Nrupen Pakalapati, Chia-Chu Chiang, Dominique M Durand
{"title":"对胼胝体的低频刺激可通过γ-氨基丁酸 B 型受体和缓慢过极化后介导的组织兴奋性降低来抑制大脑皮层的癫痫样活动。","authors":"Nrupen Pakalapati, Chia-Chu Chiang, Dominique M Durand","doi":"10.1111/epi.18135","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>Deep brain stimulation, particularly low-frequency stimulation (LFS) targeting fiber tracts, has emerged as a potential therapy for drug-resistant epilepsy (DRE) and for generalized epilepsy, both of which pose significant treatment challenges. LFS diffusely suppresses seizures in the cortex when applied to fiber tracts like the corpus callosum (CC). Nevertheless, the specific processes responsible for suppressing epileptic activity in the cortex induced by LFS remain unclear. This study investigates the mechanisms underlying the antiepileptic effect in the cortex of LFS of the CC in coronal rodent brain slices.</p><p><strong>Methods: </strong>An in vitro 4-aminopyridine (4-AP) seizure model of cortical seizures was generated. LFS stimulation parameters were optimized to provide the largest antiepileptic effect in the cortex when applied to the CC. Changes to tissue excitability and percent time spent seizing were measured due to LFS in artificial cerebrospinal fluid, 4-AP, and in the presence of various specific and nonspecific γ-aminobutyric acid type B (GABA<sub>B</sub>) and slow afterhyperpolarization (sAHP) antagonists.</p><p><strong>Results: </strong>LFS significantly suppressed seizure activity in the cortex, with an optimal frequency of 5 Hz (76.5%). Tissue excitability during LFS reduces across a wide range of interstimulus intervals, with a maximum reduction at 200 ms. Notably, the tissue excitability remains depressed at 1000 ms. LFS, in the presence of GABA<sub>B</sub> antagonists, had diminished seizure reduction (<15%) and failed to reduce tissue excitability in the 50-400-ms range. Tissue excitability measured with paired pulses in the 600-1000-ms range was depressed in the presence of GABA<sub>B</sub> antagonists, suggesting a different antiepileptic mechanism was active. Upon administering sAHP antagonists, seizure reduction was once again diminished (<15%). Upon administration of both sAHP and GABA<sub>B</sub> antagonists, LFS failed to provide any meaningful seizure reduction (<5%).</p><p><strong>Significance: </strong>LFS of the CC provides an antiepileptic effect in the cortex with well-understood mechanisms and could be an alternative to surgical intervention for patients suffering from DRE.</p>","PeriodicalId":11768,"journal":{"name":"Epilepsia","volume":null,"pages":null},"PeriodicalIF":6.6000,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Low-frequency stimulation of corpus callosum suppresses epileptiform activity in the cortex through γ-aminobutyric acid type B receptor and slow afterhyperpolarization-mediated reduction in tissue excitability.\",\"authors\":\"Nrupen Pakalapati, Chia-Chu Chiang, Dominique M Durand\",\"doi\":\"10.1111/epi.18135\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Objective: </strong>Deep brain stimulation, particularly low-frequency stimulation (LFS) targeting fiber tracts, has emerged as a potential therapy for drug-resistant epilepsy (DRE) and for generalized epilepsy, both of which pose significant treatment challenges. LFS diffusely suppresses seizures in the cortex when applied to fiber tracts like the corpus callosum (CC). Nevertheless, the specific processes responsible for suppressing epileptic activity in the cortex induced by LFS remain unclear. This study investigates the mechanisms underlying the antiepileptic effect in the cortex of LFS of the CC in coronal rodent brain slices.</p><p><strong>Methods: </strong>An in vitro 4-aminopyridine (4-AP) seizure model of cortical seizures was generated. LFS stimulation parameters were optimized to provide the largest antiepileptic effect in the cortex when applied to the CC. Changes to tissue excitability and percent time spent seizing were measured due to LFS in artificial cerebrospinal fluid, 4-AP, and in the presence of various specific and nonspecific γ-aminobutyric acid type B (GABA<sub>B</sub>) and slow afterhyperpolarization (sAHP) antagonists.