1
|
Deng F, Wan J, Li G, Dong H, Xia X, Wang Y, Li X, Zhuang C, Zheng Y, Liu L, Yan Y, Feng J, Zhao Y, Xie H, Li Y. Improved green and red GRAB sensors for monitoring spatiotemporal serotonin release in vivo. Nat Methods 2024; 21:692-702. [PMID: 38443508 PMCID: PMC11377854 DOI: 10.1038/s41592-024-02188-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 01/19/2024] [Indexed: 03/07/2024]
Abstract
The serotonergic system plays important roles in both physiological and pathological processes, and is a therapeutic target for many psychiatric disorders. Although several genetically encoded GFP-based serotonin (5-HT) sensors were recently developed, their sensitivities and spectral profiles are relatively limited. To overcome these limitations, we optimized green fluorescent G-protein-coupled receptor (GPCR)-activation-based 5-HT (GRAB5-HT) sensors and developed a red fluorescent GRAB5-HT sensor. These sensors exhibit excellent cell surface trafficking and high specificity, sensitivity and spatiotemporal resolution, making them suitable for monitoring 5-HT dynamics in vivo. Besides recording subcortical 5-HT release in freely moving mice, we observed both uniform and gradient 5-HT release in the mouse dorsal cortex with mesoscopic imaging. Finally, we performed dual-color imaging and observed seizure-induced waves of 5-HT release throughout the cortex following calcium and endocannabinoid waves. In summary, these 5-HT sensors can offer valuable insights regarding the serotonergic system in both health and disease.
Collapse
Affiliation(s)
- Fei Deng
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, China
| | - Jinxia Wan
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Guochuan Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Hui Dong
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Xiju Xia
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yipan Wang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Xuelin Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Chaowei Zhuang
- Department of Automation, Tsinghua University, Beijing, China
| | - Yu Zheng
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Laixin Liu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yuqi Yan
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Yulin Zhao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Hao Xie
- Department of Automation, Tsinghua University, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China.
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
| |
Collapse
|
2
|
Peek SI, Meller S, Twele F, Packer RMA, Volk HA. Epilepsy is more than a simple seizure disorder: Parallels between human and canine cognitive and behavioural comorbidities. Vet J 2024; 303:106060. [PMID: 38123061 DOI: 10.1016/j.tvjl.2023.106060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 12/02/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
Psychiatric and cognitive comorbidities have been known to play a major role in human epilepsy for a long time. People with epilepsy (PWE) frequently express signs of varying psychiatric and cognitive disorders affecting their quality and quantity of life (QoL/QaoL). Over the last few years, research on behavioural comorbidities and their effect on the underlying disease have been performed in canine epilepsy. The following article reviews manifestations of comorbidities in canine epilepsy with an emphasis on patterns of clinical signs and their effects on QoL and QaoL. Cognitive and behavioural alterations in epileptic dogs are mainly represented by fear-/anxiety related behaviour and cognitive impairment (CI). Reduced trainability and altered reactions to daily situations are common results of comorbid changes posing obstacles in everyday life of owners and their dog. In addition, clinical signs similar to attention deficit hyperactivity disorder (ADHD) in humans have been reported. Canine attention-deficit-hyperactivity-disorder-like (c-ADHD-like) behaviour should, however, be evaluated critically, as there are no official criteria for diagnosis of ADHD or ADHD-like behaviour in dogs, and some of the reported signs of c-ADHD-like behaviour could be confused with anxiety-associated behaviour. Many intrinsic and extrinsic factors could potentially influence the development of behavioural and cognitive comorbidities in canine epilepsy. In particular, seizure frequency/severity, signalment and factors concerning disease management, such as pharmacotherapy and nutrition, are closely linked with the presence of the aforementioned comorbid disorders. Further studies of behavioural alterations in epileptic dogs are needed to comprehend the complexity of clinical signs and their multifactorial origin.
Collapse
Affiliation(s)
- Saskia I Peek
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | - Sebastian Meller
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | - Friederike Twele
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany
| | | | - Holger A Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Germany.
| |
Collapse
|
3
|
Gu L, Yu Q, Shen Y, Wang Y, Xu Q, Zhang H. The role of monoaminergic neurons in modulating respiration during sleep and the connection with SUDEP. Biomed Pharmacother 2022; 150:112983. [PMID: 35453009 DOI: 10.1016/j.biopha.2022.112983] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/04/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among epilepsy patients, occurring even more frequently in cases with anti-epileptic drug resistance. Despite some advancements in characterizing SUDEP, the underlying mechanism remains incompletely understood. This review summarizes the latest advances in our understanding of the pathogenic mechanisms of SUDEP, in order to identify possible targets for the development of new strategies to prevent SUDEP. Based on our previous research along with the current literature, we focus on the role of sleep-disordered breathing (SDB) and its related neural mechanisms to consider the possible roles of monoaminergic neurons in the modulation of respiration during sleep and the occurrence of SUDEP. Overall, this review suggests that targeting the monoaminergic neurons is a promising approach to preventing SUDEP. The proposed roles of SDB and related monoaminergic neural mechanisms in SUDEP provide new insights for explaining the pathogenesis of SUDEP.
Collapse
Affiliation(s)
- LeYuan Gu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qian Yu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Yue Shen
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - YuLing Wang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qing Xu
- Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - HongHai Zhang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310006, China.
| |
Collapse
|
4
|
Alachkar A, Ojha SK, Sadeq A, Adem A, Frank A, Stark H, Sadek B. Experimental Models for the Discovery of Novel Anticonvulsant Drugs: Focus on Pentylenetetrazole-Induced Seizures and Associated Memory Deficits. Curr Pharm Des 2020; 26:1693-1711. [PMID: 32003682 DOI: 10.2174/1381612826666200131105324] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/30/2019] [Indexed: 02/07/2023]
Abstract
Epilepsy is a chronic neurological disorder characterized by irregular, excessive neuronal excitability, and recurrent seizures that affect millions of patients worldwide. Currently, accessible antiepileptic drugs (AEDs) do not adequately support all epilepsy patients, with around 30% patients not responding to the existing therapies. As lifelong epilepsy treatment is essential, the search for new and more effective AEDs with an enhanced safety profile is a significant therapeutic goal. Seizures are a combination of electrical and behavioral events that can induce biochemical, molecular, and anatomic changes. Therefore, appropriate animal models are required to evaluate novel potential AEDs. Among the large number of available animal models of seizures, the acute pentylenetetrazole (PTZ)-induced myoclonic seizure model is the most widely used model assessing the anticonvulsant effect of prospective AEDs, whereas chronic PTZ-kindled seizure models represent chronic models in which the repeated administration of PTZ at subconvulsive doses leads to the intensification of seizure activity or enhanced seizure susceptibility similar to that in human epilepsy. In this review, we summarized the memory deficits accompanying acute or chronic PTZ seizure models and how these deficits were evaluated applying several behavioral animal models. Furthermore, major advantages and limitations of the PTZ seizure models in the discovery of new AEDs were highlighted. With a focus on PTZ seizures, the major biochemicals, as well as morphological alterations and the modulated brain neurotransmitter levels associated with memory deficits have been illustrated. Moreover, numerous medicinal compounds with concurrent anticonvulsant, procognitive, antioxidant effects, modulating effects on several brain neurotransmitters in rodents, and several newly developed classes of compounds applying computer-aided drug design (CADD) have been under development as potential AEDs. The article details the in-silico approach following CADD, which can be utilized for generating libraries of novel compounds for AED discovery. Additionally, in vivo studies could be useful in demonstrating efficacy, safety, and novel mode of action of AEDs for further clinical development.
Collapse
Affiliation(s)
- Alaa Alachkar
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666 Al Ain, United States.,Zayed Centre for Health Sciences, United Arab Emirates University, Al Ain, United States
| | - Shreesh K Ojha
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666 Al Ain, United States.,Zayed Centre for Health Sciences, United Arab Emirates University, Al Ain, United States
| | - Adel Sadeq
- College of Pharmacy, Al Ain University, Al Ain, United Arab Emirates
| | - Abdu Adem
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666 Al Ain, United States.,Zayed Centre for Health Sciences, United Arab Emirates University, Al Ain, United States
| | - Annika Frank
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstr. 1, 40225 Düsseldorf, Germany
| | - Holger Stark
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstr. 1, 40225 Düsseldorf, Germany
| | - Bassem Sadek
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666 Al Ain, United States.,Zayed Centre for Health Sciences, United Arab Emirates University, Al Ain, United States
| |
Collapse
|
5
|
Banach M, Popławska M, Błaszczyk B, Borowicz KK, Czuczwar SJ. Pharmacokinetic/pharmacodynamic considerations for epilepsy - depression comorbidities. Expert Opin Drug Metab Toxicol 2016; 12:1067-80. [PMID: 27267259 DOI: 10.1080/17425255.2016.1198319] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Epilepsy may be frequently associated with psychiatric disorders and its co-existence with depression usually results in the reduced quality of life of patients with epilepsy. Also, the efficacy of antiepileptic treatment in depressed patients with epilepsy may be significantly reduced. AREAS COVERED Results of experimental studies indicate that antidepressants co-administered with antiepileptic drugs may either increase their anticonvulsant activity, remain neutral or decrease the protective action of antiepileptic drugs in models of seizures. Apart from purely pharmacodynamic interactions, pharmacokinetic mechanisms have been proven to contribute to the final outcome. We report on clinical data regarding the pharmacokinetic interactions of enzyme-inducing antiepileptic drugs with various antidepressants, whose plasma concentration may be significantly reduced. On the other hand, antidepressants (especially selective serotonin reuptake inhibitors) may influence the metabolism of antiepileptics, in many cases resulting in the elevation of plasma concentration of antiepileptic drugs. EXPERT OPINION The preclinical data may provide valuable clues on how to combine these two groups of drugs - antidepressant drugs neutral or potentiating the anticonvulsant action of antiepileptics are recommended in this regard. Avoidance of antidepressants clearly decreasing the convulsive threshold or decreasing the anticonvulsant efficacy of antiepileptic drugs (f.e. bupropion or mianserin) in patients with epilepsy is recommended.
