1
|
El Ghaleb Y, Flucher BE. Ca V3.3 Channelopathies. Handb Exp Pharmacol 2023; 279:263-288. [PMID: 36592228 DOI: 10.1007/164_2022_631] [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] [Indexed: 01/03/2023]
Abstract
CaV3.3 is the third member of the low-voltage-activated calcium channel family and the last to be recognized as disease gene. Previously, CACNA1I, the gene encoding CaV3.3, had been described as schizophrenia risk gene. More recently, de novo missense mutations in CACNA1I were identified in patients with variable degrees of neurodevelopmental disease with and without epilepsy. Their functional characterization indicated gain-of-function effects resulting in increased calcium load and hyperexcitability of neurons expressing CaV3.3. The amino acids mutated in the CaV3.3 disease variants are located in the vicinity of the channel's activation gate and thus are classified as gate-modifying channelopathy mutations. A persistent calcium leak during rest and prolonged calcium spikes due to increased voltage sensitivity of activation and slowed kinetics of channel inactivation, respectively, may be causal for the neurodevelopmental defects. The prominent expression of CaV3.3 in thalamic reticular nucleus neurons and its essential role in generating the rhythmic thalamocortical network activity are consistent with a role of the mutated channels in the etiology of epileptic seizures and thus suggest T-type channel blockers as a viable treatment option.
Collapse
Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| |
Collapse
|
2
|
Diindolylmethane Derivatives: New Selective Blockers for T-Type Calcium Channels. MEMBRANES 2022; 12:membranes12080749. [PMID: 36005664 PMCID: PMC9412534 DOI: 10.3390/membranes12080749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 07/28/2022] [Accepted: 07/28/2022] [Indexed: 01/27/2023]
Abstract
The natural product indole-3-carbinol (I3C) and its major digestive product 3,3′-diindolylmethane (DIM) have shown clinical promise in multiple forms of cancer including breast cancer. In this study, we explored the calcium channel activity of DIM, its synthetic derivative 3,3′-Diindolylmethanone (DIM-one) and related I3C and DIM-one analogs. For the first time, DIM, DIM-one and analog IX were identified as selective blockers for T-type CaV3.3 (IC50s DIM 2.09 µM; DIM-one 9.07 µM) while compound IX inhibited both CaV3.2 (6.68 µM) and CaV3.3 (IC50 = 3.05 µM) using a FLIPR cell-based assay to measure inhibition of T-type calcium channel window current. Further characterization of DIM by electrophysiology revealed it inhibited inward Ca2+ current through CaV3.1 (IC50 = 8.32 µM) and CaV3.3 (IC50 = 9.63 µM), while IX partially blocked CaV3.2 and CaV3.3 inward Ca2+ current. In contrast, DIM-one preferentially blocked CaV3.1 inward Ca2+ current (IC50 = 1.53 µM). The anti-proliferative activities of these compounds revealed that oxidation of the methylene group of DIM shifted the selectivity of DIMs from breast cancer cell line MCF-7 to colon cancer cell line HT-29.
Collapse
|
3
|
Pape T, Idowu TO, Etzrodt VM, Stahl K, Seeliger B, Haller H, David S. Modulation of the Permeability-Inducing Factor Angiopoietin-2 Through Bifonazole in Systemic Inflammation. Shock 2021; 56:1049-1056. [PMID: 33756505 DOI: 10.1097/shk.0000000000001777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Vascular barrier breakdown in sepsis represents a key component of the maladaptive host response to infection and the release of endothelial Angiopoietin-2 (Angpt-2) is a mechanistic driver of endothelial hyperpermeability. Angpt-2 is associated with morbidity and mortality but a targeted therapeutic approach is not available. We screened for U.S. Food and Drug Administration (FDA) approved drugs that might have off-target effects decreasing Angpt-2 and therefore, ameliorating capillary leakage. METHODS Endothelial cells were isolated from human umbilical veins (HUVECs) and used for in vitro studies at baseline and after stimulation (FDA-library screening, RT-PCR, ELISA, immunocytochemistry, MTT assay). On the functional level, we assessed real-time transendothelial electrical resistance (TER) using an electric cell-substrate impedance sensing device. RESULTS We found that the anti-fungal Bifonazole (BIFO) reduces spontaneous Angpt-2 release in a time- and dose-dependent manner after 8, 12, and 24 h (24 h: veh: 15.6 ± 0.7 vs. BIFO: 8.6 ± 0.8 ng/mL, P < 0.0001). Furthermore, we observed a reduction in its intra-cellular content by 33% (P < 0.001). Stimulation with tumor necrosis factor α induced a strong release of Angpt-2 that could analogously be blocked by additional treatment with BIFO (veh: 1.58 ± 0.2 vs. BIFO: 1.02 ± 0.1, P < 0.0001). Quantification of endothelial permeability by TER revealed that BIFO was sufficient to reduce Thrombin-induced barrier breakdown (veh: 0.82 ± 0.1 vs. BIFO: 1.01 ± 0.02, P < 0.05). CONCLUSION The antifungal BIFO reduces both release and biosynthesis of the endothelial-destabilizing factor Angpt-2 in vitro thereby improving vascular barrier function. Additional studies are needed to further investigate the underlying mechanism and to translate these findings to in vivo models.
Collapse
Affiliation(s)
- Thorben Pape
- Division of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | | | | | - Klaus Stahl
- Division of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
- Division of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Benjamin Seeliger
- Division of Respiratory Medicine and German Center for Lung Research, Hannover Medical School, Hannover, Germany
| | - Hermann Haller
- Division of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | - Sascha David
- Division of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
- Institute of Intensive Care Medicine, University Hospital Zurich, Zurich, Switzerland
| |
Collapse
|
4
|
Kumari N, Bhargava A, Rath SN. T-type calcium channel antagonist, TTA-A2 exhibits anti-cancer properties in 3D spheroids of A549, a lung adenocarcinoma cell line. Life Sci 2020; 260:118291. [PMID: 32810510 DOI: 10.1016/j.lfs.2020.118291] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/05/2020] [Accepted: 08/13/2020] [Indexed: 12/19/2022]
Abstract
AIMS Despite the advanced cancer treatments, there is increased resistance to chemotherapy and subsequent mortality. In lack of reliable data in monolayer cultures and animal models, researchers are shifting to 3D cancer spheroids, which represents the in vivo robust tumour morphology. Calcium is essential in cell signalling and proliferation. It is found that T-type calcium channels (TTCCs) are overexpressed in various cancer cells, supporting their increased proliferation. Many of the TTCCs blockers available could target other channels besides TTCCs, which can cause adverse effects. Therefore, we hypothesise that TTA-A2, a highly selective blocker towards TTCCs, can inhibit the growth of cancer spheroids, and provide an anti-cancer and an adjuvant role in cancer therapy. METHODS We studied TTA-A2 and paclitaxel (PTX-control drug) in lung adenocarcinoma cell line- A549, cancer cells and human embryonic kidney cell line- HEK 293, control cell, in their monolayer and spheroids forms for viability, proliferation, morphology change, migration, and invasion-after 48-96 h of treatment. KEY FINDINGS Though the results varied between the monolayer and spheroids studies, we found both anti-cancer as well as adjuvant effect of TTA-A2 in both the studies. TTA-A2 was able to inhibit the growth, viability, and metastasis of the cancer cells and spheroids. Differences in the results of two modes might explain that why drugs tested successfully in monolayer culture fail in clinical trials. SIGNIFICANCE This study establishes the role of TTA-A2, a potent TTCC blocker as an anti-cancer and adjuvant drug in reducing the viability and metastasis of the cancer cells.
Collapse
Affiliation(s)
- Neema Kumari
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Telangana, India; Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India
| | - Anamika Bhargava
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India
| | - Subha Narayan Rath
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Telangana, India.
| |
Collapse
|
5
|
Characterisation of d-Conotoxin TxVIA as a Mammalian T-Type Calcium Channel Modulator. Mar Drugs 2020; 18:md18070343. [PMID: 32629781 PMCID: PMC7401249 DOI: 10.3390/md18070343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/25/2020] [Accepted: 06/25/2020] [Indexed: 12/19/2022] Open
Abstract
The 27-amino acid (aa)-long d-conotoxin TxVIA, originally isolated from the mollusc-hunting cone snail Conus textile, slows voltage-gated sodium (NaV) channel inactivation in molluscan neurons, but its mammalian ion channel targets remain undetermined. In this study, we confirmed that TxVIA was inactive on mammalian NaV1.2 and NaV1.7 even at high concentrations (10 µM). Given the fact that invertebrate NaV channel and T-type calcium channels (CaV3.x) are evolutionarily related, we examined the possibility that TxVIA may act on CaV3.x. Electrophysiological characterisation of the native TxVIA on CaV3.1, 3.2 and 3.3 revealed that TxVIA preferentially inhibits CaV3.2 current (IC50 = 0.24 mM) and enhances CaV3.1 current at higher concentrations. In fish bioassays TxVIA showed little effect on zebrafish behaviours when injected intramuscular at 250 ng/100 mg fish. The binding sites for TxVIA at NaV1.7 and CaV3.1 revealed that their channel binding sites contained a common epitope.
