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El Hamamy A, Iqbal Z, Mai Le N, Ranjan A, Zhang Y, Lin HW, Tan C, Patrizz A, McCullough LD, Li J. Targeted TGF-βR2 Knockdown in the Retrotrapezoid Nucleus Mitigates Respiratory Dysfunction and Cognitive Decline in a Mouse Model of Cerebral Amyloid Angiopathy with and without Stroke. RESEARCH SQUARE 2024:rs.3.rs-4438544. [PMID: 38854014 PMCID: PMC11160887 DOI: 10.21203/rs.3.rs-4438544/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Introduction Cerebral amyloid angiopathy (CAA) is characterized by the deposition of amyloid-beta peptides within cerebral blood vessels, leading to neurovascular complications. Ischemic strokes result from acute disruptions in cerebral blood flow, triggering metabolic disturbances and neurodegeneration. Both conditions often co-occur and are associated with respiratory dysfunctions. The retrotrapezoid nucleus (RTN), which is crucial for CO2 sensing and breathing regulation in the brainstem, may play a key role in breathing disorders seen in these conditions. This study aims to investigate the role of Transforming Growth Factor Beta (TGF-β) signaling in the RTN on respiratory and cognitive functions in CAA, both with and without concurrent ischemic stroke. Methods Adult male Tg-SwDI (CAA model) mice and C57BL/6 wild-type controls underwent stereotaxic injections of lentivirus targeting TGF-β2R2 in the RTN. Stroke was induced by middle cerebral artery occlusion using a monofilament. Respiratory functions were assessed using whole-body plethysmography, while cognitive functions were evaluated through the Barnes Maze and Novel Object Recognition Test (NORT). Immunohistochemical analysis was conducted to measure TGF-βR2 and GFAP expressions in the RTN. Results CAA mice exhibited significant respiratory dysfunctions, including reduced respiratory rates and increased apnea frequency, as well as impaired cognitive performance. TGF-βR2 knockdown in the RTN improved respiratory functions and cognitive outcomes in CAA mice. In CAA mice with concurrent stroke, TGF-βR2 knockdown similarly enhanced respiratory and cognitive functions. Immunohistochemistry confirmed reduced TGF-βR2 and GFAP expressions in the RTN following knockdown. Conclusions Our findings demonstrate that increased TGF-β signaling and gliosis in the RTN contribute to respiratory and cognitive dysfunctions in CAA and CAA with stroke. Targeting TGF-βR2 signaling in the RTN offers a promising therapeutic strategy to mitigate these impairments. This study is the first to report a causal link between brainstem gliosis and both respiratory and cognitive dysfunctions in CAA and stroke models.
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Affiliation(s)
| | - Zahid Iqbal
- University of Texas Health Science Center at Houston
| | - Ngoc Mai Le
- University of Texas Health Science Center at Houston
| | - Arya Ranjan
- University of Texas Health Science Center at Houston
| | - YuXing Zhang
- University of Texas Health Science Center at Houston
| | - Hung Wen Lin
- University of Texas Health Science Center at Houston
| | - Chunfeng Tan
- University of Texas Health Science Center at Houston
| | | | | | - Jun Li
- University of Texas Health Science Center at Houston
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Wu L, Zhang D, Wu Y, Liu J, Jiang J, Zhou C. Sodium Leak Channel in Glutamatergic Neurons of the Lateral Parabrachial Nucleus Helps to Maintain Respiratory Frequency Under Sevoflurane Anesthesia. Neurosci Bull 2024:10.1007/s12264-024-01223-0. [PMID: 38767833 DOI: 10.1007/s12264-024-01223-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/15/2024] [Indexed: 05/22/2024] Open
Abstract
The lateral parabrachial nucleus (PBL) is implicated in the regulation of respiratory activity. Sodium leak channel (NALCN) mutations disrupt the respiratory rhythm and influence anesthetic sensitivity in both rodents and humans. Here, we investigated whether the NALCN in PBL glutamatergic neurons maintains respiratory function under general anesthesia. Our results showed that chemogenetic activation of PBL glutamatergic neurons increased the respiratory frequency (RF) in mice; whereas chemogenetic inhibition suppressed RF. NALCN knockdown in PBL glutamatergic neurons but not GABAergic neurons significantly reduced RF under physiological conditions and caused more respiratory suppression under sevoflurane anesthesia. NALCN knockdown in PBL glutamatergic neurons did not further exacerbate the respiratory suppression induced by propofol or morphine. Under sevoflurane anesthesia, painful stimuli rapidly increased the RF, which was not affected by NALCN knockdown in PBL glutamatergic neurons. This study suggested that the NALCN is a key ion channel in PBL glutamatergic neurons that maintains respiratory frequency under volatile anesthetic sevoflurane but not intravenous anesthetic propofol.
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Affiliation(s)
- Lin Wu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Yujie Wu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jingyao Jiang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, China.
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Nuding SC, Segers LS, Iceman K, O'Connor R, Dean JB, Valarezo PA, Shuman D, Solomon IC, Bolser DC, Morris KF, Lindsey BG. Hypoxia evokes a sequence of raphe-pontomedullary network operations for inspiratory drive amplification and gasping. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.07.566027. [PMID: 37986850 PMCID: PMC10659307 DOI: 10.1101/2023.11.07.566027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Hypoxia can trigger a sequence of breathing-related behaviors, from tachypnea to apneusis to apnea and gasping, an autoresuscitative behavior that, via large tidal volumes and altered intrathoracic pressure, can enhance coronary perfusion, carotid blood flow, and sympathetic activity, and thereby coordinate cardiac and respiratory functions. We tested the hypothesis that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and a distributed efference copy mechanism that generates coordinated gasp-like discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from 6 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated adult cats. Arterial blood pressure, phrenic nerve activity, end-tidal CO2, and other parameters were monitored. Hypoxia was produced by ventilation with a gas mixture of 5% O2 in nitrogen (N2). Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-time scale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during tachypnea, apneusis and augmented bursts, apnea, and gasping. The functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated step increments in blood pressure reported here support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping that begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea.
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4
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Zhang D, Wei Y. Role of sodium leak channel (NALCN) in sensation and pain: an overview. Front Pharmacol 2024; 14:1349438. [PMID: 38273833 PMCID: PMC10808581 DOI: 10.3389/fphar.2023.1349438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 12/29/2023] [Indexed: 01/27/2024] Open
Abstract
The sodium leak channel (NALCN) is widely expressed in the central nervous system and plays a pivotal role in regulating the resting membrane potential (RMP) by mediating the Na+ leak current. NALCN was first reported in 1999, and since then, increasing evidence has provided insights into the structure and functions of NALCN. As an essential component of neuronal background currents, NALCN has been shown to be involved in many important physiological functions, particularly in the respiratory rhythm, as NALCN mutant mice have a severely disrupted respiratory rhythm and die within 24 h of birth. Many patients with NALCN mutations also develop serious clinical syndromes, such as severe hypotonia, speech impairment, and cognitive delay. Recently, emerging studies have clarified the human NALCN structure and revealed additional properties and functions of NALCN. For instance, accumulating evidence highlights that the NALCN is involved in normal sensation and pain. Here, we review the current literature and summarize the role of the NALCN in sensation and pain.
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Affiliation(s)
- Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yiyong Wei
- Department of Anesthesiology, Longgang District Maternity and Child Healthcare Hospital of Shenzhen City (Longgang Maternity and Child Institute of Shantou University Medical College), Shenzhen, China
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5
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Monteil A, Guérineau NC, Gil-Nagel A, Parra-Diaz P, Lory P, Senatore A. New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN. Physiol Rev 2024; 104:399-472. [PMID: 37615954 DOI: 10.1152/physrev.00014.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.
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Affiliation(s)
- Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Antonio Gil-Nagel
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Paloma Parra-Diaz
- Department of Neurology, Epilepsy Program, Hospital Ruber Internacional, Madrid, Spain
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- LabEx "Ion Channel Science and Therapeutics," Montpellier, France
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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Yoda S, Onimaru H, Izumizaki M. Effects of aconitine on the respiratory activity of brainstem-spinal cord preparations isolated from newborn rats. Pflugers Arch 2023; 475:1301-1314. [PMID: 37707585 DOI: 10.1007/s00424-023-02857-1] [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: 07/29/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/15/2023]
Abstract
Aconitine is a sodium channel opener, but its effects on the respiratory center are not well understood. We investigated the dose-dependent effects of aconitine on central respiratory activity in brainstem-spinal cord preparations isolated from newborn rats. Bath application of 0.5-5 μM aconitine caused an increase in respiratory rhythm and decrease in the inspiratory burst amplitude of the fourth cervical ventral root (C4). Separate application of aconitine revealed that medullary neurons were responsible for the respiratory rhythm increase, and neurons in both the medulla and spinal cord were involved in the decrease of C4 amplitude by aconitine. A local anesthetic, lidocaine (100 μM), or a voltage-dependent sodium channel blocker, tetrodotoxin (0.1 μM), partially antagonized the C4 amplitude decrease by aconitine. Tetrodotoxin treatment tentatively decreased the respiratory rhythm, but lidocaine tended to further increase the rhythm. Treatment with 100 μM riluzole or 100 μM flufenamic acid, which are known to inhibit respiratory pacemaker activity, did not reduce the respiratory rhythm enhanced by aconitine + lidocaine. The application of 1 μM aconitine depolarized the preinspiratory, expiratory, and inspiratory motor neurons. The facilitated burst rhythm of inspiratory neurons after aconitine disappeared in a low Ca2+/high Mg2+ synaptic blockade solution. We showed the dose-dependent effects of aconitine on respiratory activity. The antagonists reversed the depressive effects of aconitine in different manners, possibly due to their actions on different sites of sodium channels. The burst-generating pacemaker properties of neurons may not be involved in the generation of the facilitated rhythm after aconitine treatment.
