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Scantlebury N, Zhao XL, Rodriguez Moncalvo VG, Camiletti A, Zahanova S, Dineen A, Xin JH, Campos AR. The Drosophila gene RanBPM functions in the mushroom body to regulate larval behavior. PLoS One 2010; 5:e10652. [PMID: 20498842 PMCID: PMC2871054 DOI: 10.1371/journal.pone.0010652] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 04/12/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In vertebrates, Ran-Binding Protein in the Microtubule Organizing Center (RanBPM) appears to function as a scaffolding protein in a variety of signal transduction pathways. In Drosophila, RanBPM is implicated in the regulation of germ line stem cell (GSC) niche organization in the ovary. Here, we addressed the role of RanBPM in nervous system function in the context of Drosophila larval behavior. METHODOLOGY/PRINCIPAL FINDINGS We report that in Drosophila, RanBPM is required for larval feeding, light-induced changes in locomotion, and viability. RanBPM is highly expressed in the Kenyon cells of the larval mushroom body (MB), a structure well studied for its role in associative learning in Drosophila and other insects. RanBPM mutants do not display major disruption in nervous system morphology besides reduced proliferation. Expression of the RanBPM gene in the Kenyon cells is sufficient to rescue all behavioral phenotypes. Through genetic epistasis experiments, we demonstrate that RanBPM participates with the Drosophila orthologue of the Fragile X Mental Retardation Protein (FMRP) in the development of neuromuscular junction (NMJ). CONCLUSIONS/SIGNIFICANCE We demonstrate that the RanBPM gene functions in the MB neurons for larval behavior. Our results suggest a role for this gene in an FMRP-dependent process. Taken together our findings point to a novel role for the MB in larval behavior.
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Affiliation(s)
- Nadia Scantlebury
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Xiao Li Zhao
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | | | - Alison Camiletti
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Stacy Zahanova
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Aidan Dineen
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Ji-Hou Xin
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Ana Regina Campos
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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2
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Abstract
Radiation damage to the neuromuscular junctions (NMJs) in mouse tongues was studied using local x-irradiation of the tongues with the rest of the body shielded. Transmission electron microscopy (TEM) revealed no significant morphological changes in the fine structures and organelles of the NMJs given 4 Gy. A dose of 8 Gy produced degenevative morphological changes associated with oxon terminal sprouting as early as 2 and 7 days following irradiation. Subsequently, 1-11 weeks later, severe degenerative changes were observed. The number of mitochondria was significantly decreased with increased occurrence of degenerative membranal features. The number of synaptic footplates without terminals or with multiple small terminals within one groove increased gradually with time. Most of these pathological changes persisted for at least 3 months after irradiation. However, the myofibres, blood vessels and interstitial cells appeared to be unaffected throughout the period of follow-up. The present study substantiates our previous reports of ageing-like changes in the tongues' NMJs induced by their excessive exposure to free radicals.
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Affiliation(s)
- R Gorodetsky
- Sharett Institute of Oncology, Hadassah University Hospital and Medical School, Jerusalem, Israel
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3
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Kharrat R, Servent D, Girard E, Ouanounou G, Amar M, Marrouchi R, Benoit E, Molgó J. The marine phycotoxin gymnodimine targets muscular and neuronal nicotinic acetylcholine receptor subtypes with high affinity. J Neurochem 2008; 107:952-63. [PMID: 18990115 DOI: 10.1111/j.1471-4159.2008.05677.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
MESH Headings
- Acetylcholine/pharmacology
- Animals
- Behavior, Animal/drug effects
- Bivalvia/chemistry
- Bungarotoxins/metabolism
- Cells, Cultured
- Chromatography, High Pressure Liquid/methods
- Dose-Response Relationship, Drug
- Drug Interactions
- Electric Stimulation/methods
- Gene Expression/drug effects
- Heterocyclic Compounds, 3-Ring/analysis
- Heterocyclic Compounds, 3-Ring/chemistry
- Heterocyclic Compounds, 3-Ring/classification
- Heterocyclic Compounds, 3-Ring/pharmacology
