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Malaník M, Čulenová M, Sychrová A, Skiba A, Skalicka-Woźniak K, Šmejkal K. Treating Epilepsy with Natural Products: Nonsense or Possibility? Pharmaceuticals (Basel) 2023; 16:1061. [PMID: 37630977 PMCID: PMC10459181 DOI: 10.3390/ph16081061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
Epilepsy is a neurological disease characterized by recurrent seizures that can lead to uncontrollable muscle twitching, changes in sensitivity to sensory perceptions, and disorders of consciousness. Although modern medicine has effective antiepileptic drugs, the need for accessible and cost-effective medication is urgent, and products derived from plants could offer a solution. For this review, we have focused on natural compounds that have shown anticonvulsant activity in in vivo models of epilepsy at relevant doses. In some cases, the effects have been confirmed by clinical data. The results of our search are summarized in tables according to their molecular targets. We have critically evaluated the data we present, identified the most promising therapeutic candidates, and discussed these in the text. Their perspectives are supported by both pharmacokinetic properties and potential interactions. This review is intended to serve as a basis for future research into epilepsy and related disorders.
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Affiliation(s)
- Milan Malaník
- Department of Natural Drugs, Faculty of Pharmacy, Masaryk University, Palackého 1946/1, 61200 Brno, Czech Republic; (A.S.); (K.Š.)
| | - Marie Čulenová
- Department of Natural Drugs, Faculty of Pharmacy, Masaryk University, Palackého 1946/1, 61200 Brno, Czech Republic; (A.S.); (K.Š.)
| | - Alice Sychrová
- Department of Natural Drugs, Faculty of Pharmacy, Masaryk University, Palackého 1946/1, 61200 Brno, Czech Republic; (A.S.); (K.Š.)
| | - Adrianna Skiba
- Department of Natural Products Chemistry, Faculty of Pharmacy, Medical University of Lublin, 1 Chodzki Str., 20-093 Lublin, Poland; (A.S.); (K.S.-W.)
| | - Krystyna Skalicka-Woźniak
- Department of Natural Products Chemistry, Faculty of Pharmacy, Medical University of Lublin, 1 Chodzki Str., 20-093 Lublin, Poland; (A.S.); (K.S.-W.)
| | - Karel Šmejkal
- Department of Natural Drugs, Faculty of Pharmacy, Masaryk University, Palackého 1946/1, 61200 Brno, Czech Republic; (A.S.); (K.Š.)
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Salehi A, Ghanadian M, Zolfaghari B, Jassbi AR, Fattahian M, Reisi P, Csupor D, Khan IA, Ali Z. Neuropharmacological Potential of Diterpenoid Alkaloids. Pharmaceuticals (Basel) 2023; 16:ph16050747. [PMID: 37242531 DOI: 10.3390/ph16050747] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
This study provides a narrative review of diterpenoid alkaloids (DAs), a family of extremely important natural products found predominantly in some species of Aconitum and Delphinium (Ranunculaceae). DAs have long been a focus of research attention due to their numerous intricate structures and diverse biological activities, especially in the central nervous system (CNS). These alkaloids originate through the amination reaction of tetra or pentacyclic diterpenoids, which are classified into three categories and 46 types based on the number of carbon atoms in the backbone structure and structural differences. The main chemical characteristics of DAs are their heterocyclic systems containing β-aminoethanol, methylamine, or ethylamine functionality. Although the role of tertiary nitrogen in ring A and the polycyclic complex structure are of great importance in drug-receptor affinity, in silico studies have emphasized the role of certain sidechains in C13, C14, and C8. DAs showed antiepileptic effects in preclinical studies mostly through Na+ channels. Aconitine (1) and 3-acetyl aconitine (2) can desensitize Na+ channels after persistent activation. Lappaconitine (3), N-deacetyllapaconitine (4), 6-benzoylheteratisine (5), and 1-benzoylnapelline (6) deactivate these channels. Methyllycaconitine (16), mainly found in Delphinium species, possesses an extreme affinity for the binding sites of α7 nicotinic acetylcholine receptors (nAChR) and contributes to a wide range of neurologic functions and the release of neurotransmitters. Several DAs such as bulleyaconitine A (17), (3), and mesaconitine (8) from Aconitum species have a drastic analgesic effect. Among them, compound 17 has been used in China for decades. Their effect is explained by increasing the release of dynorphin A, activating the inhibitory noradrenergic neurons in the β-adrenergic system, and preventing the transmission of pain messages by inactivating the Na+ channels that have been stressed. Acetylcholinesterase inhibitory, neuroprotective, antidepressant, and anxiolytic activities are other CNS effects that have been investigated for certain DAs. However, despite various CNS effects, recent advances in developing new drugs from DAs were insignificant due to their neurotoxicity.