</p><p><strong>Results: </strong>LFS significantly suppressed seizure activity in the cortex, with an optimal frequency of 5 Hz (76.5%). Tissue excitability during LFS reduces across a wide range of interstimulus intervals, with a maximum reduction at 200 ms. Notably, the tissue excitability remains depressed at 1000 ms. LFS, in the presence of GABA<sub>B</sub> antagonists, had diminished seizure reduction (<15%) and failed to reduce tissue excitability in the 50-400-ms range. Tissue excitability measured with paired pulses in the 600-1000-ms range was depressed in the presence of GABA<sub>B</sub> antagonists, suggesting a different antiepileptic mechanism was active. Upon administering sAHP antagonists, seizure reduction was once again diminished (<15%). Upon administration of both sAHP and GABA<sub>B</sub> antagonists, LFS failed to provide any meaningful seizure reduction (<5%).</p><p><strong>Significance: </strong>LFS of the CC provides an antiepileptic effect in the cortex with well-understood mechanisms and could be an alternative to surgical intervention for patients suffering from DRE.</p>\",\"PeriodicalId\":11768,\"journal\":{\"name\":\"Epilepsia\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":6.6000,\"publicationDate\":\"2024-10-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Epilepsia\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1111/epi.18135\",\"RegionNum\":1,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CLINICAL NEUROLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Epilepsia","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1111/epi.18135","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CLINICAL NEUROLOGY","Score":null,"Total":0}
Low-frequency stimulation of corpus callosum suppresses epileptiform activity in the cortex through γ-aminobutyric acid type B receptor and slow afterhyperpolarization-mediated reduction in tissue excitability.
Objective: Deep brain stimulation, particularly low-frequency stimulation (LFS) targeting fiber tracts, has emerged as a potential therapy for drug-resistant epilepsy (DRE) and for generalized epilepsy, both of which pose significant treatment challenges. LFS diffusely suppresses seizures in the cortex when applied to fiber tracts like the corpus callosum (CC). Nevertheless, the specific processes responsible for suppressing epileptic activity in the cortex induced by LFS remain unclear. This study investigates the mechanisms underlying the antiepileptic effect in the cortex of LFS of the CC in coronal rodent brain slices.
Methods: An in vitro 4-aminopyridine (4-AP) seizure model of cortical seizures was generated. LFS stimulation parameters were optimized to provide the largest antiepileptic effect in the cortex when applied to the CC. Changes to tissue excitability and percent time spent seizing were measured due to LFS in artificial cerebrospinal fluid, 4-AP, and in the presence of various specific and nonspecific γ-aminobutyric acid type B (GABAB) and slow afterhyperpolarization (sAHP) antagonists.
Results: LFS significantly suppressed seizure activity in the cortex, with an optimal frequency of 5 Hz (76.5%). Tissue excitability during LFS reduces across a wide range of interstimulus intervals, with a maximum reduction at 200 ms. Notably, the tissue excitability remains depressed at 1000 ms. LFS, in the presence of GABAB antagonists, had diminished seizure reduction (<15%) and failed to reduce tissue excitability in the 50-400-ms range. Tissue excitability measured with paired pulses in the 600-1000-ms range was depressed in the presence of GABAB antagonists, suggesting a different antiepileptic mechanism was active. Upon administering sAHP antagonists, seizure reduction was once again diminished (<15%). Upon administration of both sAHP and GABAB antagonists, LFS failed to provide any meaningful seizure reduction (<5%).
Significance: LFS of the CC provides an antiepileptic effect in the cortex with well-understood mechanisms and could be an alternative to surgical intervention for patients suffering from DRE.
期刊介绍:
Epilepsia is the leading, authoritative source for innovative clinical and basic science research for all aspects of epilepsy and seizures. In addition, Epilepsia publishes critical reviews, opinion pieces, and guidelines that foster understanding and aim to improve the diagnosis and treatment of people with seizures and epilepsy.