1
|
Belghazi M, Iborra C, Toutendji O, Lasserre M, Debanne D, Goaillard JM, Marquèze-Pouey B. High-Resolution Proteomics Unravel a Native Functional Complex of Cav1.3, SK3, and Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels in Midbrain Dopaminergic Neurons. Cells 2024; 13:944. [PMID: 38891076 PMCID: PMC11172389 DOI: 10.3390/cells13110944] [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: 03/04/2024] [Revised: 05/21/2024] [Accepted: 05/26/2024] [Indexed: 06/21/2024] Open
Abstract
Pacemaking activity in substantia nigra dopaminergic neurons is generated by the coordinated activity of a variety of distinct somatodendritic voltage- and calcium-gated ion channels. We investigated whether these functional interactions could arise from a common localization in macromolecular complexes where physical proximity would allow for efficient interaction and co-regulations. For that purpose, we immunopurified six ion channel proteins involved in substantia nigra neuron autonomous firing to identify their molecular interactions. The ion channels chosen as bait were Cav1.2, Cav1.3, HCN2, HCN4, Kv4.3, and SK3 channel proteins, and the methods chosen to determine interactions were co-immunoprecipitation analyzed through immunoblot and mass spectrometry as well as proximity ligation assay. A macromolecular complex composed of Cav1.3, HCN, and SK3 channels was unraveled. In addition, novel potential interactions between SK3 channels and sclerosis tuberous complex (Tsc) proteins, inhibitors of mTOR, and between HCN4 channels and the pro-degenerative protein Sarm1 were uncovered. In order to demonstrate the presence of these molecular interactions in situ, we used proximity ligation assay (PLA) imaging on midbrain slices containing the substantia nigra, and we could ascertain the presence of these protein complexes specifically in substantia nigra dopaminergic neurons. Based on the complementary functional role of the ion channels in the macromolecular complex identified, these results suggest that such tight interactions could partly underly the robustness of pacemaking in dopaminergic neurons.
Collapse
Affiliation(s)
- Maya Belghazi
- CRN2M Centre de Recherche Neurobiologie-Neurophysiologie, CNRS, UMR7286, Aix-Marseille Université, 13015 Marseille, France;
- Institut de Microbiologie de la Méditerranée (IMM), CNRS, Aix-Marseille Université, 13009 Marseille, France
| | - Cécile Iborra
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Ophélie Toutendji
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Manon Lasserre
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Dominique Debanne
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| | - Jean-Marc Goaillard
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
- Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, 13005 Marseille, France
| | - Béatrice Marquèze-Pouey
- Ion Channel and Synaptic Neurobiology, INSERM, UMR1072, Aix-Marseille Université, 13015 Marseille, France; (C.I.); (O.T.); (M.L.); (D.D.); (J.-M.G.)
| |
Collapse
|
2
|
Studtmann C, Ladislav M, Safari M, Khondaker R, Chen Y, Vaughan GA, Topolski MA, Tomović E, Balík A, Swanger SA. Ventral posterolateral and ventral posteromedial thalamocortical neurons have distinct physiological properties. J Neurophysiol 2023; 130:1492-1507. [PMID: 37937368 PMCID: PMC11068404 DOI: 10.1152/jn.00525.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 10/09/2023] [Accepted: 11/01/2023] [Indexed: 11/09/2023] Open
Abstract
Somatosensory information is propagated from the periphery to the cerebral cortex by two parallel pathways through the ventral posterolateral (VPL) and ventral posteromedial (VPM) thalamus. VPL and VPM neurons receive somatosensory signals from the body and head, respectively. VPL and VPM neurons may also receive cell type-specific GABAergic input from the reticular nucleus of the thalamus. Although VPL and VPM neurons have distinct connectivity and physiological roles, differences in their functional properties remain unclear as they are often studied as one ventrobasal thalamus neuron population. Here, we directly compared synaptic and intrinsic properties of VPL and VPM neurons in C57Bl/6J mice of both sexes aged P25-P32. VPL neurons showed greater depolarization-induced spike firing and spike frequency adaptation than VPM neurons. VPL and VPM neurons fired similar numbers of spikes during hyperpolarization rebound bursts, but VPM neurons exhibited shorter burst latency compared with VPL neurons, which correlated with larger sag potential. VPM neurons had larger membrane capacitance and more complex dendritic arbors. Recordings of spontaneous and evoked synaptic transmission suggested that VPL neurons receive stronger excitatory synaptic input, whereas inhibitory synapse strength was stronger in VPM neurons. This work indicates that VPL and VPM thalamocortical neurons have distinct intrinsic and synaptic properties. The observed functional differences could have important implications for their specific physiological and pathophysiological roles within the somatosensory thalamocortical network.NEW & NOTEWORTHY This study revealed that somatosensory thalamocortical neurons in the VPL and VPM have substantial differences in excitatory synaptic input and intrinsic firing properties. The distinct properties suggest that VPL and VPM neurons could process somatosensory information differently and have selective vulnerability to disease. This work improves our understanding of nucleus-specific neuron function in the thalamus and demonstrates the critical importance of studying these parallel somatosensory pathways separately.
Collapse
Affiliation(s)
- Carleigh Studtmann
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Marek Ladislav
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
| | - Mona Safari
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Rabeya Khondaker
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Yang Chen
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Grace A Vaughan
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, Virginia, United States
| | - Mackenzie A Topolski
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
| | - Eni Tomović
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Balík
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Sharon A Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States
- Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, Virginia, United States
| |
Collapse
|
3
|
Crunelli V, David F, Morais TP, Lorincz ML. HCN channels and absence seizures. Neurobiol Dis 2023; 181:106107. [PMID: 37001612 DOI: 10.1016/j.nbd.2023.106107] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
Hyperpolarization-activation cyclic nucleotide-gated (HCN) channels were for the first time implicated in absence seizures (ASs) when an abnormal Ih (the current generated by these channels) was reported in neocortical layer 5 neurons of a mouse model. Genetic studies of large cohorts of children with Childhood Absence Epilepsy (where ASs are the only clinical symptom) have identified only 3 variants in HCN1 (one of the genes that code for the 4 HCN channel isoforms, HCN1-4), with one (R590Q) mutation leading to loss-of-function. Due to the multi-faceted effects that HCN channels exert on cellular excitability and neuronal network dynamics as well as their modulation by environmental factors, it has been difficult to identify the detailed mechanism by which different HCN isoforms modulate ASs. In this review, we systematically and critically analyze evidence from established AS models and normal non-epileptic animals with area- and time-selective ablation of HCN1, HCN2 and HCN4. Notably, whereas knockout of rat HCN1 and mouse HCN2 leads to the expression of ASs, the pharmacological block of all HCN channel isoforms abolishes genetically determined ASs. These seemingly contradictory results could be reconciled by taking into account the well-known opposite effects of Ih on cellular excitability and network function. Whereas existing evidence from mouse and rat AS models indicates that pan-HCN blockers may provide a novel approach for the treatment of human ASs, the development of HCN isoform-selective drugs would greatly contribute to current research on the role for these channels in ASs generation and maintenance as well as offer new potential clinical applications.
Collapse
Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK.
| | - Francois David
- Integrative Neuroscience and Cognition Center, Paris University, Paris, France
| | - Tatiana P Morais
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, Malta University, Msida, Malta
| | - Magor L Lorincz
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK; Department of Physiology, Szeged University, Szeged, Hungary.
| |
Collapse
|
4
|
Yan Y, Zhu M, Cao X, Xu G, Shen W, Li F, Zhang J, Luo L, Zhang X, Zhang D, Liu T. Thalamocortical Circuit Controls Neuropathic Pain via Up-regulation of HCN2 in the Ventral Posterolateral Thalamus. Neurosci Bull 2023; 39:774-792. [PMID: 36538279 PMCID: PMC10169982 DOI: 10.1007/s12264-022-00989-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 09/07/2022] [Indexed: 12/24/2022] Open
Abstract
The thalamocortical (TC) circuit is closely associated with pain processing. The hyperpolarization-activated cyclic nucleotide-gated (HCN) 2 channel is predominantly expressed in the ventral posterolateral thalamus (VPL) that has been shown to mediate neuropathic pain. However, the role of VPL HCN2 in modulating TC circuit activity is largely unknown. Here, by using optogenetics, neuronal tracing, electrophysiological recordings, and virus knockdown strategies, we showed that the activation of VPL TC neurons potentiates excitatory synaptic transmission to the hindlimb region of the primary somatosensory cortex (S1HL) as well as mechanical hypersensitivity following spared nerve injury (SNI)-induced neuropathic pain in mice. Either pharmacological blockade or virus knockdown of HCN2 (shRNA-Hcn2) in the VPL was sufficient to alleviate SNI-induced hyperalgesia. Moreover, shRNA-Hcn2 decreased the excitability of TC neurons and synaptic transmission of the VPL-S1HL circuit. Together, our studies provide a novel mechanism by which HCN2 enhances the excitability of the TC circuit to facilitate neuropathic pain.
Collapse
Affiliation(s)
- Yi Yan
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Mengye Zhu
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Xuezhong Cao
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Gang Xu
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Wei Shen
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Fan Li
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Jinjin Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Lingyun Luo
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China
| | - Xuexue Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China.
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China.
| | - Daying Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
- Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, 330006, China.