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Affiliation(s)
- Shunya Yoda
- Department of Physiology, Showa University School of Medicine, Tokyo, 142-8555, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, 142-8555, Japan.
| | - Masahiko Izumizaki
- Department of Physiology, Showa University School of Medicine, Tokyo, 142-8555, Japan
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7
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Cobb-Lewis DE, Sansalone L, Khaliq ZM. Contributions of the Sodium Leak Channel NALCN to Pacemaking of Medial Ventral Tegmental Area and Substantia Nigra Dopaminergic Neurons. J Neurosci 2023; 43:6841-6853. [PMID: 37640554 PMCID: PMC10573758 DOI: 10.1523/jneurosci.0930-22.2023] [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: 05/13/2022] [Revised: 08/04/2023] [Accepted: 08/10/2023] [Indexed: 08/31/2023] Open
Abstract
We tested the role of the sodium leak channel, NALCN, in pacemaking of dopaminergic neuron (DAN) subpopulations from adult male and female mice. In situ hybridization revealed NALCN RNA in all DANs, with lower abundance in medial ventral tegmental area (VTA) relative to substantia nigra pars compacta (SNc). Despite lower relative abundance of NALCN, we found that acute pharmacological blockade of NALCN in medial VTA DANs slowed pacemaking by 49.08%. We also examined the electrophysiological properties of projection-defined VTA DAN subpopulations identified by retrograde labeling. Inhibition of NALCN reduced pacemaking in DANs projecting to medial nucleus accumbens (NAc) and others projecting to lateral NAc by 70.74% and 31.98%, respectively, suggesting that NALCN is a primary driver of pacemaking in VTA DANs. In SNc DANs, potentiating NALCN by lowering extracellular calcium concentration speeded pacemaking in wildtype but not NALCN conditional knockout mice, demonstrating functional presence of NALCN. In contrast to VTA DANs, however, pacemaking in SNc DANs was unaffected by inhibition of NALCN. Instead, we found that inhibition of NALCN increased the gain of frequency-current plots at firing frequencies slower than spontaneous firing. Similarly, inhibition of the hyperpolarization-activated cyclic nucleotide-gated (HCN) conductance increased gain but had little effect on pacemaking. Interestingly, simultaneous inhibition of NALCN and HCN resulted in significant reduction in pacemaker rate. Thus, we found NALCN makes substantial contributions to driving pacemaking in VTA DAN subpopulations. In SNc DANs, NALCN is not critical for pacemaking but inhibition of NALCN makes cells more sensitive to hyperpolarizing stimuli.SIGNIFICANCE STATEMENT Pacemaking in midbrain dopaminergic neurons (DAN) relies on multiple subthreshold conductances, including a sodium leak. Whether the sodium leak channel, NALCN, contributes to pacemaking in DANs located in the VTA and the SNc has not yet been determined. Using electrophysiology and pharmacology, we show that NALCN plays a prominent role in driving pacemaking in projection-defined VTA DAN subpopulations. By contrast, pacemaking in SNc neurons does not rely on NALCN. Instead, the presence of NALCN regulates the excitability of SNc DANs by reducing the gain of the neuron's response to inhibitory stimuli. Together, these findings will inform future efforts to obtain DAN subpopulation-specific treatments for use in neuropsychiatric disorders.
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Affiliation(s)
- Dana E Cobb-Lewis
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
- Institute for Neuroscience, George Washington University School of Medicine and Health Sciences, Washington, DC 20037
| | - Lorenzo Sansalone
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | - Zayd M Khaliq
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
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Guo X, Akanda N, Fiorino G, Nimbalkar S, Long CJ, Colón A, Patel A, Tighe PJ, Hickman JJ. Human IPSC-Derived PreBötC-Like Neurons and Development of an Opiate Overdose and Recovery Model. Adv Biol (Weinh) 2023:e2300276. [PMID: 37675827 PMCID: PMC10921423 DOI: 10.1002/adbi.202300276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Indexed: 09/08/2023]
Abstract
Opioid overdose is the leading cause of drug overdose lethality, posing an urgent need for investigation. The key brain region for inspiratory rhythm regulation and opioid-induced respiratory depression (OIRD) is the preBötzinger Complex (preBötC) and current knowledge has mainly been obtained from animal systems. This study aims to establish a protocol to generate human preBötC neurons from induced pluripotent cells (iPSCs) and develop an opioid overdose and recovery model utilizing these iPSC-preBötC neurons. A de novo protocol to differentiate preBötC-like neurons from human iPSCs is established. These neurons express essential preBötC markers analyzed by immunocytochemistry and demonstrate expected electrophysiological responses to preBötC modulators analyzed by patch clamp electrophysiology. The correlation of the specific biomarkers and function analysis strongly suggests a preBötC-like phenotype. Moreover, the dose-dependent inhibition of these neurons' activity is demonstrated for four different opioids with identified IC50's comparable to the literature. Inhibition is rescued by naloxone in a concentration-dependent manner. This iPSC-preBötC mimic is crucial for investigating OIRD and combating the overdose crisis and a first step for the integration of a functional overdose model into microphysiological systems.
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Affiliation(s)
- Xiufang Guo
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Nesar Akanda
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Gabriella Fiorino
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Siddharth Nimbalkar
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Christopher J Long
- Hesperos Inc, 12501 Research Parkway, Suite 100, Orlando, FL, 32826, USA
| | - Alisha Colón
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Aakash Patel
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
| | - Patrick J Tighe
- College of Medicine, Department of Anesthesiology, University of Florida, 1600 SW Archer Road, Gainesville, FL, 32610, USA
| | - James J Hickman
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL, 32826, USA
- Hesperos Inc, 12501 Research Parkway, Suite 100, Orlando, FL, 32826, USA
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Yang ND, Mellor RL, Hermanstyne TO, Nerbonne JM. Effects of NALCN-Encoded Na + Leak Currents on the Repetitive Firing Properties of SCN Neurons Depend on K +-Driven Rhythmic Changes in Input Resistance. J Neurosci 2023; 43:5132-5141. [PMID: 37339878 PMCID: PMC10342223 DOI: 10.1523/jneurosci.0182-23.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 06/02/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023] Open
Abstract
Neurons in the suprachiasmatic nucleus (SCN) generate circadian changes in the rates of spontaneous action potential firing that regulate and synchronize daily rhythms in physiology and behavior. Considerable evidence suggests that daily rhythms in the repetitive firing rates (higher during the day than at night) of SCN neurons are mediated by changes in subthreshold potassium (K+) conductance(s). An alternative "bicycle" model for circadian regulation of membrane excitability in clock neurons, however, suggests that an increase in NALCN-encoded sodium (Na+) leak conductance underlies daytime increases in firing rates. The experiments reported here explored the role of Na+ leak currents in regulating daytime and nighttime repetitive firing rates in identified adult male and female mouse SCN neurons: vasoactive intestinal peptide-expressing (VIP+), neuromedin S-expressing (NMS+) and gastrin-releasing peptide-expressing (GRP+) cells. Whole-cell recordings from VIP+, NMS+, and GRP+ neurons in acute SCN slices revealed that Na+ leak current amplitudes/densities are similar during the day and at night, but have a larger impact on membrane potentials in daytime neurons. Additional experiments, using an in vivo conditional knockout approach, demonstrated that NALCN-encoded Na+ currents selectively regulate daytime repetitive firing rates of adult SCN neurons. Dynamic clamp-mediated manipulation revealed that the effects of NALCN-encoded Na+ currents on the repetitive firing rates of SCN neurons depend on K+ current-driven changes in input resistances. Together, these findings demonstrate that NALCN-encoded Na+ leak channels contribute to regulating daily rhythms in the excitability of SCN neurons by a mechanism that depends on K+ current-mediated rhythmic changes in intrinsic membrane properties.SIGNIFICANCE STATEMENT Elucidating the ionic mechanisms responsible for generating daily rhythms in the rates of spontaneous action potential firing of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals, is an important step toward understanding how the molecular clock controls circadian rhythms in physiology and behavior. While numerous studies have focused on identifying subthreshold K+ channel(s) that mediate day-night changes in the firing rates of SCN neurons, a role for Na+ leak currents has also been suggested. The results of the experiments presented here demonstrate that NALCN-encoded Na+ leak currents differentially modulate daily rhythms in the daytime/nighttime repetitive firing rates of SCN neurons as a consequence of rhythmic changes in subthreshold K+ currents.
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Affiliation(s)
- Nien-Du Yang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110
| | | | - Tracey O Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jeanne M Nerbonne
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110
- Department of Medicine, Cardiovascular Division
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
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10
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Yackle K. Transformation of Our Understanding of Breathing Control by Molecular Tools. Annu Rev Physiol 2023; 85:93-113. [PMID: 36323001 PMCID: PMC9918693 DOI: 10.1146/annurev-physiol-021522-094142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The rhythmicity of breath is vital for normal physiology. Even so, breathing is enriched with multifunctionality. External signals constantly change breathing, stopping it when under water or deepening it during exertion. Internal cues utilize breath to express emotions such as sighs of frustration and yawns of boredom. Breathing harmonizes with other actions that use our mouth and throat, including speech, chewing, and swallowing. In addition, our perception of breathing intensity can dictate how we feel, such as during the slow breathing of calming meditation and anxiety-inducing hyperventilation. Heartbeat originates from a peripheral pacemaker in the heart, but the automation of breathing arises from neural clusters within the brainstem, enabling interaction with other brain areas and thus multifunctionality. Here, we document how the recent transformation of cellular and molecular tools has contributed to our appreciation of the diversity of neuronal types in the breathing control circuit and how they confer the multifunctionality of breathing.