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Affiliation(s)
- Arash Salehi
- Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran
| | - Mustafa Ghanadian
- Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran
- Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran
| | - Behzad Zolfaghari
- Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran
| | - Amir Reza Jassbi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz 71348-14336, Iran
| | - Maryam Fattahian
- Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran
| | - Parham Reisi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81745-33871, Iran
| | - Dezső Csupor
- Institute of Clinical Pharmacy, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary
| | - Ikhlas A Khan
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS 38677, USA
| | - Zulfiqar Ali
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS 38677, USA
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Li L, Zhang L, Liao T, Zhang C, Chen K, Huang Q. Advances on pharmacology and toxicology of aconitine. Fundam Clin Pharmacol 2022; 36:601-611. [PMID: 35060168 DOI: 10.1111/fcp.12761] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/16/2022] [Accepted: 01/19/2022] [Indexed: 01/10/2023]
Abstract
Aconitum alkaloids are considered to be the characteristic bioactive ingredients of Aconitum species, which are widely applied to the treatment of diverse diseases, and aconitine (AC) is found in most Aconitum plants. Research evidence shows that low-dose AC has a good therapeutic potential in heart failure, myocardial infarction, neuroinflammatory diseases, rheumatic diseases, and tumors, which has become one of the hotspots in global research in recent years. However, the cardiotoxicity and neurotoxicity of AC have also attracted extensive attention. Excessive use of AC always induces ventricular tachyarrhythmia and heart arrest, even can be potentially lethal. Therefore, AC cannot simply be regarded as a good medicine or a toxicant, but its underlying curative and toxic properties remained chaos. In order to dig the unique pharmacological value of AC while preventing its toxicity, the pharmacological activities and toxic effects of AC were summarized in this paper, providing new insight into the safe and effective use of AC in clinical practice.
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Affiliation(s)
- Liuying Li
- Department of Integrated Chinese and Western Medicine, The First People's Hospital of Zigong City, Zigong, China
| | - Limin Zhang
- Department of Gastroenterology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Tingting Liao
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Chuantao Zhang
- Department of Respiratory, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Keling Chen
- Department of Respiratory, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Qun Huang
- Department of Ophthalmology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Zhou J, Peng C, Li Q, Yan X, Yang L, Li M, Cao X, Xie X, Chen D, Rao C, Huang S, Peng F, Pan X. Dopamine Homeostasis Imbalance and Dopamine Receptors-Mediated AC/cAMP/PKA Pathway Activation are Involved in Aconitine-Induced Neurological Impairment in Zebrafish and SH-SY5Y Cells. Front Pharmacol 2022; 13:837810. [PMID: 35370746 PMCID: PMC8971779 DOI: 10.3389/fphar.2022.837810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/25/2022] [Indexed: 11/25/2022] Open
Abstract
Aconitine is one of the main bioactive and toxic ingredients of Aconitum species. Increasingly, aconitine has been reported to induce neurotoxicity. However, whether aconitine has effects on the dopaminergic nervous system remains unclear. In this study, zebrafish embryos at 6-days postfertilization were exposed to aconitine at doses of 0.5, 1, and 2 μM for 24 h, and SH-SY5Y cells were treated with 50, 100, and 200 μM of aconitine for 24 h. Results demonstrated that aconitine treatment induced deformities and enhanced the swimming behavior of zebrafish larvaes. Aconitine exposure suppressed cell proliferation and increased the number of reactive oxygen species and apoptosis in zebrafish larvaes and SH-SY5Y cells. Aconitine altered the levels of dopamine and its metabolites by regulating the expression of genes and proteins related to dopamine synthesis, storage, degradation, and reuptake in vivo and in vitro. Moreover, aconitine activated the AC/cAMP/PKA pathway by activating the dopamine D1 receptor (D1R) and inhibiting the dopamine D2 receptor (D2R) to disturb intracellular calcium homeostasis, eventually leading to the damage of nerve cells. Furthermore, the D1R antagonist SCH23390 and D2R agonist sumanirole pretreatment effectively attenuated the excitatory state of larvaes. Sumanirole and PKA antagonist H-89 pretreatment effectively decreased intracellular Ca2+ accumulation induced by aconitine in vivo. SCH23390 and sumanirole also reduced aconitine-induced cytotoxicity by inhibiting the AC/cAMP/PKA pathway in vitro. These results suggested that dopamine homeostasis imbalance and dopamine receptors (DRs)-mediated AC/cAMP/PKA pathway activation might be vital mechanisms underlying aconitine-induced neurological injury.