Collapse
Affiliation(s)
- Monika Banach
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Monika Popławska
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Barbara Błaszczyk
- b Faculty of Health Sciences , High School of Economics, Law and Medical Sciences , Kielce , Poland
| | - Kinga K Borowicz
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Stanisław J Czuczwar
- c Department of Pathophysiology , Medical University , Lublin , Poland.,d Department of Physiopathology , Institute of Rural Health , Lublin , Poland
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Fluvoxamine alleviates seizure activity and downregulates hippocampal GAP-43 expression in pentylenetetrazole-kindled mice. Behav Pharmacol 2015; 26:369-82. [DOI: 10.1097/fbp.0000000000000127] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
8
|
Paracetamol potentiates the antidepressant-like and anticompulsive-like effects of fluoxetine. Behav Pharmacol 2015; 26:268-81. [DOI: 10.1097/fbp.0000000000000104] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
9
|
Borowicz KK, Zarczuk R, Latalski M, Borowicz KM. Reboxetine and its influence on the action of classical antiepileptic drugs in the mouse maximal electroshock model. Pharmacol Rep 2014; 66:430-5. [PMID: 24905519 DOI: 10.1016/j.pharep.2013.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 11/07/2013] [Accepted: 11/18/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Our previous studies revealed that different classes of antidepressant drugs differently affect seizure phenomena. Continuing our research in this field, in the present study we wanted to investigate the influence of acute and chronic treatment with reboxetine, a selective norepinephrine reuptake inhibitor, on the anticonvulsant action of classical antiepileptic drugs. METHODS Experiments were conducted in the model of electroconvulsive threshold and maximal electroshock in mice. Motor coordination was evaluated in the chimney test and long term memory in the step-through passive avoidance task. Brain concentrations of antiepileptic drugs were detected by fluorescence polarization immunoassay. RESULTS Acute treatment with reboxetine (8-16 mg/kg) significantly raised the electroconvulsive threshold. In contrast, chronic reboxetine (2-16 mg/kg) did not affect this parameter. Single administration of the antidepressant applied at its subthreshold doses enhanced the action of valproate, carbamazepine and phenobarbital. The antielectroshock effect of phenytoin was also potentiated by acute reboxetine, but only at doses increasing the threshold. Repeated administration of reboxetine (8-12 mg/kg) enhanced the anticonvulsant action of carbamazepine, but not that of three remaining antiepileptic drugs. Neither acute nor chronic reboxetine changed the brain concentrations of valproate, carbamazepine, phenytoin or phenobarbital. Therefore, all revealed interactions seem to be pharmacodynamic. In terms of undesired effects, acute/chronic reboxetine and its combinations with classical antiepileptic drugs did not significantly impair motor performance or long-term memory in mice. CONCLUSIONS As far as the obtained data can be extrapolated into clinical conditions, it seems that reboxetine may be safely used in the treatment of depressive disorders in epileptic patients.
Collapse
Affiliation(s)
- Kinga K Borowicz
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University, Lublin, Poland.
| | - Radosław Zarczuk
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University, Lublin, Poland
| | - Michał Latalski
- Clinic for Children's Orthopaedics, Medical University, Lublin, Poland
| | - Kornel M Borowicz
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University, Lublin, Poland
| |
Collapse
|
10
|
Effect of acute and chronic tianeptine on the action of classical antiepileptics in the mouse maximal electroshock model. Pharmacol Rep 2014; 65:379-88. [PMID: 23744422 DOI: 10.1016/s1734-1140(13)71013-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/02/2012] [Indexed: 01/27/2023]
Abstract
BACKGROUND The aim of the study was to analyze the influence of acute and chronic treatment with tianeptine, an antidepressant selectively accelerating presynaptic serotonin reuptake, on the protective activity of classical antiepileptic drugs in the maximal electroshock test in mice. METHODS Electroconvulsions were produced by means of an alternating current (50 Hz, 25 mA, 0.2 s) delivered via ear-clip electrodes. Motor impairment and long-term memory deficits in animals were quantified in the chimney test and in the passive-avoidance task, respectively. Brain concentrations of antiepileptic drugs were measured by fluorescence polarization immunoassay. RESULTS Acute and chronic treatment with tianeptine (25-50 mg/kg) did not affect the electroconvulsive threshold. Furthermore, tianeptine applied in both acute and chronic protocols enhanced the anticonvulsant action of valproate and carbamazepine, but not that of phenytoin. Neither acute nor chronic tianeptine changed the brain concentrations of valproate, carbamazepine or phenytoin. On the other hand, both single and chronic administration of tianeptine diminished the brain concentration of phenobarbital. In spite of this pharmacokinetic interaction, the antidepressant enhanced the antielectroshock action of phenobarbital. In terms of adverse effects, acute/chronic tianeptine (50 mg/kg) and its combinations with classic antiepileptic drugs did not impair motor performance or long-term memory in mice. CONCLUSION The obtained results justify the conclusion that tianeptine may be beneficial in the treatment of depressive disorders in the course of epilepsy.
Collapse
|
11
|
The antidepressant drug fluoxetine inhibits persistent sodium currents and seizure-like events. Epilepsy Res 2012; 101:174-81. [DOI: 10.1016/j.eplepsyres.2012.03.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 03/12/2012] [Accepted: 03/28/2012] [Indexed: 11/23/2022]
|
12
|
Receptor targets for antidepressant therapy in bipolar disorder: an overview. J Affect Disord 2012; 138:222-38. [PMID: 21601292 DOI: 10.1016/j.jad.2011.04.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 04/27/2011] [Indexed: 11/20/2022]
Abstract
The treatment of bipolar depression is one of the most challenging issues in contemporary psychiatry. Currently only quetiapine and the olanzapine-fluoxetine combination are officially approved by the FDA against this condition. The neurobiology of bipolar depression and the possible targets of bipolar antidepressant therapy remain relatively elusive. We performed a complete and systematic review to identify agents with definite positive or negative results concerning efficacy followed by a second systematic review to identify the pharmacodynamic properties of these agents. The comparison of properties suggests that the stronger predictors for antidepressant efficacy in bipolar depression were norepinephrine alpha-1, dopamine D1 and histamine antagonism, followed by 5-HT2A, muscarinic and dopamine D2 and D3 antagonism and eventually by norepinephrine reuptake inhibition and 5HT-1A agonism. Serotonin reuptake which constitutes the cornerstone in unipolar depression treatment does not seem to play a significant role for bipolar depression. Our exhaustive review is compatible with a complex model with multiple levels of interaction between the major neurotransmitter systems without a single target being either necessary or sufficient to elicit the antidepressant effect in bipolar depression.
Collapse
|
13
|
Igelström KM. Preclinical antiepileptic actions of selective serotonin reuptake inhibitors--implications for clinical trial design. Epilepsia 2012; 53:596-605. [PMID: 22416943 DOI: 10.1111/j.1528-1167.2012.03427.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) can reduce seizure frequency in humans, but no large-scale clinical trials have been done to test the utility of SSRIs as potential antiepileptic drugs. This may be caused in part by a small number of reports on seizures triggered by SSRI treatment. The preclinical literature on SSRIs is somewhat conflicting, which is likely to contribute to the hesitance in accepting SSRIs as possible anticonvulsant drug therapy. A careful review of preclinical studies reveals that SSRIs appear to have region-specific and seizure subtype-specific effects, with models of chronic partial epilepsy being more likely to respond than models of acute generalized seizures. Moreover, this preclinical profile is similar to that of clinical antiepileptic drugs. These observations suggest that SSRIs are promising antiepileptic agents, and that clinical trials may benefit from defining patient groups according to the underlying pathology.
Collapse
Affiliation(s)
- Kajsa M Igelström
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
| |
Collapse
|
14
|
Citraro R, Scicchitano F, De Fazio S, Raggio R, Mainardi P, Perucca E, De Sarro G, Russo E. Preclinical activity profile of α-lactoalbumin, a whey protein rich in tryptophan, in rodent models of seizures and epilepsy. Epilepsy Res 2011; 95:60-9. [PMID: 21458955 DOI: 10.1016/j.eplepsyres.2011.02.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/18/2011] [Accepted: 02/27/2011] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the potential anticonvulsant activity of α-lactalbumin (ALAC), a whey protein rich in tryptophan (TRP) relative to other large neutral amino acids (LNAAs), in rodent models of seizures and epilepsy. METHODS The effects of ALAC administered per os were evaluated by standard protocols against audiogenic seizures in Genetic Epilepsy Prone Rats (GEPR-9 rats), maximal electroshock (MES)-induced seizures in rats, pilocarpine-induced seizures in mice, spontaneous chronic seizures in mice exposed to pilocarpine-induced status epilepticus (SE), and absence seizures in WAG/Rij rats. In some models, carbamazepine (CBZ) was included as an active control. Plasma TRP/LNAAs ratios were measured by GC-MS. RESULTS Single doses of ALAC up to 500 or 6000 mg/kg were devoid of anticonvulsant activity in all models tested. Conversely, 5- and 12-day treatment with ALAC (250-1000 mg/kg/day) in GEPR rats reduced dose-dependently seizure scores and prolonged latency to clonus onset, with full persistence of the effect for up to 12h. ALAC (125-500 mg/kg/day for 15 days) protected against seizures induced by 250 mg/kg pilocarpine, but was less effective against higher pilocarpine doses. Similarly to CBZ, ALAC (125-500 mg/kg/day for 15 days) was also effective against spontaneous seizures in the post-pilocarpine SE model. ALAC (up to 6000 mg/kg/day for 12 days) did not prevent MES-induced seizures, although it reduced the duration of tonic extension at doses between 250 and 1000 mg/kg/day. Absence seizures in WAG/Rij rats were not significantly affected by ALAC. Plasma TRP/LNAAS ratios increased 2- to 3-fold after dosing with ALAC (250 mg/kg/day) for 7 and 14 days, respectively. CONCLUSIONS ALAC exerts significant protective activity against seizures in animal models, the effect being especially prominent against audiogenic seizures in GEPR-9 rats, seizures induced by low-dose pilocarpine in mice, and spontaneous seizures in mice exposed to pilocarpine-induced SE. This action is likely to be mediated by increased availability of TRP in the brain, with a consequent increase in 5-HT mediated transmission.