Collapse
|
6
|
Visa A, Shaikh S, Alza L, Herreros J, Cantí C. The Hard-To-Close Window of T-Type Calcium Channels. Trends Mol Med 2019; 25:571-584. [PMID: 31031178 DOI: 10.1016/j.molmed.2019.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 01/03/2023]
Abstract
T-Type calcium channels (TTCCs) are key regulators of membrane excitability, which is the reason why TTCC pharmacology is subject to intensive research in the neurological and cardiovascular fields. TTCCs also play a role in cancer physiology, and pharmacological blockers such as tetralols and dihydroquinazolines (DHQs) reduce the viability of cancer cells in vitro and slow tumor growth in murine xenografts. However, the available compounds are better suited to blocking TTCCs in excitable membranes rather than TTCCs contributing window currents at steady potentials. Consistently, tetralols and dihydroquinazolines exhibit cytostatic/cytotoxic activities at higher concentrations than those required for TTCC blockade, which may involve off-target effects. Gene silencing experiments highlight the targetability of TTCCs, but further pharmacological research is required for TTCC blockade to become a chemotherapeutic option.
Collapse
Affiliation(s)
- Anna Visa
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Soni Shaikh
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Lía Alza
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Judit Herreros
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Carles Cantí
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain.
| |
Collapse
|
7
|
Wang D, Neupane P, Ragnarsson L, Capon RJ, Lewis RJ. Synthesis of Pseudellone Analogs and Characterization as Novel T-type Calcium Channel Blockers. Mar Drugs 2018; 16:md16120475. [PMID: 30487473 PMCID: PMC6315694 DOI: 10.3390/md16120475] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/21/2018] [Accepted: 11/26/2018] [Indexed: 11/16/2022] Open
Abstract
T-type calcium channel (CaV3.x) blockers are receiving increasing attention as potential therapeutics for the treatment of pathophysiological disorders and diseases, including absence epilepsy, Parkinson's disease (PD), hypertension, cardiovascular diseases, cancers, and pain. However, few clinically approved CaV3.x blockers are available, and selective pharmacological tools are needed to further unravel the roles of individual CaV3.x subtypes. In this work, through an efficient synthetic route to the marine fungal product pseudellone C, we obtained bisindole alkaloid analogs of pseudellone C with a modified tryptophan moiety and identified two CaV3.2 (2, IC50 = 18.24 µM; 3, IC50 = 6.59 µM) and CaV3.3 (2, IC50 = 7.71 µM; 3, IC50 = 3.81 µM) selective blockers using a FLIPR cell-based assay measuring CaV3.x window currents. Further characterization by whole-cell patch-clamp revealed a preferential block of CaV3.1 activated current (2, IC50 = 5.60 µM; 3, IC50 = 9.91 µM), suggesting their state-dependent block is subtype specific.
Collapse
Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Qld 4072, Australia.
| | - Pratik Neupane
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Qld 4072, Australia.
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Qld 4072, Australia.
| | - Robert J Capon
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Qld 4072, Australia.
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane, Qld 4072, Australia.
| |
Collapse
|
8
|
Wang D, Ragnarsson L, Lewis RJ. T-type Calcium Channels in Health and Disease. Curr Med Chem 2018; 27:3098-3122. [PMID: 30277145 DOI: 10.2174/0929867325666181001112821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022]
Abstract
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific "window current", T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
Collapse
Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| |
Collapse
|
9
|
Elmaci I, Altinoz MA. Targeting the cellular schizophrenia. Likely employment of the antipsychotic agent pimozide in treatment of refractory cancers and glioblastoma. Crit Rev Oncol Hematol 2018; 128:96-109. [DOI: 10.1016/j.critrevonc.2018.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/16/2018] [Accepted: 06/06/2018] [Indexed: 12/20/2022] Open
|
10
|
Retzlaff J, Thamm K, Ghosh CC, Ziegler W, Haller H, Parikh SM, David S. Flunarizine suppresses endothelial Angiopoietin-2 in a calcium - dependent fashion in sepsis. Sci Rep 2017; 7:44113. [PMID: 28276491 PMCID: PMC5343493 DOI: 10.1038/srep44113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 02/06/2017] [Indexed: 01/17/2023] Open
Abstract
Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to an infection leading to systemic inflammation and endothelial barrier breakdown. The vascular-destabilizing factor Angiopoietin-2 (Angpt-2) has been implicated in these processes in humans. Here we screened in an unbiased approach FDA-approved compounds with respect to Angpt-2 suppression in endothelial cells (ECs) in vitro. We identified Flunarizine – a well-known anti-migraine calcium channel (CC) blocker – being able to diminish intracellular Angpt-2 protein in a time- and dose-dependent fashion thereby indirectly reducing the released protein. Moreover, Flunarizine protected ECs from TNFα-induced increase in Angpt-2 transcription and vascular barrier breakdown. Mechanistically, we could exclude canonical Tie2 signalling being responsible but found that three structurally distinct T-type - but not L-type - CC blockers can suppress Angpt-2. Most importantly, experimental increase in intracellular calcium abolished Flunarizine’s effect. Flunarizine was also able to block the injurious increase of Angpt-2 in murine endotoxemia in vivo. This resulted in reduced pulmonary adhesion molecule expression (intercellular adhesion molecule-1) and tissue infiltration of inflammatory cells (Gr-1). Our finding could have therapeutic implications as side effects of Flunarizine are low and specific sepsis therapeutics that target the dysregulated host response are highly desirable.
Collapse
Affiliation(s)
- Jennifer Retzlaff
- Division of Nephrology and Hypertension, Hannover Medical School, Germany
| | - Kristina Thamm
- Division of Nephrology and Hypertension, Hannover Medical School, Germany
| | - Chandra C Ghosh
- Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Vascular Biology Research, Boston, MA, USA
| | - Wolfgang Ziegler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Germany
| | - Hermann Haller
- Division of Nephrology and Hypertension, Hannover Medical School, Germany
| | - Samir M Parikh
- Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Vascular Biology Research, Boston, MA, USA
| | - Sascha David
- Division of Nephrology and Hypertension, Hannover Medical School, Germany
| |
Collapse
|
11
|
Cain SM, Ahn S, Garcia E, Zhang Y, Waheed Z, Tyson JR, Yang Y, Van Sung T, Phillips AG, Snutch TP. Heantos-4, a natural plant extract used in the treatment of drug addiction, modulates T-type calcium channels and thalamocortical burst-firing. Mol Brain 2016; 9:94. [PMID: 27919294 PMCID: PMC5139062 DOI: 10.1186/s13041-016-0274-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/21/2016] [Indexed: 11/10/2022] Open
Abstract
Heantos-4 is a refined combination of plant extracts currently approved to treat opiate addiction in Vietnam. In addition to its beneficial effects on withdrawal and prevention of relapse, reports of sedation during clinical treatment suggest that arousal networks in the brain may be recruited during Heantos administration. T-type calcium channels are implicated in the generation of sleep rhythms and in this study we examined whether a Heantos-4 extraction modulates T-type calcium channel currents generated by the Cav3.1, Cav3.2 and Ca3.3 subtypes. Utilizing whole-cell voltage clamp on exogenously expressed T-type calcium channels we find that Heantos inhibits Cav3.1 and Cav3.3 currents, while selectively potentiating Cav3.2 currents. We further examined the effects of Heantos-4 extract on low-threshold burst-firing in thalamic neurons which contribute to sleep oscillations. Using whole-cell current clamp in acute thalamic brain slices Heantos-4 suppressed rebound burst-firing in ventrobasal thalamocortical neurons, which express primarily Cav3.1 channels. Conversely, Heantos-4 had no significant effect on the burst-firing properties of thalamic reticular neurons, which express a mixed population of Cav3.2 and Cav3.3 channels. Examining Heantos-4 effects following oral administration in a model of absence epilepsy revealed the potential to exacerbate seizure activity. Together, the findings indicate that Heantos-4 has selective effects both on specific T-type calcium channel isoforms and distinct populations of thalamic neurons providing a putative mechanism underlying its effects on sedation and on the thalamocortical network.
