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Tsentsevitsky AN, Khuzakhmetova VF, Bukharaeva EA, Petrov AM. The Mechanism of α2 adrenoreceptor-dependent Modulation of Neurotransmitter Release at the Neuromuscular Junctions. Neurochem Res 2024; 49:453-465. [PMID: 37897557 DOI: 10.1007/s11064-023-04052-1] [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: 07/29/2023] [Revised: 09/26/2023] [Accepted: 10/17/2023] [Indexed: 10/30/2023]
Abstract
α2-Adrenoreceptors (ARs) are main Gi-protein coupled autoreceptors in sympathetic nerve terminals and targets for dexmedetomidine (DEX), a widely used sedative. We hypothesize that α2-ARs are also potent regulators of neuromuscular transmission via G protein-gated inwardly rectifying potassium (GIRK) channels. Using extracellular microelectrode recording of postsynaptic potentials, we found DEX-induced inhibition of spontaneous and evoked neurotransmitter release as well as desynchronization of evoked exocytotic events in the mouse diaphragm neuromuscular junction. These effects were suppressed by SKF-86,466, a selective α2-AR antagonist. An activator of GIRK channels ML297 had the same effects on neurotransmitter release as DEX. By contrast, inhibition of GIRK channels with tertiapin-Q prevented the action of DEX on evoked neurotransmitter release, but not on spontaneous exocytosis. The synaptic vesicle exocytosis is strongly dependent on Ca2+ influx through voltage-gated Ca2+ channels (VGCCs), which can be negatively regulated via α2-AR - GIRK channel axis. Indeed, inhibition of P/Q-, L-, N- or R-type VGCCs prevented the inhibitory action of DEX on evoked neurotransmitter release; antagonists of P/Q- and N-type channels also suppressed the DEX-mediated desynchronization of evoked exocytotic events. Furthermore, inhibition of P/Q-, L- or N-type VGCCs precluded the frequency decrease of spontaneous exocytosis upon DEX application. Thus, α2-ARs acting via GIRK channels and VGCCs (mainly, P/Q- and N-types) exert inhibitory effect on the neuromuscular communication by attenuating and desynchronizing evoked exocytosis. In addition, α2-ARs can suppress spontaneous exocytosis through GIRK channel-independent, but VGCC-dependent pathway.
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Affiliation(s)
- Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Venera F Khuzakhmetova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Ellya A Bukharaeva
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia.
- Kazan State Medical University, 49 Butlerova St, Kazan, 420012, RT, Russia.
- Kazan Federal University, 18 Kremlyovskaya Street, Kazan, 420008, Russia.
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Kawakami N, Kobayashi K, Nishimura A, Ohmori I. Poor mother-offspring relationships in rats with <i>Cacna1a</i> mutation. Exp Anim 2020; 69:153-160. [PMID: 31723085 PMCID: PMC7220709 DOI: 10.1538/expanim.19-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Homozygous Groggy dams, which carry a Cacna1a missense mutation, often
show no interest in their offspring, leading to frequent offspring deaths due to lack of
nurturing. The present study aimed to clarify whether the Cacna1a
mutation contributes to impaired attachment behaviors between dam and offspring. The open
field test showed that homozygous female rats exhibited markedly short travel distance,
whereas no difference was found between the motor activity of heterozygous females and
that of wild types (WT). A series of behavioral tests was performed to compare the
mother–offspring relationship between WT and heterozygous rats. Performance in the pup
retrieval test was significantly less successful in heterozygous than WT dams. During the
experiment, heterozygous dams spent significantly less time licking and crouching than WT
dams. The offspring dam-seeking behavior test revealed that heterozygous pups’
vocalizations were significantly less frequent and shorter than those of WT pups. Although
no significant difference was found between WT and heterozygous offspring in the olfactory
sense test, using a piece of chocolate, heterozygous pups took significantly longer to
reach a sample of the dam’s bedding. Taken together, these findings suggest that the
Cacna1a mutation impairs both the dam’s maternal behavior and the
offspring’s attachment behavior toward the dam.