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Affiliation(s)
- Kevin Yackle
- Department of Physiology, University of California, San Francisco, California, USA;
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11
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Morgado-Valle C, Smith JC, Fernandez-Ruiz J, Lopez-Meraz L, Beltran-Parrazal L. Modulation of inspiratory burst duration and frequency by bombesin in vitro. Pflugers Arch 2023; 475:101-117. [PMID: 35066612 DOI: 10.1007/s00424-022-02663-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/19/2021] [Accepted: 01/04/2022] [Indexed: 01/31/2023]
Abstract
Mammalian respiratory rhythm-generating circuits in the brainstem are subject to neuromodulation by multiple peptidergic afferent inputs controlling circuit behavior and outputs. Although functionally important, actions of neuropeptide modulators have not been fully characterized. We analyzed at cellular and circuit levels two inspiratory patterns intrinsically generated by the preBötzinger complex (preBötC) and their modulation by the neuropeptides bombesin and substance P (SP) in neonatal rat medullary slices in vitro. We found that, in recordings of hypoglossal nerve and preBötC neuron inspiratory activity, some inspiratory bursts occurring spontaneously under basal conditions have a biphasic shape with longer duration than normal inspiratory bursts and occur at a lower frequency. This biphasic burst pattern has been proposed to represent inspiratory activity underling periodic sighs. Bath-applied bombesin or SP decreased the period and increased the duration of both normal inspiratory and biphasic bursts and their underlying synaptic drives. The ratio of the biphasic long-duration burst period to the normal inspiratory burst period and the ratio of their burst durations remained the same before and after peptidergic modulation. Bombesin increased the frequency of the inspiratory rhythm in a Ca2+-independent manner and the frequency of long-duration bursts in a Ca2+-dependent manner. This finding suggests that period and burst duration coupling are due to intrinsic mechanisms controlling simultaneously timing and burst termination within the inspiratory rhythm-generating network. We propose a model in which signaling cascades activated by bombesin and SP modulate mechanisms controlling inspiratory burst frequency and duration to coordinate preBötC circuit behavioral outputs.
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Affiliation(s)
- Consuelo Morgado-Valle
- Instituto de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa Veracruz, México, 91190. .,Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS). National Institutes of Health (NIH), Bethesda, MD, 20892, USA.
| | - Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS). National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Juan Fernandez-Ruiz
- Facultad de Medicina, Universidad Nacional Autónoma de México. Ciudad de México, México City, 04510, México
| | - Leonor Lopez-Meraz
- Instituto de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa Veracruz, México, 91190
| | - Luis Beltran-Parrazal
- Instituto de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa Veracruz, México, 91190.
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12
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Zhou C, Zhou Q, He X, He Y, Wang X, Zhu X, Zhang Y, Ma L. Differential modulation of C. elegans motor behavior by NALCN and two-pore domain potassium channels. PLoS Genet 2022; 18:e1010126. [PMID: 35482723 PMCID: PMC9049526 DOI: 10.1371/journal.pgen.1010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 02/28/2022] [Indexed: 11/18/2022] Open
Abstract
Two-pore domain potassium channels (K2P) are a large family of “background” channels that allow outward “leak” of potassium ions. The NALCN/UNC80/UNC79 complex is a non-selective channel that allows inward flow of sodium and other cations. It is unclear how K2Ps and NALCN differentially modulate animal behavior. Here, we found that loss of function (lf) in the K2P gene twk-40 suppressed the reduced body curvatures of C. elegans NALCN(lf) mutants. twk-40(lf) caused a deep body curvature and extended backward locomotion, and these phenotypes appeared to be associated with neuron-specific expression of twk-40 and distinct twk-40 transcript isoforms. To survey the functions of other less studied K2P channels, we examined loss-of-function mutants of 13 additional twk genes expressed in the motor circuit and detected defective body curvature and/or locomotion in mutants of twk-2, twk-17, twk-30, twk-48, unc-58, and the previously reported twk-7. We generated presumptive gain-of-function (gf) mutations in twk-40, twk-2, twk-7, and unc-58 and found that they caused paralysis. Further analyses detected variable genetic interactions between twk-40 and other twk genes, an interdependence between twk-40 and twk-2, and opposite behavioral effects between NALCN and twk-2, twk-7, or unc-58. Finally, we found that the hydrophobicity/hydrophilicity property of TWK-40 residue 159 could affect the channel activity. Together, our study identified twk-40 as a novel modulator of the motor behavior, uncovered potential behavioral effects of five other K2P genes and suggests that NALCN and some K2Ps can oppositely affect C. elegans behavior.
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Affiliation(s)
- Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Qian Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaohui He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yunxia He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaoqin Wang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaowei Zhu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yujia Zhang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Molecular Precision Medicine, Central South University, Changsha, Hunan, China
- * E-mail:
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13
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Li J, Chen Y, Liu J, Zhang D, Liang P, Lu P, Shen J, Miao C, Zuo Y, Zhou C. Elevated Expression and Activity of Sodium Leak Channel Contributes to Neuronal Sensitization of Inflammatory Pain in Rats. Front Mol Neurosci 2021; 14:723395. [PMID: 34512260 PMCID: PMC8430348 DOI: 10.3389/fnmol.2021.723395] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/02/2021] [Indexed: 02/05/2023] Open
Abstract
Inflammatory pain encompasses many clinical symptoms, and there is no satisfactory therapeutic target. Neuronal hyperexcitability and/or sensitization of the primary nociceptive neurons in the dorsal root ganglion (DRG) and spinal dorsal horn are critical to the development and maintenance of inflammatory pain. The sodium leak channel (NALCN), a non-selective cation channel, mediates the background Na+ leak conductance and controls neuronal excitability. It is unknown whether abnormal activity of NALCN mediates the pathological process of inflammatory pain. Complete Freund’s adjuvant (CFA) was injected into the left footpad of rats to induce inflammatory pain. The thresholds of mechanical and thermal sensation and spontaneous pain behaviors were assessed. The expression of NALCN in DRG and spinal dorsal cord was measured. NALCN currents and the contribution of NALCN to neuronal excitability in the DRG and spinal dorsal cord were recorded using whole-cell patch-clamping recording. NALCN was abundantly expressed in neurons of the DRG and spinal dorsal cord. In acutely isolated DRG neurons and spinal cord slices from rats with CFA-induced inflammatory pain, NALCN currents and neuronal excitability were increased. Subsequently, intrathecal and sciatic nerve injection of NALCN-small interfering RNA (siRNA) decreased NALCN mRNA and reverted NALCN currents to normal levels, and then reduced CFA-induced neuronal excitability and alleviated pain symptoms. Furthermore, pain-related symptoms were significantly prevented by the NALCN-shRNA-mediated NALCN knockdown in DRG and spinal cord. Therefore, increased expression and activity of NALCN contributed to neuronal sensitization in CFA-induced inflammatory pain. NALCN may be a novel molecular target for the control of inflammatory pain.
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Affiliation(s)
- Jia Li
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Anesthesiology, Xi'an Jiaotong University-Affiliated Honghui Hospital, Xi'an, China
| | - Yali Chen
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Peilin Lu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jiefei Shen
- Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases and Department of Prosthodontics, West China Stomatology Hospital of Sichuan University, Chengdu, China
| | - Changhong Miao
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Cheng Zhou
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.,Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
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14
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Magalhães KS, da Silva MP, Mecawi AS, Paton JFR, Machado BH, Moraes DJA. Intrinsic and synaptic mechanisms controlling the expiratory activity of excitatory lateral parafacial neurones of rats. J Physiol 2021; 599:4925-4948. [PMID: 34510468 DOI: 10.1113/jp281545] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/07/2021] [Indexed: 12/21/2022] Open
Abstract
Active expiration is essential for increasing pulmonary ventilation during high chemical drive (hypercapnia). The lateral parafacial (pFL ) region, which contains expiratory neurones, drives abdominal muscles during active expiration in response to hypercapnia. However, the electrophysiological properties and synaptic mechanisms determining the activity of pFL expiratory neurones, as well as the specific conditions for their emergence, are not fully understood. Using whole cell electrophysiology and single cell quantitative RT-PCR techniques, we describe the intrinsic electrophysiological properties, the phenotype and the respiratory-related synaptic inputs to the pFL expiratory neurones, as well as the mechanisms for the expression of their expiratory activity under conditions of hypercapnia-induced active expiration, using in situ preparations of juvenile rats. We also evaluated whether these neurones possess intrinsic CO2 /[H+ ] sensitivity and burst generating properties. GABAergic and glycinergic inhibition during inspiration and expiration suppressed the activity of glutamatergic pFL expiratory neurones in normocapnia. In hypercapnia, these neurones escape glycinergic inhibition and generate burst discharges at the end of expiration. Evidence for the contribution of post-inhibitory rebound, CaV 3.2 isoform of T-type Ca2+ channels and intracellular [Ca2+ ] is presented. Neither intrinsic bursting properties, mediated by persistent Na+ current, nor CO2 /[H+ ] sensitivity or expression of CO2 /[H+ ] sensitive ion channels/receptors (TASK or GPR4) were observed. On the other hand, hyperpolarisation-activated cyclic nucleotide-gated and twik-related K+ leak channels were recorded. Post-synaptic disinhibition and the intrinsic electrophysiological properties of glutamatergic neurones play important roles in the generation of the expiratory oscillations in the pFL region during hypercapnia in rats. KEY POINTS: Hypercapnia induces active expiration in rats and the recruitment of a specific population of expiratory neurones in the lateral parafacial (pFL ) region. Post-synaptic GABAergic and glycinergic inhibition both suppress the activity of glutamatergic pFL neurones during inspiratory and expiratory phases in normocapnia. Hypercapnia reduces glycinergic inhibition during expiration leading to burst generation by pFL neurones; evidence for a contribution of post-inhibitory rebound, voltage-gated Ca2+ channels and intracellular [Ca2+ ] is presented. pFL glutamatergic expiratory neurones are neither intrinsic burster neurones, nor CO2 /[H+ ] sensors, and do not express CO2 /[H+ ] sensitive ion channels or receptors. Post-synaptic disinhibition and the intrinsic electrophysiological properties of glutamatergic neurones both play important roles in the generation of the expiratory oscillations in the pFL region during hypercapnia in rats.