Collapse
Affiliation(s)
- Rita Citraro
- Chair of Pharmacology, Department of Experimental and Clinical Medicine, School of Medicine, University Magna Graecia of Catanzaro, Via T. Campanella 115, Catanzaro, Italy
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Ohno Y, Sofue N, Imaoku T, Morishita E, Kumafuji K, Sasa M, Serikawa T. Serotonergic Modulation of Absence-Like Seizures in Groggy Rats: a Novel Rat Model of Absence Epilepsy. J Pharmacol Sci 2010; 114:99-105. [DOI: 10.1254/jphs.10156fp] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
16
|
Involvement of the limbic basal ganglia in ethanol withdrawal convulsivity in mice is influenced by a chromosome 4 locus. J Neurosci 2008; 28:9840-9. [PMID: 18815268 DOI: 10.1523/jneurosci.1713-08.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Physiological dependence and associated withdrawal episodes are thought to constitute a motivational force that sustains ethanol (alcohol) use/abuse and may contribute to relapse in alcoholics. Although no animal model duplicates alcoholism, models for specific factors, like the withdrawal syndrome, are useful for identifying potential genetic and neural determinants of liability in humans. We generated congenic mice that confirm a quantitative trait locus (QTL) on chromosome 4 with a large effect on predisposition to alcohol withdrawal. Using c-Fos expression as a high-resolution marker of neuronal activation, congenic mice demonstrated significantly less neuronal activity associated with ethanol withdrawal than background strain mice in the substantia nigra pars reticulata (SNr), subthalamic nucleus (STN), rostromedial lateral globus pallidus, and ventral pallidum. Notably, neuronal activation in subregions of the basal ganglia associated with limbic function was more intense than in subregions associated with sensorimotor function. Bilateral lesions of caudolateral SNr attenuated withdrawal severity after acute and repeated ethanol exposures, whereas rostrolateral SNr and STN lesions did not reduce ethanol withdrawal severity. Caudolateral SNr lesions did not affect pentylenetetrazol-enhanced convulsions. Our results suggest that this QTL impacts ethanol withdrawal via basal ganglia circuitry associated with limbic function and that the caudolateral SNr plays a critical role. These are the first analyses to elucidate circuitry by which a confirmed addiction-relevant QTL influences behavior. This mouse QTL is syntenic with human chromosome 9p. Given the growing body of evidence that a gene(s) on chromosome 9p influences alcoholism, our results can facilitate human research on alcohol dependence and withdrawal.
Collapse
|
17
|
Serotonin hyperinnervation abolishes seizure susceptibility in Otx2 conditional mutant mice. J Neurosci 2008; 28:9271-6. [PMID: 18784307 DOI: 10.1523/jneurosci.2208-08.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The homeobox-containing transcription factor Otx2 is crucially involved in fate determination of midbrain neurons. Mutant mice, in which Otx2 was conditionally inactivated by a Cre recombinase expressed under the transcriptional control of the Engrailed1 (En1) gene (En1(cre/+); Otx2(flox/flox)), show a reduced number of dopaminergic neurons and an increased number of serotonergic neurons in the ventral midbrain. Despite these developmental anatomical alterations, En1(cre/+); Otx2(flox/flox) adult mice display normal motor function. Here, we further investigated the neurological consequences of Otx2 inactivation in adult En1(cre/+); Otx2(flox/flox) mice. Adult En1(cre/+); Otx2(flox/flox) mice showed increased serotonin (5-HT) levels in the pons, ventral midbrain, hippocampus (CA3 subfield), and cerebral cortex, as indicated by HPLC and immunohistochemistry. Conversely, SERT (5-HT transporter) levels were decreased in conditional mutant brains. As a consequence of this increased 5-HT hyperinnervation, En1(cre/+); Otx2(flox/flox) mice were resistant to generalized seizures induced by the glutamate agonist kainic acid (KA). Indeed, prolonged pretreatment of En1(cre/+); Otx2(flox/flox) mice with the 5-HT synthesis inhibitor para-chlorophenylalanine (pCPA) restored brain 5-HT content to control levels, fully reestablishing KA seizure susceptibility. Accordingly, c-fos mRNA induction after KA was restricted to the hippocampus in En1(cre/+); Otx2(flox/flox) mice, whereas a widespread c-fos mRNA labeling was observed throughout the brain of En1(cre/+); Otx2(flox/flox) mice pretreated with pCPA. These results clearly show that increased brain 5-HT levels are responsible for seizure resistance in En1(cre/+); Otx2(flox/flox) mice and confirm the important role of 5-HT in the control of seizure spread.
Collapse
|
18
|
Sung MJ, Ahn HS, Hahn SJ, Choi BH. Open channel block of Kv3.1 currents by fluoxetine. J Pharmacol Sci 2008; 106:38-45. [PMID: 18187934 DOI: 10.1254/jphs.fp0070759] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The action of fluoxetine, a serotonin reuptake inhibitor, on the cloned neuronal rat Kv3.1 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Fluoxetine reduced Kv3.1 whole-cell currents in a reversible, concentration-dependent manner, with an IC(50) value and a Hill coefficient of 13.4 muM and 1.4, respectively. Fluoxetine accelerated the decay rate of inactivation of Kv3.1 currents without modifying the kinetics of current activation. The inhibition increased steeply between 0 and +30 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to +30 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance delta of 0.38. The binding (k(+1)) and dissociation (k(-1)) rate constants for fluoxetine-induced block of Kv3.1 were 5.7 microM(-1)s(-1) and 53.5 s(-1), respectively. The theoretical K(D) value derived by k(-1)/k(+1) yielded 9.3 microM. Fluoxetine did not affect the ion selectivity of Kv3.1. Fluoxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of fluoxetine, were superimposed. Inhibition of Kv3.1 by fluoxetine was use-dependent. The present results suggest that fluoxetine acts on Kv3.1 currents as an open-channel blocker.
Collapse
Affiliation(s)
- Min Ji Sung
- Department of Pharmacology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju, Chonbuk, Republic of Korea
| | | | | | | |
Collapse
|
19
|
Fox MA, Andrews AM, Wendland JR, Lesch KP, Holmes A, Murphy DL. A pharmacological analysis of mice with a targeted disruption of the serotonin transporter. Psychopharmacology (Berl) 2007; 195:147-66. [PMID: 17712549 DOI: 10.1007/s00213-007-0910-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 06/28/2007] [Indexed: 12/16/2022]
Abstract
RATIONALE Partial or complete ablation of serotonin transporter (SERT) expression in mice leads to altered responses to serotonin receptor agonists and other classes of drugs. OBJECTIVES In the current report, we review and integrate many of the major behavioral, physiological, and neurochemical findings in the current literature regarding pharmacological assessments made in SERT mutant mice. RESULTS The absence of normal responses to serotonin reuptake inhibiting (SRI) antidepressants in SERT knockout (-/-) mice demonstrates that actions on SERT are a critical principle mechanism of action of members of this class of antidepressants. Drugs transported by SERT, (+)-3,4-methylenedioxymethamphetamine (MDMA) and 1-methyl-4-(2'-aminophenyl)-1,2,3,6-tetrahydropyridine (2'-NH(2)-MPTP), are also inactive in SERT -/- mice. Temperature, locomotor, and electrophysiological responses to various serotonin receptor agonists, including 8-hydroxy-2-(di-n-propylamino)-tetraline (8-OH-DPAT), ipsapirone, and RU24969, are reduced in SERT -/- mice, despite comparatively lesser reductions in Htr1a and Htr1b binding sites, G-proteins, and other signaling molecules. SERT -/- mice exhibit an approximately 90% reduction in head twitches in response to the Htr2a/2c agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), associated with a profound reduction in arachidonic acid signaling, yet only modest changes in Htr2a and Htr2c binding sites. SERT -/- mice also exhibit altered behavioral responses to cocaine and ethanol, related to abnormal serotonin, and possibly dopamine and norepinephrine, homeostasis. CONCLUSIONS Together, these studies demonstrate a complex and varied array of modified drug responses after constitutive deletion of SERT and provide insight into the role of serotonin, and in particular, its transporter, in the modulation of complex behavior and in the pharmacological actions of therapeutic agents and drugs of abuse.