Collapse
Affiliation(s)
- Stuart M Cain
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Soyon Ahn
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Esperanza Garcia
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Yiming Zhang
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Zeina Waheed
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - John R Tyson
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Yi Yang
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Tran Van Sung
- Institute of Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Anthony G Phillips
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada. .,Department of Psychiatry, University of British Columbia, Vancouver, Canada.
| |
Collapse
|
12
|
David F, Crunelli V, Leresche N, Lambert RC. Dynamic Analysis of the Conditional Oscillator Underlying Slow Waves in Thalamocortical Neurons. Front Neural Circuits 2016; 10:10. [PMID: 26941611 PMCID: PMC4766279 DOI: 10.3389/fncir.2016.00010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/08/2016] [Indexed: 11/29/2022] Open
Abstract
During non-REM sleep the EEG shows characteristics waves that are generated by the dynamic interactions between cortical and thalamic oscillators. In thalamic neurons, low-threshold T-type Ca(2+) channels play a pivotal role in almost every type of neuronal oscillations, including slow (< 1 Hz) waves, sleep spindles and delta waves. The transient opening of T channels gives rise to the low threshold spikes (LTSs), and associated high frequency bursts of action potentials, that are characteristically present during sleep spindles and delta waves, whereas the persistent opening of a small fraction of T channels, (i.e., ITwindow) is responsible for the membrane potential bistability underlying sleep slow oscillations. Surprisingly thalamocortical (TC) neurons express a very high density of T channels that largely exceed the amount required to generate LTSs and therefore, to support certain, if not all, sleep oscillations. Here, to clarify the relationship between T current density and sleep oscillations, we systematically investigated the impact of the T conductance level on the intrinsic rhythmic activities generated in TC neurons, combining in vitro experiments and TC neuron simulation. Using bifurcation analysis, we provide insights into the dynamical processes taking place at the transition between slow and delta oscillations. Our results show that although stable delta oscillations can be evoked with minimal T conductance, the full range of slow oscillation patterns, including groups of delta oscillations separated by Up states ("grouped-delta slow waves") requires a high density of T channels. Moreover, high levels of T conductance ensure the robustness of different types of slow oscillations.
Collapse
Affiliation(s)
- François David
- Neuroscience Division, School of Biosciences, Cardiff UniversityCardiff, UK
- Lyon Neuroscience Research Center, Centre National de la Recherche Scientifique UMR 5292Lyon, France
- Lyon Neuroscience Research Center, Institut National de la Santé et de la Recherche Médicale U1028Lyon, France
- Faculté de Médecine, Université Claude BernardLyon, France
- Sorbonne Universités, UPMC Université Paris 06, UM 119, Neuroscience Paris SeineParis, France
- Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris SeineParis, France
- Institut National de la Santé et de la Recherche Médicale, U1130, Neuroscience Paris SeineParis, France
| | - Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff UniversityCardiff, UK
- Department of Physiology and Biochemistry, University of MaltaMsida, Malta
| | - Nathalie Leresche
- Sorbonne Universités, UPMC Université Paris 06, UM 119, Neuroscience Paris SeineParis, France
- Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris SeineParis, France
- Institut National de la Santé et de la Recherche Médicale, U1130, Neuroscience Paris SeineParis, France
| | - Régis C. Lambert
- Sorbonne Universités, UPMC Université Paris 06, UM 119, Neuroscience Paris SeineParis, France
- Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris SeineParis, France
- Institut National de la Santé et de la Recherche Médicale, U1130, Neuroscience Paris SeineParis, France
| |
Collapse
|
13
|
|
14
|
Sakkaki S, Gangarossa G, Lerat B, Françon D, Forichon L, Chemin J, Valjent E, Lerner-Natoli M, Lory P. Blockade of T-type calcium channels prevents tonic-clonic seizures in a maximal electroshock seizure model. Neuropharmacology 2015; 101:320-9. [PMID: 26456350 DOI: 10.1016/j.neuropharm.2015.09.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/11/2015] [Accepted: 09/30/2015] [Indexed: 11/17/2022]
Abstract
T-type (Cav3) calcium channels play important roles in neuronal excitability, both in normal and pathological activities of the brain. In particular, they contribute to hyper-excitability disorders such as epilepsy. Here we have characterized the anticonvulsant properties of TTA-A2, a selective T-type channel blocker, in mouse. Using the maximal electroshock seizure (MES) as a model of tonic-clonic generalized seizures, we report that mice treated with TTA-A2 (0.3 mg/kg and higher doses) were significantly protected against tonic seizures. Although no major change in Local Field Potential (LFP) pattern was observed during the MES seizure, analysis of the late post-ictal period revealed a significant increase in the delta frequency power in animals treated with TTA-A2. Similar results were obtained for Cav3.1-/- mice, which were less prone to develop tonic seizures in the MES test, but not for Cav3.2-/- mice. Analysis of extracellular signal-regulated kinase 1/2 (ERK) phosphorylation and c-Fos expression revealed a rapid and elevated neuronal activation in the hippocampus following MES clonic seizures, which was unchanged in TTA-A2 treated animals. Overall, our data indicate that TTA-A2 is a potent anticonvulsant and that the Cav3.1 isoform plays a prominent role in mediating TTA-A2 tonic seizure protection.
Collapse
Affiliation(s)
- Sophie Sakkaki
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France; LabEx 'Ion Channel Science and Therapeutics', Montpellier F34094, France; Sanofi R&D, F-91385 Chilly-Mazarin, France
| | - Giuseppe Gangarossa
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France
| | - Benoit Lerat
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France
| | | | - Luc Forichon
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France
| | - Jean Chemin
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France; LabEx 'Ion Channel Science and Therapeutics', Montpellier F34094, France
| | - Emmanuel Valjent
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France
| | - Mireille Lerner-Natoli
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France
| | - Philippe Lory
- Université de Montpellier, CNRS UMR 5203, Département Neuroscience & Ion Channel Biology, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; INSERM U1191, Montpellier F34094, France; LabEx 'Ion Channel Science and Therapeutics', Montpellier F34094, France.
| |
Collapse
|
15
|
Leuchter AF, Hunter AM, Krantz DE, Cook IA. Rhythms and blues: modulation of oscillatory synchrony and the mechanism of action of antidepressant treatments. Ann N Y Acad Sci 2015; 1344:78-91. [PMID: 25809789 DOI: 10.1111/nyas.12742] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Treatments for major depressive disorder (MDD) act at different hierarchical levels of biological complexity, ranging from the individual synapse to the brain as a whole. Theories of antidepressant medication action traditionally have focused on the level of cell-to-cell interaction and synaptic neurotransmission. However, recent evidence suggests that modulation of synchronized electrical activity in neuronal networks is a common effect of antidepressant treatments, including not only medications, but also neuromodulatory treatments such as repetitive transcranial magnetic stimulation. Synchronization of oscillatory network activity in particular frequency bands has been proposed to underlie neurodevelopmental and learning processes, and also may be important in the mechanism of action of antidepressant treatments. Here, we review current research on the relationship between neuroplasticity and oscillatory synchrony, which suggests that oscillatory synchrony may help mediate neuroplastic changes related to neurodevelopment, learning, and memory, as well as medication and neuromodulatory treatment for MDD. We hypothesize that medication and neuromodulation treatments may have related effects on the rate and pattern of neuronal firing, and that these effects underlie antidepressant efficacy. Elucidating the mechanisms through which oscillatory synchrony may be related to neuroplasticity could lead to enhanced treatment strategies for MDD.
Collapse
Affiliation(s)
- Andrew F Leuchter
- Laboratory of Brain, Behavior, and Pharmacology, and the Depression Research and Clinic Program, Semel Institute for Neuroscience and Human Behavior at UCLA, Los Angeles, California; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, California
| | | | | | | |
Collapse
|
16
|
Powell KL, Cain SM, Snutch TP, O'Brien TJ. Low threshold T-type calcium channels as targets for novel epilepsy treatments. Br J Clin Pharmacol 2015; 77:729-39. [PMID: 23834404 DOI: 10.1111/bcp.12205] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022] Open
Abstract
Low voltage-activated T-type calcium channels were originally cloned in the 1990s and much research has since focused on identifying the physiological roles of these channels in health and disease states. T-type calcium channels are expressed widely throughout the brain and peripheral tissues, and thus have been proposed as therapeutic targets for a variety of diseases such as epilepsy, insomnia, pain, cancer and hypertension. This review discusses the literature concerning the role of T-type calcium channels in physiological and pathological processes related to epilepsy. T-type calcium channels have been implicated in pathology of both the genetic and acquired epilepsies and several anti-epileptic drugs (AEDs) in clinical use are known to suppress seizures via inhibition of T-type calcium channels. Despite the fact that more than 15 new AEDs have become clinically available over the past 20 years at least 30% of epilepsy patients still fail to achieve seizure control, and many patients experience unwanted side effects. Furthermore there are no treatments that prevent the development of epilepsy or mitigate the epileptic state once established. Therefore there is an urgent need for the development of new AEDs that are effective in patients with drug resistant epilepsy, are anti-epileptogenic and are better tolerated. We also review the mechanisms of action of the current AEDs with known effects on T-type calcium channels and discuss novel compounds that are being investigated as new treatments for epilepsy.