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Affiliation(s)
- Jie Zhou
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Pharmacy, Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Cheng Peng
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Qiuju Li
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaoyu Yan
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Liang Yang
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Mengting Li
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaoyu Cao
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaofang Xie
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Dayi Chen
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Chaolong Rao
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Sizhou Huang
- Development and Regeneration Key Laboratory of Sichuan Province, Department of Anatomy and Histology and Embryology, School of Basic Medicine, Chengdu Medical College, Chengdu, China
| | - Fu Peng
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Fu Peng, ; Xiaoqi Pan,
| | - Xiaoqi Pan
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy and School of Public Health, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- *Correspondence: Fu Peng, ; Xiaoqi Pan,
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Van Theemsche KM, Van de Sande DV, Snyders DJ, Labro AJ. Hydrophobic Drug/Toxin Binding Sites in Voltage-Dependent K + and Na + Channels. Front Pharmacol 2020; 11:735. [PMID: 32499709 PMCID: PMC7243439 DOI: 10.3389/fphar.2020.00735] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/04/2020] [Indexed: 12/26/2022] Open
Abstract
In the Nav channel family the lipophilic drugs/toxins binding sites and the presence of fenestrations in the channel pore wall are well defined and categorized. No such classification exists in the much larger Kv channel family, although certain lipophilic compounds seem to deviate from binding to well-known hydrophilic binding sites. By mapping different compound binding sites onto 3D structures of Kv channels, there appear to be three distinct lipid-exposed binding sites preserved in Kv channels: the front and back side of the pore domain, and S2-S3/S3-S4 clefts. One or a combination of these sites is most likely the orthologous equivalent of neurotoxin site 5 in Nav channels. This review describes the different lipophilic binding sites and location of pore wall fenestrations within the Kv channel family and compares it to the knowledge of Nav channels.
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Affiliation(s)
- Kenny M Van Theemsche
- Laboratory of Molecular, Cellular, and Network Excitability, University of Antwerp, Antwerp, Belgium
| | - Dieter V Van de Sande
- Laboratory of Molecular, Cellular, and Network Excitability, University of Antwerp, Antwerp, Belgium
| | - Dirk J Snyders
- Laboratory of Molecular, Cellular, and Network Excitability, University of Antwerp, Antwerp, Belgium
| | - Alain J Labro
- Laboratory of Molecular, Cellular, and Network Excitability, University of Antwerp, Antwerp, Belgium
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Peng F, Zhang N, Wang C, Wang X, Huang W, Peng C, He G, Han B. Aconitine induces cardiomyocyte damage by mitigating BNIP3-dependent mitophagy and the TNFα-NLRP3 signalling axis. Cell Prolif 2019; 53:e12701. [PMID: 31657084 PMCID: PMC6985658 DOI: 10.1111/cpr.12701] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/02/2019] [Accepted: 09/02/2019] [Indexed: 02/05/2023] Open
Abstract
Objectives Aconitine, the natural product extracted from Aconitum species, is widely used for the treatment of various diseases, including rheumatism, arthritis, bruises, fractures and pains. However, many studies have reported cardiotoxicity and neurotoxicity caused by aconitine, but the detailed mechanism underlying aconitine's effect on these processes remains unclear. Materials and methods The effects of aconitine on the inflammation, apoptosis and viability of H9c2 rat cardiomyocytes were evaluated by flow cytometry, Western blot, RNA sequencing and bioinformatics analysis. Results Aconitine suppressed cardiomyocyte proliferation and induced inflammation and apoptosis in a dose‐ and time‐dependent manner. These inflammatory damages could be reversed by a TNFα inhibitor and BNIP3‐mediated mitophagy. Consistent with the in vitro results, overexpression of BNIP3 in heart tissue partially suppressed the cardiotoxicity of aconitine by inhibiting apoptosis and the NLRP3 inflammasome. Conclusions Our findings lay a foundation for the application of a TNFα inhibitor and BNIP3 to aconitine‐induced cardiac toxicity prevention and therapy, thereby demonstrating potential for further investigation.
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Affiliation(s)
- Fu Peng
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Nan Zhang
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Chunting Wang
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoyun Wang
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Huang
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Cheng Peng
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Gu He
- West China School of Pharmacy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Bo Han
- Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Gao X, Hu J, Zhang X, Zuo Y, Wang Y, Zhu S. Research progress of aconitine toxicity and forensic analysis of aconitine poisoning. Forensic Sci Res 2018; 5:25-31. [PMID: 32490307 PMCID: PMC7241456 DOI: 10.1080/20961790.2018.1452346] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/12/2018] [Indexed: 12/18/2022] Open
Abstract
Chinese herbal medicines have been extensively used in China and other countries for centuries. Aconitine, a diterpenoid alkaloid extracted from Aconitum plants, has anti-inflammatory and analgesic activities, but can also induce severe arrhythmia and neurotoxicity. Aconitine poisoning accidents caused by misuse, suicide, or homicide have been reported in recent years. In China, fatal aconitine poisoning can occasionally happen on account of accidental ingestion of some wild plants or consumption of herbal decoction made from the roots of Aconitum plants. However, it is rather difficult for forensic experts to find the specific results in present forensic autopsy of aconitine-induced death. To further clarify its potential risk following the widespread application of aconitine, toxicological characteristics and pharmacokinetics of aconitine are reviewed. Moreover, gastrointestinal, neurological, and cardiovascular symptoms were observed frequently in aconitine poisoning cases. In addition, the review also aims at providing some convincing evidences for forensic experts to identify unexplained death with postmortem examination.