Collapse
Affiliation(s)
- Meredith A Fox
- Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, Building 10, Room 3D41, Bethesda, MD 20892, USA.
| | | | | | | | | | | |
Collapse
|
20
|
Kondziella D, Alvestad S, Vaaler A, Sonnewald U. Which clinical and experimental data link temporal lobe epilepsy with depression? J Neurochem 2007; 103:2136-52. [PMID: 17887964 DOI: 10.1111/j.1471-4159.2007.04926.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The association of temporal lobe epilepsy with depression and other neuropsychiatric disorders has been known since the early beginnings of neurology and psychiatry. However, only recently have in vivo and ex vivo techniques such as Positron Emission Tomography, Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in combination with refined animal models and behavioral tests made it possible to identify an emerging pattern of common pathophysiological mechanisms. We now have growing evidence that in both disorders altered interaction of serotonergic and noradrenergic neurons with glutamatergic systems is associated with abnormal neuronal circuits and hyperexcitability. Neuronal hyperexcitability can possibly evoke seizure activity as well as disturbed emotions. Moreover, decreased synaptic levels of neurotransmitters and high glucocorticoid levels influence intracellular signaling pathways such as cAMP, causing disturbances of brain-derived and other neurotrophic factors. These may be associated with hippocampal atrophy seen on Magnetic Resonance Imaging and memory impairment as well as altered fear processing and transient hypertrophy of the amygdala. Positron Emission Tomography studies additionally suggest hypometabolism of glucose in temporal and frontal lobes. Last, but not least, in temporal lobe epilepsy and depression astrocytes play a role that reaches far beyond their involvement in hippocampal sclerosis and ultimately, therapeutic regulation of glial-neuronal interactions may be a target for future research. All these mechanisms are strongly intertwined and probably bidirectional such that the structural and functional alterations from one disease increase the risk for developing the other. This review provides an integrative update of the most relevant experimental and clinical data on temporal lobe epilepsy and its association with depression.
Collapse
Affiliation(s)
- Daniel Kondziella
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
| | | | | | | |
Collapse
|
21
|
Martinez RCR, Ribeiro de Oliveira A, Brandão ML. Serotonergic mechanisms in the basolateral amygdala differentially regulate the conditioned and unconditioned fear organized in the periaqueductal gray. Eur Neuropsychopharmacol 2007; 17:717-24. [PMID: 17398077 DOI: 10.1016/j.euroneuro.2007.02.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2006] [Revised: 02/14/2007] [Accepted: 02/20/2007] [Indexed: 01/19/2023]
Abstract
The amygdala is an important filter for unconditioned and conditioned aversive information. The amygdala synthesizes the stimuli input from the environment and then signals the degree of threat that they represent to the dorsal periaqueductal gray (dPAG), which would be in charge of selecting, organizing and executing the appropriate defense reaction. In this study, we examined the influence of fluoxetine microinjections (1.75 and 3.5 nmol/0.2 microL) into the lateral (LaA) and basolateral (BLA) amygdaloid nuclei on the freezing and escape responses induced by electrical stimulation of the dPAG. Freezing behavior was also measured after the interruption of the electrical stimulation of the dPAG. On the following day, these rats were also submitted to a contextual fear paradigm to examine whether these microinjections would affect the conditioned freezing to contextual cues previously associated with foot shocks. Fluoxetine injections into both amygdaloid nuclei did not change the freezing and escape thresholds, but disrupted the dPAG-post-stimulation freezing. Moreover, the conditioned freezing was enhanced by fluoxetine. Whereas 5-HT mechanisms in the amygdala facilitate the acquisition of conditioned fear they inhibit the dPAG-post-stimulation freezing. However, the unconditioned fear triggered by activation of the dPAG is produced downstream of the amygdala. These findings have important implications for the understanding of the neurochemical substrates that underlie panic and generalized anxiety disorders.
Collapse
|
22
|
Alper K, Schwartz KA, Kolts RL, Khan A. Seizure incidence in psychopharmacological clinical trials: an analysis of Food and Drug Administration (FDA) summary basis of approval reports. Biol Psychiatry 2007; 62:345-54. [PMID: 17223086 DOI: 10.1016/j.biopsych.2006.09.023] [Citation(s) in RCA: 287] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/08/2006] [Accepted: 09/25/2006] [Indexed: 12/20/2022]
Abstract
BACKGROUND Clinical trial data provide an approach to the investigation of the effects of psychopharmacological agents, and psychiatric disorders themselves, on seizure threshold. METHODS We accessed public domain data from Food and Drug Administration (FDA) Phase II and III clinical trials as Summary Basis of Approval (SBA) reports that noted seizure incidence in trials of psychotropic drugs approved in the United States between 1985 and 2004, involving a total of 75,873 patients. We compared seizure incidence among active drug and placebo groups in psychopharmacological clinical trials and the published rates of unprovoked seizures in the general population. RESULTS Increased seizure incidence was observed with antipsychotics that was accounted for by clozapine and olanzapine, and with drugs indicated for the treatment of OCD that was accounted for by clomipramine. Alprazolam, bupropion immediate release (IR) form, and quetiapine were also associated with higher seizure incidence. The incidence of seizures was significantly lower among patients assigned to antidepressants compared to placebo (standardized incidence ratio = .48; 95% CI, .36- .61). In patients assigned to placebo, seizure incidence was greater than the published incidence of unprovoked seizures in community nonpatient samples. CONCLUSIONS Proconvulsant effects are associated with a subgroup of psychotropic drugs. Second-generation antidepressants other than bupropion have an apparent anticonvulsant effect. Depression, psychotic disorders, and OCD are associated with reduced seizure threshold.
Collapse
Affiliation(s)
- Kenneth Alper
- Department of Psychiatry, Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY 10016, USA.
| | | | | | | |
Collapse
|
23
|
Sheridan J, Butler R, Wilkins C, Russell B. Legal piperazine-containing party pills--a new trend in substance misuse. Drug Alcohol Rev 2007; 26:335-43. [PMID: 17454024 DOI: 10.1080/09595230701255791] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In this Harm Reduction Digest Sheridan, Butler, Wilkins and Russell address the emergent phenomenon of so-called 'legal party pills' which have become a significant drug issue in New Zealand and elsewhere. Although banned in a number of countries, they are currently legally available in New Zealand where they are marketed as 'safe' alternatives' to 'illicit' drugs often used in the dance scene such as MDMA and amphetamines. The authors describe the availability and use of these substances in New Zealand, summarize what is known about their effects, and speculate on harm reduction interventions and mechanisms of control and their possible sequelae. The paper provides a timely account of an emerging drug issue of relevance to harm reduction internationally.
Collapse
Affiliation(s)
- Janie Sheridan
- The School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand.
| | | | | | | |
Collapse
|
24
|
Kim DS, Kim JE, Kwak SE, Kim DW, Choi SY, Kwon OS, Kang TC. Seizure activity selectively reduces 5-HT1A receptor immunoreactivity in CA1 interneurons in the hippocampus of seizure-prone gerbils. Brain Res 2007; 1154:181-93. [PMID: 17493597 DOI: 10.1016/j.brainres.2007.03.084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 03/29/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Since the correlation between the serotonin (5-hydroxytryptamine, 5-HT) system and seizure activity remains to be clarified, we investigated the 5-HT system in the hippocampus of seizure-resistant (SR) and seizure-sensitive (SS) gerbils. There was no difference of the 5-HT system in the hippocampi of young animals (predisposed and juvenile gerbils) in both SR and SS gerbils. 5-HT immunoreactivity in the dorsal raphe nucleus and the median raphe nucleus was also similarly detected in both animal groups. As compared to SR adult gerbils, only 5-HT1A receptor immunoreactivity was selectively reduced in CA1 interneurons within SS adult gerbils. (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin (a 5-HT1A receptor agonist, 1 and 2 mg/kg) markedly reduced paired-pulse inhibition in the CA1 region of SS adult gerbils only. These findings suggest that the selective reduction in 5-HT1A receptor expression on CA1 interneurons of SS adult gerbil may not be developmental defects, but be an acquired compensatory change induced by repeated seizure activity.
Collapse
Affiliation(s)
- Duk-Soo Kim
- Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, South Korea
| | | | | | | | | | | | | |
Collapse
|
25
|
Borowicz KK, Furmanek-Karwowska K, Sawicka K, Luszczki JJ, Czuczwar SJ. Chronically administered fluoxetine enhances the anticonvulsant activity of conventional antiepileptic drugs in the mouse maximal electroshock model. Eur J Pharmacol 2007; 567:77-82. [PMID: 17481604 DOI: 10.1016/j.ejphar.2007.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 03/08/2007] [Accepted: 03/13/2007] [Indexed: 10/23/2022]
Abstract
Interactions between chronically administered fluoxetine and valproate, carbamazepine, phenytoin, or phenobarbital were studied in the maximal electroshock test in mice. Fluoxetine administered for 14 days at doses up to 20 mg/kg failed to affect the electroconvulsive threshold. Nevertheless the drug (at 15 and 20 mg) enhanced the anticonvulsant activity of valproate, carbamazepine, and phenytoin. When applied at 20 mg/kg, it potentiated the protective action of phenobarbital. Fluoxetine, antiepileptic drugs, and their combinations did not produce significant adverse effects evaluated in the chimney test (motor coordination) and passive-avoidance task (long-term memory). Chronically applied fluoxetine significantly increased the brain concentrations of valproate, carbamazepine, phenobarbital and phenytoin, indicating a pharmacokinetic contribution to the observed pharmacodynamic interactions. In conclusion, long-term treatment with fluoxetine exhibited some favorable effects on the anticonvulsant properties of conventional antiepileptic drugs, resulting, however, from pharmacokinetic interactions.