Collapse
Affiliation(s)
- Kim L Powell
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
17
|
Guan W, Stephens RF, Spafford JD. Cav3 T-type channels as drug targets for treating epilepsy. FUTURE NEUROLOGY 2014. [DOI: 10.2217/fnl.14.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Wendy Guan
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Robert F Stephens
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - J David Spafford
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| |
Collapse
|
18
|
Taylor H, Schmiedt JT, Carçak N, Onat F, Di Giovanni G, Lambert R, Leresche N, Crunelli V, David F. Investigating local and long-range neuronal network dynamics by simultaneous optogenetics, reverse microdialysis and silicon probe recordings in vivo. J Neurosci Methods 2014; 235:83-91. [PMID: 25004203 PMCID: PMC4164909 DOI: 10.1016/j.jneumeth.2014.06.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 06/27/2014] [Accepted: 06/27/2014] [Indexed: 02/02/2023]
Abstract
Optogenetics and microdialysis can be successfully combined. How to manipulate circuits of spontaneous and evoked activities with drugs and lights? Thalamic control of delta waves and sleep spindles.
Background The advent of optogenetics has given neuroscientists the opportunity to excite or inhibit neuronal population activity with high temporal resolution and cellular selectivity. Thus, when combined with recordings of neuronal ensemble activity in freely moving animals optogenetics can provide an unprecedented snapshot of the contribution of neuronal assemblies to (patho)physiological conditions in vivo. Still, the combination of optogenetic and silicone probe (or tetrode) recordings does not allow investigation of the role played by voltage- and transmitter-gated channels of the opsin-transfected neurons and/or other adjacent neurons in controlling neuronal activity. New method and results We demonstrate that optogenetics and silicone probe recordings can be combined with intracerebral reverse microdialysis for the long-term delivery of neuroactive drugs around the optic fiber and silicone probe. In particular, we show the effect of antagonists of T-type Ca2+ channels, hyperpolarization-activated cyclic nucleotide-gated channels and metabotropic glutamate receptors on silicone probe-recorded activity of the local opsin-transfected neurons in the ventrobasal thalamus, and demonstrate the changes that the block of these thalamic channels/receptors brings about in the network dynamics of distant somatotopic cortical neuronal ensembles. Comparison with existing methods This is the first demonstration of successfully combining optogenetics and neuronal ensemble recordings with reverse microdialysis. This combination of techniques overcomes some of the disadvantages that are associated with the use of intracerebral injection of a drug-containing solution at the site of laser activation. Conclusions The combination of reverse microdialysis, silicone probe recordings and optogenetics can unravel the short and long-term effects of specific transmitter- and voltage-gated channels on laser-modulated firing at the site of optogenetic stimulation and the actions that these manipulations exert on distant neuronal populations.
Collapse
Affiliation(s)
- Hannah Taylor
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Joscha T Schmiedt
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Nihan Carçak
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Pharmacology, Faculty of Pharmacy, Instanbul University, Istanbul, Turkey
| | - Filiz Onat
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK; Department of Biochemistry and Physiology, University of Malta, Malta
| | - Régis Lambert
- Sorbonne Universités, UPMC Univ Paris 06, UM CR18, Neuroscience Paris Seine (NPS), Paris F-75005, France; CNRS, UMR 8246, NPS, Paris F-75005, France
| | - Nathalie Leresche
- Sorbonne Universités, UPMC Univ Paris 06, UM CR18, Neuroscience Paris Seine (NPS), Paris F-75005, France; CNRS, UMR 8246, NPS, Paris F-75005, France
| | - Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Francois David
- Neuroscience Division, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| |
Collapse
|
19
|
Chemin J, Cazade M, Lory P. Modulation of T-type calcium channels by bioactive lipids. Pflugers Arch 2014; 466:689-700. [PMID: 24531745 DOI: 10.1007/s00424-014-1467-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 01/24/2014] [Accepted: 01/29/2014] [Indexed: 01/10/2023]
Abstract
T-type calcium channels (T-channels/CaV3) have unique biophysical properties allowing a calcium influx at resting membrane potential of most cells. T-channels are ubiquitously expressed in many tissues and contribute to low-threshold spikes and burst firing in central neurons as well as to pacemaker activities in cardiac cells. They also emerged as potential targets to treat cancer and hypertension. Regulation of these channels appears complex, and several studies have indicated that CaV3.1, CaV3.2, and CaV3.3 currents are directly inhibited by multiple endogenous lipids independently of membrane receptors or intracellular pathways. These bioactive lipids include arachidonic acid and ω3 poly-unsaturated fatty acids; the endocannabinoid anandamide and other N-acylethanolamides; the lipoamino-acids and lipo-neurotransmitters; the P450 epoxygenase metabolite 5,6-epoxyeicosatrienoic acid; as well as similar molecules with 18-22 carbons in the alkyl chain. In this review, we summarize evidence for direct effects of these signaling molecules, the molecular mechanisms underlying the current inhibition, and the involved chemical features. The impact of this modulation in physiology and pathophysiology is discussed with a special emphasis on pain aspects and vasodilation. Overall, these data clearly indicate that T-current inhibition is an important mechanism by which bioactive lipids mediate their physiological functions.
Collapse
Affiliation(s)
- Jean Chemin
- Institut de Génomique Fonctionnelle, Universités Montpellier 1 & 2, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5203, 141, rue de la Cardonille, 34094, Montpellier cedex 05, France,
| | | | | |
Collapse
|
20
|
T-type Ca2+ channels in absence epilepsy. Pflugers Arch 2014; 466:719-34. [DOI: 10.1007/s00424-014-1461-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 01/22/2014] [Indexed: 11/25/2022]
|
21
|
Senatore A, Guan W, Spafford JD. Cav3 T-type channels: regulators for gating, membrane expression, and cation selectivity. Pflugers Arch 2014; 466:645-60. [PMID: 24515291 DOI: 10.1007/s00424-014-1449-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/10/2014] [Accepted: 01/12/2014] [Indexed: 12/13/2022]
Abstract
Cav3 T-type channels are low-voltage-gated channels with rapid kinetics that are classified among the calcium-selective Cav1 and Cav2 type channels. Here, we outline the fundamental and unique regulators of T-type channels. An ubiquitous and proximally located "gating brake" works in concert with the voltage-sensor domain and S6 alpha-helical segment from domain II to set the canonical low-threshold and transient gating features of T-type channels. Gene splicing of optional exon 25c (and/or exon 26) in the short III-IV linker provides a developmental switch between modes of activity, such as activating in response to membrane depolarization, to channels requiring hyperpolarization input before being available to activate. Downstream of the gating brake in the I-II linker is a key region for regulating channel expression where alternative splicing patterns correlate with functional diversity of spike patterns, pacemaking rate (especially in the heart), stage of development, and animal size. A small but persistent window conductance depolarizes cells and boosts excitability at rest. T-type channels possess an ion selectivity that can resemble not only the calcium ion exclusive Cav1 and Cav2 channels but also the sodium ion selectivity of Nav1 sodium channels too. Alternative splicing in the extracellular turret of domain II generates highly sodium-permeable channels, which contribute to low-threshold sodium spikes. Cav3 channels are more ubiquitous among multicellular animals and more widespread in tissues than the more brain centric Nav1 sodium channels in invertebrates. Highly sodium-permeant Cav3 channels can functionally replace Nav1 channels in species where they are lacking, such as in Caenorhabditis elegans.