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Affiliation(s)
- Karolyne S Magalhães
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Melina P da Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - André S Mecawi
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Julian F R Paton
- Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Park Road, Grafton, Auckland, New Zealand
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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15
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Um KB, Hahn S, Kim SW, Lee YJ, Birnbaumer L, Kim HJ, Park MK. TRPC3 and NALCN channels drive pacemaking in substantia nigra dopaminergic neurons. eLife 2021; 10:70920. [PMID: 34409942 PMCID: PMC8456572 DOI: 10.7554/elife.70920] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/18/2021] [Indexed: 01/16/2023] Open
Abstract
Midbrain dopamine (DA) neurons are slow pacemakers that maintain extracellular DA levels. During the interspike intervals, subthreshold slow depolarization underlies autonomous pacemaking and determines its rate. However, the ion channels that determine slow depolarization are unknown. Here we show that TRPC3 and NALCN channels together form sustained inward currents responsible for the slow depolarization of nigral DA neurons. Specific TRPC3 channel blockade completely blocked DA neuron pacemaking, but the pacemaking activity in TRPC3 knock-out (KO) mice was perfectly normal, suggesting the presence of compensating ion channels. Blocking NALCN channels abolished pacemaking in both TRPC3 KO and wild-type mice. The NALCN current and mRNA and protein expression are increased in TRPC3 KO mice, indicating that NALCN compensates for TRPC3 currents. In normal conditions, TRPC3 and NALCN contribute equally to slow depolarization. Therefore, we conclude that TRPC3 and NALCN are two major leak channels that drive robust pacemaking in nigral DA neurons.
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Affiliation(s)
- Ki Bum Um
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Suyun Hahn
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - So Woon Kim
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Yoon Je Lee
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Lutz Birnbaumer
- Neurobiology Laboratory. National Institute of Environmental Health Sciences, North Carolina 27709, USA; and Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Hyun Jin Kim
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
| | - Myoung Kyu Park
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
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16
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Impheng H, Lemmers C, Bouasse M, Legros C, Pakaprot N, Guérineau NC, Lory P, Monteil A. The sodium leak channel NALCN regulates cell excitability of pituitary endocrine cells. FASEB J 2021; 35:e21400. [PMID: 33793981 DOI: 10.1096/fj.202000841rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 11/11/2022]
Abstract
Anterior pituitary endocrine cells that release hormones such as growth hormone and prolactin are excitable and fire action potentials. In these cells, several studies previously showed that extracellular sodium (Na+ ) removal resulted in a negative shift of the resting membrane potential (RMP) and a subsequent inhibition of the spontaneous firing of action potentials, suggesting the contribution of a Na+ background conductance. Here, we show that the Na+ leak channel NALCN conducts a Ca2+ - Gd3+ -sensitive and TTX-resistant Na+ background conductance in the GH3 cell line, a cell model of pituitary endocrine cells. NALCN knockdown hyperpolarized the RMP, altered GH3 cell electrical properties and inhibited prolactin secretion. Conversely, the overexpression of NALCN depolarized the RMP, also reshaping the electrical properties of GH3 cells. Overall, our results indicate that NALCN is functional in GH3 cells and involved in endocrine cell excitability as well as in hormone secretion. Indeed, the GH3 cell line suitably models native pituitary cells that display a similar Na+ background conductance and appears as a proper cellular model to study the role of NALCN in cellular excitability.
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Affiliation(s)
- Hathaichanok Impheng
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Céline Lemmers
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,PVM, BCM, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Malik Bouasse
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Christian Legros
- MITOVASC Institute, UMR CNRS 6015 - UMR INSERM U1083, Université d'Angers, Angers, France
| | - Narawut Pakaprot
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nathalie C Guérineau
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Arnaud Monteil
- IGF, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France.,PVM, BCM, Université de Montpellier, CNRS, INSERM, Montpellier, France
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17
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Ramirez JM, Burgraff NJ, Wei AD, Baertsch NA, Varga AG, Baghdoyan HA, Lydic R, Morris KF, Bolser DC, Levitt ES. Neuronal mechanisms underlying opioid-induced respiratory depression: our current understanding. J Neurophysiol 2021; 125:1899-1919. [PMID: 33826874 DOI: 10.1152/jn.00017.2021] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Opioid-induced respiratory depression (OIRD) represents the primary cause of death associated with therapeutic and recreational opioid use. Within the United States, the rate of death from opioid abuse since the early 1990s has grown disproportionally, prompting the classification as a nationwide "epidemic." Since this time, we have begun to unravel many fundamental cellular and systems-level mechanisms associated with opioid-related death. However, factors such as individual vulnerability, neuromodulatory compensation, and redundancy of opioid effects across central and peripheral nervous systems have created a barrier to a concise, integrative view of OIRD. Within this review, we bring together multiple perspectives in the field of OIRD to create an overarching viewpoint of what we know, and where we view this essential topic of research going forward into the future.
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Affiliation(s)
- Jan-Marino Ramirez
- Department of Neurological Surgery, University of Washington, Seattle, Washington.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nicholas J Burgraff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Aguan D Wei
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Adrienn G Varga
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Helen A Baghdoyan
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Ralph Lydic
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Erica S Levitt
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
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18
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Zhang D, Zhao W, Liu J, Ou M, Liang P, Li J, Chen Y, Liao D, Bai S, Shen J, Chen X, Huang H, Zhou C. Sodium leak channel contributes to neuronal sensitization in neuropathic pain. Prog Neurobiol 2021; 202:102041. [PMID: 33766679 DOI: 10.1016/j.pneurobio.2021.102041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 02/08/2021] [Accepted: 03/18/2021] [Indexed: 02/08/2023]
Abstract
Neuropathic pain affects up to 10 % of the total population and no specific target is ideal for therapeutic need. The sodium leak channel (NALCN), a non-selective cation channel, mediates the background Na+ leak conductance and controls neuronal excitability and rhythmic behaviors. Here, we show that increases of NALCN expression and function in dorsal root ganglion (DRG) and dorsal spinal cord contribute to chronic constriction injury (CCI)-induced neuropathic pain in rodents. NALCN current and neuronal excitability in acutely isolated DRG neurons and spinal cord slices of rats were increased after CCI which were decreased to normal levels by NALCN-siRNA. Accordingly, pain-related symptoms were significantly alleviated by NALCN-siRNA-mediated NALCN knockdown and completely prevented by NALCN-shRNA-mediated NALCN knockdown in rats or by conditional NALCN knockout in mice. Our results indicate that increases in NALCN expression and function contribute to CCI-induced neuronal sensitization; therefore, NALCN may be a novel molecular target for control of neuropathic pain.
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Affiliation(s)
- Donghang Zhang
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Wenling Zhao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jin Liu
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Mengchan Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jia Li
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Yali Chen
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Daqing Liao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Siqi Bai
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Jiefei Shen
- Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases and Department of Prosthodontics, West China Stomatology Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Xiangdong Chen
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei, China
| | - Han Huang
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology & Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital of Sichuan University, Chengdu 610041, Sichuan, China.
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China.
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19
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Burgraff NJ, Baertsch NA, Ramirez JM. Peptides, Breathing, and Sudden Infant Death Syndrome. Trends Neurosci 2021; 44:167-169. [PMID: 33549332 DOI: 10.1016/j.tins.2021.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 11/19/2022]
Abstract
Shi et al. recently identified a brainstem peptidergic circuit in mice that is activated at birth and stabilizes breathing during the transition from the intra-utero environment to air breathing. This network remains important for maintaining stable breathing and respiratory homeostasis throughout development, and deficiencies in this network may be linked to sudden infant death syndrome (SIDS).