Collapse
Affiliation(s)
- Kinga K Borowicz
- Department of Pathophysiology, Lublin Medical University, Jaczewskiego 8, 20-090 Lublin, Poland.
| | | | | | | | | |
Collapse
|
26
|
Abstract
In recent years, there has been increasing evidence that serotonergic neurotransmission modulates a wide variety of experimentally induced seizures. Generally, agents that elevate extracellular serotonin (5-HT) levels, such as 5-hydroxytryptophan and serotonin reuptake blockers, inhibit both focal and generalized seizures, although exceptions have been described, too. Conversely, depletion of brain 5-HT lowers the threshold to audiogenically, chemically and electrically evoked convulsions. Furthermore, it has been shown that several anti-epileptic drugs increase endogenous extracellular 5-HT concentration. 5-HT receptors are expressed in almost all networks involved in epilepsies. Currently, the role of at least 5-HT(1A), 5-HT(2C), 5-HT(3) and 5-HT(7) receptor subtypes in epileptogenesis and/or propagation has been described. Mutant mice lacking 5-HT(1A) or 5-HT(2C) receptors show increased seizure activity and/or lower threshold. In general, hyperpolarization of glutamatergic neurons by 5-HT(1A) receptors and depolarization of GABAergic neurons by 5-HT(2C) receptors as well as antagonists of 5-HT(3) and 5-HT(7) receptors decrease the excitability in most, but not all, networks involved in epilepsies. Imaging data and analysis of resected tissue of epileptic patients, and studies in animal models all provide evidence that endogenous 5-HT, the activity of its receptors, and pharmaceuticals with serotonin agonist and/or antagonist properties play a significant role in the pathogenesis of epilepsies.
Collapse
Affiliation(s)
- Gyorgy Bagdy
- Laboratory of Neurochemistry and Experimental Medicine, National Institute of Psychiatry and Neurology, Budapest, Hungary.
| | | | | | | |
Collapse
|
27
|
Wesołowska A, Nikiforuk A, Chojnacka-Wójcik E. Anticonvulsant effect of the selective 5-HT1B receptor agonist CP 94253 in mice. Eur J Pharmacol 2006; 541:57-63. [PMID: 16765343 DOI: 10.1016/j.ejphar.2006.04.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 04/27/2006] [Accepted: 04/28/2006] [Indexed: 11/25/2022]
Abstract
The effect of the selective 5-hydroxytryptamine1B (5-HT1B) receptor agonist 5-propoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-pyrrolo[3,2-b]pyridine (CP 94253) and the 5-HT1A/1B/1D receptor agonist 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridyl)-1H-indole (RU 24969) in maximal electroshock- and pentylenetetrazol-induced seizures in mice was examined. CP 94253 (10-40 mg/kg) afforded no protection against maximal electroshock-evoked convulsions, but produced anticonvulsant action in the pentylenetetrazol-induced seizures (ED50 = 29 mg/kg). The anticonvulsant effect of CP 94253 was abolished by the selective 5-HT1B receptor antagonist N-[3-(2-dimethylamino)ethoxy-4-methoxyphenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)-(1,1'-biphenyl)-4-carboxamide (SB 216641; 20 mg/kg) but it was maintained following the p-chlorophenylalanine (p-CPA; 3 x 300 mg/kg)-induced 5-HT depletion. Interestingly, CP 94253 potentiated the anticonvulsant activity of diazepam in the pentylenetetrazol test; on the other hand, the benzodiazepine receptor antagonist, flumazenil (10 mg/kg), did not modify the anticonvulsant effect of CP 94253. RU 24969 (5 mg/kg) evoked no effect in the maximal electroshock model, but it produced anticonvulsant activity in the pentylenetetrazol assay, the latter effect being attenuated by the selective 5-HT1A receptor antagonist N-(2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl)-N-(2-pyridyl)-cyclohexanecarboxamide (WAY 100635; 0.3 mg/kg) and SB 216641 (10-20 mg/kg). The obtained results suggest that CP 94253 exerts anticonvulsant activity on pentylenetetrazol-induced seizures in mice, as a consequence of stimulation of 5-HT1B receptors (probably located postsynaptically and/or as heteroreceptors); the antiseizure activity of RU 24969 seems to depend on the stimulation of both 5-HT1A and 5-HT1B receptors.
Collapse
Affiliation(s)
- Anna Wesołowska
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, Kraków, PL 31-343, Poland
| | | | | |
Collapse
|
28
|
Pinna G, Costa E, Guidotti A. Fluoxetine and norfluoxetine stereospecifically and selectively increase brain neurosteroid content at doses that are inactive on 5-HT reuptake. Psychopharmacology (Berl) 2006; 186:362-72. [PMID: 16432684 DOI: 10.1007/s00213-005-0213-2] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 09/23/2005] [Indexed: 11/29/2022]
Abstract
It has recently become more clearly understood that in human brain pathophysiology, neurosteroids play a role in anxiety disorders, premenstrual syndrome, postpartum depression, posttraumatic stress disorder, and depression. In the treatment of major depression, recent clinical studies indicate that the pharmacological profiles of fluoxetine and fluvoxamine are correlated with the ability of these drugs to increase the brain and cerebrospinal fluid content of allopregnanolone (Allo), a potent positive allosteric modulator of gamma-aminobutyric acid (GABA) action at GABAA receptors. Thus, the neurosteroid-induced positive allosteric modulation of GABA action at GABAA receptors is facilitated by fluoxetine or its congeners (i.e., paroxetine, fluvoxamine, sertraline), which may not block 5-HT reuptake at the doses currently prescribed in the clinic. However, these doses are effective in the treatment of premenstrual dysphoria, anxiety, and depression. In socially isolated mice, we tested the hypothesis that fluoxetine, norfluoxetine, and other specific serotonin reuptake inhibitor (SSRI) congeners stereoselectively upregulate neurosteroid content at doses insufficient to inhibit 5-HT reuptake; although they potentiate pentobarbital-induced sedation and exert antiaggressive action. Very importantly, the inhibition of 5-HT reuptake lacks stereospecificity and requires fluoxetine and norfluoxetine doses that are 50-fold greater than those required to increase brain Allo content, potentiate the action of pentobarbital, or antagonize isolation-induced aggression. Based on these findings, it could be inferred that the increase of brain Allo content elicited by fluoxetine and norfluoxetine, rather than the inhibition selective of 5-HT reuptake, may be operative in the fluoxetine-induced remission of the behavioral abnormalities associated with mood disorders. Therefore, the term "SSRI" may be misleading in defining the pharmacological profile of fluoxetine and its congeners. To this extent, the term "selective brain steroidogenic stimulants" (SBSSs) could be proposed.
Collapse
Affiliation(s)
- Graziano Pinna
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, 1601 W. Taylor Street, Chicago, IL 60612, USA.
| | | | | |
Collapse
|
29
|
Jobe PC, Browning RA. The serotonergic and noradrenergic effects of antidepressant drugs are anticonvulsant, not proconvulsant. Epilepsy Behav 2005; 7:602-19. [PMID: 16169281 DOI: 10.1016/j.yebeh.2005.07.014] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 07/19/2005] [Indexed: 11/22/2022]
Abstract
Contrary to existing evidence, convulsant liability of the antidepressants has been attributed to noradrenergic and serotonergic increments. This is a classic case of confusing treatment effects with the manifestations of illness. In fact, the remarkable anticonvulsant effectiveness of antidepressant-induced noradrenergic and serotonergic activation has been ignored. Some antidepressant drugs such as the specific serotonin reuptake inhibitor (SSRI) fluoxetine may be devoid of convulsant liability entirely, while having distinct anticonvulsant properties. Some authorities advance the notion that the seizure predisposition of patients with epilepsy increases risks for antidepressant-induced seizures. However, evidence does not support this contention. Instead, data increasingly support the concept that noradrenergic and serotonergic deficiencies contribute to seizure predisposition. Indeed, the antidepressants have the potential to overcome seizure predisposition in epilepsy. Whereas therapeutic doses of antidepressants elevate noradrenergic and serotonergic transmission, larger doses can activate other biological processes that may be convulsant.
Collapse
Affiliation(s)
- Phillip C Jobe
- University of Illinois College of Medicine, Peoria, IL, USA.
| | | |
Collapse
|
30
|
Stean TO, Atkins AR, Heidbreder CA, Quinn LP, Trail BK, Upton N. Postsynaptic 5-HT1B receptors modulate electroshock-induced generalised seizures in rats. Br J Pharmacol 2005; 144:628-35. [PMID: 15678098 PMCID: PMC1576040 DOI: 10.1038/sj.bjp.0706027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Although an important regulatory role for serotonin (5-HT) in seizure activation and propagation is well established, relatively little is known of the function of specific 5-HT receptor subtypes on seizure modulation. 2. The aim of the present study was to investigate the role of 5-HT(1A, 1B and 1D) receptors in modulating generalised seizures in the rat maximal electroshock seizure threshold (MEST) test. 3. The mixed 5-HT receptor agonists SKF 99101 (5-20 mg kg(-1) i.p.) and RU 24969 (1-5 mg kg(-1) i.p.), 0.5 h pretest, both produced marked dose-related increases in seizure threshold. These agents share high affinity for 5-HT(1A, 1B and 1D) receptors. 4. Antiseizure effects induced by submaximal doses of these agonists were maintained following p-chlorophenylalanine (150 mg kg(-1) i.p. x 3 days)-induced 5-HT depletion. 5. The anticonvulsant action of both SKF 99101 (15 mg kg(-1) i.p.) and RU 24969 (2.5 mg kg(-1) i.p.) was dose-dependently abolished by the selective 5-HT1B receptor antagonist SB-224289 (0.1-3 mg kg(-1) p.o., 3 h pretest) but was unaffected by the selective 5-HT1A receptor antagonist WAY 100635 (0.01-0.3 mg kg(-1) s.c., 1 h pretest). This indicates that 5-HT1B receptors are primarily involved in mediating the anticonvulsant properties of these agents. 6. In addition, the ability of the 5-HT(1B/1D) receptor antagonist GR 127935 (0.3-3 mg kg(-1) s.c., 60 min pretest) to dose-dependently inhibit SKF 99101-induced elevation of seizure threshold also suggests possible downstream involvement of 5-HT1D receptors in the action of this agonist, although confirmation awaits the identification of a selective 5-HT1D receptor antagonist. 7. Overall, these data demonstrate that stimulation of postsynaptic 5-HT1B receptors inhibits electroshock-induced seizure spread in rats.