Collapse
Affiliation(s)
- A Senatore
- Department of Biology, University of Waterloo, B1-173, Waterloo, ON, N2L 3G1, Canada
| | | | | |
Collapse
|
22
|
Abstract
Chronic pain is a major therapeutic problem as the current treatment options are unsatisfactory with low efficacy and deleterious side effects. Voltage-gated Ca2+ channels (VGCCs), which are multi-complex proteins consisting of α1, β, γ, and α2δ subunits, play an important role in pain signaling. These channels are involved in neurogenic inflammation, excitability, and neurotransmitter release in nociceptors. It has been previously shown that N-type VGCCs (Cav2.2) are a major pain target. U.S. FDA approval of three Cav2.2 antagonists, gabapentin, pregabalin, and ziconotide, for chronic pain underlies the importance of this channel subtype. Also, there has been increasing evidence that L-type (Cav1.2) or T-type (Cav3.2) VGCCs may be involved in pain signaling and chronic pain. In order to develop novel pain therapeutics and to understand the role of VGCC subtypes, discovering subtype selective VGCC inhibitors or methods that selectively target the inhibitor into nociceptors would be essential. This review describes the various VGCC subtype inhibitors and the potential of utilizing VGCC subtypes as targets of chronic pain. Development of VGCC subtype inhibitors and targeting them into nociceptors will contribute to a better understanding of the roles of VGCC subtypes in pain at a spinal level as well as development of a novel class of analgesics for chronic pain.
Collapse
Affiliation(s)
- Seungkyu Lee
- F. M. Kirby Neurobiology Center, Children's Hospital Boston, Boston MA 02115 USA; ; Department of Neurobiology, Harvard Medical School, Boston MA 02115 USA
| |
Collapse
|
23
|
Yu Z, Klaasse E, Heitman LH, IJzerman AP. Allosteric modulators of the hERG K+ channel. Toxicol Appl Pharmacol 2014; 274:78-86. [DOI: 10.1016/j.taap.2013.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 11/29/2022]
|
24
|
David F, Schmiedt JT, Taylor HL, Orban G, Di Giovanni G, Uebele VN, Renger JJ, Lambert RC, Leresche N, Crunelli V. Essential thalamic contribution to slow waves of natural sleep. J Neurosci 2013; 33:19599-610. [PMID: 24336724 PMCID: PMC3858629 DOI: 10.1523/jneurosci.3169-13.2013] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/22/2013] [Accepted: 11/06/2013] [Indexed: 11/21/2022] Open
Abstract
Slow waves represent one of the prominent EEG signatures of non-rapid eye movement (non-REM) sleep and are thought to play an important role in the cellular and network plasticity that occurs during this behavioral state. These slow waves of natural sleep are currently considered to be exclusively generated by intrinsic and synaptic mechanisms within neocortical territories, although a role for the thalamus in this key physiological rhythm has been suggested but never demonstrated. Combining neuronal ensemble recordings, microdialysis, and optogenetics, here we show that the block of the thalamic output to the neocortex markedly (up to 50%) decreases the frequency of slow waves recorded during non-REM sleep in freely moving, naturally sleeping-waking rats. A smaller volume of thalamic inactivation than during sleep is required for observing similar effects on EEG slow waves recorded during anesthesia, a condition in which both bursts and single action potentials of thalamocortical neurons are almost exclusively dependent on T-type calcium channels. Thalamic inactivation more strongly reduces spindles than slow waves during both anesthesia and natural sleep. Moreover, selective excitation of thalamocortical neurons strongly entrains EEG slow waves in a narrow frequency band (0.75-1.5 Hz) only when thalamic T-type calcium channels are functionally active. These results demonstrate that the thalamus finely tunes the frequency of slow waves during non-REM sleep and anesthesia, and thus provide the first conclusive evidence that a dynamic interplay of the neocortical and thalamic oscillators of slow waves is required for the full expression of this key physiological EEG rhythm.
Collapse
Affiliation(s)
- François David
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
- Unité Mixte de Recherche 7102 Centre National de la Recherche Scientifique and
- Université Pierre et Marie Curie, Université Paris 6, 75005 Paris, France
| | - Joscha T. Schmiedt
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany
| | - Hannah L. Taylor
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Gergely Orban
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
- Physiology and Biochemistry Department, Malta University, 2080 Malta, and
| | | | | | - Régis C. Lambert
- Unité Mixte de Recherche 7102 Centre National de la Recherche Scientifique and
- Université Pierre et Marie Curie, Université Paris 6, 75005 Paris, France
| | - Nathalie Leresche
- Unité Mixte de Recherche 7102 Centre National de la Recherche Scientifique and
- Université Pierre et Marie Curie, Université Paris 6, 75005 Paris, France
| | - Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| |
Collapse
|
25
|
Carballosa-Gonzalez MM, Vitores A, Hentall ID. Hindbrain raphe stimulation boosts cyclic adenosine monophosphate and signaling proteins in the injured spinal cord. Brain Res 2013; 1543:165-72. [PMID: 24246733 DOI: 10.1016/j.brainres.2013.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/05/2013] [Accepted: 11/09/2013] [Indexed: 12/20/2022]
Abstract
Early recovery from incomplete spinal cord contusion is improved by prolonged stimulation of the hindbrain's serotonergic nucleus raphe magnus (NRM). Here we examine whether increases in cyclic adenosine monophosphate (cAMP), an intracellular signaling molecule with several known restorative actions on damaged neural tissue, could play a role. Subsequent changes in cAMP-dependent phosphorylation of protein kinase A (PKA) and PKA-dependent phosphorylation of the transcription factor "cAMP response element-binding protein" (CREB) are also analyzed. Rats with moderate weight-drop injury at segment T8 received 2h of NRM stimulation beginning three days after injury, followed immediately by separate extraction of cervical, thoracic and lumbar spinal cord for immunochemical assay. Controls lacked injury, stimulation or both. Injury reduced cAMP levels to under half of normal in all three spinal regions. NRM stimulation completely restored these levels, while producing no significant change in non-injured rats. Pretreatment with the 5-HT7 receptor antagonist pimozide (1 mg/kg, intraperitoneal) lowered cAMP in non-injured rats to injury amounts, which were unchanged by NRM stimulation. The phosphorylated fraction of PKA (pPKA) and CREB (pCREB) was reduced significantly in all three regions after SCI and restored by NRM stimulation, except for pCREB in lumbar segments. In conclusion, SCI produces spreading deficits in cAMP, pPKA and pCREB that are reversible by Gs protein-coupled 5-HT receptors responding to raphe-spinal activity, although these signaling molecules are not reactive to NRM stimulation in normal tissue. These findings can partly explain the benefits of NRM stimulation after SCI.
Collapse
Affiliation(s)
| | - Alberto Vitores
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ian D Hentall
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
| |
Collapse
|
26
|
Cazade M, Nuss CE, Bidaud I, Renger JJ, Uebele VN, Lory P, Chemin J. Cross-modulation and molecular interaction at the Cav3.3 protein between the endogenous lipids and the T-type calcium channel antagonist TTA-A2. Mol Pharmacol 2013; 85:218-25. [PMID: 24214826 DOI: 10.1124/mol.113.089581] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
T-type calcium channels (T/Ca(v)3-channels) are implicated in various physiologic and pathophysiologic processes such as epilepsy, sleep disorders, hypertension, and cancer. T-channels are the target of endogenous signaling lipids including the endocannabinoid anandamide, the ω3-fatty acids, and the lipoamino-acids. However, the precise molecular mechanism by which these molecules inhibit T-current is unknown. In this study, we provided a detailed electrophysiologic and pharmacologic analysis indicating that the effects of the major N-acyl derivatives on the Ca(v)3.3 current share many similarities with those of TTA-A2 [(R)-2-(4-cyclopropylphenyl)-N-(1-(5-(2,2,2-trifluoroethoxy)pyridin-2-yl)ethyl)acetamide], a synthetic T-channel inhibitor. Using radioactive binding assays with the TTA-A2 derivative [(3)H]TTA-A1 [(R)-2-(4-(tert-butyl)phenyl)-N-(1-(5-methoxypyridin-2-yl)ethyl)acetamide], we demonstrated that polyunsaturated lipids, which inhibit the Ca(v)3.3 current, as NAGly (N-arachidonoyl glycine), NASer (N-arachidonoyl-l-serine), anandamide, NADA (N-arachidonoyl dopamine), NATau (N-arachidonoyl taurine), and NA-5HT (N-arachidonoyl serotonin), all displaced [(3)H]TTA-A1 binding to membranes prepared from cells expressing Ca(v)3.3, with Ki in a micromolar or submicromolar range. In contrast, lipids with a saturated alkyl chain, as N-arachidoyl glycine and N-arachidoyl ethanolamine, which did not inhibit the Ca(v)3.3 current, had no effect on [(3)H]TTA-A1 binding. Accordingly, bio-active lipids occluded TTA-A2 effect on Ca(v)3.3 current. In addition, TTA-Q4 [(S)-4-(6-chloro-4-cyclopropyl-3-(2,2-difluoroethyl)-2-oxo-1,2,3,4-tetrahydroquinazolin-4-yl)benzonitrile], a positive allosteric modulator of [(3)H]TTA-A1 binding and TTA-A2 functional inhibition, acted in a synergistic manner to increase lipid-induced inhibition of the Ca(v)3.3 current. Overall, our results demonstrate a common molecular mechanism for the synthetic T-channel inhibitors and the endogenous lipids, and indicate that TTA-A2 and TTA-Q4 could be important pharmacologic tools to dissect the involvement of T-current in the physiologic effects of endogenous lipids.