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Affiliation(s)
- Nicholas J Burgraff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA; Department of Neurological Surgery, University of Washington, Seattle, WA, USA
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20
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Milman A, Ventéo S, Bossu JL, Fontanaud P, Monteil A, Lory P, Guérineau NC. A sodium background conductance controls the spiking pattern of mouse adrenal chromaffin cells in situ. J Physiol 2021; 599:1855-1883. [PMID: 33450050 PMCID: PMC7986707 DOI: 10.1113/jp281044] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Mouse chromaffin cells in acute adrenal slices exhibit two distinct spiking patterns, a repetitive mode and a bursting mode. A sodium background conductance operates at rest as demonstrated by the membrane hyperpolarization evoked by a low Na+ -containing extracellular saline. This sodium background current is insensitive to TTX, is not blocked by Cs+ ions and displays a linear I-V relationship at potentials close to chromaffin cell resting potential. Its properties are reminiscent of those of the sodium leak channel NALCN. In the adrenal gland, Nalcn mRNA is selectively expressed in chromaffin cells. The study fosters our understanding of how the spiking pattern of chromaffin cells is regulated and adds a sodium background conductance to the list of players involved in the stimulus-secretion coupling of the adrenomedullary tissue. ABSTRACT Chromaffin cells (CCs) are the master neuroendocrine units for the secretory function of the adrenal medulla and a finely-tuned regulation of their electrical activity is required for appropriate catecholamine secretion in response to the organismal demand. Here, we aim at deciphering how the spiking pattern of mouse CCs is regulated by the ion conductances operating near the resting membrane potential (RMP). At RMP, mouse CCs display a composite firing pattern, alternating between active periods composed of action potentials spiking with a regular or a bursting mode, and silent periods. RMP is sensitive to changes in extracellular sodium concentration, and a low Na+ -containing saline hyperpolarizes the membrane, regardless of the discharge pattern. This RMP drive reflects the contribution of a depolarizing conductance, which is (i) not blocked by tetrodotoxin or caesium, (ii) displays a linear I-V relationship between -110 and -40 mV, and (iii) is carried by cations with a conductance sequence gNa > gK > gCs . These biophysical attributes, together with the expression of the sodium-leak channel Nalcn transcript in CCs, state credible the contribution of NALCN. This inaugural report opens new research routes in the field of CC stimulus-secretion coupling, and extends the inventory of tissues in which NALCN is expressed to neuroendocrine glands.
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Affiliation(s)
- Alexandre Milman
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | | | - Jean-Louis Bossu
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212, Strasbourg, France
| | - Pierre Fontanaud
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
| | - Nathalie C Guérineau
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx "Ion Channel Science and Therapeutics", Montpellier, France
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21
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Moreira TS, Sobrinho CR, Falquetto B, Oliveira LM, Lima JD, Mulkey DK, Takakura AC. The retrotrapezoid nucleus and the neuromodulation of breathing. J Neurophysiol 2020; 125:699-719. [PMID: 33427575 DOI: 10.1152/jn.00497.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Breathing is regulated by a host of arousal and sleep-wake state-dependent neuromodulators to maintain respiratory homeostasis. Modulators such as acetylcholine, norepinephrine, histamine, serotonin (5-HT), adenosine triphosphate (ATP), substance P, somatostatin, bombesin, orexin, and leptin can serve complementary or off-setting functions depending on the target cell type and signaling mechanisms engaged. Abnormalities in any of these modulatory mechanisms can destabilize breathing, suggesting that modulatory mechanisms are not overly redundant but rather work in concert to maintain stable respiratory output. The present review focuses on the modulation of a specific cluster of neurons located in the ventral medullary surface, named retrotrapezoid nucleus, that are activated by changes in tissue CO2/H+ and regulate several aspects of breathing, including inspiration and active expiration.
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Affiliation(s)
- Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Barbara Falquetto
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Janayna D Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
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22
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Volatile Anesthetics Activate a Leak Sodium Conductance in Retrotrapezoid Nucleus Neurons to Maintain Breathing during Anesthesia in Mice. Anesthesiology 2020; 133:824-838. [PMID: 32773689 DOI: 10.1097/aln.0000000000003493] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Volatile anesthetics moderately depress respiratory function at clinically relevant concentrations. Phox2b-expressing chemosensitive neurons in the retrotrapezoid nucleus, a respiratory control center, are activated by isoflurane, but the underlying mechanisms remain unclear. The hypothesis of this study was that the sodium leak channel contributes to the volatile anesthetics-induced modulation of retrotrapezoid nucleus neurons and to respiratory output. METHODS The contribution of sodium leak channels to isoflurane-, sevoflurane-, and propofol-evoked activity of Phox2b-expressing retrotrapezoid nucleus neurons and respiratory output were evaluated in wild-type and genetically modified mice lacking sodium leak channels (both sexes). Patch-clamp recordings were performed in acute brain slices. Whole-body plethysmography was used to measure the respiratory activity. RESULTS Isoflurane at 0.42 to 0.50 mM (~1.5 minimum alveolar concentration) increased the sodium leak channel-mediated holding currents and conductance from -75.0 ± 12.9 to -130.1 ± 34.9 pA (mean ± SD, P = 0.002, n = 6) and 1.8 ± 0.5 to 3.6 ± 1.0 nS (P = 0.001, n = 6), respectively. At these concentrations, isoflurane increased activity of Phox2b-expressing retrotrapezoid nucleus neurons from 1.1 ± 0.2 to 2.8 ± 0.2 Hz (P < 0.001, n = 5), which was eliminated by bath application of gadolinium or genetic silencing of sodium leak channel. Genetic silencing of sodium leak channel in the retrotrapezoid nucleus resulted in a diminished ventilatory response to carbon dioxide in mice under control conditions and during isoflurane anesthesia. Sevoflurane produced an effect comparable to that of isoflurane, whereas propofol did not activate sodium leak channel-mediated holding conductance. CONCLUSIONS Isoflurane and sevoflurane increase neuronal excitability of chemosensitive retrotrapezoid nucleus neurons partly by enhancing sodium leak channel conductance. Sodium leak channel expression in the retrotrapezoid nucleus is required for the ventilatory response to carbon dioxide during anesthesia by isoflurane and sevoflurane, thus identifying sodium leak channel as a requisite determinant of respiratory output during anesthesia of volatile anesthetics. EDITOR’S PERSPECTIVE
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23
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A Leptin-Mediated Neural Mechanism Linking Breathing to Metabolism. Cell Rep 2020; 33:108358. [PMID: 33176139 DOI: 10.1016/j.celrep.2020.108358] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/27/2020] [Accepted: 10/16/2020] [Indexed: 01/10/2023] Open
Abstract
Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of the solitary tract (NTS) mimics the respiratory stimulation after systemic leptin administration. We show that leptin activates the sodium leak channel (NALCN), thereby depolarizing a subset of glutamatergic (VGluT2) LepRb NTS neurons expressing galanin. Mice with selective deletion of NALCN in LepRb neurons have increased breathing irregularity and central apneas. On a high-fat diet, these mice gain weight with an associated depression of minute ventilation and tidal volume, which are not detected in control littermates. Anatomical mapping reveals LepRb NTS-originating glutamatergic axon terminals in a brainstem inspiratory premotor region (rVRG) and dorsomedial hypothalamus. These findings directly link a defined subset of NTS LepRb cells to the matching of ventilation to energy balance.
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24
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Karimi AH, Karimi MR, Farnia P, Parvini F, Foroutan M. A Homozygous Truncating Mutation in NALCN Causing IHPRF1: Detailed Clinical Manifestations and a Review of Literature. APPLICATION OF CLINICAL GENETICS 2020; 13:151-157. [PMID: 32943903 PMCID: PMC7459142 DOI: 10.2147/tacg.s261781] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/08/2020] [Indexed: 12/15/2022]
Abstract
Infantile hypotonia, with psychomotor retardation and characteristic facies 1 (IHPRF1), is a rare disorder characterized by global developmental delay and dysmorphic features. This syndrome is caused by genetic anomalies within the NALCN gene. The current report examines a 9-year-old female IHPRF1 patient. Our objective was to contribute to the delineation of the underlying factors influencing this rare condition. Whole exome sequencing (WES) was utilized to identify the disease-causing mutation in the affected individual. Subsequently, Sanger sequencing was performed for the patient, her parents, and two close relatives in order to confirm the detected mutation. Moreover, detailed clinical examinations including EEG, echocardiography, and biochemical/physical tests were carried out to elucidate the effects of the mutation. WES identified a homozygous nonsense mutation in the NALCN gene (c.2563C>T p.R855X). This mutation was confirmed by Sanger sequencing in the patient and her family members and segregated with the autosomal recessive inheritance pattern of IHPRF1. Moreover, genotype-phenotype correlation analysis confirmed the disease-causing nature of this mutation. The current report provides the first detailed description of a patient with this homozygous nonsense mutation (c.2563C>T p.R855X) and expands the clinical spectrum of IHPRF1 disease. Possible influences of sex and other factors on this disease are discussed and a review of the literature is also provided.
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Affiliation(s)
- Amir Hossein Karimi
- Department of Biology, Faculty of Basic Sciences, Semnan University, Semnan, Iran
| | - Mohammad Reza Karimi
- Department of Biology, Faculty of Basic Sciences, Semnan University, Semnan, Iran
| | - Poopak Farnia
- Mycobacteriology Research Centre (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farshid Parvini
- Department of Biology, Faculty of Basic Sciences, Semnan University, Semnan, Iran
| | - Majid Foroutan
- Department of Internal Medicine, Semnan University of Medical Sciences, Semnan, Iran
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25
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Wie J, Bharthur A, Wolfgang M, Narayanan V, Ramsey K, Aranda K, Zhang Q, Zhou Y, Ren D. Intellectual disability-associated UNC80 mutations reveal inter-subunit interaction and dendritic function of the NALCN channel complex. Nat Commun 2020; 11:3351. [PMID: 32620897 PMCID: PMC7335163 DOI: 10.1038/s41467-020-17105-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 06/11/2020] [Indexed: 01/08/2023] Open
Abstract
The sodium-leak channel NALCN forms a subthreshold sodium conductance that controls the resting membrane potentials of neurons. The auxiliary subunits of the channel and their functions in mammals are largely unknown. In this study, we demonstrate that two large proteins UNC80 and UNC79 are subunits of the NALCN complex. UNC80 knockout mice are neonatal lethal. The C-terminus of UNC80 contains a domain that interacts with UNC79 and overcomes a soma-retention signal to achieve dendritic localization. UNC80 lacking this domain, as found in human patients, still supports whole-cell NALCN currents but lacks dendritic localization. Our results establish the subunit composition of the NALCN complex, uncover the inter-subunit interaction domains, reveal the functional significance of regulation of dendritic membrane potential by the sodium-leak channel complex, and provide evidence supporting that genetic variations found in individuals with intellectual disability are the causes for the phenotype observed in patients.