- Key Laboratory of Neuropathic Pain, Healthcare Commission of Jiangxi Province, Nanchang, 330006, China.
| | - Tao Liu
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
| |
Collapse
|
5
|
Kessi M, Peng J, Duan H, He H, Chen B, Xiong J, Wang Y, Yang L, Wang G, Kiprotich K, Bamgbade OA, He F, Yin F. The Contribution of HCN Channelopathies in Different Epileptic Syndromes, Mechanisms, Modulators, and Potential Treatment Targets: A Systematic Review. Front Mol Neurosci 2022; 15:807202. [PMID: 35663267 PMCID: PMC9161305 DOI: 10.3389/fnmol.2022.807202] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Background Hyperpolarization-activated cyclic nucleotide-gated (HCN) current reduces dendritic summation, suppresses dendritic calcium spikes, and enables inhibitory GABA-mediated postsynaptic potentials, thereby suppressing epilepsy. However, it is unclear whether increased HCN current can produce epilepsy. We hypothesized that gain-of-function (GOF) and loss-of-function (LOF) variants of HCN channel genes may cause epilepsy. Objectives This systematic review aims to summarize the role of HCN channelopathies in epilepsy, update genetic findings in patients, create genotype–phenotype correlations, and discuss animal models, GOF and LOF mechanisms, and potential treatment targets. Methods The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, for all years until August 2021. Results We identified pathogenic variants of HCN1 (n = 24), HCN2 (n = 8), HCN3 (n = 2), and HCN4 (n = 6) that were associated with epilepsy in 74 cases (43 HCN1, 20 HCN2, 2 HCN3, and 9 HCN4). Epilepsy was associated with GOF and LOF variants, and the mechanisms were indeterminate. Less than half of the cases became seizure-free and some developed drug-resistant epilepsy. Of the 74 cases, 12 (16.2%) died, comprising HCN1 (n = 4), HCN2 (n = 2), HCN3 (n = 2), and HCN4 (n = 4). Of the deceased cases, 10 (83%) had a sudden unexpected death in epilepsy (SUDEP) and 2 (16.7%) due to cardiopulmonary failure. SUDEP affected more adults (n = 10) than children (n = 2). HCN1 variants p.M234R, p.C329S, p.V414M, p.M153I, and p.M305L, as well as HCN2 variants p.S632W and delPPP (p.719–721), were associated with different phenotypes. HCN1 p.L157V and HCN4 p.R550C were associated with genetic generalized epilepsy. There are several HCN animal models, pharmacological targets, and modulators, but precise drugs have not been developed. Currently, there are no HCN channel openers. Conclusion We recommend clinicians to include HCN genes in epilepsy gene panels. Researchers should explore the possible underlying mechanisms for GOF and LOF variants by identifying the specific neuronal subtypes and neuroanatomical locations of each identified pathogenic variant. Researchers should identify specific HCN channel openers and blockers with high binding affinity. Such information will give clarity to the involvement of HCN channelopathies in epilepsy and provide the opportunity to develop targeted treatments.
Collapse
Affiliation(s)
- Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Department of Pediatrics, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Haolin Duan
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Hailan He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Guoli Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Karlmax Kiprotich
- Department of Epidemiology and Medical Statistics, School of Public Health, Moi University, Eldoret, Kenya
| | - Olumuyiwa A. Bamgbade
- Department of Anesthesiology and Pharmacology, University of British Columbia, Vancouver, BC, Canada
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- *Correspondence: Fei Yin
| |
Collapse
|
6
|
Daniel NH, Aravind A, Thakur P. Are ion channels potential therapeutic targets for Parkinson's disease? Neurotoxicology 2021; 87:243-257. [PMID: 34699791 DOI: 10.1016/j.neuro.2021.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/15/2021] [Accepted: 10/21/2021] [Indexed: 01/31/2023]
Abstract
Parkinson's disease (PD) is primarily associated with the progressive neurodegeneration of the dopaminergic neurons in the substantia nigra region of the brain. The resulting motor symptoms are managed with the help of dopamine replacement therapies. However, these therapeutics do not prevent the neurodegeneration underlying the disease and therefore lose their effectiveness in managing disease symptoms over time. Thus, there is an urgent need to develop newer therapeutics for the benefit of patients. The release of dopamine and the firing activity of substantia nigra neurons is regulated by several ion channels that act in concert. Dysregulations of these channels cause the aberrant movement of various ions in the intracellular milieu. This eventually leads to disruption of intracellular signalling cascades, alterations in cellular homeostasis, and bioenergetic deficits. Therefore, ion channels play a central role in driving the high vulnerability of dopaminergic neurons to degenerate during PD. Targeting ion channels offers an attractive mechanistic strategy to combat the process of neurodegeneration. In this review, we highlight the evidence pointing to the role of various ion channels in driving the PD processes. In addition, we also discuss the various drugs or compounds that target the ion channels and have shown neuroprotective potential in the in-vitro and in-vivo models of PD. We also discuss the current clinical status of various drugs targeting the ion channels in the context of PD.
Collapse
Affiliation(s)
- Neha Hanna Daniel
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India
| | - Ananya Aravind
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India
| | - Poonam Thakur
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India.
| |
Collapse
|
7
|
Combe CL, Gasparini S. I h from synapses to networks: HCN channel functions and modulation in neurons. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:119-132. [PMID: 34181891 DOI: 10.1016/j.pbiomolbio.2021.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/25/2021] [Accepted: 06/03/2021] [Indexed: 01/16/2023]
Abstract
Hyperpolarization-activated cyclic nucleotide gated (HCN) channels and the current they carry, Ih, are widely and diversely distributed in the central nervous system (CNS). The distribution of the four subunits of HCN channels is variable within the CNS, within brain regions, and often within subcellular compartments. The precise function of Ih can depend heavily on what other channels are co-expressed. In this review, we give an overview of HCN channel structure, distribution, and modulation by cyclic adenosine monophosphate (cAMP). We then discuss HCN channel and Ih functions, where we have parsed the roles into two main effects: a steady effect on maintaining the resting membrane potential at relatively depolarized values, and slow channel dynamics. Within this framework, we discuss Ih involvement in resonance, synaptic integration, transmitter release, plasticity, and point out a special case, where the effects of Ih on the membrane potential and its slow channel dynamics have dual roles in thalamic neurons.
Collapse
Affiliation(s)
- Crescent L Combe
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Sonia Gasparini
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA.
| |
Collapse
|
8
|
Dwivedi D, Bhalla US. Physiology and Therapeutic Potential of SK, H, and M Medium AfterHyperPolarization Ion Channels. Front Mol Neurosci 2021; 14:658435. [PMID: 34149352 PMCID: PMC8209339 DOI: 10.3389/fnmol.2021.658435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/13/2021] [Indexed: 12/19/2022] Open
Abstract
SK, HCN, and M channels are medium afterhyperpolarization (mAHP)-mediating ion channels. The three channels co-express in various brain regions, and their collective action strongly influences cellular excitability. However, significant diversity exists in the expression of channel isoforms in distinct brain regions and various subcellular compartments, which contributes to an equally diverse set of specific neuronal functions. The current review emphasizes the collective behavior of the three classes of mAHP channels and discusses how these channels function together although they play specialized roles. We discuss the biophysical properties of these channels, signaling pathways that influence the activity of the three mAHP channels, various chemical modulators that alter channel activity and their therapeutic potential in treating various neurological anomalies. Additionally, we discuss the role of mAHP channels in the pathophysiology of various neurological diseases and how their modulation can alleviate some of the symptoms.
Collapse
Affiliation(s)
- Deepanjali Dwivedi
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.,Department of Neurobiology, Harvard Medical School, Boston, MA, United States.,Stanley Center at the Broad, Cambridge, MA, United States
| | - Upinder S Bhalla
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India
| |
Collapse
|
9
|
O'Reilly C, Iavarone E, Yi J, Hill SL. Rodent somatosensory thalamocortical circuitry: Neurons, synapses, and connectivity. Neurosci Biobehav Rev 2021; 126:213-235. [PMID: 33766672 DOI: 10.1016/j.neubiorev.2021.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 02/15/2021] [Accepted: 03/14/2021] [Indexed: 01/21/2023]
Abstract
As our understanding of the thalamocortical system deepens, the questions we face become more complex. Their investigation requires the adoption of novel experimental approaches complemented with increasingly sophisticated computational modeling. In this review, we take stock of current data and knowledge about the circuitry of the somatosensory thalamocortical loop in rodents, discussing common principles across modalities and species whenever appropriate. We review the different levels of organization, including the cells, synapses, neuroanatomy, and network connectivity. We provide a complete overview of this system that should be accessible for newcomers to this field while nevertheless being comprehensive enough to serve as a reference for seasoned neuroscientists and computational modelers studying the thalamocortical system. We further highlight key gaps in data and knowledge that constitute pressing targets for future experimental work. Filling these gaps would provide invaluable information for systematically unveiling how this system supports behavioral and cognitive processes.
Collapse
Affiliation(s)
- Christian O'Reilly
- Azrieli Centre for Autism Research, Montreal Neurological Institute, McGill University, Montreal, Canada; Ronin Institute, Montclair, NJ, USA; Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland.
| | - Elisabetta Iavarone
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Jane Yi
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Sean L Hill
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland; Department of Psychiatry, University of Toronto, Toronto, Canada; Centre for Addiction and Mental Health, Toronto, Canada.
| |
Collapse
|
10
|
Schwerin S, Kopp C, Pircher E, Schneider G, Kreuzer M, Haseneder R, Kratzer S. Attenuation of Native Hyperpolarization-Activated, Cyclic Nucleotide-Gated Channel Function by the Volatile Anesthetic Sevoflurane in Mouse Thalamocortical Relay Neurons. Front Cell Neurosci 2021; 14:606687. [PMID: 33551750 PMCID: PMC7858256 DOI: 10.3389/fncel.2020.606687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/18/2020] [Indexed: 11/24/2022] Open
Abstract
As thalamocortical relay neurons are ascribed a crucial role in signal propagation and information processing, they have attracted considerable attention as potential targets for anesthetic modulation. In this study, we analyzed the effects of different concentrations of sevoflurane on the excitability of thalamocortical relay neurons and hyperpolarization-activated, cyclic-nucleotide gated (HCN) channels, which play a decisive role in regulating membrane properties and rhythmic oscillatory activity. The effects of sevoflurane on single-cell excitability and native HCN channels were investigated in acutely prepared brain slices from adult wild-type mice with the whole-cell patch-clamp technique, using voltage-clamp and current-clamp protocols. Sevoflurane dose-dependently depressed membrane biophysics and HCN-mediated parameters of neuronal excitability. Respective half-maximal inhibitory and effective concentrations ranged between 0.30 (95% CI, 0.18–0.50) mM and 0.88 (95% CI, 0.40–2.20) mM. We witnessed a pronounced reduction of HCN dependent Ih current amplitude starting at a concentration of 0.45 mM [relative change at −133 mV; 0.45 mM sevoflurane: 0.85 (interquartile range, 0.79–0.92), n = 12, p = 0.011; 1.47 mM sevoflurane: 0.37 (interquartile range, 0.34–0.62), n = 5, p < 0.001] with a half-maximal inhibitory concentration of 0.88 (95% CI, 0.40–2.20) mM. In contrast, effects on voltage-dependent channel gating were modest with significant changes only occurring at 1.47 mM [absolute change of half-maximal activation potential; 1.47 mM: −7.2 (interquartile range, −10.3 to −5.8) mV, n = 5, p = 0.020]. In this study, we demonstrate that sevoflurane inhibits the excitability of thalamocortical relay neurons in a concentration-dependent manner within a clinically relevant range. Especially concerning its effects on native HCN channel function, our findings indicate substance-specific differences in comparison to other anesthetic agents. Considering the importance of HCN channels, the observed effects might mechanistically contribute to the hypnotic properties of sevoflurane.