Collapse
Affiliation(s)
- Tania O Stean
- Neurology & GI-CEDD, GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW.
| | | | | | | | | | | |
Collapse
|
31
|
Pericić D, Lazić J, Svob Strac D. Anticonvulsant effects of acute and repeated fluoxetine treatment in unstressed and stressed mice. Brain Res 2005; 1033:90-5. [PMID: 15680343 DOI: 10.1016/j.brainres.2004.11.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2004] [Indexed: 10/26/2022]
Abstract
Comorbidity of epilepsy and depression is not rare. Stress can affect both depression and seizures. Therefore, it is important to know whether an antidepressant drug has pro- or anticonvulsant properties and whether these properties will be modified by stress. We tested the effects of the antidepressant drug fluoxetine on the seizure threshold for picrotoxin in unstressed and swim-stressed mice. The mice were, prior to exposure to swim stress and the intravenous infusion of picrotoxin (a non-competitive GABA(A) receptor antagonist), pretreated with fluoxetine (a selective serotonin reuptake inhibitor), either acutely or repeatedly (5 days), and the latency to the onset of two convulsant signs and death was registered. The convulsant signs were running/bouncing clonus and tonic hindlimb extension. As expected, swim stress enhanced the seizure threshold for picrotoxin. Fluoxetine (20 mg/kg ip) given acutely increased in unstressed and swim-stressed mice the dose of picrotoxin producing tonic hindlimb extension and in unstressed mice the dose of picrotoxin producing death. Neither 10 nor 20 mg/kg of fluoxetine affected doses of picrotoxin needed to produce running bouncing/clonus. Repeated treatment with fluoxetine (20 mg/kg ip) enhanced significantly in unstressed and swim-stressed mice doses of picrotoxin needed to produce tonic hindlimb extension and death, and in stressed mice also the dose of picrotoxin producing running/bouncing clonus. The results demonstrate that the antidepressant drug fluoxetine, given acutely or repeatedly, shows anticonvulsant properties against convulsions induced in unstressed and swim-stressed mice by antagonist of GABA(A) receptors, picrotoxin. Swim stress failed to modify the anticonvulsant properties of fluoxetine.
Collapse
Affiliation(s)
- Danka Pericić
- Laboratory for Molecular Neuropharmacology, Division of Molecular Medicine, Ruder Bosković Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb, Croatia.
| | | | | |
Collapse
|
32
|
Dubrovsky BO. Steroids, neuroactive steroids and neurosteroids in psychopathology. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:169-92. [PMID: 15694225 DOI: 10.1016/j.pnpbp.2004.11.001] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2004] [Indexed: 10/26/2022]
Abstract
The term "neurosteroid" (NS) was introduced by Baulieu in 1981 to name a steroid hormone, dehydroepiandrosterone sulfate (DHEAS), that was found at high levels in the brain long after gonadectomy and adrenalectomy, and shown later to be synthetized by the brain. Later, androstenedione, pregnenolone and their sulfates and lipid derivatives as well as tetrahydrometabolites of progesterone (P) and deoxycorticosterone (DOC) were identified as neurosteroids. The term "neuroactive steroid" (NAS) refers to steroids which, independent of their origin, are capable of modifying neural activities. NASs bind and modulate different types of membrane receptors. The GABA and sigma receptor complexes have been the most extensively studied, while glycine-activated chloride channels, nicotinic acetylcholine receptors, voltage-activated calcium channels, although less explored, are also modulated by NASs. Within the glutamate receptor family, N-methyl-d-aspartate (NMDA) receptors, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and kainate receptors have also been demonstrated to be a target for steroid modulation. Besides their membrane effects, once inside the neuron oxidation of Ring A reduced pregnanes, THP and THDOC, bind to the progesterone intracellular receptor and regulate gene expression through this path. The involvement of NASs on depression syndromes, anxiety disorders, stress responses to different stress stimuli, memory processes and related phenomena such as long-term potentiation are reviewed and critically evaluated. The importance of context for the interpretation of behavioral effects of hormones as well as for hormonal levels in body fluids is emphasized. Some suggestions for further research are given.
Collapse
Affiliation(s)
- Bernardo O Dubrovsky
- McGill University, 3445 Drummond Street, #701, Montreal, Quebec, H3G 1X9, Canada.
| |
Collapse
|
33
|
Giorgi FS, Pizzanelli C, Ferrucci M, Lazzeri G, Faetti M, Giusiani M, Pontarelli F, Busceti CL, Murri L, Fornai F. Previous exposure to (±) 3,4-methylenedioxymethamphetamine produces long-lasting alteration in limbic brain excitability measured by electroencephalogram spectrum analysis, brain metabolism and seizure susceptibility. Neuroscience 2005; 136:43-53. [PMID: 16203101 DOI: 10.1016/j.neuroscience.2005.07.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 07/04/2005] [Accepted: 07/19/2005] [Indexed: 11/30/2022]
Abstract
Seizures represent the most common neurological emergency in ecstasy abusers; however, no study addressed whether (+/-) 3,4-methylenedioxymethamphetamine ("ecstasy") per se might produce long-lasting alterations in brain excitability related to a pro-convulsant effect. C57 Black mice were treated with three regimens of (+/-) 3,4-methylenedioxymethamphetamine (5mg/kg x 2 for 1, 2 or three consecutive days). Following the last dose of (+/-) 3,4-methylenedioxymethamphetamine, during a time interval of 8 weeks, the following procedures were carried out: 1) cortical electroencephalographic recordings, including power-spectrum analysis; 2) administration of sub-threshold doses of kainate; 3) measurement of regional [(14)C]2-deoxyglucose uptake; 4) monoamine assay. We demonstrate that all mice pre-treated with (+/-) 3,4-methylenedioxymethamphetamine showed long-lasting encephalographic changes with frequencies peaking at 3-4.5 Hz at the power-spectrum analysis. This is concomitant with latent brain hyperexcitability within selected limbic brain regions, as shown by seizure facilitation and long-lasting latent metabolic hyperactivity which can be unraveled by phasic glutamate stimulation. This study sheds new light into the brain targets of (+/-) 3,4-methylenedioxymethamphetamine and discloses the occurrence of (+/-) 3,4-methylenedioxymethamphetamine-induced latent hyperexcitability within limbic areas, while it might provide a model to study in controlled experimental conditions limbic seizures and status epilepticus in C57 Black mice. Persistent changes produced by (+/-) 3,4-methylenedioxymethamphetamine in limbic brain excitability might be responsible for seizures and limbic-related disorders in chronic (+/-) 3,4-methylenedioxymethamphetamine abusers.
Collapse
Affiliation(s)
- F S Giorgi
- Department of Human Morphology and Applied Biology, University of Pisa, Via Roma 55, 56126 Pisa, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Ugale RR, Mittal N, Hirani K, Chopde CT. Essentiality of central GABAergic neuroactive steroid allopregnanolone for anticonvulsant action of fluoxetine against pentylenetetrazole-induced seizures in mice. Brain Res 2004; 1023:102-11. [PMID: 15364024 DOI: 10.1016/j.brainres.2004.07.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2004] [Indexed: 11/16/2022]
Abstract
Fluoxetine, a selective serotonin reuptake inhibitor, is known to increase the cortical content of allopregnanolone (ALLO) without altering the level of other neurosteroids. In contrast to the proconvulsant effect of many antidepressants, fluoxetine exhibits anticonvulsant effects. The present study was undertaken to examine the role of ALLO in the anticonvulsant action of fluoxetine against pentylenetetrazole (PTZ)-induced seizures in mice. Prior administration of GABA(A) receptor agonist muscimol or neurosteroid ALLO or progesterone, a precursor of ALLO or neurosteroidogenic drugs like FGIN 1-27, an agonist at the mitochondrial diazepam binding inhibitor receptor (MDR) or metyrapone, an 11beta-hydroxylase inhibitor, significantly potentiated the anticonvulsant effect of fluoxetine. In contrast, the effect of fluoxetine was counteracted by inhibition of the neurosteroid biosynthesis using drugs like 5alpha-reductase inhibitor, finasteride; 3beta-hydroxysteroid dehydrogenase inhibitor, trilostane; 3alpha-hydroxysteroid dehydrogenase inhibitor, indomethacin; MDR antagonist, PK 11195; or the GABA(A) receptor antagonist, bicuculline. Further, bilateral adrenalectomy had no significant effect on the anticonvulsant action of fluoxetine, suggesting negligible contribution from peripheral steroidogenesis. The anticonvulsant effect of fluoxetine was partially abolished in 5,7-DHT treated mice, indicating that the effect may also, in part, be dependent on serotonergic transmission. Thus, our data indicate that increased synthesis of ALLO in CNS is a major factor that ultimately leads to anticonvulsant effects of fluoxetine against PTZ-induced seizures.