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Affiliation(s)
- Xiangting Gao
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Jun Hu
- Department of Forensic Medicine, Soochow University, Suzhou, China.,Laboratory of Biomedical Technology, Jiangsu Vocational College of Medicine, Yancheng, China
| | - Xincai Zhang
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Yuanyi Zuo
- Department of Forensic Medicine, Soochow University, Suzhou, China.,Department of Forensic Sciences, Binhai People's Hospital, Yancheng, China
| | - Yun Wang
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Shaohua Zhu
- Department of Forensic Medicine, Soochow University, Suzhou, China
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Varró P, Kovács M, Világi I. The insecticide esfenvalerate modulates neuronal excitability in mammalian central nervous system in vitro. Toxicol Lett 2017; 267:39-44. [PMID: 28007640 DOI: 10.1016/j.toxlet.2016.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/07/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
Pyrethroids are neurotoxic insecticides showing significant selective toxicity on insects over mammals, but effects on mammalian nervous system are not negligible. These substances act on the voltage-gated sodium channel, prolonging the duration of the open state. The present study focused on the effect of the pyrethroid esfenvalerate on the excitability of neuronal networks in vitro. From isolated rat brain slices, neocortical and hippocampal evoked field potentials were recorded; four concentrations (5-40μM) of esfenvalerate were tested using in vitro administration of the commercial product Sumi-Alpha 5 EC®. Basic excitability and short- and long-term synaptic plasticity were studied. Application of the lowest concentration elicited epileptiform discharges in neocortex, while the highest concentration exerted a strong inhibitory effect on the excitability of both brain areas. The amplitude of population spikes in hippocampal slices was decreased by all applied concentrations. Significant decrease in basic excitability was accompanied by increase of paired-pulse facilitation in hippocampus and decreased efficacy of the development of long-term potentiation in both regions. Pyrethroids have been scarcely studied on brain slices so far, but our results are in concordance with literary data obtained on other in vitro neuronal test systems. It has been described previously that lower concentrations of pyrethroids lead to overexcitation of neurons and repetitive firing (which is in the background of hyperexcitatory symptoms occurring in case of in vivo exposure). Higher concentrations, however, may lead to depolarization block and to inhibition of neuronal firing.
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Affiliation(s)
- Petra Varró
- Department of Physiology and Neurobiology, Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary.
| | - Melinda Kovács
- MTA-KE Mycotoxins in the Food Chain Research Group, Guba Sándor utca 40, 7400 Kaposvár, Hungary
| | - Ildikó Világi
- Department of Physiology and Neurobiology, Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary
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Wang FP, Chen QH. The C19-Diterpenoid Alkaloids. THE ALKALOIDS: CHEMISTRY AND BIOLOGY 2010; 69:1-577, xi. [DOI: 10.1016/s1099-4831(10)69001-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Study of neurotoxic effects and underlying mechanisms of aconitine on cerebral cortex neuron cells. Arch Pharm Res 2009; 32:1533-43. [DOI: 10.1007/s12272-009-2105-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 08/24/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
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Aconitine induces prolonged seizure-like events in rat neocortical brain slices. Eur J Pharmacol 2008; 584:291-6. [DOI: 10.1016/j.ejphar.2008.02.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 12/04/2007] [Accepted: 02/12/2008] [Indexed: 11/21/2022]
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Lin MW, Wang YJ, Liu SI, Lin AA, Lo YC, Wu SN. Characterization of aconitine-induced block of delayed rectifier K+ current in differentiated NG108-15 neuronal cells. Neuropharmacology 2008; 54:912-23. [PMID: 18336846 DOI: 10.1016/j.neuropharm.2008.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 12/21/2007] [Accepted: 01/28/2008] [Indexed: 11/24/2022]
Abstract
The effects of aconitine (ACO), a highly toxic alkaloid, on ion currents in differentiated NG108-15 neuronal cells were investigated in this study. ACO (0.3-30 microM) suppressed the amplitude of delayed rectifier K+ current (I K(DR)) in a concentration-dependent manner with an IC50 value of 3.1 microM. The presence of ACO enhanced the rate and extent of I K(DR) inactivation, although it had no effect on the initial activation phase of I K(DR). It could shift the inactivation curve of I K(DR) to a hyperpolarized potential with no change in the slope factor. Cumulative inactivation for I K(DR) was also enhanced by ACO. Orphenadrine (30 microM) or methyllycaconitine (30 microM) slightly suppressed I K(DR) without modifying current decay. ACO (10 microM) had an inhibitory effect on voltage-dependent Na+ current (I Na). Under current-clamp recordings, ACO increased the firing and widening of action potentials in these cells. With the aid of the minimal binding scheme, the ACO actions on I K(DR) was quantitatively provided with a dissociation constant of 0.6 microM. A modeled cell was designed to duplicate its inhibitory effect on spontaneous pacemaking. ACO also blocked I K(DR) in neuroblastoma SH-SY5Y cells. Taken together, the experimental data and simulations show that ACO can block delayed rectifier K+ channels of neurons in a concentration- and state-dependent manner. Changes in action potentials induced by ACO in neurons in vivo can be explained mainly by its blocking actions on I K(DR) and I Na.