Collapse
Affiliation(s)
- Stefan Schwerin
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Claudia Kopp
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Elisabeth Pircher
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Gerhard Schneider
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Matthias Kreuzer
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Rainer Haseneder
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| | - Stephan Kratzer
- Department of Anesthesiology and Intensive Care Medicine, Technical University of Munich School of Medicine, Munich, Germany
| |
Collapse
|
11
|
Testing broad-spectrum and isoform-preferring HCN channel blockers for anticonvulsant properties in mice. Epilepsy Res 2020; 168:106484. [DOI: 10.1016/j.eplepsyres.2020.106484] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/23/2020] [Accepted: 10/05/2020] [Indexed: 12/19/2022]
|
12
|
Hsieh LS, Wen JH, Nguyen LH, Zhang L, Getz S, Torres-Reveron J, Wang Y, Spencer DD, Bordey A. Ectopic HCN4 expression drives mTOR-dependent epilepsy in mice. Sci Transl Med 2020; 12:12/570/eabc1492. [PMID: 33208499 PMCID: PMC9888000 DOI: 10.1126/scitranslmed.abc1492] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/31/2020] [Indexed: 02/03/2023]
Abstract
The causative link between focal cortical malformations (FCMs) and epilepsy is well accepted, especially among patients with focal cortical dysplasia type II (FCDII) and tuberous sclerosis complex (TSC). However, the mechanisms underlying seizures remain unclear. Using a mouse model of TSC- and FCDII-associated FCM, we showed that FCM neurons were responsible for seizure activity via their unexpected abnormal expression of the hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4), which is normally not present in cortical pyramidal neurons after birth. Increasing intracellular cAMP concentrations, which preferentially affects HCN4 gating relative to the other isoforms, drove repetitive firing of FCM neurons but not control pyramidal neurons. Ectopic HCN4 expression was dependent on the mechanistic target of rapamycin (mTOR), preceded the onset of seizures, and was also found in diseased neurons in tissue resected from patients with TSC and FCDII. Last, blocking HCN4 channel activity in FCM neurons prevented epilepsy in the mouse model. These findings suggest that HCN4 play a main role in seizure and identify a cAMP-dependent seizure mechanism in TSC and FCDII. Furthermore, the unique expression of HCN4 exclusively in FCM neurons suggests that gene therapy targeting HCN4 might be effective in reducing seizures in FCDII or TSC.
Collapse
Affiliation(s)
- Lawrence S. Hsieh
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - John H. Wen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Lena H. Nguyen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Longbo Zhang
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Stephanie Getz
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Juan Torres-Reveron
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Ying Wang
- Emergency Department, Xiangya Hospital, Central South University, 87 Xiangya Street, Changsha, Hunan 410008, China
| | - Dennis D. Spencer
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Angélique Bordey
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,To whom correspondence should be addressed: Angélique Bordey, Ph.D., Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, FMB 422, New Haven, CT 06520-8082, Phone: 203-737-2515, Fax: 203-737-2159,
| |
Collapse
|
13
|
Wei F, Wang Q, Han J, Goswamee P, Gupta A, McQuiston AR, Liu Q, Zhou L. Photodynamic Modification of Native HCN Channels Expressed in Thalamocortical Neurons. ACS Chem Neurosci 2020; 11:851-863. [PMID: 32078767 DOI: 10.1021/acschemneuro.9b00475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The photodynamic process requires three elements: light, oxygen, and photosensitizer, and involves the formation of singlet oxygen, the molecular oxygen in excited electronic states. Previously, we reported that heterologously expressed hyperpolarization-activated cAMP-gated (HCN) channels in excised membrane patches are sensitive to photodynamic modification (PDM). Here we extend this study to native HCN channels expressed in thalamocortical (TC) neurons in the ventrobasal (VB) complex of the thalamus and dopaminergic neurons (DA) of the ventral tegmental area (VTA). To do this, we introduced the photosensitizer FITC-cAMP into TCs or DAs of rodent brain slices via a whole-cell patch-clamp recording pipette. After illumination with blue light pulses, we observed an increase in the voltage-insensitive, instantaneous Iinst component, accompanied by a long-lasting decrease in the hyperpolarization-dependent Ih component. Both Ih and the increased Iinst after PDM could be blocked by the HCN blockers Cs+ and ZD7288. When FITC and cAMP were dissociated and loaded into neurons as two separate chemicals, light application did not result in any long-lasting changes of the HCN currents. In contrast, light pulses applied to HCN2-/- neurons loaded with FITC-cAMP generated a much greater reduction in the Iinst component compared to that of WT neurons. Next, we investigated the impact of the long-lasting increases in Iinst after PDM on the cellular physiology of VB neurons. Consistent with an upregulation of HCN channel function, PDM elicited a depolarization of the resting membrane potential (RMP). Importantly, Trolox-C, an effective quencher for singlet oxygen, could block the PDM-dependent increase in Iinst and depolarization of the RMP. We propose that PDM of native HCN channels under physiological conditions may provide a photodynamic approach to alleviate HCN channelopathy in certain pathological conditions.
Collapse
Affiliation(s)
- Fusheng Wei
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang 330031, Jiangxi, China
| | - Qiang Wang
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Jizhong Han
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Priyodarshan Goswamee
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Ankush Gupta
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Adam Rory McQuiston
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Qinglian Liu
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Lei Zhou
- Department of Physiology and Biophysics, Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| |
Collapse
|
14
|
Yavuz M, Albayrak N, Özgür M, Gülçebi İdriz Oğlu M, Çavdar S, Onat F. The effect of prenatal and postnatal caffeine exposure on pentylentetrazole induced seizures in the non-epileptic and epileptic offsprings. Neurosci Lett 2019; 713:134504. [PMID: 31539618 DOI: 10.1016/j.neulet.2019.134504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/27/2019] [Accepted: 09/16/2019] [Indexed: 11/29/2022]
Abstract
Caffeine, a central nervous system stimulant, has been reported to modulate seizure activity in various studies. In this study the effects of caffeine exposure on the pentylenetetrazole (PTZ) induced seizure thresholds and seizure stages in the Wistar and genetic absence epilepsy model offsprings were examined. Adult female and male Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS) consumed caffeine dissolved in water (0.3 g/L) before conception, during the gestational periods and lactation period whereas control groups of each strain received tap water. All offsprings at postnatal day 30 (PN30) subjected to 70 mg/kg of PTZ were evaluated in terms of overall seizure stages, the latency to the first generalized seizure and the c-Fos protein activity in the brain regions of somatosensorial cortex (SSCx), reticular thalamic nucleus (Rt), ventrobasal thalamus (VB), centromedial nucleus (CM) and lateral geniculate nucleus (LGN). The Wistar caffeine group had significantly shorter latency to the first generalized seizure (1.53 ± 0.49 min) comparing to the Wistar control offsprings (3.40 ± 0.68 min). GAERS caffeine group (6.52 ± 2.48 min) showed significantly longer latency comparing to Wistar caffeine group (1.53 ± 0.49 min). Although statistically not significant, GAERS caffeine group showed a longer latency comparing to the GAERS control group (4.71 ± 1.82 min). In all regions of SSCx, Rt, VB, CM and LGN, GAERS caffeine group had lower c-Fos protein expression comparing to the GAERS control group (p < 0.05). Wistar caffeine rats had lower expression of c-Fos protein comparing to the Wistar control group only in SSCx. In CM, GAERS rats expressed lower c-Fos protein comparing to the Wistar control (p < 0.05). In conclusion differential effects of caffeine in the seizure modulation may involve c-Fos protein activity-dependent protection mechanisms.
Collapse
Affiliation(s)
- Melis Yavuz
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Nazlı Albayrak
- School of Medicine, Acibadem M. A. Aydınlar University, Istanbul, Turkey
| | - Merve Özgür
- Department of Anatomy, School of Medicine, Koç University, Istanbul, Turkey
| | - Medine Gülçebi İdriz Oğlu
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey; Epilepsy Research Centre (EPAM), Marmara University, Istanbul, Turkey
| | - Safiye Çavdar
- Department of Anatomy, School of Medicine, Koç University, Istanbul, Turkey
| | - Filiz Onat
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey; Epilepsy Research Centre (EPAM), Marmara University, Istanbul, Turkey.
| |
Collapse
|
15
|
Zobeiri M, Chaudhary R, Blaich A, Rottmann M, Herrmann S, Meuth P, Bista P, Kanyshkova T, Lüttjohann A, Narayanan V, Hundehege P, Meuth SG, Romanelli MN, Urbano FJ, Pape HC, Budde T, Ludwig A. The Hyperpolarization-Activated HCN4 Channel is Important for Proper Maintenance of Oscillatory Activity in the Thalamocortical System. Cereb Cortex 2019; 29:2291-2304. [PMID: 30877792 PMCID: PMC6458902 DOI: 10.1093/cercor/bhz047] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/15/2019] [Accepted: 02/21/2019] [Indexed: 11/14/2022] Open
Abstract
Hyperpolarization-activated cation channels are involved, among other functions, in learning and memory, control of synaptic transmission and epileptogenesis. The importance of the HCN1 and HCN2 isoforms for brain function has been demonstrated, while the role of HCN4, the third major neuronal HCN subunit, is not known. Here we show that HCN4 is essential for oscillatory activity in the thalamocortical (TC) network. HCN4 is selectively expressed in various thalamic nuclei, excluding the thalamic reticular nucleus. HCN4-deficient TC neurons revealed a massive reduction of Ih and strongly reduced intrinsic burst firing, whereas the current was normal in cortical pyramidal neurons. In addition, evoked bursting in a thalamic slice preparation was strongly reduced in the mutant mice probes. HCN4-deficiency also significantly slowed down thalamic and cortical oscillations during active wakefulness. Taken together, these results establish that thalamic HCN4 channels are essential for the production of rhythmic intrathalamic oscillations and determine regular TC oscillatory activity during alert states.
