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Theyel BB, Stevenson RJ, Connors BW. Activity-Dependent Ectopic Spiking in Parvalbumin-Expressing Interneurons of the Neocortex. eNeuro 2024; 11:ENEURO.0314-23.2024. [PMID: 38637152 PMCID: PMC11069434 DOI: 10.1523/eneuro.0314-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/12/2024] [Accepted: 03/17/2024] [Indexed: 04/20/2024] Open
Abstract
Canonically, action potentials of most mammalian neurons initiate at the axon initial segment (AIS) and propagate bidirectionally: orthodromically along the distal axon and retrogradely into the soma and dendrites. Under some circumstances, action potentials may initiate ectopically, at sites distal to the AIS, and propagate antidromically along the axon. These "ectopic action potentials" (EAPs) have been observed in experimental models of seizures and chronic pain, and more rarely in nonpathological forebrain neurons. Here we report that a large majority of parvalbumin-expressing (PV+) interneurons in the upper layers of mouse neocortex, from both orbitofrontal and primary somatosensory areas, fire EAPs after sufficient activation of their somata. Somatostatin-expressing interneurons also fire EAPs, though less robustly. Ectopic firing in PV+ cells occurs in varying temporal patterns and can persist for several seconds. PV+ cells evoke strong synaptic inhibition in pyramidal neurons and interneurons and play critical roles in cortical function. Our results suggest that ectopic spiking of PV+ interneurons is common and may contribute to both normal and pathological network functions of the neocortex.
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Affiliation(s)
- Brian B Theyel
- Department of Psychiatry and Human Behavior, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02912
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
- Care New England Medical Group, Providence, Rhode Island 02906
| | - Rachel J Stevenson
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
| | - Barry W Connors
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
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2
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Zhang YZ, Sapantzi S, Lin A, Doelfel SR, Connors BW, Theyel BB. Activity-dependent ectopic action potentials in regular-spiking neurons of the neocortex. Front Cell Neurosci 2023; 17:1267687. [PMID: 38034593 PMCID: PMC10685889 DOI: 10.3389/fncel.2023.1267687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/10/2023] [Indexed: 12/02/2023] Open
Abstract
Introduction Action potentials usually travel orthodromically along a neuron's axon, from the axon initial segment (AIS) toward the presynaptic terminals. Under some circumstances action potentials also travel in the opposite direction, antidromically, after being initiated at a distal location. Given their initiation at an atypical site, we refer to these events as "ectopic action potentials." Ectopic action potentials (EAPs) were initially observed in pathological conditions including seizures and nerve injury. Several studies have described regular-spiking (RS) pyramidal neurons firing EAPs in seizure models. Under nonpathological conditions, EAPs were reported in a few populations of neurons, and our group has found that EAPs can be induced in a large proportion of parvalbumin-expressing interneurons in the neocortex. Nevertheless, to our knowledge there have been no prior reports of ectopic firing in the largest population of neurons in the neocortex, pyramidal neurons, under nonpathological conditions. Methods We performed in vitro recordings utilizing the whole-cell patch clamp technique. To elicit EAPs, we triggered orthodromic action potentialswith either long, progressively increasing current steps, or with trains of brief pulses at 30, 60, or 100 Hz delivered in 3 different ways, varying in stimulus and resting period duration. Results We found that a large proportion (72.7%) of neocortical RS cells from mice can fire EAPs after a specific stimulus in vitro, and that most RS cells (56.1%) are capable of firing EAPs across a broad range of stimulus conditions. Of the 37 RS neurons in which we were able to elicit EAPs, it took an average of 863.8 orthodromic action potentials delivered over the course of an average of ~81.4 s before the first EAP was seen. We observed that some cells responded to specific stimulus frequencies while less selective, suggesting frequency tuning in a subset of the cells. Discussion Our findings suggest that pyramidal cells can integrate information over long time-scales before briefly entering a mode of self-generated firing that originates in distal axons. The surprising ubiquity of EAP generation in RS cells raises interesting questions about the potential roles of ectopic spiking in information processing, cortical oscillations, and seizure susceptibility.