Collapse
Affiliation(s)
- Magali Cazade
- Institut de Génomique Fonctionnelle, Universités Montpellier 1 and 2, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Santé et de la Recherche Médicale U661, LabEx Ion Channel Science and Therapeutics, Montpellier, France (M.C., I.B., P.L., J.C.); and Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania (C.E.N., J.J.R., V.N.U.)
| | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Low-voltage-activated T-type Ca(2+) channels are widely expressed in various types of neurons. Once deinactivated by hyperpolarization, T-type channels are ready to be activated by a small depolarization near the resting membrane potential and, therefore, are optimal for regulating the excitability and electroresponsiveness of neurons under physiological conditions near resting states. Ca(2+) influx through T-type channels engenders low-threshold Ca(2+) spikes, which in turn trigger a burst of action potentials. Low-threshold burst firing has been implicated in the synchronization of the thalamocortical circuit during sleep and in absence seizures. It also has been suggested that T-type channels play an important role in pain signal transmission, based on their abundant expression in pain-processing pathways in peripheral and central neurons. In this review, we will describe studies on the role of T-type Ca(2+) channels in the physiological as well as pathological generation of brain rhythms in sleep, absence epilepsy, and pain signal transmission. Recent advances in studies of T-type channels in the control of cognition will also be briefly discussed.
Collapse
Affiliation(s)
- Eunji Cheong
- Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
| | | |
Collapse
|
28
|
Choi KH. The design and discovery of T-type calcium channel inhibitors for the treatment of central nervous system disorders. Expert Opin Drug Discov 2013; 8:919-31. [DOI: 10.1517/17460441.2013.796926] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
29
|
Cheong E, Shin HS. T-type Ca²⁺ channels in absence epilepsy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1560-71. [PMID: 23416255 DOI: 10.1016/j.bbamem.2013.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/15/2013] [Accepted: 02/01/2013] [Indexed: 11/28/2022]
Abstract
Low-voltage-activated T-type Ca²⁺ channels are highly expressed in the thalamocortical circuit, suggesting that they play a role in this brain circuit. Indeed, low-threshold burst firing mediated by T-type Ca²⁺ channels has long been implicated in the synchronization of the thalamocortical circuit. Over the past few decades, the conventional view has been that rhythmic burst firing mediated by T-type channels in both thalamic reticular nuclie (TRN) and thalamocortical (TC) neurons are equally critical in the generation of thalamocortical oscillations during sleep rhythms and spike-wave-discharges (SWDs). This review broadly investigates recent studies indicating that even though both TRN and TC nuclei are required for thalamocortical oscillations, the contributions of T-type channels to TRN and TC neurons are not equal in the genesis of sleep spindles and SWDs. T-type channels in TC neurons are an essential component of SWD generation, whereas the requirement for TRN T-type channels in SWD generation remains controversial at least in the GBL model of absence seizures. Therefore, a deeper understanding of the functional consequences of modulating each T-type channel subtype could guide the development of therapeutic tools for absence seizures while minimizing side effects on physiological thalamocortical oscillations. This article is part of a Special Issue entitled: Calcium channels.
Collapse
Affiliation(s)
- Eunji Cheong
- Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
| | | |
Collapse
|
30
|
Francois A, Kerckhove N, Meleine M, Alloui A, Barrere C, Gelot A, Uebele VN, Renger JJ, Eschalier A, Ardid D, Bourinet E. State-dependent properties of a new T-type calcium channel blocker enhance Ca(V)3.2 selectivity and support analgesic effects. Pain 2012; 154:283-293. [PMID: 23257507 DOI: 10.1016/j.pain.2012.10.023] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 09/06/2012] [Accepted: 10/30/2012] [Indexed: 01/01/2023]
Abstract
T-type calcium channels encoded by the Ca(V)3.2 isoform are expressed in nociceptive primary afferent neurons where they contribute to hyperalgesia and thus are considered as a potential therapeutic target to treat pathological pain. Here we report that the small organic state-dependent T-type channel antagonist TTA-A2 efficiently inhibits recombinant and native Ca(V)3.2 currents. Although TTA-A2 is a pan Ca(V)3 blocker, it demonstrates a higher potency for Ca(V)3.2 compared to Ca(V)3.1. TTA-A2 selectivity for T-type currents was demonstrated in sensory neurons where it lowered cell excitability uniquely on neurons expressing T-type channels. In vivo pharmacology in Ca(V)3.2 knockout and wild type mice reveal that TTA-A2-mediated antinociception critically depends on Ca(V)3.2 expression. The pathophysiology of irritable bowel syndrome (IBS) was recently demonstrated to involve Ca(V)3.2 in a rat model of this disease. Oral administration of TTA-A2 produced a dose-dependent reduction of hypersensitivity in an IBS model, demonstrating its therapeutic potential for the treatment of pathological pain. Overall, our results suggest that the high potency of TTA-A2 in the depolarized state strengthen its analgesic efficacy and selectivity toward pathological pain syndromes. This characteristic would be beneficial for the development of analgesics targeting T-type channels, in particular for the treatment of pain associated with IBS.
Collapse
Affiliation(s)
- Amaury Francois
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094 Montpellier, France CNRS UMR5203, Montpellier, France INSERM, U661, Montpellier, France IFR3 Universités Montpellier I & II, Montpellier, France Clermont Université, Université d'Auvergne, Pharmacologie fondamentale et clinique de la douleur, BP 10448, F-63000 Clermont-Ferrand, France Inserm, U 766, F-63001 Clermont-Ferrand, France Merck Research Laboratories, West Point, PA, USA CHU Clermont-Ferrand, Service de Pharmacologie, F-63003 Clermont-Ferrand, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
T-type calcium channels in burst-firing, network synchrony, and epilepsy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1572-8. [PMID: 22885138 DOI: 10.1016/j.bbamem.2012.07.028] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 07/23/2012] [Accepted: 07/25/2012] [Indexed: 11/23/2022]
Abstract
Low voltage-activated (LVA) T-type calcium channels are well regarded as a key mechanism underlying the generation of neuronal burst-firing. Their low threshold for activation combined with a rapid and transient calcium conductance generates low-threshold calcium potentials (LTCPs), upon the crest of which high frequency action potentials fire for a brief period. Experiments using simultaneous electroencephalography (EEG) and intracellular recordings demonstrate that neuronal burst-firing is a likely causative component in the generation of normal sleep patterns as well as some pathophysiological conditions, such as epileptic seizures. However, less is known as to how these neuronal bursts impact brain behavior, in particular network synchronization. In this review we summarize recent findings concerning the role of T-type calcium channels in burst-firing and discuss how they likely contribute to the generation of network synchrony. We further outline the function of burst-firing and network synchrony in terms of epileptic seizures. This article is part of a Special Issue entitled: Calcium channels.
Collapse
|
32
|
Nerve terminal nicotinic acetylcholine receptors initiate quantal GABA release from perisomatic interneurons by activating axonal T-type (Cav3) Ca²⁺ channels and Ca²⁺ release from stores. J Neurosci 2011; 31:13546-61. [PMID: 21940446 DOI: 10.1523/jneurosci.2781-11.2011] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Release of conventional neurotransmitters is mainly controlled by calcium (Ca²⁺) influx via high-voltage-activated (HVA), Ca(v)2, channels ("N-, P/Q-, or R-types") that are opened by action potentials. Regulation of transmission by subthreshold depolarizations does occur, but there is little evidence that low-voltage-activated, Ca(v)3 ("T-type"), channels take part. GABA release from cortical perisomatic-targeting interneurons affects numerous physiological processes, and yet its underlying control mechanisms are not fully understood. We investigated whether T-type Ca²⁺ channels are involved in regulating GABA transmission from these cells in rat hippocampal CA1 using a combination of whole-cell voltage-clamp, multiple-fluorescence confocal microscopy, dual-immunolabeling electron-microscopy, and optogenetic methods. We show that Ca(v)3.1, T-type Ca²⁺ channels can be activated by α3β4 nicotinic acetylcholine receptors (nAChRs) that are located on the synaptic regions of the GABAergic perisomatic-targeting interneuronal axons, including the parvalbumin-expressing cells. Asynchronous, quantal GABA release can be triggered by Ca²⁺ influx through presynaptic T-type Ca²⁺ channels, augmented by Ca²⁺ from internal stores, following focal microiontophoretic activation of the α3β4 nAChRs. The resulting GABA release can inhibit pyramidal cells. The T-type Ca²⁺ channel-dependent mechanism is not dependent on, or accompanied by, HVA channel Ca²⁺ influx, and is insensitive to agonists of cannabinoid, μ-opioid, or GABA(B) receptors. It may therefore operate in parallel with the normal HVA-dependent processes. The results reveal new aspects of the regulation of GABA transmission and contribute to a deeper understanding of ACh and nicotine actions in CNS.