Collapse
Affiliation(s)
- Mehrnoush Zobeiri
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Rahul Chaudhary
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Anne Blaich
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Rottmann
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Patrick Meuth
- Klinik für Neurologie mit Institut für Translationale Neurologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Pawan Bista
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Tatyana Kanyshkova
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Annika Lüttjohann
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Venu Narayanan
- Klinik für Neurologie mit Institut für Translationale Neurologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Petra Hundehege
- Klinik für Neurologie mit Institut für Translationale Neurologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Sven G Meuth
- Klinik für Neurologie mit Institut für Translationale Neurologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research and Child Health, University of Florence, Via Ugo Schiff 6, Sesto Fiorentino, Italy
| | | | - Hans-Christian Pape
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Thomas Budde
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| |
Collapse
|
16
|
David F, Çarçak N, Furdan S, Onat F, Gould T, Mészáros Á, Di Giovanni G, Hernández VM, Chan CS, Lőrincz ML, Crunelli V. Suppression of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel Function in Thalamocortical Neurons Prevents Genetically Determined and Pharmacologically Induced Absence Seizures. J Neurosci 2018; 38:6615-6627. [PMID: 29925625 PMCID: PMC6067077 DOI: 10.1523/jneurosci.0896-17.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/13/2018] [Accepted: 05/05/2018] [Indexed: 12/31/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and the Ih current they generate contribute to the pathophysiological mechanisms of absence seizures (ASs), but their precise role in neocortical and thalamic neuronal populations, the main components of the network underlying AS generation, remains controversial. In diverse genetic AS models, Ih amplitude is smaller in neocortical neurons and either larger or unchanged in thalamocortical (TC) neurons compared with nonepileptic strains. A lower expression of neocortical HCN subtype 1 channels is present in genetic AS-prone rats, and HCN subtype 2 knock-out mice exhibit ASs. Furthermore, whereas many studies have characterized Ih contribution to "absence-like" paroxysmal activity in vitro, no data are available on the specific role of cortical and thalamic HCN channels in behavioral seizures. Here, we show that the pharmacological block of HCN channels with the antagonist ZD7288 applied via reverse microdialysis in the ventrobasal thalamus (VB) of freely moving male Genetic Absence Epilepsy Rats from Strasbourg decreases TC neuron firing and abolishes spontaneous ASs. A similar effect is observed on γ-hydroxybutyric acid-elicited ASs in normal male Wistar rats. Moreover, thalamic knockdown of HCN channels via virally delivered shRNA into the VB of male Stargazer mice, another genetic AS model, decreases spontaneous ASs and Ih-dependent electrophysiological properties of VB TC neurons. These findings provide the first evidence that block of TC neuron HCN channels prevents ASs and suggest that any potential anti-absence therapy that targets HCN channels should carefully consider the opposite role for cortical and thalamic Ih in the modulation of absence seizures.SIGNIFICANCE STATEMENT Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play critical roles in the fine-tuning of cellular and network excitability and have been suggested to be a key element of the pathophysiological mechanism underlying absence seizures. However, the precise contribution of HCN channels in neocortical and thalamic neuronal populations to these nonconvulsive seizures is still controversial. In the present study, pharmacological block and genetic suppression of HCN channels in thalamocortical neurons in the ventrobasal thalamic nucleus leads to a marked reduction in absence seizures in one pharmacological and two genetic rodent models of absence seizures. These results provide the first evidence that block of TC neuron HCN channels prevents absence seizures.
Collapse
Affiliation(s)
- François David
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom,
- Lyon Neuroscience Research Center, CNRS UMR 5292-INSERM U1028-Université Claude Bernard, 69008 Lyon, France
| | - Nihan Çarçak
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Szabina Furdan
- Department of Physiology, Anatomy, and Neuroscience, University of Szeged, Szeged 6726, Hungary
| | - Filiz Onat
- Department of Pharmacology and Clinical 34452 Pharmacology, Marmara University School of Medicine, Istanbul 81326, Turkey
| | - Timothy Gould
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Ádám Mészáros
- Department of Physiology, Anatomy, and Neuroscience, University of Szeged, Szeged 6726, Hungary
| | - Giuseppe Di Giovanni
- Department of Physiology and Biochemistry, University of Malta, Msida MSD 2080, Malta, and
| | - Vivian M Hernández
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Robert H Lurie Medical Research Center, Chicago, Illinois 60611
| | - C Savio Chan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Robert H Lurie Medical Research Center, Chicago, Illinois 60611
| | - Magor L Lőrincz
- Department of Physiology, Anatomy, and Neuroscience, University of Szeged, Szeged 6726, Hungary
| | - Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom,
- Department of Physiology and Biochemistry, University of Malta, Msida MSD 2080, Malta, and
| |
Collapse
|
17
|
Riegelhaupt PM, Tibbs GR, Goldstein PA. HCN and K 2P Channels in Anesthetic Mechanisms Research. Methods Enzymol 2018; 602:391-416. [PMID: 29588040 DOI: 10.1016/bs.mie.2018.01.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ability of a diverse group of agents to produce general anesthesia has long been an area of intense speculation and investigation. Over the past century, we have seen a paradigm shift from proposing that the anesthetized state arises from nonspecific interaction of anesthetics with the lipid membrane to the recognition that the function of distinct, and identifiable, membrane-embedded proteins is dramatically altered in the presence of intravenous and inhaled agents. Among proteinaceous targets, metabotropic and ionotropic receptors garnered much of the attention over the last 30 years, and it is only relatively recently that voltage-gated ion channels have clearly and rigorously been shown to be important molecular targets. In this review, we will consider the experimental issues relevant to two important ion channel anesthetic targets, HCN and K2P.
Collapse
Affiliation(s)
| | - Gareth R Tibbs
- Weill Cornell Medical College, New York, NY, United States
| | | |
Collapse
|
18
|
Putrenko I, Yip R, Schwarz SKW, Accili EA. Cation and voltage dependence of lidocaine inhibition of the hyperpolarization-activated cyclic nucleotide-gated HCN1 channel. Sci Rep 2017; 7:1281. [PMID: 28455536 PMCID: PMC5430837 DOI: 10.1038/s41598-017-01253-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 03/28/2017] [Indexed: 12/17/2022] Open
Abstract
Lidocaine is known to inhibit the hyperpolarization-activated mixed cation current (Ih) in cardiac myocytes and neurons, as well in cells transfected with cloned Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels. However, the molecular mechanism of Ih inhibition by this drug has been limitedly explored. Here, we show that inhibition of Ih by lidocaine, recorded from Chinese hamster ovary (CHO) cells expressing the HCN1 channel, reached a steady state within one minute and was reversible. Lidocaine inhibition of Ih was greater at less negative voltages and smaller current amplitudes whereas the voltage-dependence of Ih activation was unchanged. Lidocaine inhibition of Ih measured at −130 mV (a voltage at which Ih is fully activated) was reduced, and Ih amplitude was increased, when the concentration of extracellular potassium was raised to 60 mM from 5.4 mM. By contrast, neither Ih inhibition by the drug nor Ih amplitude at +30 mV (following a test voltage-pulse to −130 mV) were affected by this rise in extracellular potassium. Together, these data indicate that lidocaine inhibition of Ih involves a mechanism which is antagonized by hyperpolarizing voltages and current flow.
Collapse
Affiliation(s)
- Igor Putrenko
- Department of Cellular and Physiological Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Raymond Yip
- Department of Cellular and Physiological Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephan K W Schwarz
- Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Anesthesia, St. Paul's Hospital/Providence Health Care, Vancouver, British Columbia, Canada
| | - Eric A Accili
- Department of Cellular and Physiological Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
| |
Collapse
|
19
|
Luo P, Chen C, Lu Y, Fu T, Lu Q, Xu X, Li C, He Z, Guo L. Baclofen ameliorates spatial working memory impairments induced by chronic cerebral hypoperfusion via up-regulation of HCN2 expression in the PFC in rats. Behav Brain Res 2016; 308:6-13. [PMID: 27085590 DOI: 10.1016/j.bbr.2016.04.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/19/2016] [Accepted: 04/12/2016] [Indexed: 12/26/2022]
Abstract
Chronic cerebral hypoperfusion (CCH) causes memory deficits and increases the risk of vascular dementia (VD) through several biologically plausible pathways. However, whether CCH causes prefrontal cortex (PFC)-dependent spatial working memory impairments and Baclofen, a GABAB receptor agonist, could ameliorate the impairments is still not clear especially the mechanisms underlying the process. In this study, rats were subjected to permanent bilateral occlusion of the common carotid arteries (two-vessel occlusion, 2VO) to induce CCH. Two weeks later, rats were treated with 25mg/kg Baclofen (intraperitioneal injection, i.p.) for 3 weeks. Spatial working memory was evaluated in a Morris water maze using a modified delayed matching-to-place (DMP) procedure. Western blotting and immunohistochemistry were used to quantify the protein levels and protein localization. Our results showed that 2VO caused striking spatial working memory impairments, accompanied with a decreased HCN2 expression in PFC, but the protein levels of protein gene product 9.5 (PGP9.5, a neuron specific protein), glial fibrillary acidic protein (GFAP), synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), parvalbumin (PV) and HCN1 were not distinguishably changed as compared with sham-operated rats. Baclofen treatment significantly improved the spatial working memory impairments caused by 2VO, accompanied with a reversion of 2VO-induced down-regulation of HCN2. Furthermore, there was a co-localization of HCN2 subunits and parvalbumin-positive neurons in PFC. Therefore, HCN2 may target inhibitory interneurons that is implicated in working memory processes, which may be a possible mechanism of the up-regulation of HCN2 by Baclofen treatment that reliefs spatial working memory deficits in rats with CCH.