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Affiliation(s)
- Yizhen Z. Zhang
- Department of Neuroscience, Brown University, Providence, RI, United States
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Stella Sapantzi
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Alice Lin
- Department of Neuroscience, Brown University, Providence, RI, United States
| | | | - Barry W. Connors
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Brian B. Theyel
- Department of Neuroscience, Brown University, Providence, RI, United States
- Department of Psychiatry and Human Behavior, Brown University, Providence, RI, United States
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Cai B, Wu D, Xie H, Chen Y, Wang H, Jin S, Song Y, Li A, Huang S, Wang S, Lu Y, Bao L, Xu F, Gong H, Li C, Zhang X. A direct spino-cortical circuit bypassing the thalamus modulates nociception. Cell Res 2023; 33:775-789. [PMID: 37311832 PMCID: PMC10542357 DOI: 10.1038/s41422-023-00832-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/19/2023] [Indexed: 06/15/2023] Open
Abstract
Nociceptive signals are usually transmitted to layer 4 neurons in somatosensory cortex via the spinothalamic-thalamocortical pathway. The layer 5 corticospinal neurons in sensorimotor cortex are reported to receive the output of neurons in superficial layers; and their descending axons innervate the spinal cord to regulate basic sensorimotor functions. Here, we show that a subset of layer 5 neurons receives spinal inputs through a direct spino-cortical circuit bypassing the thalamus, and thus define these neurons as spino-cortical recipient neurons (SCRNs). Morphological studies revealed that the branches from spinal ascending axons formed a kind of disciform structure with the descending axons from SCRNs in the basilar pontine nucleus (BPN). Electron microscopy and calcium imaging further confirmed that the axon terminals from spinal ascending neurons and SCRNs made functional synaptic contacts in the BPN, linking the ascending sensory pathway to the descending motor control pathway. Furthermore, behavioral tests indicated that the spino-cortical connection in the BPN was involved in nociceptive responses. In vivo calcium imaging showed that SCRNs responded to peripheral noxious stimuli faster than neighboring layer 4 cortical neurons in awake mice. Manipulating activities of SCRNs could modulate nociceptive behaviors. Therefore, this direct spino-cortical circuit represents a noncanonical pathway, allowing a fast sensory-motor transition of the brain in response to noxious stimuli.
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Affiliation(s)
- Bing Cai
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China
- Research Unit of Pain Medicine, Chinese Academy of Medical Sciences, Hengqin, Zhuhai, Guangdong, China
| | - Dan Wu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, CAS, Shanghai, China
| | - Hong Xie
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China
- Institute of Photonic Chips; School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Yan Chen
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China
- Research Unit of Pain Medicine, Chinese Academy of Medical Sciences, Hengqin, Zhuhai, Guangdong, China
| | - Huadong Wang
- Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, CAS, Shenzhen, Guangdong, China
| | - Sen Jin
- Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, CAS, Shenzhen, Guangdong, China
| | - Yuran Song
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China
- Research Unit of Pain Medicine, Chinese Academy of Medical Sciences, Hengqin, Zhuhai, Guangdong, China
| | - Anan Li
- HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu, China
| | - Shiqi Huang
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Sashuang Wang
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People's Hospital, Shenzhen, Guangdong, China
| | - Yingjin Lu
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
| | - Lan Bao
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, CAS, Shanghai, China
| | - Fuqiang Xu
- Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, CAS, Shenzhen, Guangdong, China
| | - Hui Gong
- HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu, China
| | - Changlin Li
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China.
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Shenzhen Nanshan People's Hospital, Shenzhen, Guangdong, China.
| | - Xu Zhang
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China.
- SIMR Joint Lab of Drug Innovation, Shanghai Advanced Research Institute, Chinese Academy of Sciences (CAS); Xuhui Central Hospital, Shanghai, China.
