) receptor may also be involved in drug-induced locomotion that is 5-HT-dependent. OBJECTIVES This study investigated the effects of the 5-HT(2C) receptor antagonist 6-chloro-5-methyl-1-[[2-[(2-methyl-3-pyridyl)oxy]-5-pyridyl]carbamoyl]-indoline (SB242084) on hyperlocomotion induced by psychomotor stimulants with selective, or mixed, actions on serotonergic and/or dopaminergic systems. MATERIALS AND METHODS Male Sprague-Dawley rats were treated in the presence or absence of SB242084 with releasers/reuptake inhibitors of DA (amphetamine and methylphenidate), 5-HT (fenfluramine and citalopram), or both 5-HT and DA (MDMA and cocaine). In addition, the effects of SB242084 combined with nicotine, morphine, or the 5-HT(1A/1B) receptor agonist RU24969 were examined. Locomotor activity was recorded for 2 h. RESULTS SB242084 potentiated hyperactivity induced by MDMA (2.5-5 mg/kg), amphetamine (0.5 mg/kg), fenfluramine (5 mg/kg), cocaine (10 mg/kg), and methylphenidate (5 mg/kg). SB242084 modestly potentiated nicotine-induced (0.2-0.4 mg/kg) and morphine-induced (2.5 mg/kg) hyperactivity. SB242084 failed to influence hyperactivity induced by RU24969 (0.5-1 mg/kg) or citalopram (10-20mg/kg). CONCLUSION SB242084 potentiated the locomotor stimulant effects of both indirect DA and 5-HT agonists. This potentiation may reflect two distinct mechanisms. The first involves direct enhancement of DA activity as shown by potentiation of the effects of amphetamine and methylphenidate. The second mechanism reflects an unmasking of stimulatory 5-HT receptors activated by 5-HT releasers (possibly 5-HT(1B/2A)) through blockade of inhibitory 5-HT(2C) receptors. The failure of SB242084 to potentiate the effect of citalopram might reflect differences between changes in synaptic levels of 5-HT produced by release compared to reuptake inhibition.
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Affiliation(s)
- Paul J Fletcher
- Section of Biopsychology, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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BAUMANN MICHAELH, AYESTAS MARIOA, ROTHMAN RICHARDB. In Vivo
Correlates of Central Serotonin Function after High-Dose Fenfluramine Administration. Ann N Y Acad Sci 2006; 844:138-152. [DOI: 10.1111/j.1749-6632.1998.tb08229.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Deiró TCBJ, Manhães-de-Castro R, Cabral-Filho JE, Barreto-Medeiros JM, Souza SL, Marinho SMOC, Castro FMM, Toscano AE, Jesus-Deiró RA, Barros KMFT. Sertraline delays the somatic growth and reflex ontogeny in neonate rats. Physiol Behav 2006; 87:338-44. [PMID: 16406031 DOI: 10.1016/j.physbeh.2005.10.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 08/22/2005] [Accepted: 10/21/2005] [Indexed: 11/28/2022]
Abstract
This study investigated the somatic maturation and ontogeny of reflexes in neonate rats treated with sertraline (Sert) during the suckling period. The animals were divided into four groups; three that received daily doses of Sert (5, 10 or 15 mg/kg s.c.; groups Sert5, Sert10, and Sert15, respectively), and a fourth group that received distilled water (Dw) (1 ml/kg/b.w.). Growth indicators (body weight, axis of the head and tail length) were measured daily, from the 1st to the 21st postnatal day. The reflexes (righting, free-fall righting, negative geotaxis, cliff avoidance, auditory startle response, vibrissa placing and palm grasp) and physical-feature maturation (ear unfolding, auditory conduit opening, irruption of the lower incisors and eye opening) were recorded each day of the animal's life. All groups were compared to the Dw group. The body weight gain was reduced in all the Sert groups. Moreover, a delay in the growth of the body length was observed in all the Sert groups. Higher Sert doses reduced the speed of growth in the tail length. The medio-lateral head axis reduced in Sert15 and Sert5 doses. Otherwise, Sert10 had a temporary acceleration in this growth, but the growth of the anteroposterior head axis had a delay in all the Sert groups. The highest doses induced a delay in physical-feature maturation. The palm grasp reflex (disappearance) was retarded in Sert10; cliff avoidance advanced in Sert10; negative-geotaxis and free-fall righting retarded in Sert15. The findings suggest that altered serotonergic system activity induced by sertraline early in life could play a role in the retardation of the somatic growth ontogeny as well as a delay in the maturation of some reflexes.