Collapse
Affiliation(s)
- Pan Luo
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Cheng Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yun Lu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - TianLi Fu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qing Lu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xulin Xu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Changjun Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhi He
- Department of Neuropsychopharmacology, Medical School of China Three Gorges University, Yichang 443002, China.
| | - Lianjun Guo
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| |
Collapse
|
20
|
Heuermann RJ, Jaramillo TC, Ying SW, Suter BA, Lyman KA, Han Y, Lewis AS, Hampton TG, Shepherd GMG, Goldstein PA, Chetkovich DM. Reduction of thalamic and cortical Ih by deletion of TRIP8b produces a mouse model of human absence epilepsy. Neurobiol Dis 2016; 85:81-92. [PMID: 26459112 PMCID: PMC4688217 DOI: 10.1016/j.nbd.2015.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/22/2015] [Accepted: 10/08/2015] [Indexed: 12/19/2022] Open
Abstract
Absence seizures occur in several types of human epilepsy and result from widespread, synchronous feedback between the cortex and thalamus that produces brief episodes of loss of consciousness. Genetic rodent models have been invaluable for investigating the pathophysiological basis of these seizures. Here, we identify tetratricopeptide-containing Rab8b-interacting protein (TRIP8b) knockout mice as a new model of absence epilepsy, featuring spontaneous spike-wave discharges on electroencephalography (EEG) that are the electrographic hallmark of absence seizures. TRIP8b is an auxiliary subunit of the hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which have previously been implicated in the pathogenesis of absence seizures. In contrast to mice lacking the pore-forming HCN channel subunit HCN2, TRIP8b knockout mice exhibited normal cardiac and motor function and a less severe seizure phenotype. Evaluating the circuit that underlies absence seizures, we found that TRIP8b knockout mice had significantly reduced HCN channel expression and function in thalamic-projecting cortical layer 5b neurons and thalamic relay neurons, but preserved function in inhibitory neurons of the reticular thalamic nucleus. Our results expand the known roles of TRIP8b and provide new insight into the region-specific functions of TRIP8b and HCN channels in constraining cortico-thalamo-cortical excitability.
Collapse
Affiliation(s)
- Robert J Heuermann
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Thomas C Jaramillo
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Shui-Wang Ying
- C.V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College of Cornell University, 1300 York Ave., Room A-1050, New York, New York 10021, USA.
| | - Benjamin A Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Kyle A Lyman
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Ye Han
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Alan S Lewis
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Thomas G Hampton
- Mouse Specifics, Inc., 2 Central Street, Level 1 Suite 1, Framingham, MA 01701, USA.
| | - Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Peter A Goldstein
- C.V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College of Cornell University, 1300 York Ave., Room A-1050, New York, New York 10021, USA.
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA; Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| |
Collapse
|
21
|
Fluoxetine ameliorates cognitive impairments induced by chronic cerebral hypoperfusion via down-regulation of HCN2 surface expression in the hippocampal CA1 area in rats. Pharmacol Biochem Behav 2016; 140:1-7. [DOI: 10.1016/j.pbb.2015.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 12/29/2022]
|
22
|
Novella Romanelli M, Sartiani L, Masi A, Mannaioni G, Manetti D, Mugelli A, Cerbai E. HCN Channels Modulators: The Need for Selectivity. Curr Top Med Chem 2016; 16:1764-91. [PMID: 26975509 PMCID: PMC5374843 DOI: 10.2174/1568026616999160315130832] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 12/27/2022]
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, the molecular correlate of the hyperpolarization-activated current (If/Ih), are membrane proteins which play an important role in several physiological processes and various pathological conditions. In the Sino Atrial Node (SAN) HCN4 is the target of ivabradine, a bradycardic agent that is, at the moment, the only drug which specifically blocks If. Nevertheless, several other pharmacological agents have been shown to modulate HCN channels, a property that may contribute to their therapeutic activity and/or to their side effects. HCN channels are considered potential targets for developing drugs to treat several important pathologies, but a major issue in this field is the discovery of isoform-selective compounds, owing to the wide distribution of these proteins into the central and peripheral nervous systems, heart and other peripheral tissues. This survey is focused on the compounds that have been shown, or have been designed, to interact with HCN channels and on their binding sites, with the aim to summarize current knowledge and possibly to unveil useful information to design new potent and selective modulators.
Collapse
Affiliation(s)
- Maria Novella Romanelli
- University of Florence, Department of Neurosciences, Psychology, Drug Research and Child's Health, Section of Pharmaceutical and Nutraceutical Sciences, via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy.
| | | | | | | | | | | | | |
Collapse
|
23
|
Long-lasting spatial learning and memory impairments caused by chronic cerebral hypoperfusion associate with a dynamic change of HCN1/HCN2 expression in hippocampal CA1 region. Neurobiol Learn Mem 2015; 123:72-83. [DOI: 10.1016/j.nlm.2015.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 01/17/2023]
|
24
|
Sekulić V, Chen TC, Lawrence JJ, Skinner FK. Dendritic distributions of I h channels in experimentally-derived multi-compartment models of oriens-lacunosum/moleculare (O-LM) hippocampal interneurons. Front Synaptic Neurosci 2015; 7:2. [PMID: 25774132 PMCID: PMC4343010 DOI: 10.3389/fnsyn.2015.00002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 02/02/2015] [Indexed: 01/14/2023] Open
Abstract
The O-LM cell type mediates feedback inhibition onto hippocampal pyramidal cells and gates information flow in the CA1. Its functions depend on the presence of voltage-gated channels (VGCs), which affect its integrative properties and response to synaptic input. Given the challenges associated with determining densities and distributions of VGCs on interneuron dendrites, we take advantage of computational modeling to consider different possibilities. In this work, we focus on hyperpolarization-activated channels (h-channels) in O-LM cells. While h-channels are known to be present in O-LM cells, it is unknown whether they are present on their dendrites. In previous work, we used ensemble modeling techniques with experimental data to obtain insights into potentially important conductance balances. We found that the best O-LM models that included uniformly distributed h-channels in the dendrites could not fully capture the “sag” response. This led us to examine activation kinetics and non-uniform distributions of h-channels in the present work. In tuning our models, we found that different kinetics and non-uniform distributions could better reproduce experimental O-LM cell responses. In contrast to CA1 pyramidal cells where higher conductance densities of h-channels occur in more distal dendrites, decreasing conductance densities of h-channels away from the soma were observed in O-LM models. Via an illustrative scenario, we showed that having dendritic h-channels clearly speeds up back-propagating action potentials in O-LM cells, unlike when h-channels are present only in the soma. Although the present results were morphology-dependent, our work shows that it should be possible to determine the distributions and characteristics of O-LM cells with recordings and morphologies from the same cell. We hypothesize that h-channels are distributed in O-LM cell dendrites and endow them with particular synaptic integration properties that shape information flow in hippocampus.
Collapse
Affiliation(s)
- Vladislav Sekulić
- Department of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada
| | - Tse-Chiang Chen
- Department of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network Toronto, ON, Canada
| | - J Josh Lawrence
- Center for Structural and Functional Neuroscience, University of Montana Missoula, MT, USA ; Department of Biomedical and Pharmaceutical Sciences, University of Montana Missoula, MT, USA
| | - Frances K Skinner
- Department of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada ; Department of Medicine (Neurology), University of Toronto Toronto, ON, Canada
| |
Collapse
|
25
|
Herrmann S, Schnorr S, Ludwig A. HCN channels--modulators of cardiac and neuronal excitability. Int J Mol Sci 2015; 16:1429-47. [PMID: 25580535 PMCID: PMC4307311 DOI: 10.3390/ijms16011429] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 01/06/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1-4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.
Collapse
Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| |
Collapse
|
26
|
Ulrich D. Subthreshold delta-frequency resonance in thalamic reticular neurons. Eur J Neurosci 2014; 40:2600-7. [PMID: 24891125 DOI: 10.1111/ejn.12630] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 03/18/2014] [Accepted: 04/22/2014] [Indexed: 01/27/2023]
Abstract
The thalamic reticular nucleus (nRt) is an assembly of GABAergic projection neurons that participate in the generation of brain rhythms during synchronous sleep and absence epilepsy. NRt cells receive inhibitory and excitatory synaptic inputs, and are endowed with an intricate set of intrinsic conductances. However, little is known about how intrinsic and synaptic properties interact to generate rhythmic discharges in these neurons. In order to better understand this interaction, I studied the subthreshold responses of nRt cells to time-varying inputs. Patch-clamp recordings were performed in acute slices of rat thalamus (postnatal days 12-21). Sinusoidal current waveforms of linearly changing frequencies were injected into the soma, and the resulting voltage oscillations were recorded. At the resting membrane potential, the impedance profile showed a characteristic resonance at 1.7 Hz. The relative strength of the resonance was 1.2, and increased with membrane hyperpolarization. Small suprathreshold current injections led to preferred spike generation at the resonance frequency. Bath application of ZD7288 or Cs(+) , inhibitors of the hyperpolarization-activated cation current (Ih ), transformed the resonance into low-pass behaviour, whereas the T-channel blockers mibefradil and Ni(2+) decreased the strength of the resonance. It is concluded that nRt cells have an Ih -mediated intrinsic frequency preference in the subthreshold voltage range that favours action potential generation in the delta-frequency band.