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Affiliation(s)
- Jinhong Wie
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Apoorva Bharthur
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Morgan Wolfgang
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, 85012, USA
| | - Kimberly Aranda
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Qi Zhang
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yandong Zhou
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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26
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Hahn S, Kim SW, Um KB, Kim HJ, Park MK. N-benzhydryl quinuclidine compounds are a potent and Src kinase-independent inhibitor of NALCN channels. Br J Pharmacol 2020; 177:3795-3810. [PMID: 32436268 DOI: 10.1111/bph.15104] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 05/01/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE NALCN is a Na+ leak, GPCR-activated channel that regulates the resting membrane potential and neuronal excitability. Despite numerous possible roles for NALCN in both normal physiology and disease processes, lack of specific blockers hampers further investigation. EXPERIMENTAL APPROACH The effect of N-benzhydryl quinuclidine compounds on NALCN channels was demonstrated using whole-cell patch-clamp recordings in HEK293T cells overexpressing NALCN and acutely isolated nigral dopaminergic neurons that express NALCN endogenously. Src kinase activity was measured using a Src kinase assay kit, and voltage and current-clamp recordings from nigral dopaminergic neurons were used to measure NALCN currents and membrane potentials. KEY RESULTS N-benzhydryl quinuclidine compounds inhibited NALCN channels without affecting TRPC channels, another important route for Na+ leak. In HEK293T cells overexpressing NALCN, N-benzhydryl quinuclidine compounds potently suppressed muscarinic M3 receptor-activated NALCN currents. Structure-function relationship studies suggest that the quinuclidine ring with a benzhydryl group imparts the ability to inhibit NALCN currents regardless of Src family kinases. Moreover, N-benzhydryl quinuclidine compounds inhibited not only GPCR-activated NALCN currents but also background Na+ leak currents and hyperpolarized the membrane potential in native midbrain dopaminergic neurons that express NALCN endogenously. CONCLUSION AND IMPLICATIONS These findings suggest that N-benzhydryl quinuclidine compounds have a pharmacological potential to directly inhibit NALCN channels and could be a useful tool to investigate functions of NALCN channels.
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Affiliation(s)
- Suyun Hahn
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - So Woon Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Ki Bum Um
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
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27
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The NALCN Channel Regulator UNC-80 Functions in a Subset of Interneurons To Regulate Caenorhabditis elegans Reversal Behavior. G3-GENES GENOMES GENETICS 2020; 10:199-210. [PMID: 31690562 PMCID: PMC6945035 DOI: 10.1534/g3.119.400692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
NALCN (Na+leak channel, non-selective) is a conserved, voltage-insensitive cation channel that regulates resting membrane potential and neuronal excitability. UNC79 and UNC80 are key regulators of the channel function. However, the behavioral effects of the channel complex are not entirely clear and the neurons in which the channel functions remain to be identified. In a forward genetic screen for C. elegans mutants with defective avoidance response to the plant hormone methyl salicylate (MeSa), we isolated multiple loss-of-function mutations in unc-80 and unc-79. C. elegans NALCN mutants exhibited similarly defective MeSa avoidance. Interestingly, NALCN, unc-80 and unc-79 mutants all showed wild type-like responses to other attractive or repelling odorants, suggesting that NALCN does not broadly affect odor detection or related forward and reversal behaviors. To understand in which neurons the channel functions, we determined the identities of a subset of unc-80-expressing neurons. We found that unc-79 and unc-80 are expressed and function in overlapping neurons, which verified previous assumptions. Neuron-specific transgene rescue and knockdown experiments suggest that the command interneurons AVA and AVE and the anterior guidepost neuron AVG can play a sufficient role in mediating unc-80 regulation of the MeSa avoidance. Though primarily based on genetic analyses, our results further imply that MeSa might activate NALCN by direct or indirect actions. Altogether, we provide an initial look into the key neurons in which the NALCN channel complex functions and identify a novel function of the channel in regulating C. elegans reversal behavior through command interneurons.
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28
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Sun X, Thörn Pérez C, Halemani D N, Shao XM, Greenwood M, Heath S, Feldman JL, Kam K. Opioids modulate an emergent rhythmogenic process to depress breathing. eLife 2019; 8:e50613. [PMID: 31841107 PMCID: PMC6938398 DOI: 10.7554/elife.50613] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
How mammalian neural circuits generate rhythmic activity in motor behaviors, such as breathing, walking, and chewing, remains elusive. For breathing, rhythm generation is localized to a brainstem nucleus, the preBötzinger Complex (preBötC). Rhythmic preBötC population activity consists of strong inspiratory bursts, which drive motoneuronal activity, and weaker burstlets, which we hypothesize reflect an emergent rhythmogenic process. If burstlets underlie inspiratory rhythmogenesis, respiratory depressants, such as opioids, should reduce burstlet frequency. Indeed, in medullary slices from neonatal mice, the μ-opioid receptor (μOR) agonist DAMGO slowed burstlet generation. Genetic deletion of μORs in a glutamatergic preBötC subpopulation abolished opioid-mediated depression, and the neuropeptide Substance P, but not blockade of inhibitory synaptic transmission, reduced opioidergic effects. We conclude that inspiratory rhythmogenesis is an emergent process, modulated by opioids, that does not rely on strong bursts of activity associated with motor output. These findings also point to strategies for ameliorating opioid-induced depression of breathing.
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Affiliation(s)
- Xiaolu Sun
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Carolina Thörn Pérez
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Nagaraj Halemani D
- Department of Cell Biology and AnatomyChicago Medical School, Rosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
| | - Xuesi M Shao
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Morgan Greenwood
- RFUMS/DePaul Research Internship ProgramRosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
| | - Sarah Heath
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Jack L Feldman
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Kaiwen Kam
- Department of Cell Biology and AnatomyChicago Medical School, Rosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
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29
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Baertsch NA, Ramirez JM. Insights into the dynamic control of breathing revealed through cell-type-specific responses to substance P. eLife 2019; 8:51350. [PMID: 31804180 PMCID: PMC6957314 DOI: 10.7554/elife.51350] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/04/2019] [Indexed: 12/23/2022] Open
Abstract
The rhythm generating network for breathing must continuously adjust to changing metabolic and behavioral demands. Here, we examined network-based mechanisms in the mouse preBötzinger complex using substance P, a potent excitatory modulator of breathing frequency and stability, as a tool to dissect network properties that underlie dynamic breathing. We find that substance P does not alter the balance of excitation and inhibition during breaths or the duration of the resulting refractory period. Instead, mechanisms of recurrent excitation between breaths are enhanced such that the rate that excitation percolates through the network is increased. We propose a conceptual framework in which three distinct phases of inspiration, the burst phase, refractory phase, and percolation phase, can be differentially modulated to control breathing dynamics and stability. Unraveling mechanisms that support this dynamic control may improve our understanding of nervous system disorders that destabilize breathing, many of which involve changes in brainstem neuromodulatory systems.
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Affiliation(s)
- Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, United States
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30
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Abstract
Breathing is a well-described, vital and surprisingly complex behaviour, with behavioural and physiological outputs that are easy to directly measure. Key neural elements for generating breathing pattern are distinct, compact and form a network amenable to detailed interrogation, promising the imminent discovery of molecular, cellular, synaptic and network mechanisms that give rise to the behaviour. Coupled oscillatory microcircuits make up the rhythmic core of the breathing network. Primary among these is the preBötzinger Complex (preBötC), which is composed of excitatory rhythmogenic interneurons and excitatory and inhibitory pattern-forming interneurons that together produce the essential periodic drive for inspiration. The preBötC coordinates all phases of the breathing cycle, coordinates breathing with orofacial behaviours and strongly influences, and is influenced by, emotion and cognition. Here, we review progress towards cracking the inner workings of this vital core.
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31
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Steuer I, Guertin PA. Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences. Rev Neurosci 2019; 30:107-164. [PMID: 30543520 DOI: 10.1515/revneuro-2017-0102] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Central pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs in in vivo animal models, in vitro preparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.