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Affiliation(s)
- Ming-Wei Lin
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan
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Frigeni V, Samuelli G, Miragoli L, Grotti A, Lorusso V. Effect of iomeprol on rat hippocampal slice synaptic transmission: comparison with other X-ray contrast agents. Invest Radiol 2002; 37:222-31. [PMID: 11923645 DOI: 10.1097/00004424-200204000-00008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVES All contrast agents should be neurologically safe because although some are not indicated for procedures, such as myelography, just the same they may come in contact with nervous tissue during contrast-enhanced imaging. This is because even when they are intravascularly injected, the presence of undiagnosed blood-brain barrier damage may allow them to penetrate the brain barrier. In the present study, we investigated the neurologic safety of iomeprol by studying in vitro its potential effects on the central nervous system (CNS) synaptic transmission. Other widely used x-ray contrast agents were also assessed for comparative purposes. METHODS CNS synaptic transmission was evaluated in terms of evoked field potentials recorded from the pyramidal region of rat hippocampal slices. The field potentials were evoked by electrical stimulation of the Schaffer collateral pathway. The effects of the contrast agents were evaluated in terms of number and amplitude of population spikes (PS) and as the maximal slope of the excitatory postsynaptic potentials (EPSP). The contrast agents were tested at final concentrations of 3, 10, and 30 mg(iodine)/mL in iso-osmolal condition with respect to artificial cerebrospinal fluid (CSF). RESULTS Iomeprol, like ioversol, principally exerted a mild inhibitory effect on CNS synaptic transmission, an effect that was preceded by a weak, transient excitation. Iopentol exerted a rapid and complete inhibition of synaptic transmission without showing any excitatory effects. Iobitridol, though belonging to the nonionic monomeric class, exerted, surprisingly, an epileptogenic action at the highest concentration, whereas its inhibitory action was slow and mild. Diatrizoate, as expected, exerted an epileptogenic activity even at the lowest concentration, followed by a marked inhibitory action. Ioxaglate, as expected because it is an ionic though dimeric contrast agent, exerted an epileptogenic action at the intermediate concentration, whereas it barely demonstrated an inhibitory effect at all. All the contrast agent effects observed in the study reversed or tended to reverse during washout. CONCLUSIONS Even taking in account the limitation because of the use of an in vitro approach and high contrast agent concentrations, we can conclude that the positive neuro-tolerability of iomeprol is further confirmed by this model as it proved to be devoid of epileptogenic activity and, among the contrast agents exhibiting inhibitory action, it was the contrast agent with the least amount of activity. In addition, contrary to that generally reported in the literature, nonionic, low osmolal contrast agents are not all identical in their neuro-tolerability when assessed in the rat hippocampal slice model.
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Ameri A, Simmet T. Interaction of the structurally related aconitum alkaloids, aconitine and 6-benzyolheteratisine, in the rat hippocampus. Eur J Pharmacol 1999; 386:187-94. [PMID: 10618469 DOI: 10.1016/s0014-2999(99)00692-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aconitine is a highly toxic diterpenoid alkaloid occurring in plants of the Aconitum genus. Aconitine is known to shift the voltage-dependence of the voltage-dependent Na(+) channel towards hyperpolarized direction, thereby leading to a permanent activation of the channel. 6-benzoylheteratisine is a plant alkaloid which is structurally related with aconitine. The aim of the present study was to investigate the interaction of aconitine and 6-benzoylheteratisine in the rat hippocampus. The experiments were carried out as extracellular recordings of stimulus evoked population spikes and field excitatory postsynaptic potential (EPSP) in rat hippocampal slices. Aconitine (10-100 nM) exerted a concentration-dependent decrease in the amplitude of the orthodromic population spike. When aconitine was applied in presence of 6-benzoylheteratisine (3 microM), the concentration-response curve was shifted to the right. Furthermore, the complete suppression of the population spike evoked by 100 nM aconitine was reversed by 10 microM 6-benzoylheteratisine. The closely related alkaloid heteratisine (3 and 30 microM), however, was not capable to antagonize the aconitine action. 6-benzoylheteratisine shifted the input-output relationship of the presynaptic fiber spike as function of the stimulation intensity and the input-output relationship of the field EPSP as function of the presynaptic fiber spike to the right. Thus, electrophysiologically this alkaloid seems to inhibit predominantly the excitability of the afferent fibres and, in consequence, neurotransmission between Schaffer collaterals and the CA1 neurons, thereby suppressing the firing of the latter. Spontaneously occurring epileptiform activity in area CA3 elicited by omission of Mg(2+) and elevation of K(+) was attenuated by 6-benzoylheteratisine (1 and 10 microM). Patch clamp studies performed on cultured rat hippocampal pyramidal cells revealed an inhibitory action of 6-benzoylheteratisine on whole cell Na(+) currents. It is concluded that the inhibitory and antiepileptiform effect of ajacine and lappaconitine is mediated by an inhibition of the voltage-dependent Na(+) channel which might be important for filtering high frequency bursts of action potentials characteristic for epileptiform activity in the hippocampus. Thus, 6-benzoylheteratisine seems to be a naturally occurring antagonist of the Na(+) channel activator aconitine.