Collapse
|
33
|
Boehme R, Uebele VN, Renger JJ, Pedroarena C. Rebound excitation triggered by synaptic inhibition in cerebellar nuclear neurons is suppressed by selective T-type calcium channel block. J Neurophysiol 2011; 106:2653-61. [PMID: 21849607 DOI: 10.1152/jn.00612.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Following hyperpolarizing inputs, many neurons respond with an increase in firing rate, a phenomenon known as rebound excitation. Rebound excitation has been proposed as a mechanism to encode and process inhibitory signals and transfer them to target structures. Activation of low-voltage-activated T-type calcium channels and the ensuing low-threshold calcium spikes is one of the mechanisms proposed to support rebound excitation. However, there is still not enough evidence that the hyperpolarization provided by inhibitory inputs, particularly those dependent on chloride ions, is adequate to deinactivate a sufficient number of T-type calcium channels to drive rebound excitation on return to baseline. Here, this issue was investigated in the deep cerebellar nuclear neurons (DCNs), which receive the output of the cerebellar cortex conveyed exclusively by the inhibitory Purkinje cells and are also known to display rebound excitation. Using cerebellar slices and whole cell recordings of large DCNs, we show that a novel piperidine-based compound that selectively antagonizes T-type calcium channel activity, 3,5-dichloro-N-[1-(2,2-dimethyl-tetrahydropyran-4-ylmethyl)-4-fluoro-piperidin-4-ylmethyl]-benzamide (TTA-P2), suppressed rebound excitation elicited by current injection as well as by synaptic inhibition, whereas other electrophysiological properties of large DCNs were unaltered. Furthermore, TTA-P2 suppressed transient high-frequency rebounds found in DCNs with low-threshold spikes as well as the slow rebounds present in DCNs without low-threshold spikes. These findings demonstrate that chloride-dependent synaptic inhibition effectively triggers T-type calcium channel-mediated rebounds and that the latter channels may support slow rebound excitation in neurons without low-threshold spikes.
Collapse
Affiliation(s)
- Rebecca Boehme
- Dept. of Cognitive Neurology, Hertie Institute, Univ. of Tübingen, Otfried Müller Str. 27, 72076 Tübingen, Germany
| | | | | | | |
Collapse
|
34
|
Vortherms TA, Swensen AM, Niforatos W, Limberis JT, Neelands TR, Janis RS, Thimmapaya R, Donnelly-Roberts DL, Namovic MT, Zhang D, Brent Putman C, Martin RL, Surowy CS, Jarvis MF, Scott VE. Comparative analysis of inactivated-state block of N-type (Cav2.2) calcium channels. Inflamm Res 2011; 60:683-93. [DOI: 10.1007/s00011-011-0322-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 02/18/2011] [Accepted: 02/21/2011] [Indexed: 12/01/2022] Open
|
35
|
Reger TS, Yang ZQ, Schlegel KAS, Shu Y, Mattern C, Cube R, Rittle KE, McGaughey GB, Hartman GD, Tang C, Ballard J, Kuo Y, Prueksaritanont T, Nuss CE, Doran SM, Fox SV, Garson SL, Li Y, Kraus RL, Uebele VN, Renger JJ, Barrow JC. Pyridyl amides as potent inhibitors of T-type calcium channels. Bioorg Med Chem Lett 2011; 21:1692-6. [PMID: 21316226 DOI: 10.1016/j.bmcl.2011.01.089] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/19/2011] [Accepted: 01/20/2011] [Indexed: 11/18/2022]
Abstract
A novel series of amide T-type calcium channel antagonists were prepared and evaluated using in vitro and in vivo assays. Optimization of the screening hit 3 led to identification of the potent and selective T-type antagonist 37 that displayed in vivo efficacy in rodent models of epilepsy and sleep.
Collapse
Affiliation(s)
- Thomas S Reger
- Department of Medicinal Chemistry, Merck Research Laboratories, West Point, PA 19486, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Bergson P, Lipkind G, Lee SP, Duban ME, Hanck DA. Verapamil block of T-type calcium channels. Mol Pharmacol 2010; 79:411-9. [PMID: 21149638 DOI: 10.1124/mol.110.069492] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Verapamil is a prototypical phenylalkylamine (PAA), and it was the first calcium channel blocker to be used clinically. It tonically blocks L-type channels in the inner pore with micromolar affinity, and its affinity increases at depolarized membrane potentials. In T-type calcium channels, verapamil blocks with micromolar affinity and has modestly increased affinity at depolarized potentials. We found that a related PAA, 4-desmethoxyverapamil (D888), is comparable with verapamil both in affinity and in state-dependence. Permanently charged verapamil was more effective intracellularly than neutral verapamil. Charged PAAs were able to access their binding site from both inside and outside the cell. Furthermore, membrane-impermeant [2-(trimethylammonium)ethyl]methanethiosulfonate was able to access the inner pore from outside of the cell. We examined a homology model of the T-type calcium channel to look for possible routes of drug entry. Mutation of L1825W produced a channel that was blocked significantly more slowly by charged verapamil from the outside, with an increase in apparent affinity when the drug was applied from the inside. Data suggest that T-type channels have a back pathway through which charged drugs can access the inner pore of the channel without passing through the plasma membrane.
Collapse
Affiliation(s)
- Pamela Bergson
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | | | | | | | | |
Collapse
|
37
|
Yang ZQ, Schlegel KAS, Shu Y, Reger TS, Cube R, Mattern C, Coleman PJ, Small J, Hartman GD, Ballard J, Tang C, Kuo Y, Prueksaritanont T, Nuss CE, Doran S, Fox SV, Garson SL, Li Y, Kraus RL, Uebele VN, Taylor AB, Zeng W, Fang W, Chavez-Eng C, Troyer MD, Luk JA, Laethem T, Cook WO, Renger JJ, Barrow JC. Short-acting T-type calcium channel antagonists significantly modify sleep architecture in rodents. ACS Med Chem Lett 2010; 1:504-9. [PMID: 24900239 DOI: 10.1021/ml100170e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 08/18/2010] [Indexed: 01/16/2023] Open
Abstract
A novel phenyl acetamide series of short-acting T-type calcium channel antagonists has been identified and evaluated using in vitro and in vivo assays. Heterocycle substitutions of the 4-position of the phenyl acetamides afforded potent and selective antagonists that exhibited desired short plasma half-lives across preclinical species. Lead compound TTA-A8 emerged as a compound with excellent in vivo efficacy as indicated by its significant modulation of rat sleep architecture in an EEG telemetry model, favorable pharmacokinetic properties, and excellent preclinical safety. TTA-A8 recently progressed into human clinical trials, and in line with our predictions, preliminary studies (n = 12) with a 20 mg oral dose afforded a high C max of 1.82 ± 0.274 μM with an apparent terminal half-life of 3.0 ± 1.1 h.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Wei Zeng
- Drug Metabolism and Pharmacokinetics
| | - Wei Fang
- Drug Metabolism and Pharmacokinetics
| | | | | | | | | | | | | | | |
Collapse
|
38
|
T-type calcium channel antagonism produces antipsychotic-like effects and reduces stimulant-induced glutamate release in the nucleus accumbens of rats. Neuropharmacology 2010; 62:1413-21. [PMID: 21110986 DOI: 10.1016/j.neuropharm.2010.11.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/08/2010] [Accepted: 11/17/2010] [Indexed: 11/23/2022]
Abstract
T-type calcium channels are important in burst firing and expressed in brain regions implicated in schizophrenia. Therefore, we examined the effects of novel selective T-type calcium channel antagonists in preclinical assays predictive of antipsychotic-like activity. TTA-A2 blocked the psychostimulant effects of amphetamine and MK-801 and decreased conditioned avoidance responding. These effects appeared mechanism based, rather than compound specific, as two structurally dissimilar T-type antagonists also reduced amphetamine-induced psychomotor activity. Importantly, the ability to reduce amphetamine's effects was maintained following 20 days pre-treatment with TTA-A2. To explore the neural substrates mediating the observed behavioral effects, we examined the influence of TTA-A2 on amphetamine-induced c-fos expression as well as basal and stimulant-evoked dopamine and glutamate release in the nucleus accumbens. TTA-A2 decreased amphetamine-induced c-fos expression as well as MK-801-induced, but not basal, glutamate levels in the nucleus accumbens. Basal, amphetamine- and MK-801-induced dopamine efflux was altered. These findings suggest that T-type calcium channel antagonism could represent a novel mechanism for treating schizophrenia.