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Affiliation(s)
- T C B J Deiró
- Departamento de Nutrição, Centro de Ciências da Saúde, Universidade Federal de Pernambuco (UFPE), Av. Morais Rego, 1235, Cidade Universitária, 50670-901 Recife, PE, Brazil
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Jorge SD, Pobbe RLH, de Paula Soares V, de Oliveira AM, Zangrossi H. Effects of sibutramine on anxiety-related behaviours in rats. Pharmacol Res 2004; 50:517-22. [PMID: 15458773 DOI: 10.1016/j.phrs.2004.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2004] [Indexed: 10/26/2022]
Abstract
Sibutramine is an anorexiant drug that inhibits the reuptake of noradrenaline and serotonin, a pharmacological property shared with drugs clinically effective in treating anxiety pathologies. However, the effects of this compound on experimental and clinical anxiety have not been assessed yet. In this study, we evaluated the effects of sibutramine on anxiety-related behaviours which have been related to specific anxiety disorders. Acute injection of sibutramine (5, 10 or 20 mg kg(-1); intraperitoneally) in male Wistar rats impaired inhibitory avoidance in the elevated T-maze (ETM) and in the light/dark transition test, indicative of an anxiolytic effect. The drug also inhibited one-way escape in the ETM. Sibutramine, however, was ineffective in changing rat performance in the elevated plus-maze. Therefore, sibutramine decreased the expression of defensive behaviours that have been associated with generalized anxiety disorder (inhibitory avoidance) and with panic disorder (one-way escape). Yet, in contrast to what has been reported with drugs such as the tricyclic anti-depressants that also inhibit monoamine reuptake, the anxiolytic effects of sibutramine were revealed after a single administration.
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Affiliation(s)
- Salim Demétrio Jorge
- Department of Pharmacology, School of Medicine, University of São Paulo. Av. Bandeirantes, 3900, 14049-900 Ribeirão Preto, São Paulo, Brazil
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Mennini T, Gobbi M. The antidepressant mechanism of Hypericum perforatum. Life Sci 2004; 75:1021-7. [PMID: 15207650 DOI: 10.1016/j.lfs.2004.04.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Accepted: 04/01/2004] [Indexed: 10/26/2022]
Abstract
Clinical data indicate that hydroalcoholic extracts of Hypericum perforatum might be as valuable as conventional antidepressants in mild-to-moderate depression, with fewer side effects. One clinical trial using two extracts with different hyperforin contents indicated it as the main active principle responsible for the antidepressant activity. Behavioural models in rodents confirm the antidepressant-like effect of Hypericum extracts and also of pure hyperforin and hypericin. A hydroalcoholic extract lacking hyperforin also lacks the antidepressant-like effect. According to pharmacokinetic data and binding studies, it appears that the antidepressant effect of Hypericum extract is unlikely be due to an interaction of hypericin with central neurotransmitter receptors. The main in vitro effects of hyperforin (at concentrations of 0.1-1 microM) are non-specific presynaptic effects, resulting in the non-selective inhibition of the uptake of many neurotransmitters, and the interaction with dopamine D1 and opioid receptors. However, it is still not clear whether these mechanisms can be activated in vivo, since after administration of Hypericum extract brain concentrations of hyperforin are well below those active in vitro. In the rat, Hypericum extract might indirectly activate sigma receptors in vivo (through the formation of an unknown metabolite or production of an endogenous ligand), suggesting a new target for its antidepressant effects.
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Affiliation(s)
- Tiziana Mennini
- Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157, Milano, Italy.
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Mantella RC, Rinaman L, Vollmer RR, Amico JA. Cholecystokinin and D-fenfluramine inhibit food intake in oxytocin-deficient mice. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1037-45. [PMID: 14557235 DOI: 10.1152/ajpregu.00383.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Results from previous studies indicate that oxytocin (OT)-containing neural pathways are activated in laboratory rats after systemic administration of CCK or d-fenfluramine and that centrally released OT may participate in the anorexigenic effects of these treatments. To explore the relationship between feeding behavior and OT function, the effects of CCK and d-fenfluramine on feeding and central c-Fos expression were compared in wild-type (OT+/+) and OT-deficient mice (OT-/-) of C57BL/6 background. Male OT+/+ and OT-/- mice were administered saline or CCK (1, 3, or 10 microg/kg ip) after overnight food deprivation. Saline-treated OT+/+ and OT-/- mice consumed equivalent amounts of food after an overnight fast. CCK inhibited deprivation-induced food intake in a dose-dependent manner to a similar extent in both genotypes. CCK treatment also induced similar hindbrain and forebrain patterns of increased c-Fos expression in mice of both genotypes. After treatment with d-fenfluramine (10 mg/kg ip), both OT+/+ and OT-/- mice consumed significantly less food than untreated controls, with no difference between genotypes. We conclude that OT signaling pathways are unnecessary for the anorexigenic effects of systemically administered CCK and d-fenfluramine in C57BL/6 mice.
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Affiliation(s)
- Rose C Mantella
- Dept. of Pharmaceutical Sciences, Univ. of Pittsburgh, 904 Salk Hall, Pittsburgh, PA 15261, USA.
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Baumann MH, Pablo J, Ali SF, Rothman RB, Mash DC. Comparative neuropharmacology of ibogaine and its O-desmethyl metabolite, noribogaine. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2002; 56:79-113. [PMID: 11705118 DOI: 10.1016/s0099-9598(01)56009-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- M H Baumann
- Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
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