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Affiliation(s)
- Nozomi Kawakami
- Department of Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 5-1 Shikatacho 2-chome, Kita-ku, Okayama 700-8558, Japan
| | - Kiyoka Kobayashi
- Department of Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 5-1 Shikatacho 2-chome, Kita-ku, Okayama 700-8558, Japan
| | - Ayumu Nishimura
- Okayama University, 5-1 Shikatacho 2-chome, Kita-ku, Okayama 700-8558, Japan
| | - Iori Ohmori
- Department of Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 5-1 Shikatacho 2-chome, Kita-ku, Okayama 700-8558, Japan
- Graduate School of Education, Okayama University, 5-1 Shikatacho 2-chome, Kita-ku, Okayama 700-8558, Japan
- Department of Child Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1 Tsushimanaka 3-chome, Kita-ku, Okayama 700-8558, Japan
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Gamlin CR, Yu WQ, Wong ROL, Hoon M. Assembly and maintenance of GABAergic and Glycinergic circuits in the mammalian nervous system. Neural Dev 2018; 13:12. [PMID: 29875009 PMCID: PMC5991458 DOI: 10.1186/s13064-018-0109-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/06/2018] [Indexed: 12/19/2022] Open
Abstract
Inhibition in the central nervous systems (CNS) is mediated by two neurotransmitters: gamma-aminobutyric acid (GABA) and glycine. Inhibitory synapses are generally GABAergic or glycinergic, although there are synapses that co-release both neurotransmitter types. Compared to excitatory circuits, much less is known about the cellular and molecular mechanisms that regulate synaptic partner selection and wiring patterns of inhibitory circuits. Recent work, however, has begun to fill this gap in knowledge, providing deeper insight into whether GABAergic and glycinergic circuit assembly and maintenance rely on common or distinct mechanisms. Here we summarize and contrast the developmental mechanisms that regulate the selection of synaptic partners, and that promote the formation, refinement, maturation and maintenance of GABAergic and glycinergic synapses and their respective wiring patterns. We highlight how some parts of the CNS demonstrate developmental changes in the type of inhibitory transmitter or receptor composition at their inhibitory synapses. We also consider how perturbation of the development or maintenance of one type of inhibitory connection affects other inhibitory synapse types in the same circuit. Mechanistic insight into the development and maintenance of GABAergic and glycinergic inputs, and inputs that co-release both these neurotransmitters could help formulate comprehensive therapeutic strategies for treating disorders of synaptic inhibition.
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Affiliation(s)
- Clare R Gamlin
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Mrinalini Hoon
- Department of Biological Structure, University of Washington, Seattle, WA, USA. .,Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA.
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Isolated P/Q Calcium Channel Deletion in Layer VI Corticothalamic Neurons Generates Absence Epilepsy. J Neurosci 2016; 36:405-18. [PMID: 26758833 DOI: 10.1523/jneurosci.2555-15.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Generalized spike-wave seizures involving abnormal synchronization of cortical and underlying thalamic circuitry represent a major category of childhood epilepsy. Inborn errors of Cacna1a, the P/Q-type voltage-gated calcium channel α subunit gene, expressed throughout the brain destabilize corticothalamic rhythmicity and produce this phenotype. To determine the minimal cellular lesion required for this network disturbance, we used neurotensin receptor 1 (Ntsr1) cre-driver mice to ablate floxed Cacna1a in layer VI pyramidal neurons, which supply the sole descending cortical synaptic input to thalamocortical relay cells and reticular interneurons and activate intrathalamic circuits. Targeted Cacna1a ablation in layer VI cells resulted in mice that display a robust spontaneous spike-wave absence seizure phenotype accompanied by behavioral arrest and inhibited by ethosuximide. To verify the selectivity of the molecular lesion, we determined that P/Q subunit proteins were reduced in corticothalamic relay neuron terminal zones, and confirmed that P/Q-mediated glutamate release was reduced at these synapses. Spike-triggered exocytosis was preserved by N-type calcium channel rescue, demonstrating that evoked release at layer VI terminals relies on both P/Q and N-type channels. Whereas intrinsic excitability of the P/Q channel depleted layer VI neurons was unaltered, T-type calcium currents in the postsynaptic thalamic relay and reticular cells were dramatically elevated, favoring rebound bursting and seizure generation. We find that an early P/Q-type release defect, limited to synapses of a single cell-type within the thalamocortical circuit, is sufficient to remodel synchronized firing behavior and produce a stable generalized epilepsy phenotype. SIGNIFICANCE STATEMENT This study dissects a critical component of the corticothalamic circuit in spike-wave epilepsy and identifies the developmental importance of P/Q-type calcium channel-mediated presynaptic glutamate release at layer VI pyramidal neuron terminals. Genetic ablation of Cacna1a in layer VI neurons produced synchronous spike-wave discharges in the cortex and thalamus that were inhibited by ethosuximide. These mice also displayed N-type calcium channel compensation at descending thalamic synapses, and consistent with other spike-wave models increased low-threshold T-type calcium currents within postsynaptic thalamic relay and reticular neurons. These results demonstrate, for the first time, that preventing the developmental homeostatic switch from loose to tightly coupled synaptic release at a single class of deep layer cortical excitatory output neurons results in generalized spike-wave epilepsy.