Collapse
|
39
|
Giordanetto F, Knerr L, Wållberg A. T-type calcium channels inhibitors: a patent review. Expert Opin Ther Pat 2010; 21:85-101. [PMID: 21087200 DOI: 10.1517/13543776.2011.536532] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD T-type calcium channels are transmembrane proteins that regulate calcium entry in the cell in a voltage-dependent manner. Intracellular calcium levels are the key to many physiological processes, ranging from neuron firing to cardiac pacemaking. Inhibition of T-type calcium channels is heralded as a potential treatment to peripheral and CNS disorders, including hypertension, heart failure, sleep, epilepsy, drug addiction and neuropathic pain. AREAS COVERED IN THIS REVIEW A comprehensive summary of patent literature disclosing T-type calcium channels inhibitors is provided. WHAT THE READER WILL GAIN In all, 46 patent applications including 15 chemical structure classes are reviewed. Available in vitro, in vivo and clinical results are also discussed. TAKE HOME MESSAGE Several selective T-type calcium channels inhibitors with demonstrated in vitro and in vivo effects, including one Phase I clinical candidate, are now available. While future clinical results will be paramount to assess target validity in patients, these novel inhibitors represent excellent tools to further investigate the role of T-type channels in pathophysiological conditions.
Collapse
|
40
|
Uslaner JM, Vardigan JD, Drott JM, Uebele VN, Renger JJ, Lee A, Li Z, Lê AD, Hutson PH. T-type calcium channel antagonism decreases motivation for nicotine and blocks nicotine- and cue-induced reinstatement for a response previously reinforced with nicotine. Biol Psychiatry 2010; 68:712-8. [PMID: 20579972 DOI: 10.1016/j.biopsych.2010.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 05/03/2010] [Accepted: 05/03/2010] [Indexed: 11/15/2022]
Abstract
BACKGROUND Recent evidence suggests an involvement of T-type calcium channels in the effects of drugs of abuse. METHODS We examined the influence of the novel, potent, and selective T-type calcium channel antagonist [2-(4-cyclopropylphenyl)-N-((1R)-1-{5-[2,2,2-trifluoroethyl]oxo}pyridine-2-yl)ethyl]acetamide] (TTA-A2) (.3, 1, or 3 mg/kg) on motivation for nicotine, as measured by nicotine self-administration on a progressive ratio (PR) schedule, and nicotine- and cue-induced reinstatement for a response previously reinforced with nicotine delivery (n = 11 or 12 Long Evans rats/group). Furthermore, we examined the specificity of the TTA-A2 effects by characterizing its influence on PR responding for food (in the absence or presence of nicotine-potentiated responding), food- versus nicotine-induced cue-potentiated reinstatement for a response previously reinforced by food administration (n = 11 or 12 Wistar Hannover rats/group), and its ability to induce a conditioned place aversion. RESULTS TTA-A2 dose-dependently decreased self-administration of nicotine on a PR schedule and the ability of both nicotine and a cue paired with nicotine to reinstate responding. The effects were specific for nicotine's incentive motivational properties, as TTA-A2 did not influence responding for food on a PR schedule but did attenuate the ability of nicotine to potentiate responding for food. Likewise, TTA-A2 did not alter food-induced cue-potentiated reinstatement for a response previously reinforced by food but did decrease nicotine-induced cue-potentiated reinstatement. Finally, TTA-A2 did not produce an aversive state, as indicated by a lack of ability to induce conditioned place aversion. CONCLUSIONS These data suggest that T-type calcium channel antagonists have potential for alleviating nicotine addiction by selectively decreasing the incentive motivational properties of nicotine.
Collapse
Affiliation(s)
- Jason M Uslaner
- Department of Neuroscience, Merck & Co., Inc., West Point, Pennsylvania 19486, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Schlegel KAS, Yang ZQ, Reger TS, Shu Y, Cube R, Rittle KE, Bondiskey P, Bock MG, Hartman GD, Tang C, Ballard J, Kuo Y, Prueksaritanont T, Nuss CE, Doran SM, Fox SV, Garson SL, Kraus RL, Li Y, Uebele VN, Renger JJ, Barrow JC. Discovery and expanded SAR of 4,4-disubstituted quinazolin-2-ones as potent T-type calcium channel antagonists. Bioorg Med Chem Lett 2010; 20:5147-52. [DOI: 10.1016/j.bmcl.2010.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 07/02/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
|
42
|
Kraus RL, Li Y, Gregan Y, Gotter AL, Uebele VN, Fox SV, Doran SM, Barrow JC, Yang ZQ, Reger TS, Koblan KS, Renger JJ. In vitro characterization of T-type calcium channel antagonist TTA-A2 and in vivo effects on arousal in mice. J Pharmacol Exp Ther 2010; 335:409-17. [PMID: 20682849 DOI: 10.1124/jpet.110.171058] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
T-type calcium channels have been implicated in many behaviorally important neurophysiological processes, and altered channel activity has been linked to the pathophysiology of neurological disorders such as insomnia, epilepsy, Parkinson's disease, depression, schizophrenia, and pain. We have previously identified a number of potent and selective T-type channel antagonists (Barrow et al., 2007; Shipe et al., 2008; Yang et al., 2008). Here we describe the properties of the antagonist TTA-A2 [2-(4-cyclopropylphenyl)-N-((1R)-1-{5-[(2,2,2-trifluoroethyl)oxo]-pyridin-2-yl}ethyl)acetamide], assessed in patch-clamp experiments. TTA-A2 blocks T-type channels (Ca(v)3.1, 3.2, 3.3) voltage dependently and with high potency (IC(50) ∼100 nM). Stimulation at 3 Hz revealed additional use dependence of inhibition. A hyperpolarized shift of the channel availability curve and delayed channel recovery from inactivation suggest that the compound preferentially interacts with and stabilizes inactivated channels. The compound showed a ∼300-fold selectivity for Ca(v)3 channels over high-voltage activated calcium channels. Inhibitory effects on native T-type currents were confirmed in brain slice recordings from the dorsal lateral geniculate nucleus and the subthalamic nucleus. Furthermore, we demonstrate that in vivo T-type channel inhibition by TTA-A2 suppresses active wake and promotes slow-wave sleep in wild-type mice but not in mice lacking both Ca(v)3.1 and Ca(v)3.3, suggesting the selective effect of TTA-A2 on recurrent thalamocortical network activity. The discovery of the potent and selective T-type channel antagonist TTA-A2 has enabled us to study the in vivo effects of pharmacological T-channel inhibition on arousal in mice, and it will help to explore the validity of these channels as potential drug targets for sleep-related and other neurological diseases.
Collapse
Affiliation(s)
- Richard L Kraus
- Department of Neuroscience, Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Barrow JC, Rittle KE, Reger TS, Yang ZQ, Bondiskey P, McGaughey GB, Bock MG, Hartman GD, Tang C, Ballard J, Kuo Y, Prueksaritanont T, Nuss CE, Doran SM, Fox SV, Garson SL, Kraus RL, Li Y, Marino MJ, Kuzmick Graufelds V, Uebele VN, Renger JJ. Discovery of 4,4-Disubstituted Quinazolin-2-ones as T-Type Calcium Channel Antagonists. ACS Med Chem Lett 2010; 1:75-9. [PMID: 24900180 DOI: 10.1021/ml100004r] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/22/2010] [Indexed: 11/28/2022] Open
Abstract
A novel series of quinazolinone T-type calcium channel antagonists have been prepared and evaluated using in vitro and in vivo assays. Optimization of the screening hit 3 by modifications of the 3- and 4-positions of the quinazolinone ring afforded potent and selective antagonists that displayed in vivo central nervous system efficacy in epilepsy and tremor models, as well as significant effects on rat active wake as measured by electrocorticogram.
Collapse
|
44
|
Voltage-Gated Calcium Channel Antagonists for the Central Nervous System. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1016/s0065-7743(10)45001-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|