Collapse
Affiliation(s)
- Rajesh Ramesh Ugale
- University Department of Pharmaceutical Sciences, Nagpur University Campus, Nagpur 440 033, Maharashtra, India
| | | | | | | |
Collapse
|
35
|
Specchio LM, Iudice A, Specchio N, La Neve A, Spinelli A, Galli R, Rocchi R, Ulivelli M, de Tommaso M, Pizzanelli C, Murri L. Citalopram as Treatment of Depression in Patients With Epilepsy. Clin Neuropharmacol 2004; 27:133-6. [PMID: 15190237 DOI: 10.1097/00002826-200405000-00009] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To assess the safety of citalopram as a treatment of depression in patients with epilepsy. METHODS This is an open, multicentered, uncontrolled study. Depressed epileptic patients on antiepileptic drugs (AEDs) took part in the study. Patients who had a mild frequency of seizures in the 4 previous months underwent treatment with citalopram (20 mg/d) for 4 consecutive months. A change in seizure frequency from the baseline was chosen as the primary measure for the safety of citalopram and efficacy against depressive symptoms was taken as secondary measure. Depression was rated using the Montgomery-Asberg and Zung depression rating scales. Clinical assessments were performed at baseline, and at 2 and 4 months of citalopram therapy. RESULTS Forty-five patients were enrolled. Six patients dropped out of the study early: none of them because of a deterioration of seizure frequency. An overall improvement in seizure frequency was observed in the 39 patients who completed the study. Plasma AED concentrations were unchanged during therapy, and depressive symptoms improved markedly. Twenty-two patients complained of adverse effects, mainly headache, nausea, dizziness, somnolence, and fatigue. CONCLUSIONS In this open, multicentered, uncontrolled study, 4 months' of treatment with citalopram (20 mg/d) were associated with an improvement in depressive symptoms and reduction in seizure frequency.
Collapse
Affiliation(s)
- Luigi M Specchio
- Department of Medical and Occupational Sciences, Section of Clinic of the Nervous System Diseases, University of Foggia, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
Studies in experimental models have suggested a potential role for serotonergic transmission in epilepsy, and interest in this research has been increased by the development of positron emission tomography (PET) ligands that can be used to study 5-hydroxytryptamine (5-HT) receptors and transporters. The serotonergic system is very complex. At least 13 distinct G protein-coupled 5-HT receptors and one ligand-gated ion channel receptor (5-HT(3)) are divided into seven distinct classes (5-HT(1) to 5-HT(7)) ((1)). The receptors vary widely in their distribution and effects, innervating vascular structures and gut smooth muscle as well as neuronal tissue. Several receptor subtypes may be relevant to epilepsy.
Collapse
|
37
|
Hernandez EJ, Williams PA, Dudek FE. Effects of fluoxetine and TFMPP on spontaneous seizures in rats with pilocarpine-induced epilepsy. Epilepsia 2002; 43:1337-45. [PMID: 12423383 DOI: 10.1046/j.1528-1157.2002.48701.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Fluoxetine is a selective serotonin [5-hydroxytryptamine (5-HT)] reuptake inhibitor (SSRI) commonly used to treat depression. Some uncontrolled clinical studies have reported that SSRIs increase seizures, but animal experiments with evoked-seizure models have suggested that SSRIs at therapeutic doses decrease seizure susceptibility. We tested the hypothesis that fluoxetine and trifluoromethylphenylpiperazine (TFMPP, a nonselective 5-HT-receptor agonist) reduce the frequency of spontaneous motor seizures in pilocarpine-treated rats. METHODS Fluoxetine (20 mg/kg) and TFMPP (5 mg/kg) were administered to rats with pilocarpine-induced epilepsy. Phenobarbital (PB; 10 mg/kg) was a positive control, and saline (i.e., 0.5 ml) controlled for the injection protocol. Each rat received each treatment (intraperitoneally) once per day for 5 consecutive days with 1 week between treatments. Rats were continuously video-monitored for the last 72 h of each treatment. RESULTS When compared with saline over the entire 72-h observation period, PB and fluoxetine treatment, but not TFMPP, reduced the spontaneous-seizure rate. Plots of magnitude of the drug effect as a function of seizure frequency after saline treatment revealed larger drug effects for fluoxetine and PB in the rats with the highest control seizure rate. When the data from the five rats with the highest seizure frequency in saline were analyzed for the first 6 h after treatment, TFMPP also significantly reduced seizure frequency. CONCLUSIONS Animal models with spontaneous seizures can be used to screen potential antiepileptic drugs, and fluoxetine and TFMPP reduce spontaneous seizures in the pilocarpine model of temporal lobe epilepsy.
Collapse
Affiliation(s)
- Eric J Hernandez
- Department of Anatomy and Neurobiology, Colorado State University, Fort Collins, Colorado 80523, USA.
| | | | | |
Collapse
|
38
|
Choi BH, Choi JS, Yoon SH, Rhie DJ, Min DS, Jo YH, Kim MS, Hahn SJ. Effects of norfluoxetine, the major metabolite of fluoxetine, on the cloned neuronal potassium channel Kv3.1. Neuropharmacology 2001; 41:443-53. [PMID: 11543764 DOI: 10.1016/s0028-3908(01)00088-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of fluoxetine and its major metabolite, norfluoxetine, were studied using the patch-clamp technique on the cloned neuronal rat K(+) channel Kv3.1, expressed in Chinese hamster ovary cells. In whole-cell recordings, fluoxetine and norfluoxetine inhibited Kv3.1 currents in a reversible concentration-dependent manner, with an IC(50) value and a Hill coefficient of 13.11+/-0.91 microM and 1.33+/-0.08 for fluoxetine and 0.80+/-0.06 microM and 1.65+/-0.08 for norfluoxetine at +40 mV, respectively. In inside-out patches, norfluoxetine applied to the cytoplasmic surface inhibited Kv3.1 with an IC(50) value of 0.19+/-0.01 microM. The inhibition of Kv3.1 currents by both drugs was characterized by an acceleration in the apparent rate of current decay, without modification of the activation time course and with relatively fewer effects on peak amplitude. The degree of inhibition of Kv3.1 by norfluoxetine was voltage-dependent. The inhibition increased steeply between 0 and +30 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to +30 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance delta of 0.31+/-0.05. The association (k(+1)) and dissociation (k(-1)) rate constants for norfluoxetine-induced inhibition of Kv3.1 were 21.70+/-3.39 microM(-1) s(-1) and 14.68+/-3.94 s(-1), respectively. The theoretical K(D) value derived by k(-1)/k(+1) yielded 0.68 microM. Norfluoxetine did not affect the ion selectivity of Kv3.1. The reversal potential under control conditions was about -85 mV and was not affected by norfluoxetine. Norfluoxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of norfluoxetine, were superimposed. The voltage dependence of steady-state inactivation was not changed by the drug. Norfluoxetine produced use-dependent inhibition of Kv3.1 at a frequency of 1 Hz and slowed the recovery from inactivation. It is concluded that at clinically relevant concentrations, both fluoxetine and its major metabolite norfluoxetine inhibit Kv3.1, and that norfluoxetine directly inhibits Kv3.1 as an open channel blocker.
Collapse
Affiliation(s)
- B H Choi
- Department of Physiology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Raju SS, Noor AR, Gurthu S, Giriyappanavar CR, Acharya SB, Low HC, Quah SH. Effect of fluoxetine on maximal electroshock seizures in mice: acute vs chronic administration. Pharmacol Res 1999; 39:451-4. [PMID: 10373242 DOI: 10.1006/phrs.1999.0466] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are no definite reports regarding the effects of chronic fluoxetine on animal models of epilepsy. Since chronically administered fluoxetine, in comparison to acutely administered fluoxetine has different effects on CNS, the present study was undertaken to investigate the effect of acute and chronic fluoxetine pretreatment, on a median anticonvulsant dose (ED50) of phenytoin in male ICR albino mice. Additionally, the effects of fluoxetine pretreatment on median convulsive current (CC50) in the presence and absence of phenytoin were investigated and results were compared. The maximal electroshock seizure (MES) test was used to estimate the ED50of phenytoin. The electroshock threshold test was used to estimate CC50. ED50and CC50values were calculated by probit analysis. The effects of the chronic and acute fluoxetine groups on the ED50of phenytoin were significantly different (P<0.05), and on CC50this difference was not statistically significant. Chronic fluoxetine insignificantly increased the ED50of phenytoin and decreased the CC50while acute fluoxetine decreased the ED50of phenytoin and increased the CC50. Our results indicate that chronic fluoxetine does not have an antiepileptic property and it may have dubious proconvulsant properties, contrary to acute fluoxetine.
Collapse
Affiliation(s)
- S S Raju
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Kubang Kerian, 16150, Malaysia
| | | | | | | | | | | | | |
Collapse
|
40
|
Applegate CD, Tecott LH. Global increases in seizure susceptibility in mice lacking 5-HT2C receptors: a behavioral analysis. Exp Neurol 1998; 154:522-30. [PMID: 9878187 DOI: 10.1006/exnr.1998.6901] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that mice bearing a targeted disruption of the 5-HT2C receptor gene exhibit an epilepsy syndrome associated with sporadic spontaneous seizures that occasionally result in death. In this study, we have defined the seizure susceptibility profiles of these 5-HT2C receptor mutant mice backcrossed onto a C57BL/6 background. Wild-type and mutant animals were either electrically kindled from the olfactory bulb, exposed to corneal electroshock, or tested with the chemoconvulsant, flurothyl. In all paradigms, mice lacking the 5-HT2C receptor were significantly more seizure susceptible than wild-type controls. Results indicate that mutants have lower focal seizure thresholds, increased focal seizure excitability, and facilitated propagation within the forebrain seizure system. Mutants also exhibit lower generalized seizure thresholds for the expression of both generalized clonic and generalized tonic seizures. Importantly, the 5-HT receptor antagonist, mesulergine (2 or 4 mg/kg), administered prior to electroshock testing, recapitulated the mutant phenotype in wild-type mice. Together, these data strongly implicate a role for serotonin and 5-HT2C receptors in the modulation of neuronal network excitability and seizure propagation globally, throughout the CNS.