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Urbano FJ, Lino NG, González-Inchauspe CMF, González LE, Colettis N, Vattino LG, Wunsch AM, Wemmie JA, Uchitel OD. Acid-sensing ion channels 1a (ASIC1a) inhibit neuromuscular transmission in female mice. Am J Physiol Cell Physiol 2013; 306:C396-406. [PMID: 24336653 PMCID: PMC3919981 DOI: 10.1152/ajpcell.00301.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Acid-sensing ion channels (ASIC) open in response to extracellular acidosis. ASIC1a, a particular subtype of these channels, has been described to have a postsynaptic distribution in the brain, being involved not only in ischemia and epilepsy, but also in fear and psychiatric pathologies. High-frequency stimulation of skeletal motor nerve terminals (MNTs) can induce presynaptic pH changes in combination with an acidification of the synaptic cleft, known to contribute to muscle fatigue. Here, we studied the role of ASIC1a channels on neuromuscular transmission. We combined a behavioral wire hanging test with electrophysiology, pharmacological, and immunofluorescence techniques to compare wild-type and ASIC1a lacking mice (ASIC1a −/− knockout). Our results showed that 1) ASIC1a −/− female mice were weaker than wild type, presenting shorter times during the wire hanging test; 2) spontaneous neurotransmitter release was reduced by ASIC1a activation, suggesting a presynaptic location of these channels at individual MNTs; 3) ASIC1a-mediated effects were emulated by extracellular local application of acid saline solutions (pH = 6.0; HEPES/MES-based solution); and 4) immunofluorescence techniques revealed the presence of ASIC1a antigens on MNTs. These results suggest that ASIC1a channels might be involved in controlling neuromuscular transmission, muscle contraction and fatigue in female mice.
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Affiliation(s)
- Francisco J Urbano
- Laboratorio de Fisiología y Biología Molecular (LFBM), Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, UBA-CONICET), Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires, Argentina; and
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Bukharaeva EA, Nikolskii EE. Changes in the Kinetics of Evoked Secretion of Transmitter Quanta – an Effective Mechanism Modulating the Synaptic Transmission of Excitation. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s11055-011-9548-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Accorsi-Mendonça D, Castania J, Bonagamba L, Machado B, Leão R. Synaptic profile of nucleus tractus solitarius neurons involved with the peripheral chemoreflex pathways. Neuroscience 2011; 197:107-20. [DOI: 10.1016/j.neuroscience.2011.08.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 10/17/2022]
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Liu Y, Sugiura Y, Lin W. The role of synaptobrevin1/VAMP1 in Ca2+-triggered neurotransmitter release at the mouse neuromuscular junction. J Physiol 2011; 589:1603-18. [PMID: 21282288 DOI: 10.1113/jphysiol.2010.201939] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptobrevin (Syb)/vesicle-associated membrane protein (VAMP) is a small, integral membrane protein of synaptic vesicles. Two homologous isoforms of synaptobrevin, Syb1/VAMP1 and Syb2/VAMP2, exhibit distinct but partially overlapping patterns of expression in adult mammalian neurons: Syb1 is predominantly expressed in the spinal cord, especially in motor neurons and motor nerve terminals of the neuromuscular junction (NMJ), whereas Syb2 is primarily expressed in central synapses in the brain. Whereas many studies have focused on the function of Syb2 in the brain, few studies have examined the role of Syb1. Here we report that Syb1 plays a critical role in neuromuscular synaptic transmission. A null mutation of Syb1 resulting from a spontaneous, nonsense mutation in mice significantly impairs the function, but not the structure, of the NMJ. In particular, both spontaneous and evoked synaptic activities in Syb1 mutant mice are reduced significantly relative to control mice. Short-term synaptic plasticity in Syb1-deficient NMJs is markedly altered: paired-pulse facilitation is significantly enhanced, suggesting a reduction in the initial release probability of synaptic vesicles. Furthermore, Syb1-deficient NMJs display a pronounced asynchrony in neurotransmitter release. These impairments are not due to an alteration of the size of the readily releasable pool of vesicles, but are attributable to reduced sensitivity and cooperativity to calcium (Ca2+) due to the absence of Syb1. Our findings demonstrate that Syb1 plays an essential, non-redundant role in Ca2+-triggered vesicle exocytosis at the mouse NMJ.