Collapse
Affiliation(s)
- Daniel Ulrich
- Department of Physiology & Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| |
Collapse
|
27
|
He C, Chen F, Li B, Hu Z. Neurophysiology of HCN channels: From cellular functions to multiple regulations. Prog Neurobiol 2014; 112:1-23. [DOI: 10.1016/j.pneurobio.2013.10.001] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 10/01/2013] [Accepted: 10/07/2013] [Indexed: 12/18/2022]
|
28
|
Abbas SY, Hamade KC, Yang EJ, Nawy S, Smith RG, Pettit DL. Directional summation in non-direction selective retinal ganglion cells. PLoS Comput Biol 2013; 9:e1002969. [PMID: 23516351 PMCID: PMC3597528 DOI: 10.1371/journal.pcbi.1002969] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 01/21/2013] [Indexed: 01/03/2023] Open
Abstract
Retinal ganglion cells receive inputs from multiple bipolar cells which must be integrated before a decision to fire is made. Theoretical studies have provided clues about how this integration is accomplished but have not directly determined the rules regulating summation of closely timed inputs along single or multiple dendrites. Here we have examined dendritic summation of multiple inputs along On ganglion cell dendrites in whole mount rat retina. We activated inputs at targeted locations by uncaging glutamate sequentially to generate apparent motion along On ganglion cell dendrites in whole mount retina. Summation was directional and dependent13 on input sequence. Input moving away from the soma (centrifugal) resulted in supralinear summation, while activation sequences moving toward the soma (centripetal) were linear. Enhanced summation for centrifugal activation was robust as it was also observed in cultured retinal ganglion cells. This directional summation was dependent on hyperpolarization activated cyclic nucleotide-gated (HCN) channels as blockade with ZD7288 eliminated directionality. A computational model confirms that activation of HCN channels can override a preference for centripetal summation expected from cell anatomy. This type of direction selectivity could play a role in coding movement similar to the axial selectivity seen in locust ganglion cells which detect looming stimuli. More generally, these results suggest that non-directional retinal ganglion cells can discriminate between input sequences independent of the retina network. Visual information is coded by the output of retinal ganglion cells. Through evolution retinal ganglion cells acquired unique properties that allowed them to transmit to the brain such signals as direction of movement. The quest for the cellular mechanism of the detection of movement by retinal ganglion cells has been the holy grail of research on direction selectivity. In this study we have found a mechanism that allows individual non-direction selective On retinal ganglion cells to code sequences of excitatory inputs moving either away or toward the soma. We observed that inputs moving away from the soma resulted in enhanced, supralinear EPSP summation. Evidence from computational modeling suggests that expression of a specific set of voltage-dependent channels in dendrites introduces nonlinearities that could give a ganglion cell the ability to code looming motion. We predict that in a retinal network, such a directional tuning mechanism, together with asymmetric presynaptic inhibition, could be the building block for the development of more complex detection of visual motion.
Collapse
Affiliation(s)
- Syed Y. Abbas
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Khaldoun C. Hamade
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ellen J. Yang
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Scott Nawy
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Robert G. Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Diana L. Pettit
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
29
|
Optogenetically induced sleep spindle rhythms alter sleep architectures in mice. Proc Natl Acad Sci U S A 2012; 109:20673-8. [PMID: 23169668 DOI: 10.1073/pnas.1217897109] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sleep spindles are rhythmic patterns of neuronal activity generated within the thalamocortical circuit. Although spindles have been hypothesized to protect sleep by reducing the influence of external stimuli, it remains to be confirmed experimentally whether there is a direct relationship between sleep spindles and the stability of sleep. We have addressed this issue by using in vivo photostimulation of the thalamic reticular nucleus of mice to generate spindle oscillations that are structurally and functionally similar to spontaneous sleep spindles. Such optogenetic generation of sleep spindles increased the duration of non-rapid eye movement (NREM) sleep. Furthermore, the density of sleep spindles was correlated with the amount of NREM sleep. These findings establish a causal relationship between sleep spindles and the stability of NREM sleep, strongly supporting a role for the thalamocortical circuit in sleep regulation.
Collapse
|
30
|
The Role of HCN Channels on Membrane Excitability in the Nervous System. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:619747. [PMID: 22934165 PMCID: PMC3425855 DOI: 10.1155/2012/619747] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 06/19/2012] [Indexed: 01/07/2023]
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels were first reported in heart cells and are recently known to be involved in a variety of neural functions in healthy and diseased brains. HCN channels generate inward currents when the membrane potential is hyperpolarized. Voltage dependence of HCN channels is regulated by intracellular signaling cascades, which contain cyclic AMP, PIP(2), and TRIP8b. In addition, voltage-gated potassium channels have a strong influence on HCN channel activity. Because of these funny features, HCN channel currents, previously called funny currents, can have a wide range of functions that are determined by a delicate balance of modulatory factors. These multifaceted features also make it difficult to predict and elucidate the functional role of HCN channels in actual neurons. In this paper, we focus on the impacts of HCN channels on neural activity. The functions of HCN channels reported previously will be summarized, and their mechanisms will be explained by using numerical simulation of simplified model neurons.
Collapse
|
31
|
Ying SW, Kanda VA, Hu Z, Purtell K, King EC, Abbott GW, Goldstein PA. Targeted deletion of Kcne2 impairs HCN channel function in mouse thalamocortical circuits. PLoS One 2012; 7:e42756. [PMID: 22880098 PMCID: PMC3411840 DOI: 10.1371/journal.pone.0042756] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/12/2012] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels generate the pacemaking current, I(h), which regulates neuronal excitability, burst firing activity, rhythmogenesis, and synaptic integration. The physiological consequence of HCN activation depends on regulation of channel gating by endogenous modulators and stabilization of the channel complex formed by principal and ancillary subunits. KCNE2 is a voltage-gated potassium channel ancillary subunit that also regulates heterologously expressed HCN channels; whether KCNE2 regulates neuronal HCN channel function is unknown. METHODOLOGY/PRINCIPAL FINDINGS We investigated the effects of Kcne2 gene deletion on I(h) properties and excitability in ventrobasal (VB) and cortical layer 6 pyramidal neurons using brain slices prepared from Kcne2(+/+) and Kcne2(-/-) mice. Kcne2 deletion shifted the voltage-dependence of I(h) activation to more hyperpolarized potentials, slowed gating kinetics, and decreased I(h) density. Kcne2 deletion was associated with a reduction in whole-brain expression of both HCN1 and HCN2 (but not HCN4), although co-immunoprecipitation from whole-brain lysates failed to detect interaction of KCNE2 with HCN1 or 2. Kcne2 deletion also increased input resistance and temporal summation of subthreshold voltage responses; this increased intrinsic excitability enhanced burst firing in response to 4-aminopyridine. Burst duration increased in corticothalamic, but not thalamocortical, neurons, suggesting enhanced cortical excitatory input to the thalamus; such augmented excitability did not result from changes in glutamate release machinery since miniature EPSC frequency was unaltered in Kcne2(-/-) neurons. CONCLUSIONS/SIGNIFICANCE Loss of KCNE2 leads to downregulation of HCN channel function associated with increased excitability in neurons in the cortico-thalamo-cortical loop. Such findings further our understanding of the normal physiology of brain circuitry critically involved in cognition and have implications for our understanding of various disorders of consciousness.
Collapse
Affiliation(s)
- Shui-Wang Ying
- Department of Anesthesiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Vikram A. Kanda
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, United States of America
| | - Zhaoyang Hu
- Departments of Pharmacology, and Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Kerry Purtell
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, United States of America
| | - Elizabeth C. King
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, United States of America
| | - Geoffrey W. Abbott
- Departments of Pharmacology, and Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Peter A. Goldstein
- Department of Anesthesiology, Weill Cornell Medical College, New York, New York, United States of America
| |
Collapse
|
32
|
Zhou C, Liu J, Chen XD. General anesthesia mediated by effects on ion channels. World J Crit Care Med 2012; 1:80-93. [PMID: 24701405 PMCID: PMC3953864 DOI: 10.5492/wjccm.v1.i3.80] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 10/24/2011] [Accepted: 05/25/2012] [Indexed: 02/06/2023] Open
Abstract
Although it has been more than 165 years since the first introduction of modern anesthesia to the clinic, there is surprisingly little understanding about the exact mechanisms by which general anesthetics induce unconsciousness. As a result, we do not know how general anesthetics produce anesthesia at different levels. The main handicap to understanding the mechanisms of general anesthesia is the diversity of chemically unrelated compounds including diethyl ether and halogenated hydrocarbons, gases nitrous oxide, ketamine, propofol, benzodiazepines and etomidate, as well as alcohols and barbiturates. Does this imply that general anesthesia is caused by many different mechanisms Until now, many receptors, molecular targets and neuronal transmission pathways have been shown to contribute to mechanisms of general anesthesia. Among these molecular targets, ion channels are the most likely candidates for general anesthesia, in particular γ-aminobutyric acid type A, potassium and sodium channels, as well as ion channels mediated by various neuronal transmitters like acetylcholine, amino acids amino-3-hydroxy-5-methyl-4-isoxazolpropionic acid or N-methyl-D-aspartate. In addition, recent studies have demonstrated the involvement in general anesthesia of other ion channels with distinct gating properties such as hyperpolarization-activated, cyclic- nucleotide-gated channels. The main aim of the present review is to summarize some aspects of current knowledge of the effects of general anesthetics on various ion channels.