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Affiliation(s)
- Inge Steuer
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
| | - Pierre A Guertin
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Laval University, Quebec City, Quebec G1V 0A6, Canada
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32
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Bouasse M, Impheng H, Servant Z, Lory P, Monteil A. Functional expression of CLIFAHDD and IHPRF pathogenic variants of the NALCN channel in neuronal cells reveals both gain- and loss-of-function properties. Sci Rep 2019; 9:11791. [PMID: 31409833 PMCID: PMC6692409 DOI: 10.1038/s41598-019-48071-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/29/2019] [Indexed: 12/24/2022] Open
Abstract
The excitability of neurons is tightly dependent on their ion channel repertoire. Among these channels, the leak sodium channel NALCN plays a crucial role in the maintenance of the resting membrane potential. Importantly, NALCN mutations lead to complex neurodevelopmental syndromes, including infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of limbs and face, hypotonia and developmental delay (CLIFAHDD), which are recessively and dominantly inherited, respectively. Unfortunately, the biophysical properties of NALCN are still largely unknown to date, as well as the functional consequences of both IHPRF and CLIFAHDD mutations on NALCN current. Here we have set-up the heterologous expression of NALCN in the neuronal cell line NG108-15 to investigate the electrophysiological properties of NALCN carrying representative IHPRF and CLIFAHDD mutations. Several original properties of the wild-type (wt) NALCN current were retrieved: mainly carried by external Na+, blocked by Gd3+, insensitive to TTX and potentiated by low external Ca2+ concentration. However, we found that this current displays a time-dependent inactivation in the −80/−40 mV range of membrane potential, and a non linear current-voltage relationship indicative of voltage sensitivity. Importantly, no detectable current was recorded with the IHPRF missense mutation p.Trp1287Leu (W1287L), while the CLIFAHDD mutants, p.Leu509Ser (L509S) and p.Tyr578Ser (Y578S), showed higher current densities and slower inactivation, compared to wt NALCN current. This study reveals that heterologous expression of NALCN channel can be achieved in the neuronal cell line NG108-15 to study the electrophysiological properties of wt and mutants. From our results, we conclude that IHPRF and CLIFAHDD missense mutations are loss- and gain-of-function variants, respectively.
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Affiliation(s)
- Malik Bouasse
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Hathaichanok Impheng
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Zoe Servant
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Arnaud Monteil
- IGF, CNRS, INSERM, University of Montpellier, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France.
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33
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Golowasch J. Neuromodulation of central pattern generators and its role in the functional recovery of central pattern generator activity. J Neurophysiol 2019; 122:300-315. [PMID: 31066614 DOI: 10.1152/jn.00784.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Neuromodulators play an important role in how the nervous system organizes activity that results in behavior. Disruption of the normal patterns of neuromodulatory release or production is known to be related to the onset of severe pathologies such as Parkinson's disease, Rett syndrome, Alzheimer's disease, and affective disorders. Some of these pathologies involve neuronal structures that are called central pattern generators (CPGs), which are involved in the production of rhythmic activities throughout the nervous system. Here I discuss the interplay between CPGs and neuromodulatory activity, with particular emphasis on the potential role of neuromodulators in the recovery of disrupted neuronal activity. I refer to invertebrate and vertebrate model systems and some of the lessons we have learned from research on these systems and propose a few avenues for future research. I make one suggestion that may guide future research in the field: neuromodulators restrict the parameter landscape in which CPG components operate, and the removal of neuromodulators may enable a perturbed CPG in finding a new set of parameter values that can allow it to regain normal function.
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Affiliation(s)
- Jorge Golowasch
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark , Newark, New Jersey
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34
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Abstract
Spinal projection neurons convey nociceptive signals to multiple brain regions including the parabrachial (PB) nucleus, which contributes to the emotional valence of pain perception. Despite the clear importance of projection neurons to pain processing, our understanding of the factors that shape their intrinsic membrane excitability remains limited. Here, we investigate a potential role for the Na leak channel NALCN in regulating the activity of spino-PB neurons in the developing rodent. Pharmacological reduction of NALCN current (INALCN), or the genetic deletion of NALCN channels, significantly reduced the intrinsic excitability of lamina I spino-PB neurons. In addition, substance P (SP) activated INALCN in ascending projection neurons through downstream Src kinase signaling, and the knockout of NALCN prevented SP-evoked action potential discharge in this neuronal population. These results identify, for the first time, NALCN as a strong regulator of neuronal activity within central pain circuits and also elucidate an additional ionic mechanism by which SP can modulate spinal nociceptive processing. Collectively, these findings indicate that the level of NALCN conductance within spino-PB neurons tightly governs ascending nociceptive transmission to the brain and thereby potentially influences pain perception.
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Philippart F, Khaliq ZM. G i/o protein-coupled receptors in dopamine neurons inhibit the sodium leak channel NALCN. eLife 2018; 7:40984. [PMID: 30556810 PMCID: PMC6305199 DOI: 10.7554/elife.40984] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/17/2018] [Indexed: 12/13/2022] Open
Abstract
Dopamine (D2) receptors provide autoinhibitory feedback onto dopamine neurons through well-known interactions with voltage-gated calcium channels and G protein-coupled inwardly-rectifying potassium (GIRK) channels. Here, we reveal a third major effector involved in D2R modulation of dopaminergic neurons - the sodium leak channel, NALCN. We found that activation of D2 receptors robustly inhibits isolated sodium leak currents in wild-type mice but not in NALCN conditional knockout mice. Intracellular GDP-βS abolished the inhibition, indicating a G protein-dependent signaling mechanism. The application of dopamine reliably slowed pacemaking even when GIRK channels were pharmacologically blocked. Furthermore, while spontaneous activity was observed in nearly all dopaminergic neurons in wild-type mice, neurons from NALCN knockouts were mainly silent. Both observations demonstrate the critical importance of NALCN for pacemaking in dopaminergic neurons. Finally, we show that GABA-B receptor activation also produces inhibition of NALCN-mediated currents. Therefore, we identify NALCN as a core effector of inhibitory G protein-coupled receptors.
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Affiliation(s)
- Fabian Philippart
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Maryland, United States
| | - Zayd M Khaliq
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Maryland, United States
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36
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Follmann R, Goldsmith CJ, Stein W. Multimodal sensory information is represented by a combinatorial code in a sensorimotor system. PLoS Biol 2018; 16:e2004527. [PMID: 30321170 PMCID: PMC6201955 DOI: 10.1371/journal.pbio.2004527] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 10/25/2018] [Accepted: 10/02/2018] [Indexed: 11/22/2022] Open
Abstract
A ubiquitous feature of the nervous system is the processing of simultaneously arriving sensory inputs from different modalities. Yet, because of the difficulties of monitoring large populations of neurons with the single resolution required to determine their sensory responses, the cellular mechanisms of how populations of neurons encode different sensory modalities often remain enigmatic. We studied multimodal information encoding in a small sensorimotor system of the crustacean stomatogastric nervous system that drives rhythmic motor activity for the processing of food. This system is experimentally advantageous, as it produces a fictive behavioral output in vitro, and distinct sensory modalities can be selectively activated. It has the additional advantage that all sensory information is routed through a hub ganglion, the commissural ganglion, a structure with fewer than 220 neurons. Using optical imaging of a population of commissural neurons to track each individual neuron's response across sensory modalities, we provide evidence that multimodal information is encoded via a combinatorial code of recruited neurons. By selectively stimulating chemosensory and mechanosensory inputs that are functionally important for processing of food, we find that these two modalities were processed in a distributed network comprising the majority of commissural neurons imaged. In a total of 12 commissural ganglia, we show that 98% of all imaged neurons were involved in sensory processing, with the two modalities being processed by a highly overlapping set of neurons. Of these, 80% were multimodal, 18% were unimodal, and only 2% of the neurons did not respond to either modality. Differences between modalities were represented by the identities of the neurons participating in each sensory condition and by differences in response sign (excitation versus inhibition), with 46% changing their responses in the other modality. Consistent with the hypothesis that the commissural network encodes different sensory conditions in the combination of activated neurons, a new combination of excitation and inhibition was found when both pathways were activated simultaneously. The responses to this bimodal condition were distinct from either unimodal condition, and for 30% of the neurons, they were not predictive from the individual unimodal responses. Thus, in a sensorimotor network, different sensory modalities are encoded using a combinatorial code of neurons that are activated or inhibited. This provides motor networks with the ability to differentially respond to categorically different sensory conditions and may serve as a model to understand higher-level processing of multimodal information.
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Affiliation(s)
- Rosangela Follmann
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | | | - Wolfgang Stein
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
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van der Heijden ME, Zoghbi HY. Loss of Atoh1 from neurons regulating hypoxic and hypercapnic chemoresponses causes neonatal respiratory failure in mice. eLife 2018; 7:e38455. [PMID: 29972353 PMCID: PMC6067883 DOI: 10.7554/elife.38455] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/01/2018] [Indexed: 12/12/2022] Open
Abstract
Atoh1-null mice die at birth from respiratory failure, but the precise cause has remained elusive. Loss of Atoh1 from various components of the respiratory circuitry (e.g. the retrotrapezoid nucleus (RTN)) has so far produced at most 50% neonatal lethality. To identify other Atoh1-lineage neurons that contribute to postnatal survival, we examined parabrachial complex neurons derived from the rostral rhombic lip (rRL) and found that they are activated during respiratory chemochallenges. Atoh1-deletion from the rRL does not affect survival, but causes apneas and respiratory depression during hypoxia, likely due to loss of projections to the preBötzinger Complex and RTN. Atoh1 thus promotes the development of the neural circuits governing hypoxic (rRL) and hypercapnic (RTN) chemoresponses, and combined loss of Atoh1 from these regions causes fully penetrant neonatal lethality. This work underscores the importance of modulating respiratory rhythms in response to chemosensory information during early postnatal life.