- Humans
- Hydrocarbons, Cyclic/analysis
- Hydrocarbons, Cyclic/chemistry
- Hydrocarbons, Cyclic/classification
- Hydrocarbons, Cyclic/pharmacology
- Imines/analysis
- Imines/chemistry
- Imines/classification
- Imines/pharmacology
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Membrane Potentials/radiation effects
- Mice
- Mice, Inbred C57BL
- Muscle Cells/drug effects
- Muscle Cells/metabolism
- Neuromuscular Junction/drug effects
- Neuromuscular Junction/physiology
- Neuromuscular Junction/radiation effects
- Oocytes
- Patch-Clamp Techniques
- Protein Binding/drug effects
- Receptors, Nicotinic/metabolism
- Synaptic Transmission/drug effects
- Xenopus laevis
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Riadh Kharrat
- Laboratoire de Neurobiologie Cellulaire et Moléculaire-UPR9040, CNRS, Institut de Neurobiologie Alfred Fessard-FRC2118, Gif sur Yvette, France
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4
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Favero M, Lorenzetto E, Bidoia C, Buffelli M, Busetto G, Cangiano A. Synapse formation and elimination: role of activity studied in different models of adult muscle reinnervation. J Neurosci Res 2008; 85:2610-9. [PMID: 17139683 DOI: 10.1002/jnr.21143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Synapse competition and elimination are a general developmental process both in central and in peripheral nervous systems that is strongly activity dependent. Some common features regulate synapse competition, and one of these is an application to development of the Hebb's postulate of learning: repeated coincident spike activity in competing presynaptic inputs on the same target cell inhibits competition, whereas noncoincident activity promotes weakening of some of the inputs and ultimately their elimination. Here we report experiments that indicate that the development of muscle innervation (initial polyneuronal innervation and subsequent synapse elimination) follows the Hebb's paradigm. We utilized two different models of muscle reinnervation in the adult rat: 1) we crushed nerves going to soleus or extensor digitorum longus muscles, to activate regeneration of the presynaptic component of the neuromuscular junctions (NMJ), or 2) we injected the soleus muscle with Marcaine (a myotoxic agent) to activate regeneration of the postsynaptic component, the muscle fiber. A condition of transient polyneuronal innervation occurs during NMJ regeneration in both cases, although the two models differ insofar as the relative strength of the competing inputs is concerned. During the period of competition (a few days or weeks, in Marcaine or crush experiments, respectively), we imposed a synchronous firing pattern on the competing inputs by stimulating motor axons distal to a chronic conduction block and demonstrated that this procedure strongly inhibits synapse elimination, with respect to control muscles in which regeneration occurs under natural impulse activity of motoneurons.
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Affiliation(s)
- Morgana Favero
- Dipartimento di Scienze Neurologiche e della Visione, Sezione di Fisiologia, Università di Verona, Verona, Italy
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5
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Mattaliano MD, Montana ES, Parisky KM, Littleton JT, Griffith LC. The Drosophila ARC homolog regulates behavioral responses to starvation. Mol Cell Neurosci 2007; 36:211-21. [PMID: 17707655 PMCID: PMC2094000 DOI: 10.1016/j.mcn.2007.06.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 05/19/2007] [Accepted: 06/29/2007] [Indexed: 11/15/2022] Open
Abstract
The gene encoding dARC1, one of three Drosophila homologs of mammalian activity-regulated cytoskeleton-associated protein (ARC), is upregulated in both seizure and muscular hypercontraction mutants. In this study we generate a null mutant for dArc1 and show that this gene is not involved in synaptic plasticity at the larval neuromuscular junction or in formation or decay of short-term memory of courtship conditioning, but rather is a modifier of stress-induced behavior. dARC1 is expressed in a number of neurosecretory cells and mutants are starvation-resistant, exhibiting an increased time of survival in the absence of food. Starvation resistance is likely due to the fact that dArc1 mutants lack the normal hyperlocomotor response to starvation, which is almost universal in the animal kingdom. dARC1 acts in insulin-producing neurons of the pars intercerebralis to control this behavior, but does not appear to be a general regulator of insulin signaling. This suggests that there are multiple modes of communication between the pars and the ring gland that control starvation-induced behavioral responses.