- Research Unit of Pain Medicine, Chinese Academy of Medical Sciences, Hengqin, Zhuhai, Guangdong, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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Trigo F, Kawaguchi SY. Analogue signaling of somatodendritic synaptic activity to axon enhances GABA release in young cerebellar molecular layer interneurons. eLife 2023; 12:e85971. [PMID: 37565643 PMCID: PMC10421593 DOI: 10.7554/elife.85971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/21/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are equipped with the digital signaling capacity by which they generate and faithfully propagate action potentials (APs), and also with the analogue signaling capacity by which subthreshold activity in dendrites and soma is transmitted down the axon. Despite intense work, the extent and physiological role for subthreshold synaptic activity reaching the presynaptic boutons has remained elusive because of the technical limitation to record from them. To address this issue, we made simultaneous patch-clamp recordings from the presynaptic varicosities of cerebellar GABAergic interneurons together with their parent soma or postsynaptic target cells in young rat slices and/or primary cultures. Our tour-de-force direct functional dissection indicates that the somatodendritic spontaneous excitatory synaptic potentials are transmitted down the axon for significant distances, depolarizing presynaptic boutons. These analogously transmitted excitatory synaptic potentials augment presynaptic Ca++ influx upon arrival of an immediately following AP through a mechanism that involves a voltage-dependent priming of the Ca++ channels, leading to an increase in GABA release, without any modification in the presynaptic AP waveform or residual Ca++. Our work highlights the role of the axon in synaptic integration.
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Affiliation(s)
- Federico Trigo
- Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente EstableMontevideoUruguay
| | - Shin-ya Kawaguchi
- Department of Biophysics, Graduate School of Science, Kyoto University Oiwake-choKyotoJapan
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El-Sayed RM, Fawzy MN, Zaki HF, Abd El-Haleim EA. Neuroprotection impact of biochanin A against pentylenetetrazol-kindled mice: Targeting NLRP3 inflammasome/TXNIP pathway and autophagy modulation. Int Immunopharmacol 2023; 115:109711. [PMID: 36640710 DOI: 10.1016/j.intimp.2023.109711] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/29/2022] [Accepted: 01/06/2023] [Indexed: 01/15/2023]
Abstract
Recurrent seizures characterize epilepsy, a complicated and multifaceted neurological disease. Several neurological alterations, such as cell death and the growth of gorse fibers, have been linked to epilepsy. The dentate gyrus of the hippocampus is particularly vulnerable to neuronal loss and abnormal neuroplastic changes in the pentylenetetrazol (PTZ) kindling model. Biochanin A has potent anti-inflammatory and antioxidant properties, according to previous evidence and its possible impact in epilepsy has never previously been claimed. The current work aimed to investigate biochanin A's anti-epileptic potential in PTZ-induced kindling model in mice. Chronic epilepsy was established in mice by giving PTZ (35 mg/kg, i.p) every other day for 21 days. Biochanin A (20 mg/kg) was given daily till the end of the experiment. Biochanin A pretreatment significantly reduced the severity of epileptogenesis by 51.7% and downregulated the histological changes in the CA3 region of the hippocampus by 42% along with displaying antioxidant/anti-inflammatory efficacy through upregulated hemeoxygenase-1 (HO-1) and, erythroid 2-related factor 2 (Nrf2) levels in the brain by 1.9-fold and 2-fold respectively, parallel to reduction of malondialdehyde (MDA), myeloperoxidase (MPO), glial fibrillary acidic protein (GFAP) and L-glutamate/IL-1β/TXNIB/NLRP3 axis. Moreover, biochanin A suppressed neuronal damage by reducing the astrocytes' activation and significantly attenuated the PTZ-induced increase in LC3 levels by 55.5%. Furthermore, molecular docking findings revealed that BIOCHANIN A has a higher affinity for phosphoinositide 3-kinase (PI3k), threonine kinase2 (AKT2), and mammalian target of rapamycin complex 1 (mTORC1) indicating the neuroprotective and anti-epileptic characteristics of biochanin A in the brain tissue of PTZ-kindled mice.
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Affiliation(s)
- Rehab M El-Sayed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Sinai University, El-Arish, Egypt
| | - Mohamed N Fawzy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Sinai University, El-Arish, Egypt.