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Affiliation(s)
- Meike E van der Heijden
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research InstituteTexas Children’s HospitalHoustonUnited States
| | - Huda Y Zoghbi
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research InstituteTexas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Department of PediatricsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical InstituteBaylor College of MedicineHoustonUnited States
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38
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Yuan M, Ma MN, Wang TY, Feng Y, Chen P, He C, Liu S, Guo YX, Wang Y, Fan Y, Wang LQ, E XQ, Qiao GF, Li BY. Direct activation of tachykinin receptors within baroreflex afferent pathway and neurocontrol of blood pressure regulation. CNS Neurosci Ther 2018; 25:123-135. [PMID: 29900692 DOI: 10.1111/cns.12993] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/12/2018] [Accepted: 05/20/2018] [Indexed: 12/16/2022] Open
Abstract
AIM Substance P (SP) causes vasodilation and blood pressure (BP) reduction. However, the involvement of tachykinin receptors (NKRs) within baroreflex afferent pathway in SP-mediated BP regulation is largely unknown. METHODS Under control and hypertensive condition, NKRs' expressions were evaluated in nodose (NG) and nucleus of tractus solitary (NTS) of male, female, and ovariectomized (OVX) rats; BP was recorded after microinjection of SP and NKRs agonists into NG; Baroreceptor sensitivity (BRS) was tested as well. RESULTS Immunostaining and immunoblotting data showed that NK1R and NK2R were estrogen-dependently expressed on myelinated and unmyelinated afferents in NG. A functional study showed that BP was reduced dose-dependently by SP microinjection, which was more dramatic in males and can be mimicked by NK1R and NK2R agonists. Notably, further BP elevation and BRS dysfunction were confirmed in desoxycorticosterone acetate (DOCA)-salt model in OVX compared with DOCA-salt model in intact female rats. Additionally, similar changes in NKRs' expression in NG were also detected using DOCA-salt and SHR. Compared with NG, inversed expression profiles of NKRs were also found in NTS with either gender. CONCLUSION The estrogen-dependent NKRs' expression in baroreflex afferent pathway participates at least partially in sexual-dimorphic and SP-mediated BP regulation under physiological and hypertensive conditions.
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Affiliation(s)
- Mei Yuan
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Mei-Na Ma
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ting-Yu Wang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yan Feng
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Pei Chen
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Chao He
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Sijie Liu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yun-Xia Guo
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yue Wang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yao Fan
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Lu-Qi Wang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xiao-Qiang E
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Guo-Fen Qiao
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Bai-Yan Li
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, China
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Orengo JP, van der Heijden ME, Hao S, Tang J, Orr HT, Zoghbi HY. Motor neuron degeneration correlates with respiratory dysfunction in SCA1. Dis Model Mech 2018; 11:dmm.032623. [PMID: 29419414 PMCID: PMC5894948 DOI: 10.1242/dmm.032623] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/19/2018] [Indexed: 12/11/2022] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is characterized by adult-onset cerebellar degeneration with attendant loss of motor coordination. Bulbar function is eventually impaired and patients typically die from an inability to clear the airway. We investigated whether motor neuron degeneration is at the root of bulbar dysfunction by studying SCA1 knock-in (Atxn1154Q/+) mice. Spinal cord and brainstem motor neurons were assessed in Atxn1154Q/+ mice at 1, 3 and 6 months of age. Specifically, we assessed breathing physiology, diaphragm histology and electromyography, and motor neuron histology and immunohistochemistry. Atxn1154Q/+ mice show progressive neuromuscular respiratory abnormalities, neurogenic changes in the diaphragm, and motor neuron degeneration in the spinal cord and brainstem. Motor neuron degeneration is accompanied by reactive astrocytosis and accumulation of Atxn1 aggregates in the motor neuron nuclei. This observation correlates with previous findings in SCA1 patient tissue. Atxn1154Q/+ mice develop bulbar dysfunction because of motor neuron degeneration. These findings confirm the Atxn1154Q/+ line as a SCA1 model with face and construct validity for this understudied disease feature. Furthermore, this model is suitable for studying the pathogenic mechanism driving motor neuron degeneration in SCA1 and possibly other degenerative motor neuron diseases. From a clinical standpoint, the data indicate that pulmonary function testing and employment of non-invasive ventilator support could be beneficial in SCA1 patients. The physiological tests used in this study might serve as valuable biomarkers for future therapeutic interventions and clinical trials. This article has an associated First Person interview with the first author of the paper. Summary: In this manuscript, we discovered motor neuron degeneration which correlates with respiratory failure in a knock-in mouse model of spinocerebellar ataxia type 1 (SCA1).
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Affiliation(s)
- James P Orengo
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA
| | - Meike E van der Heijden
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shuang Hao
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jianrong Tang
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA .,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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40
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Takenouchi T, Inaba M, Uehara T, Takahashi T, Kosaki K, Mizuno S. Biallelic mutations in NALCN: Expanding the genotypic and phenotypic spectra of IHPRF1. Am J Med Genet A 2017; 176:431-437. [PMID: 29168298 DOI: 10.1002/ajmg.a.38543] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 09/09/2017] [Accepted: 10/20/2017] [Indexed: 01/05/2023]
Abstract
Loss-of function mutations in NALCN on chromosome 13q, a sodium leak channel that maintains baseline neuronal excitability, cause infantile hypotonia with psychomotor retardation and characteristic faces 1 (IHPRF1, OMIM #615419). Here, we document two individuals with early onset hypotonia with poor feeding and intellectual disability who were compatible with a diagnosis of IHPRF1. The two patients had bi-allelic mutations in NALCN through two different genetic mechanisms: Patient 1 had bi-allelic splice site mutations, that is c.1267-2A>G, derived from heterozygous parents, while Patient 2 had a partial maternal uniparental isodisomy that harbored a frameshift mutation, that is c.2022_2023delAT, in chromosome 13 that was detected through a dedicated algorithm for homozygosity data mapping in whole exome sequencing. The delineation of the exact pattern of inheritance provided vital information regarding the risk of recurrence. In animal models with Nalcn mutations, two behavioral phenotypes, that are, postnatal dyspnea and sleep disturbance, have been reported. Our observations of the two patients with postnatal dyspnea and one patient with sleep disturbance support an association between these two behavioral phenotypes and NALCN mutations in humans. The routine use of a detection algorithm for homozygosity data mapping might improve the diagnostic yields of next-generation sequencing.
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Affiliation(s)
- Toshiki Takenouchi
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Mie Inaba
- Department of Pediatrics, Aichi Human Service Center, Central Hospital, Aichi, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Takao Takahashi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Seiji Mizuno
- Department of Pediatrics, Aichi Human Service Center, Central Hospital, Aichi, Japan
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Phasic inhibition as a mechanism for generation of rapid respiratory rhythms. Proc Natl Acad Sci U S A 2017; 114:12815-12820. [PMID: 29133427 DOI: 10.1073/pnas.1711536114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Central neural networks operate continuously throughout life to control respiration, yet mechanisms regulating ventilatory frequency are poorly understood. Inspiration is generated by the pre-Bötzinger complex of the ventrolateral medulla, where it is thought that excitation increases inspiratory frequency and inhibition causes apnea. To test this model, we used an in vitro optogenetic approach to stimulate select populations of hindbrain neurons and characterize how they modulate frequency. Unexpectedly, we found that inhibition was required for increases in frequency caused by stimulation of Phox2b-lineage, putative CO2-chemosensitive neurons. As a mechanistic explanation for inhibition-dependent increases in frequency, we found that phasic stimulation of inhibitory neurons can increase inspiratory frequency via postinhibitory rebound. We present evidence that Phox2b-mediated increases in frequency are caused by rebound excitation following an inhibitory synaptic volley relayed by expiration. Thus, although it is widely thought that inhibition between inspiration and expiration simply prevents activity in the antagonistic phase, we instead propose a model whereby inhibitory coupling via postinhibitory rebound excitation actually generates fast modes of inspiration.
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42
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Topalidou I, Cooper K, Pereira L, Ailion M. Dopamine negatively modulates the NCA ion channels in C. elegans. PLoS Genet 2017; 13:e1007032. [PMID: 28968387 PMCID: PMC5638609 DOI: 10.1371/journal.pgen.1007032] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 10/12/2017] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
The NALCN/NCA ion channel is a cation channel related to voltage-gated sodium and calcium channels. NALCN has been reported to be a sodium leak channel with a conserved role in establishing neuronal resting membrane potential, but its precise cellular role and regulation are unclear. The Caenorhabditis elegans orthologs of NALCN, NCA-1 and NCA-2, act in premotor interneurons to regulate motor circuit activity that sustains locomotion. Recently we found that NCA-1 and NCA-2 are activated by a signal transduction pathway acting downstream of the heterotrimeric G protein Gq and the small GTPase Rho. Through a forward genetic screen, here we identify the GPCR kinase GRK-2 as a new player affecting signaling through the Gq-Rho-NCA pathway. Using structure-function analysis, we find that the GPCR phosphorylation and membrane association domains of GRK-2 are required for its function. Genetic epistasis experiments suggest that GRK-2 acts on the D2-like dopamine receptor DOP-3 to inhibit Go signaling and positively modulate NCA-1 and NCA-2 activity. Through cell-specific rescuing experiments, we find that GRK-2 and DOP-3 act in premotor interneurons to modulate NCA channel function. Finally, we demonstrate that dopamine, through DOP-3, negatively regulates NCA activity. Thus, this study identifies a pathway by which dopamine modulates the activity of the NCA channels.
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Affiliation(s)
- Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (IT); (MA)
| | - Kirsten Cooper
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Laura Pereira
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (IT); (MA)
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