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Affiliation(s)
- A Ameri
- Institute of Pharmacology, Toxicology and Natural Products, University of Ulm, Helmholtzstr. 20, D-89081, Ulm, Germany
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Ameri A, Simmet T. Antagonism of the aconitine-induced inexcitability by the structurally related Aconitum alkaloids, lappaconitine and ajacine. Brain Res 1999; 842:332-41. [PMID: 10526129 DOI: 10.1016/s0006-8993(99)01838-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Aconitine, lappaconitine and ajacine are structurally related alkaloids occurring in several species of the Aconitum genus. While aconitine is known to activate the voltage-dependent sodium channel, lappaconitine has been reported to block this channel. To investigate a possible antagonism of the aconitine action on neuronal activity by lappaconitine and the closely related alkaloid ajacine, we have performed extracellular recordings of stimulus evoked population spikes and field excitatory postsynaptic potential (EPSP) in rat hippocampal slices. Aconitine (10-100 nM) diminished the amplitude of the orthodromic population spike in a concentration-dependent manner. When aconitine was applied in presence of 10 microM lappaconitine, the concentration-response curve was shifted to the right. Furthermore, the complete suppression of the population spike evoked by 100 nM aconitine was reversed by 10 microM lappaconitine. The action of lappaconitine was mimicked by ajacine, however, the latter alkaloid was less potent. Both lappaconitine and ajacine shifted the input-output relationship of the presynaptic fiber spike as function of the stimulation intensity and of the field EPSP as function of the presynaptic fiber spike to the right. After pharmacological isolation, the presynaptic fiber spike was decreased by both compounds in a frequency-dependent manner indicative for a use-dependent action. Thus, electrophysiologically these alkaloids seem to inhibit predominantly the excitability of the afferent fibres and, in consequence, neurotransmission between Schaffer collaterals and the CA1 neurons, thereby suppressing the firing of the latter. Ajacine and lappaconitine inhibited stimulus-triggered epileptiform population bursts in area CA1 elicited by omission of Mg(2+) as well as spontaneously occurring epileptiform discharges in area CA3 elicited by omission of Mg(2+) and elevation of K(+). It is concluded that the inhibitory and antiepileptiform effect of ajacine and lappaconitine is mediated by a frequency-dependent inhibition of the voltage-dependent sodium channel, thereby decreasing the excitability which might be important for filtering high frequency bursts of action potentials characteristic for epileptiform activity in the hippocampus. Moreover, these alkaloids are naturally occurring antagonists of the sodium channel activator aconitine.
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Affiliation(s)
- A Ameri
- Institute of Pharmacology, Toxicology and Natural Products, University of Ulm, Helmholtzstr. 20, D-89081, Ulm, Germany
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Seitz U, Ameri A. Different effects on [3H]noradrenaline uptake of the Aconitum alkaloids aconitine, 3-acetylaconitine, lappaconitine, and N-desacetyllappaconitine in rat hippocampus. Biochem Pharmacol 1998; 55:883-8. [PMID: 9586961 DOI: 10.1016/s0006-2952(97)00545-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effect of the Aconitum alkaloids aconitine, 3-acetylaconitine, lappaconitine, and N-desacetyllappaconitine to inhibit [3H]noradrenaline uptake was investigated in rat hippocampal synaptosomes. Aconitine and 3-acetylaconitine, which are known to activate sodium channels, had comparable inhibitory potencies and yielded Ki (inhibitor constant) values of 230 +/- 66 nM and 316 +/- 96 nM, respectively. In contrast, lappaconitine and N-desacetyllappaconitine failed to inhibit [3H]noradrenaline uptake. When either lappaconitine or N-desacetyllappaconitine was applied in combination with aconitine, [3H]noradrenaline uptake was not affected. The sodium channel blocker tetrodotoxin enhanced [3H]noradrenaline uptake, whereas uptake was completely blocked in sodium-free incubation medium. The inhibitory action of aconitine and 3-acetylaconitine on [3H]noradrenaline uptake was blocked by addition of tetrodotoxin. Patch clamp studies performed on cultured rat hippocampal neurons revealed an inhibitory action of lappaconitine and N-desacetyllappaconitine on whole cell sodium currents. It is concluded that the blockade of [3H]noradrenaline uptake evoked by aconitine and 3-acetylaconitine is mediated indirectly by an increased sodium concentration in the synaptosomes.