Collapse
MESH Headings
- Animals
- Behavior, Animal/physiology
- Brain Chemistry/drug effects
- Brain Chemistry/physiology
- Convulsants/pharmacology
- Cornea
- Disease Susceptibility
- Dopamine Agonists/pharmacology
- Electroshock
- Epilepsies, Myoclonic/chemically induced
- Epilepsies, Myoclonic/genetics
- Epilepsy/chemically induced
- Epilepsy/genetics
- Ergolines/pharmacology
- Flurothyl/pharmacology
- Kindling, Neurologic/drug effects
- Kindling, Neurologic/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Receptor, Serotonin, 5-HT2C
- Receptors, Serotonin/genetics
Collapse
Affiliation(s)
- C D Applegate
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, USA.
| | | |
Collapse
|
41
|
Guidotti A, Costa E. Can the antidysphoric and anxiolytic profiles of selective serotonin reuptake inhibitors be related to their ability to increase brain 3 alpha, 5 alpha-tetrahydroprogesterone (allopregnanolone) availability? Biol Psychiatry 1998; 44:865-73. [PMID: 9807641 DOI: 10.1016/s0006-3223(98)00070-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Neurosteroids synthesized in the nervous system are potent modulators of synaptic activity. Allopregnanolone (ALLO) is of great significance for neuropsychiatric research because it binds with high affinity at nanomolar concentration to various gamma-aminobutyric acid (GABA)A receptor subtypes and potently facilitates GABA action at these receptors. Fluoxetine and paroxetine, two selective serotonin reuptake inhibitors (SSRIs), when administered to rats increase brain ALLO content without altering the brain content of other steroids, including ALLO's precursor 5 alpha dihydroprogesterone. Moreover the improvement in depression symptomatology following administration of fluoxetine or fluvoxamine to unipolar depressed patients for 8-10 weeks is related to the increase of ALLO content in cerebrospinal fluid. Because ALLO via its action at GABAA receptors may relieve anxiety and dysphoria, the increase in ALLO brain content elicited by fluoxetine or other SSRIs may participate in the beneficial anxiolytic and antidysphoric clinical action of this class of drugs. Preliminary experiments suggest that the effect of SSRIs on ALLO biosynthesis is independent from serotonin reuptake inhibition and may be due to a specific SSRI action on the enzymes that synthesize ALLO from its precursor.
Collapse
Affiliation(s)
- A Guidotti
- Department of Psychiatry, University of Illinois at Chicago, College of Medicine 60612, USA
| | | |
Collapse
|
42
|
Lu KT, Gean PW. Endogenous serotonin inhibits epileptiform activity in rat hippocampal CA1 neurons via 5-hydroxytryptamine1A receptor activation. Neuroscience 1998; 86:729-37. [PMID: 9692713 DOI: 10.1016/s0306-4522(98)00106-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The modulatory effects of endogenous serotonin on the synaptic transmission and epileptiform activity were studied in the rat hippocampus with the use of extracellular and intracellular recording techniques. Field excitatory postsynaptic potential was reversibly depressed by serotonin in a concentration-dependent manner. Intracellular recordings revealed that serotonin-mediated synaptic depression was unaffected by extracellular Ba2+ or intracellular application of Cs+ while the postsynaptic hyperpolarizing effect was completely blocked. Epileptiform activity induced by picrotoxin (50 microM), a GABA(A) receptor antagonist, was also dose-dependently suppressed by serotonin. The antiepileptic effect was mimicked by 5-hydroxytryptamine1A agonist and was blocked by 5-hydroxytryptamine1A antagonists. 5-Hydroxytryptamine2 antagonist had no effect on the modulation. Similarly, fluoxetine, a selective serotonin re-uptake blocker, potently inhibited the epileptiform activity and this effect was blocked by 5-hydroxytryptamine1A receptor antagonist. Depletion of endogenous serotonin by pretreating the slices with p-chloroamphetamine completely prevented the antiepileptic action of fluoxetine, without modifying the action of serotonin in the same cells. These results suggest that the antiepileptic action of fluoxetine is due to an enhancement of endogenous serotonin which in turn is mediated by 5-hydroxytryptamine1A receptor. Endogenous serotonin transmission in the hippocampus is therefore capable of limiting the development and propagation of seizure activity.
Collapse
Affiliation(s)
- K T Lu
- Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan
| | | |
Collapse
|
43
|
Fong PP, Huminski PT, D'Urso LM. Induction and potentiation of parturition in fingernail clams (Sphaerium striatinum) by selective serotonin re-uptake inhibitors (SSRIs). THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1998; 280:260-4. [PMID: 9472482 DOI: 10.1002/(sici)1097-010x(19980215)280:3<260::aid-jez7>3.0.co;2-l] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Parturition in fingernail clams (Sphaerium spp.) can be induced by external application of serotonin and serotonergic ligands. Selective serotonin re-uptake inhibitors (SSRIs) increase neurotransmission at serotonergic synapses by blocking re-uptake transporters. We tested the efficacy of SSRIs (fluvoxamine, fluoxetine, paroxetine) at inducing parturition in the fingernail clam Sphaerium striatinum. Parturition was induced by fluvoxamine and paroxetine, but only potentiated by fluoxetine. Fluvoxamine was potent, significantly inducing parturition at concentrations from 10 nM to 100 microM compared with negative controls. Fluvoxamine also significantly potentiated a subthreshold (10 microM) concentration of serotonin. Paroxetine also induced parturition but was less potent. Only 10 microM paroxetine significantly induced parturition compared with controls. Fluoxetine (1-100 microM) did not induce any parturitions, but at 5 microM it potentiated parturition in subthreshold serotonin concentrations as low as 50 nM. These results suggest the presence of serotonin re-uptake transporters in bivalve molluscs and may provide a way of stimulating serotonergic mechanisms without using serotonin or its ligands.
Collapse
Affiliation(s)
- P P Fong
- Department of Biology, Gettysburg College, Pennsylvania 17325, USA.
| | | | | |
Collapse
|
44
|
Salgado-Commissariat D, Alkadhi KA. Serotonin inhibits epileptiform discharge by activation of 5-HT1A receptors in CA1 pyramidal neurons. Neuropharmacology 1997; 36:1705-12. [PMID: 9517442 DOI: 10.1016/s0028-3908(97)00134-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The anti-epileptiform effect of serotonin was characterized in cellular models of epilepsy using electrophysiological recording techniques. In the bicuculline model, both serotonin (20 microM) and its 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 10 microM) completely blocked the epileptiform discharge and caused membrane hyperpolarization and reduction in input resistance. These effects were completely antagonized by the 5-HT1A receptor antagonist N-t-butyl-3(4-[2-methoxyphenyl]piperazin-1-yl)-2-phenyl-propanamid e(WAY 100135) (10 microM). Epileptiform discharge induced by positive current injection was also blocked by serotonin. The presence of WAY 100135 renders serotonin ineffective in the same model. In the bicuculline model, epileptiform discharge blocked by serotonin reappeared and was also intensified when BaCl2 was added to the medium. To rule out the possibility of serotonin-induced hyperpolarization strengthening the inhibitory effect of endogenous Mg2+ on glutamate N-methyl-D-aspartic acid (NMDA) receptor we studied the antiepileptic effect of serotonin in the 0 Mg2+ model. Spontaneous activity and evoked bursts seen with the 0 Mg2+ model were completely blocked by serotonin. WAY 100135 completely antagonized serotonin effects in this model as well. This study provides evidence suggesting that in rat CA1 pyramidal neurons, serotonin can inhibit epileptiform activity in a variety of accepted epilepsy cellular models and that inhibition of epileptiform bursts by serotonin may be mediated by activation of the 5-HT1A receptor subtype.
Collapse
Affiliation(s)
- D Salgado-Commissariat
- Department of Pharmacological and Pharmaceutical Sciences University of Houston, TX 77204-5515, USA
| | | |
Collapse
|
45
|
Browning RA, Wood AV, Merrill MA, Dailey JW, Jobe PC. Enhancement of the anticonvulsant effect of fluoxetine following blockade of 5-HT1A receptors. Eur J Pharmacol 1997; 336:1-6. [PMID: 9384247 DOI: 10.1016/s0014-2999(97)01215-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Serotonin reuptake inhibitors, such as fluoxetine, have been shown to exert anticonvulsant effects in several animal models of epilepsy. In view of recent studies showing that 5-HT1A receptor antagonists (somatodendritic autoreceptor antagonists) enhance the increase in extracellular 5-hydroxytryptamine (5-HT, serotonin) produced by serotonin reuptake inhibitors, it was of interest to determine if these antagonists also enhance the anticonvulsant effect of fluoxetine in Genetically Epilepsy-Prone Rats (GEPRs). The 5-HT1A receptor antagonists (-)-pindolol and LY 206130 (1-[1-H-indol-4-yloxy]-3-[cyclohexylamino]-2-propanol maleate) were examined in the present study and both enhanced the anticonvulsant action of fluoxetine in severe seizure GEPRs (GEPR-9s). The latter effect of LY 206130 was found to be dose- and 5-HT-dependent. These findings provide further evidence that the increase in extracellular serotonin observed after administering fluoxetine in combination with a 5-HT1A receptor antagonist is physiologically important and that the anticonvulsant effect of fluoxetine in the GEPR is mediated through an increase in extracellular 5-HT.
Collapse
Affiliation(s)
- R A Browning
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, USA
| | | | | | | | | |
Collapse
|