| | - Hala F Zaki
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Enas A Abd El-Haleim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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6
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Mateus JC, Lopes C, Aroso M, Costa AR, Gerós A, Meneses J, Faria P, Neto E, Lamghari M, Sousa MM, Aguiar P. Bidirectional flow of action potentials in axons drives activity dynamics in neuronal cultures. J Neural Eng 2021; 18. [PMID: 34891149 DOI: 10.1088/1741-2552/ac41db] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/10/2021] [Indexed: 12/20/2022]
Abstract
Objective. Recent technological advances are revealing the complex physiology of the axon and challenging long-standing assumptions. Namely, while most action potential (AP) initiation occurs at the axon initial segment in central nervous system neurons, initiation in distal parts of the axon has been reported to occur in both physiological and pathological conditions. The functional role of these ectopic APs, if exists, is still not clear, nor its impact on network activity dynamics.Approach. Using an electrophysiology platform specifically designed for assessing axonal conduction we show here for the first time regular and effective bidirectional axonal conduction in hippocampal and dorsal root ganglia cultures. We investigate and characterize this bidirectional propagation both in physiological conditions and after distal axotomy.Main results.A significant fraction of APs are not coming from the canonical synapse-dendrite-soma signal flow, but instead from signals originating at the distal axon. Importantly, antidromic APs may carry information and can have a functional impact on the neuron, as they consistently depolarize the soma. Thus, plasticity or gene transduction mechanisms triggered by soma depolarization can also be affected by these antidromic APs. Conduction velocity is asymmetrical, with antidromic conduction being slower than orthodromic.Significance.Altogether these findings have important implications for the study of neuronal functionin vitro, reshaping our understanding on how information flows in neuronal cultures.
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Affiliation(s)
- J C Mateus
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Cdf Lopes
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - M Aroso
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - A R Costa
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - A Gerós
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP-Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - J Meneses
- CDRSP-IPL-Centre for Rapid and Sustainable Product Development-Instituto Politécnico de Leiria, Marinha Grande, Portugal.,IBEB-Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - P Faria
- CDRSP-IPL-Centre for Rapid and Sustainable Product Development-Instituto Politécnico de Leiria, Marinha Grande, Portugal
| | - E Neto
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - M Lamghari
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - M M Sousa
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - P Aguiar
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
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7
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Daur N, Zhang Y, Nadim F, Bucher D. Mutual Suppression of Proximal and Distal Axonal Spike Initiation Determines the Output Patterns of a Motor Neuron. Front Cell Neurosci 2019; 13:477. [PMID: 31708748 PMCID: PMC6819512 DOI: 10.3389/fncel.2019.00477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/10/2019] [Indexed: 11/13/2022] Open
Abstract
Axonal spike initiation at sites far from somatodendritic integration occurs in a range of systems, but its contribution to neuronal output activity is not well understood. We studied the interactions of distal and proximal spike initiation in an unmyelinated motor axon of the stomatogastric nervous system in the lobster, Homarus americanus. The peripheral axons of the pyloric dilator (PD) neurons generate tonic spiking in response to dopamine application. Centrally generated bursting activity and peripheral spike initiation had mutually suppressive effects. The two PD neurons and the electrically coupled oscillatory anterior burster (AB) neuron form the pacemaker ensemble of the pyloric central pattern generator, and antidromic invasion of central compartments by peripherally generated spikes caused spikelets in AB. Antidromic spikes suppressed burst generation in an activity-dependent manner: slower rhythms were diminished or completely disrupted, while fast rhythmic activity remained robust. Suppression of bursting was based on interference with the underlying slow wave oscillations in AB and PD, rather than a direct effect on spike initiation. A simplified multi-compartment circuit model of the pacemaker ensemble replicated this behavior. Antidromic activity disrupted slow wave oscillations by resetting the inward and outward current trajectories in each spike interval. Centrally generated bursting activity in turn suppressed peripheral spike initiation in an activity-dependent manner. Fast bursting eliminated peripheral spike initiation, while slower bursting allowed peripheral spike initiation to continue during the intervals between bursts. The suppression of peripheral spike initiation was associated with a small after-hyperpolarization in the sub-millivolt range. A realistic model of the PD axon replicated this behavior and showed that a sub-millivolt cumulative after-hyperpolarization across bursts was sufficient to eliminate peripheral spike initiation. This effect was based on the dynamic interaction between slow activity-dependent hyperpolarization caused by the Na+/K+-pump and inward rectification through the hyperpolarization-activated inward current, I h . These results demonstrate that interactions between different spike initiation sites based on spike propagation can shift the relative contributions of different types of activity in an activity-dependent manner. Therefore, distal axonal spike initiation can play an important role in shaping neural output, conditional on the relative level of centrally generated activity.