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Affiliation(s)
- U Seitz
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Ameri A. Inhibition of stimulus-triggered and spontaneous epileptiform activity in rat hippocampal slices by the Aconitum alkaloid mesaconitine. Eur J Pharmacol 1998; 342:183-91. [PMID: 9548384 DOI: 10.1016/s0014-2999(97)01498-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of the present study was to investigate if the plant alkaloid, mesaconitine, which has been reported to have antinociceptive effects via stimulation of the noradrenergic system, inhibits epileptiform field potentials. The experiments were performed as extracellular recordings on rat hippocampal slices. Epileptiform activity was induced by omission of Mg2+ from the bathing medium or by addition of bicuculline and stimulus-evoked population bursts were recorded in the CA1 region. Spontaneous epileptiform activity was elicited by perfusing a nominally Mg2+-free bathing medium with high K+ concentration (5 mM). Both stimulus-triggered and spontaneous epileptiform activity was attenuated in a concentration-dependent manner by mesaconitine (30 nM-1 microM). The inhibitory effect was rather variable in appearance when lower concentrations (30 and 100 nM) of mesaconitine were applied. Pretreatment of the slices with the alpha-adrenoceptor antagonist yohimbine (1 microM) prevented the effect of mesaconitine. It is concluded that the inhibitory action of mesaconitine at low concentration is mediated via alpha-adrenoceptors.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Ameri A. Effects of the Aconitum alkaloid mesaconitine in rat hippocampal slices and the involvement of alpha- and beta-adrenoceptors. Br J Pharmacol 1998; 123:243-50. [PMID: 9489612 PMCID: PMC1565163 DOI: 10.1038/sj.bjp.0701608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1 The effects of mesaconitine, the main alkaloid contained in Aconiti tuber, were investigated by use of extracellular recordings of stimulus-evoked population spikes and field excitatory postsynaptic potentials (e.p.s.ps) in the CA1 region of rat hippocampal slices. 2 At a concentration of 10 nM, mesaconitine evoked excitations, which were manifested as an increase in the amplitude of the orthodromic spike and the appearance of multiple spikes following the first postsynaptic spike, without affecting the magnitude of paired-pulse facilitation. The increase in spike amplitude was persistent and was not reversed by up to 90 min of washout. At concentrations of 30 and 100 nM, the alkaloid produced a biphasic effect, that is an excitation followed by an inhibition without having any effect upon the field e.p.s.p. At concentrations above 100 nM, mesaconitine suppressed the orthodromic population spike and the field e.p.s.p. 3 The excitatory effect was also observed when electrical stimulation was stopped completely during the application of mesaconitine (10 nM) and during the first 15 min of washout. 4 The enhancement of the population spike and the appearance of multiple spikes induced by mesaconitine (10-100 nM) were blocked by pretreatment with the beta-adrenoceptor antagonists propranolol (1 microM) and timolol (1 microM), whereas the inhibitory effect was blocked by the alpha-adrenoceptor antagonists yohimbine (1 microM) and phentolamine (10 microM). However, when the beta-adrenoceptor antagonist timolol was added 10 min after the application of mesaconitine, it failed to block the long-lasting enhancement of the spike amplitude and the appearance of multiple population spikes. 5 Application of the selective beta-adrenoceptor agonist isoprenaline (500 nM) to the hippocampal slices induced an increase in the amplitude of the orthodromic population spike and elicited 2-3 additional spikes. Mesaconitine (10 nM) did not further potentiate this enhancement of the spike amplitude when added after a 15 min pretreatment with isoprenaline. 6 Perfusion of forskolin, which directly activates adenylate cyclase, enhanced the population spike. Mesaconitine had no additional effect when applied after pretreatment with forskolin. 7 It is concluded that the excitatory effects evoked by lower concentrations of the plant alkaloid mesaconitine are mediated by stimulation of beta-adrenoceptors and the consequent activation of intracellular processes which lead to the long-lasting changes in excitability.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Friese J, Gleitz J, Gutser UT, Heubach JF, Matthiesen T, Wilffert B, Selve N. Aconitum sp. alkaloids: the modulation of voltage-dependent Na+ channels, toxicity and antinociceptive properties. Eur J Pharmacol 1997; 337:165-74. [PMID: 9430411 DOI: 10.1016/s0014-2999(97)01268-5] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alkaloids from Aconitum sp., used as analgesics in traditional Chinese medicine, were investigated to elucidate their antinociceptive and toxic properties considering: (1) binding to Na+ channel epitope site 2, (2) alterations in synaptosomal Na+ and Ca2+ concentration ([Na+]i, [Ca2+]i), (3) arrhythmogenic action of isolated atria, (4) antinociceptive and (5) acute toxic action in mice. The study revealed a high affinity group (Ki 1 microM) and a low affinity group (Ki 10 microM) of alkaloids binding to site 2. The compounds of the high affinity group induce an increase in synaptosomal [Na+]i and [Ca2+]i (EC50 3 microM), are antinociceptive (ED50, 25 microg/kg), provoke tachyarrhythmia and are highly toxic (LD50 70 microg/kg), whereas low affinity alkaloids reduce [Ca2+]i, induce bradycardia and are less antinociceptive (ED50 20 mg/kg) and less toxic (LD50 30 mg/kg). These results suggest that the alkaloids can be grouped in Na+ channel activating and blocking compounds, but none of the alkaloids seem to be suitable as analgesics because of the low LD50/ED50 values.