Collapse
Affiliation(s)
- Cheng Zhou
- Cheng Zhou, Jin Liu, Xiang-Dong Chen, Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Jin Liu
- Cheng Zhou, Jin Liu, Xiang-Dong Chen, Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Xiang-Dong Chen
- Cheng Zhou, Jin Liu, Xiang-Dong Chen, Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| |
Collapse
|
33
|
PIP2-mediated HCN3 channel gating is crucial for rhythmic burst firing in thalamic intergeniculate leaflet neurons. J Neurosci 2011; 31:10412-23. [PMID: 21753018 DOI: 10.1523/jneurosci.0021-11.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels generate a pacemaking current, I(h), which regulates neuronal excitability and oscillatory activity in the brain. Although all four HCN isoforms are expressed in the brain, the functional contribution of HCN3 is unknown. Using immunohistochemistry, confocal microscopy, and whole-cell patch-clamp recording techniques, we investigated HCN3 function in thalamic intergeniculate leaflet (IGL) neurons, as HCN3 is reportedly preferentially expressed in these cells. We observed that I(h) recorded from IGL, but not ventral geniculate nucleus, neurons in HCN2(+/+) mice and rats activated slowly and were cAMP insensitive, which are hallmarks of HCN3 channels. We also observed strong immunolabeling for HCN3, with no labeling for HCN1 and HCN4, and only very weak labeling for HCN2. Deletion of HCN2 did not alter I(h) characteristics in mouse IGL neurons. These data together indicate that the HCN3 channel isoform generated I(h) in IGL neurons. Intracellular phosphatidylinositol-4,5-bisphosphate (PIP(2)) shifted I(h) activation to more depolarized potentials and accelerated activation kinetics. Upregulation of HCN3 function by PIP(2) augmented low-threshold burst firing and spontaneous oscillations; conversely, depletion of PIP(2) or pharmacologic block of I(h) resulted in a profound inhibition of excitability. The results indicate that functional expression of HCN3 channels in IGL neurons is crucial for intrinsic excitability and rhythmic burst firing, and PIP(2) serves as a powerful modulator of I(h)-dependent properties via an effect on HCN3 channel gating. Since the IGL is a major input to the suprachiasmatic nucleus, regulation of pacemaking function by PIP(2) in the IGL may influence sleep and circadian rhythms.
Collapse
|
34
|
Stradleigh TW, Ogata G, Partida GJ, Oi H, Greenberg KP, Krempely KS, Ishida AT. Colocalization of hyperpolarization-activated, cyclic nucleotide-gated channel subunits in rat retinal ganglion cells. J Comp Neurol 2011; 519:2546-73. [PMID: 21456027 PMCID: PMC3287082 DOI: 10.1002/cne.22638] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The current-passing pore of mammalian hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels is formed by subunit isoforms denoted HCN1-4. In various brain areas, antibodies directed against multiple isoforms bind to single neurons, and the current (I(h)) passed during hyperpolarizations differs from that of heterologously expressed homomeric channels. By contrast, retinal rod, cone, and bipolar cells appear to use homomeric HCN channels. Here, we assess the generality of this pattern by examining HCN1 and HCN4 immunoreactivity in rat retinal ganglion cells, measuring I(h) in dissociated cells, and testing whether HCN1 and HCN4 proteins coimmunoprecipitate. Nearly half of the ganglion cells in whole-mounted retinae bound antibodies against both isoforms. Consistent with colocalization and physical association, 8-bromo-cAMP shifted the voltage sensitivity of I(h) less than that of HCN4 channels and more than that of HCN1 channels, and HCN1 coimmunoprecipitated with HCN4 from membrane fraction proteins. Finally, the immunopositive somata ranged in diameter from the smallest to the largest in rat retina, the dendrites of immunopositive cells arborized at various levels of the inner plexiform layer and over fields of different diameters, and I(h) activated with similar kinetics and proportions of fast and slow components in small, medium, and large somata. These results show that different HCN subunits colocalize in single retinal ganglion cells, identify a subunit that can reconcile native I(h) properties with the previously reported presence of HCN4 in these cells, and indicate that I(h) is biophysically similar in morphologically diverse retinal ganglion cells and differs from I(h) in rods, cones, and bipolar cells.
Collapse
Affiliation(s)
- Tyler W Stradleigh
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California 95616, USA
| | | | | | | | | | | | | |
Collapse
|
35
|
Kelmendi B, Holsbach-Beltrame M, McIntosh AM, Hilt L, George ED, Kitchen RR, Carlyle BC, Pittenger C, Coric V, Nolen-Hoeksema S, Sanacora G, Simen AA. Association of polymorphisms in HCN4 with mood disorders and obsessive compulsive disorder. Neurosci Lett 2011; 496:195-9. [PMID: 21529705 DOI: 10.1016/j.neulet.2011.04.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 01/20/2023]
Abstract
Hyperpolarization activated cyclic nucleotide-gated (HCN) potassium channels are implicated in the control of neuronal excitability and are expressed widely in the brain. HCN4 is expressed in brain regions relevant to mood and anxiety disorders including specific thalamic nuclei, the basolateral amygdala, and the midbrain dopamine system. We therefore examined the association of HCN4 with a group of mood and anxiety disorders. We genotyped nine tag SNPs in the HCN4 gene using Sequenom iPLEX Gold technology in 285 Caucasian patients with DSM-IV mood disorders and/or obsessive compulsive disorder and 384 Caucasian controls. HCN4 polymorphisms were analyzed using single marker and haplotype-based association methods. Three SNPs showed nominal association in our population (rs12905211, rs3859014, rs498005). SNP rs12905211 maintained significance after Bonferroni correction, with allele T and haplotype CTC overrepresented in cases. These findings suggest HCN4 as a genetic susceptibility factor for mood and anxiety disorders; however, these results will require replication using a larger sample.
Collapse
Affiliation(s)
- Benjamin Kelmendi
- Department of Psychiatry, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, United States
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Lewis AS, Chetkovich DM. HCN channels in behavior and neurological disease: too hyper or not active enough? Mol Cell Neurosci 2010; 46:357-67. [PMID: 21130878 DOI: 10.1016/j.mcn.2010.11.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 11/11/2010] [Indexed: 02/08/2023] Open
Abstract
The roles of cells within the nervous system are based on their properties of excitability, which are in part governed by voltage-gated ion channels. HCN channels underlie the hyperpolarization-activated current, I(h), an important regulator of excitability and rhythmicity through control of basic membrane properties. I(h) is present in multiple neuronal types and regions of the central nervous system, and changes in I(h) alter cellular input-output properties and neuronal circuitry important for behavior such as learning and memory. Furthermore, the pathophysiology of neurological diseases of both the central and peripheral nervous system involves defects in excitability, rhythmicity, and signaling, and animal models of many of these disorders have implicated changes in HCN channels and I(h) as critical for pathogenesis. In this review, we focus on recent research elucidating the role of HCN channels and I(h) in behavior and disease. These studies have utilized knockout mice as well as animal models of disease to examine how I(h) may be important in regulating learning and memory, sleep, and consciousness, as well as how misregulation of I(h) may contribute to epilepsy, chronic pain, and other neurological disorders. This review will help guide future studies aimed at further understanding the function of this unique conductance in both health and disease of the mammalian brain.
Collapse
Affiliation(s)
- Alan S Lewis
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| | | |
Collapse
|
37
|
Focal cortical infarcts alter intrinsic excitability and synaptic excitation in the reticular thalamic nucleus. J Neurosci 2010; 30:5465-79. [PMID: 20392967 DOI: 10.1523/jneurosci.5083-09.2010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Focal cortical injuries result in death of cortical neurons and their efferents and ultimately in death or damage of thalamocortical relay (TCR) neurons that project to the affected cortical area. Neurons of the inhibitory reticular thalamic nucleus (nRT) receive excitatory inputs from corticothalamic and thalamocortical axons and are thus denervated by such injuries, yet nRT cells generally survive these insults to a greater degree than TCR cells. nRT cells inhibit TCR cells, regulate thalamocortical transmission, and generate cerebral rhythms including those involved in thalamocortical epilepsies. The survival and reorganization of nRT after cortical injury would determine recovery of thalamocortical circuits after injury. However, the physiological properties and connectivity of the survivors remain unknown. To study possible alterations in nRT neurons, we used the rat photothrombosis model of cortical stroke. Using in vitro patch-clamp recordings at various times after the photothrombotic injury, we show that localized strokes in the somatosensory cortex induce long-term reductions in intrinsic excitability and evoked synaptic excitation of nRT cells by the end of the first week after the injury. We find that nRT neurons in injured rats show (1) decreased membrane input resistance, (2) reduced low-threshold calcium burst responses, and (3) weaker evoked excitatory synaptic responses. Such alterations in nRT cellular excitability could lead to loss of nRT-mediated inhibition in relay nuclei, increased output of surviving TCR cells, and enhanced thalamocortical excitation, which may facilitate recovery of thalamic and cortical sensory circuits. In addition, such changes could be maladaptive, leading to injury-induced epilepsy.
Collapse
|
38
|
Biel M, Wahl-Schott C, Michalakis S, Zong X. Hyperpolarization-activated cation channels: from genes to function. Physiol Rev 2009; 89:847-85. [PMID: 19584315 DOI: 10.1152/physrev.00029.2008] [Citation(s) in RCA: 719] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a small subfamily of proteins within the superfamily of pore-loop cation channels. In mammals, the HCN channel family comprises four members (HCN1-4) that are expressed in heart and nervous system. The current produced by HCN channels has been known as I(h) (or I(f) or I(q)). I(h) has also been designated as pacemaker current, because it plays a key role in controlling rhythmic activity of cardiac pacemaker cells and spontaneously firing neurons. Extensive studies over the last decade have provided convincing evidence that I(h) is also involved in a number of basic physiological processes that are not directly associated with rhythmicity. Examples for these non-pacemaking functions of I(h) are the determination of the resting membrane potential, dendritic integration, synaptic transmission, and learning. In this review we summarize recent insights into the structure, function, and cellular regulation of HCN channels. We also discuss in detail the different aspects of HCN channel physiology in the heart and nervous system. To this end, evidence on the role of individual HCN channel types arising from the analysis of HCN knockout mouse models is discussed. Finally, we provide an overview of the impact of HCN channels on the pathogenesis of several diseases and discuss recent attempts to establish HCN channels as drug targets.