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Affiliation(s)
- Nelly Daur
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark, Newark, NJ, United States
| | - Yang Zhang
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, United States
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark, Newark, NJ, United States.,Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, United States
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark, Newark, NJ, United States
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Abstract
Analog signaling describes the use of graded voltage changes as signals in the axonal compartment. Analog signaling has been described originally in invertebrates but more recent work has established its presence in the mammalian brain (Alle and Geiger, 2006; Shu et al., 2006). In recent years, many different groups have contributed to the understanding of the physiological significance of analog signaling from a cellular perspective (for a recent review the reader may take a look at the work by Zbili and Debanne, 2019 in this Frontiers in Neuroscience Special Issue). The great majority of the experimental work related to analog signaling, however, concerns the propagation of subthreshold voltage changes from the soma to the axon. Much less attention has been paid to the propagation of subthreshold voltage changes in the opposite direction, from the axon to the soma, or to the propagation of local signals within the axon. In this mini review we will describe these other variants of analog signaling that we call here “antidromic” coupling and “local” coupling.
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Affiliation(s)
- Federico F Trigo
- CNRS UMR8003, SPPIN Laboratory, Cerebellar Neurophysiology Group, Faculté des Sciences Fondamentales et Biomédicales, Université de Paris, Paris, France.,Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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9
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Rong S, Wan D, Fan Y, Liu S, Sun K, Huo J, Zhang P, Li X, Xie X, Wang F, Sun T. Amentoflavone Affects Epileptogenesis and Exerts Neuroprotective Effects by Inhibiting NLRP3 Inflammasome. Front Pharmacol 2019; 10:856. [PMID: 31417409 PMCID: PMC6682693 DOI: 10.3389/fphar.2019.00856] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/04/2019] [Indexed: 01/03/2023] Open
Abstract
Brain inflammation is one of the main causes of epileptogenesis, a chronic process triggered by various insults, including genetic or acquired factors that enhance susceptibility to seizures. Amentoflavone, a naturally occurring biflavonoid compound that has anti-inflammatory effects, exerts neuroprotective effects against nervous system diseases. In the present study, we aimed to investigate the effects of amentoflavone on epilepsy in vivo and in vitro and elucidate the underlying mechanism. The chronic epilepsy model and BV2 microglial cellular inflammation model were established by pentylenetetrazole (PTZ) kindling or lipopolysaccharide (LPS) stimulation. Cognitive dysfunction was tested by Morris water maze while hippocampal neuronal apoptosis was evaluated by immunofluorescence staining. The levels of nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome complexes and inflammatory cytokines were determined using quantitative real-time polymerase chain reaction, Western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay. Amentoflavone reduced seizure susceptibility, minimized PTZ-induced cognitive dysfunction, and blocked the apoptosis of hippocampal neurons in PTZ-induced kindling mice. Amentoflavone also inhibited the activation of the NLRP3 inflammasome and decreased the levels of inflammatory cytokines in the hippocampus of PTZ-induced kindling mice. Additionally, amentoflavone could alleviate the LPS-induced inflammatory response by inhibiting the NLRP3 inflammasome in LPS-induced BV2 microglial cells. Our results indicated that amentoflavone affects epileptogenesis and exerts neuroprotective effects by inhibiting the NLRP3 inflammasome and, thus, mediating the inflammatory process in PTZ-induced kindling mice and LPS-induced BV2 microglial cells. Therefore, amentoflavone may be a potential treatment option for epilepsy.
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Affiliation(s)
- Shikuo Rong
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Ding Wan
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China.,Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Yayun Fan
- Department of Gynaecology, Jingzhou Central Hospital affiliated to Huazhong University of Science and Technology, Jingzhou, China
| | - Shenhai Liu
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Kuisheng Sun
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Junming Huo
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Peng Zhang
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Xinxiao Li
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Xiaoliang Xie
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China.,Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Tao Sun
- Ningxia Key Laboratory of Cerebrocranial Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China.,Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
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10
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Fékété A, Debanne D. Somatic modulation of ectopic action potential initiation in distal axons. J Physiol 2018; 596:5067-5068. [PMID: 30198556 DOI: 10.1113/jp277012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Aurélie Fékété
- UNIS, UMR-1072, INSERM, Aix-Marseille University, Marseille, France
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