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Affiliation(s)
- J Friese
- Institute of Naturheilkunde, University Clinics Ulm, Germany.
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Ameri A. Inhibition of rat hippocampal excitability by the Aconitum alkaloid, 1-benzoylnapelline, but not by napelline. Eur J Pharmacol 1997; 335:145-52. [PMID: 9369367 DOI: 10.1016/s0014-2999(97)01205-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of the two structurally related Aconitum alkaloids, 1-benzoylnapelline and napelline, were investigated by extracellular recording of the stimulus-evoked population spike in the CA1 region of rat hippocampal slices in vitro. 1-Benzoylnapelline (1-100 microM) exerted a depressant action on the orthodromic as well as on the antidromic population spike. Napelline failed to evoke a significant effect at concentrations up to 100 microM. The inhibitory action induced by 1-benzoylnapelline was enhanced when the frequency of electrical stimulation was increased. In contrast, reversal of the inhibitory effect was accelerated when stimulation frequency was decreased. The activity-dependent mode of action of 1-benzoylnapelline raised the question of whether the drug is effective to suppress epileptiform activity. The results obtained from experiments on epileptiform hippocampal slices revealed a reduction of the burst duration and of the number of spikes in the burst as well as attenuation of the amplitude of the population spikes. These data support the conclusion that 1-benzoylnapelline, in contrast to the structurally related compound, napelline, has an activity-dependent inhibitory action on central neurons.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Ameri A, Gleitz J, Peters T. Inhibition of neuronal activity in rat hippocampal slices by Aconitum alkaloids. Brain Res 1996; 738:154-7. [PMID: 8949940 DOI: 10.1016/0006-8993(96)00990-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The structurally related Aconitum alkaloids aconitine, lappaconitine, and 6-benzoylheteratisine inhibited the orthodromic and antidromic population spike in hippocampal CA1 area in a frequency-dependent manner. Aconitine (1 microM) completely suppressed epileptiform activity induced by omission of Mg2+ as well as normal neuronal activity, whereas lappaconitine (10 microM) and 6-benzoylheteratisine (10 microM) diminished epileptiform activity by sparing normal neuronal activity.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Abstract
The effect of aconitine, a plant alkaloid known to bind at site 2 of the sodium channel, was investigated on neuronal excitability in hippocampal slices of adult and juvenile rats. Aconitine (0.01-1 microM) diminished the extracellularly recorded population spike in a concentration-dependent manner. At each concentration, the inhibitory action of aconitine was significantly stronger and was obtained after a shorter latency in slices of juvenile rats (20-25 days) as compared with slices of adult rats (45-50 days). When maximal inhibition was achieved, a prolonged application of aconitine evoked an increase in spike amplitude of up to 15% in slices of juvenile but not of adult rats. The latency of recovery from the aconitine-induced inhibition was also significantly shorter in slices of juvenile rats. This effect was concentration-dependent and significantly stronger in slices of juvenile rats. These observations indicate that juvenile hippocampi have a higher susceptibility to the effect of aconitine, but also provide a partial protective mechanism.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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Ameri A, Metzmeier P, Peters T. Frequency-dependent inhibition of neuronal activity by lappaconitine in normal and epileptic hippocampal slices. Br J Pharmacol 1996; 118:577-84. [PMID: 8762080 PMCID: PMC1909728 DOI: 10.1111/j.1476-5381.1996.tb15440.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. Extracellular recording of the stimulus-evoked population spike in the CA1 region of rat hippocampal slices in vitro was performed in order to investigate whether lappaconitine affects neuronal excitability. Lappaconitine is a diterpene alkaloid of plants of the Aconitum genus and has analgesic properties. 2. The results reveal an inhibitory action of lappaconitine (10 microM) manifested in a slow attenuation of the orthodromic and antidromic population spike. 3. The lappaconitine-induced inhibitory action was activity-dependent, that is, it was potentiated when frequency of electrical stimulation was increased. In contrast, washout of the neurotoxin was accelerated when stimulation frequency was decreased. 4. The activity-dependent action of lappaconitine raised the question of whether the drug is effective in suppressing the aberrant neuronal activity that occurs during an epileptic seizure. The results obtained from experiments on epileptic hippocampal slices demonstrated a selective reduction of the later spikes in the bursts with less effect on normal neuronal activity. 5. These data support the conclusion that lappaconitine, in addition to its antinociceptive effect, also has antiepileptic potency due to its highly activity-dependent mode of action.
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Affiliation(s)
- A Ameri
- Department of Pharmacy and Pharmacology of Natural Compounds, University of Ulm, Germany
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