Collapse
Affiliation(s)
- Martin Biel
- Center for Integrated Protein Science CIPS-M and Zentrum für Pharmaforschung, Department Pharmazie, Pharmakologie für Naturwissenschaften, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich D-81377, Germany.
| | | | | | | |
Collapse
|
39
|
Chung WK, Shin M, Jaramillo TC, Leibel RL, LeDuc CA, Fischer SG, Tzilianos E, Gheith AA, Lewis AS, Chetkovich DM. Absence epilepsy in apathetic, a spontaneous mutant mouse lacking the h channel subunit, HCN2. Neurobiol Dis 2008; 33:499-508. [PMID: 19150498 DOI: 10.1016/j.nbd.2008.12.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 11/13/2008] [Accepted: 12/04/2008] [Indexed: 01/18/2023] Open
Abstract
Analysis of naturally occurring mutations that cause seizures in rodents has advanced understanding of the molecular mechanisms underlying epilepsy. Abnormalities of I(h) and h channel expression have been found in many animal models of absence epilepsy. We characterized a novel spontaneous mutant mouse, apathetic (ap/ap), and identified the ap mutation as a 4 base pair insertion within the coding region of Hcn2, the gene encoding the h channel subunit 2 (HCN2). We demonstrated that Hcn2(ap) mRNA is reduced by 90% compared to wild type, and the predicted truncated HCN2(ap) protein is absent from the brain tissue of mice carrying the ap allele. ap/ap mice exhibited ataxia, generalized spike-wave absence seizures, and rare generalized tonic-clonic seizures. ap/+ mice had a normal gait, occasional absence seizures and an increased severity of chemoconvulsant-induced seizures. These findings help elucidate basic mechanisms of absence epilepsy and suggest HCN2 may be a target for therapeutic intervention.
Collapse
Affiliation(s)
- Wendy K Chung
- Division of Molecular Genetics and the Naomi Berrie Diabetes Center, Columbia University Medical College, Russell Berrie Medical Science Pavilion, Room 620, 1150 St. Nicholas Avenue, New York, NY 10032, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
The dorsal lateral geniculate nucleus (dLGN) not only serves as the obligatory pathway for visual information transfer from the retina to neocortex but can also generate intrathalamic rhythmic activities associated with different arousal states and certain pathological conditions. The gating activity of thalamocortical circuits is under neuromodulatory control by various brainstem nuclei as well as intrinsic thalamic neurons (e.g. thalamic reticular nucleus (TRN) neurons and dLGN interneurons). In this study, we examined the effect of the putative neuromodulator nitric oxide (NO) on thalamic neuron excitability. There are multiple potential sources of NO in thalamus: cholinergic terminals originating from brainstem nuclei, GABAergic TRN neurons, and local GABAergic interneurons. Using whole cell recording techniques in in vitro thalamic slices, we found that the NO donor SNAP produced a robust, long-lasting depolarization in TRN neurons, a weaker depolarization in thalamocortical relay neurons, and no effect in local interneurons. SNAP preferentially depolarized stereotypical TRN neurons that could produced strong burst discharge. In contrast, SNAP had little effect on atypical burst and non-burst TRN cells. The NO donor SIN-1 and the endogenous NO precursor, L-arginine, mimicked the SNAP-mediated actions. The NO-mediated depolarizations were blocked by the guanylyl cyclase inhibitor ODQ indicating involvement of the cGMP pathway. In addition, the phosphodiesterase (PDE) inhibitor zaprinast depolarized and occluded the NO-mediated depolarization in TRN neurons. At the circuit level, NO activation significantly attenuated intrathalamic rhythmic activities likely resulting from the shifting of the firing mode of thalamic neurons, perhaps both TRN and thalamocortical neurons, from burst- to tonic-discharge mode. These alterations in thalamic neuron excitability not only change rhythmic circuit activity, but could also influence sensory information processing through thalamocortical circuits.
Collapse
Affiliation(s)
- Sunggu Yang
- Department of Molecular and Integrative Physiology, University of Illinois, 2357 Beckman Institute, 405 North Mathews, Urbana, IL 61801, USA
| | | |
Collapse
|
41
|
Cataldi M, Lariccia V, Marzaioli V, Cavaccini A, Curia G, Viggiano D, Canzoniero LMT, di Renzo G, Avoli M, Annunziato L. Zn2+ Slows Down CaV3.3 Gating Kinetics: Implications for Thalamocortical Activity. J Neurophysiol 2007; 98:2274-84. [PMID: 17699699 DOI: 10.1152/jn.00889.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We employed whole cell patch-clamp recordings to establish the effect of Zn2+ on the gating the brain specific, T-type channel isoform CaV3.3 expressed in HEK-293 cells. Zn2+ (300 μM) modified the gating kinetics of this channel without influencing its steady-state properties. When inward Ca2+ currents were elicited by step depolarizations at voltages above the threshold for channel opening, current inactivation was significantly slowed down while current activation was moderately affected. In addition, Zn2+ slowed down channel deactivation but channel recovery from inactivation was only modestly changed. Zn2+ also decreased whole cell Ca2+ permeability to 45% of control values. In the presence of Zn2+, Ca2+ currents evoked by mock action potentials were more persistent than in its absence. Furthermore, computer simulation of action potential generation in thalamic reticular cells performed to model the gating effect of Zn2+ on T-type channels (while leaving the kinetic parameters of voltage-gated Na+ and K+ unchanged) revealed that Zn2+ increased the frequency and the duration of burst firing, which is known to depend on T-type channel activity. In line with this finding, we discovered that chelation of endogenous Zn2+ decreased the frequency of occurrence of ictal-like epileptiform discharges in rat thalamocortical slices perfused with medium containing the convulsant 4-aminopyridine (50 μM). These data demonstrate that Zn2+ modulates CaV3.3 channel gating thus leading to increased neuronal excitability. We also propose that endogenous Zn2+ may have a role in controlling thalamocortical oscillations.
Collapse
Affiliation(s)
- M Cataldi
- Divisione di Farmacologia, Dipartimento di Neuroscienze, Facoltà di Medicina e Chirurgia, Università di Napoli Federico II, Naples, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Ying SW, Jia F, Abbas SY, Hofmann F, Ludwig A, Goldstein PA. Dendritic HCN2 channels constrain glutamate-driven excitability in reticular thalamic neurons. J Neurosci 2007; 27:8719-32. [PMID: 17687049 PMCID: PMC6672930 DOI: 10.1523/jneurosci.1630-07.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hyperpolarization activated cyclic nucleotide (HCN) gated channels conduct a current, I(h); how I(h) influences excitability and spike firing depends primarily on channel distribution in subcellular compartments. For example, dendritic expression of HCN1 normalizes somatic voltage responses and spike output in hippocampal and cortical neurons. We reported previously that HCN2 is predominantly expressed in dendritic spines in reticular thalamic nucleus (RTN) neurons, but the functional impact of such nonsomatic HCN2 expression remains unknown. We examined the role of HCN2 expression in regulating RTN excitability and GABAergic output from RTN to thalamocortical relay neurons using wild-type and HCN2 knock-out mice. Pharmacological blockade of I(h) significantly increased spike firing in RTN neurons and large spontaneous IPSC frequency in relay neurons; conversely, pharmacological enhancement of HCN channel function decreased spontaneous IPSC frequency. HCN2 deletion abolished I(h) in RTN neurons and significantly decreased sensitivity to 8-bromo-cAMP and lamotrigine. Recapitulating the effects of I(h) block, HCN2 deletion increased both temporal summation of EPSPs in RTN neurons as well as GABAergic output to postsynaptic relay neurons. The enhanced excitability of RTN neurons after I(h) block required activation of ionotropic glutamate receptors; consistent with this was the colocalization of HCN2 and glutamate receptor 4 subunit immunoreactivities in dendritic spines of RTN neurons. The results indicate that, in mouse RTN neurons, HCN2 is the primary functional isoform underlying I(h) and expression of HCN2 constrains excitatory synaptic integration.
Collapse
Affiliation(s)
- Shui-Wang Ying
- C. V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College, Cornell University, New York, New York 10021
| | - Fan Jia
- C. V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College, Cornell University, New York, New York 10021
| | - Syed Y. Abbas
- C. V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College, Cornell University, New York, New York 10021
| | - Franz Hofmann
- Institut für Pharmakologie und Toxikologie, 80802 München, Germany, and
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Peter A. Goldstein
- C. V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College, Cornell University, New York, New York 10021
| |
Collapse
|
43
|
Whitaker GM, Angoli D, Nazzari H, Shigemoto R, Accili EA. HCN2 and HCN4 isoforms self-assemble and co-assemble with equal preference to form functional pacemaker channels. J Biol Chem 2007; 282:22900-9. [PMID: 17553794 DOI: 10.1074/jbc.m610978200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-modulated (HCN) "pacemaker" channel subunits are integral membrane proteins that assemble as tetramers to form channels in cardiac conduction tissue and nerve cells. Previous studies have suggested that the HCN2 and HCN4 channel isoforms physically interact when overexpressed in mammalian cells, but whether they are able to co-assemble and form functional channels remains unclear. The extent to which co-assembly occurs over self-assembly and whether HCN2-HCN4 heteromeric channels are formed in native tissue are not known. In this study, we show co-assembly of HCN2 and HCN4 in live Chinese hamster ovary cells using bioluminescence resonance energy transfer (BRET(2)), a novel approach for studying tetramerization of ion channel subunits. Together with results from electrophysiological and imaging approaches, the BRET(2) data show that HCN2 and HCN4 subunits self-assemble and co-assemble with equal preference. We also demonstrate colocalization of HCN2 and HCN4 and a positive correlation of their intensities in the embryonic mouse heart using immunohistochemistry, as well as physical interactions between these isoforms in the rat thalamus by coimmunoprecipitation. Together, these data support the formation of HCN2-HCN4 heteromeric channels in native tissue.
Collapse
Affiliation(s)
- Gina M Whitaker
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | | | | | |
Collapse
|