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Affiliation(s)
- Yun Liu
- Department of Neuroscience, UT Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX 75390-9111, USA
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Kovyazina IV, Tsentsevitsky AN, Nikolsky EE, Bukharaeva EA. Kinetics of acetylcholine quanta release at the neuromuscular junction during high-frequency nerve stimulation. Eur J Neurosci 2010; 32:1480-9. [DOI: 10.1111/j.1460-9568.2010.07430.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Vasin AL, Samigullin DV, Bukharaeva EA. The role of calcium in modulation of the kinetics of synchronous and asynchronous quantal release at the neuromuscular junction. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2010. [DOI: 10.1134/s1990747810010125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gargus JJ. Genetic calcium signaling abnormalities in the central nervous system: seizures, migraine, and autism. Ann N Y Acad Sci 2009; 1151:133-56. [PMID: 19154521 DOI: 10.1111/j.1749-6632.2008.03572.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The calcium ion is one of the most versatile, ancient, and universal of biological signaling molecules, known to regulate physiological systems at every level from membrane potential and ion transporters to kinases and transcription factors. Disruptions of intracellular calcium homeostasis underlie a host of emerging diseases, the calciumopathies. Cytosolic calcium signals originate either as extracellular calcium enters through plasma membrane ion channels or from the release of an intracellular store in the endoplasmic reticulum (ER) via inositol triphosphate receptor and ryanodine receptor channels. Therefore, to a large extent, calciumopathies represent a subset of the channelopathies, but include regulatory pathways and the mitochondria, the major intracellular calcium repository that dynamically participates with the ER stores in calcium signaling, thereby integrating cellular energy metabolism into these pathways, a process of emerging importance in the analysis of the neurodegenerative and neuropsychiatric diseases. Many of the calciumopathies are common complex polygenic diseases, but leads to their understanding come most prominently from rare monogenic channelopathy paradigms. Monogenic forms of common neuronal disease phenotypes-such as seizures, ataxia, and migraine-produce a constitutionally hyperexcitable tissue that is susceptible to periodic decompensations. The gene families and genetic lesions underlying familial hemiplegic migraine, FHM1/CACNA1A, FHM2/ATP1A2, and FHM3/SCN1A, and monogenic mitochondrial migraine syndromes, provide a robust platform from which genes, such as CACNA1C, which encodes the calcium channel mutated in Timothy syndrome, can be evaluated for their role in autism and bipolar disease.
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Affiliation(s)
- J Jay Gargus
- Department of Physiology & Biophysics, Section of Human Genetics, School of Medicine, University of California-Irvine, Irvine, CA 92697, USA.
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Tsentsevitsky AN, Vasin AL, Bukharaeva EA, Nikolsky EE. Participation of different types of voltage-dependent calcium channels in evoked quantal transmitter release in frog neuromuscular junctions. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2008; 423:389-391. [PMID: 19213416 DOI: 10.1134/s0012496608060069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- A N Tsentsevitsky
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, 420111 Tatarstan, Russia
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Urbano FJ, Pagani MR, Uchitel OD. Calcium channels, neuromuscular synaptic transmission and neurological diseases. J Neuroimmunol 2008; 201-202:136-44. [PMID: 18678414 DOI: 10.1016/j.jneuroim.2008.06.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 01/20/2023]
Abstract
Voltage-dependent calcium channels are essential in neuronal signaling and synaptic transmission, and their functional alterations underlie numerous human disorders whether monogenic (e.g., ataxia, migraine, etc.) or autoimmune. We review recent work on Ca(V)2.1 or P/Q channelopathies, mostly using neuromuscular junction preparations, and focus specially on the functional hierarchy among the calcium channels recruited to mediate neurotransmitter release when Ca(V)2.1 channels are mutated or depleted. In either case, synaptic transmission is greatly compromised; evidently, none of the reported functional replacements with other calcium channels compensates fully.
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Affiliation(s)
- Francisco J Urbano
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología y Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428-Buenos Aires, Argentina
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