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Affiliation(s)
- Mark D Mattaliano
- Department of Biology and National Center for Behavior Genomics, Brandeis University, Waltham, MA 02454-9110, USA
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6
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Santafé MM, Lanuza MA, Garcia N, Tomàs J. Muscarinic autoreceptors modulate transmitter release through protein kinase C and protein kinase A in the rat motor nerve terminal. Eur J Neurosci 2006; 23:2048-56. [PMID: 16630052 DOI: 10.1111/j.1460-9568.2006.04753.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have used intracellular recording to investigate the existence of a functional link between muscarinic presynaptic acetylcholine (ACh) autoreceptors, the intracellular serine-threonine kinases-mediated transduction pathways and transmitter release in the motor nerve terminals of adult rats. We found the following. (1) Transmitter release was reduced by the M1 muscarinic acetylcholine receptor (mAChR) blocker pirenzepine and enhanced by the M2 blocker methoctramine. The unselective mAChR blocker atropine increased ACh release, which suggests the unmasking of another parallel release-potentiating mechanism. There are therefore two opposite, though finely balanced, M1-M2 mAChR-operated mechanisms that tonically modulate transmitter release. (2) Both M1 and M2 mechanisms were altered when protein kinase C (PKC), protein kinase A (PKA) or the P/Q-type calcium channel were blocked. (3) Both PKC and PKA potentiated release when they were specifically stimulated [with phorbol 12-myristate 13-acetate (PMA) and Sp-8-Br cAMPs, respectively], and both needed the P/Q channel. (4) In normal conditions PKC seemed not to be directly involved in transmitter release (the PKC blocker calphostin C did not reduce release), whereas PKA was coupled to potentiate release (the PKA blocker H-89 reduced release). However, when an imbalance of the M1-M2 mAChRs function was experimentally produced with selective blockers, an inversion of the kinase function occurred and PKC could then stimulate transmitter release, whereas PKA was uncoupled. (5) The muscarinic function may be explained by the existence of an M1-mediated increased PKC activity-dependent potentiation of release and an M2-mediated PKA decreased activity-dependent release reduction. These findings show that there is a precise interrelation pattern of the mAChRs, PKC and PKA in the control of the neurotransmitter release.
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Affiliation(s)
- Manel M Santafé
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, carrer St. Llorenç num 21, 43201-Reus, Spain.
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7
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Dong XP, Li XM, Gao TM, Zhang EE, Feng GS, Xiong WC, Mei L. Shp2 Is Dispensable in the Formation and Maintenance of the Neuromuscular Junction. Neurosignals 2006; 15:53-63. [PMID: 16837792 DOI: 10.1159/000094484] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Accepted: 05/04/2006] [Indexed: 01/23/2023] Open
Abstract
SHP2, a protein tyrosine phosphatase with two SH2 domains, has been implicated in regulating acetylcholine receptor (AChR) gene expression and cluster formation in cultured muscle cells. To understand the role of SHP2 in neuromuscular junction (NMJ) formation in vivo, we generated mus cle-specific deficient mice by using a loxP/Cre strategy since Shp2 null mutation causes embryonic lethality. Shp2(floxed/floxed) mice were crossed with mice expressing the Cre gene under the control of the human skeletal alpha-actin (HSA) promoter. Expression of SHP2 was reduced or diminished specifically in skeletal muscles of the conditional knockout (CKO) mice. The mutant mice were viable and fertile, without apparent muscle defects. The mRNA of the AChR alpha subunit and AChR clusters in CKO mice were localized in a narrow central region surrounding the phrenic nerve primary branches, without apparent change in intensity. AChR clusters colocalized with markers of synaptic vesicles and Schwann cells, suggesting proper differentiation of presynaptic terminals and Schwann cells. In comparison with age-matched littermates, no apparent difference was observed in the size and length of AChR clusters in CKO mice. Both the frequency and amplitude of mEPPs in CKO mice were similar to those in controls, suggesting normal neurotransmission when SHP2 was deficient. These results suggest that Shp2 is not required for NMJ formation and/or maintenance.
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Affiliation(s)
- Xian-Ping Dong
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA
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8
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Hayworth CR, Moody SE, Chodosh LA, Krieg P, Rimer M, Thompson WJ. Induction of neuregulin signaling in mouse schwann cells in vivo mimics responses to denervation. J Neurosci 2006; 26:6873-84. [PMID: 16793894 PMCID: PMC6673827 DOI: 10.1523/jneurosci.1086-06.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neuregulins play crucial roles in early development of Schwann cells (SCs), but their roles in the activities of SCs during denervation and reinnervation of muscle are less clear. In the present study, the Tet-On system has been used in transgenic mice to enable inducible expression of a mutant, constitutively active neuregulin receptor (ErbB2) in SCs. This induction simulates neuregulin signaling to these cells. Reporter transgenes were used to show a tightly regulated, SC-selective expression in muscle. Induction leads to a number of changes in SCs at neuromuscular junctions that mimic the response to muscle denervation/reinnervation. These include process extension, soma migration, and proliferation. SCs also come to express nestin, a protein characteristic of their reaction to muscle denervation. This activation of SCs results in the sprouting of nerve terminals, and these sprouts follow the extensions of the SCs. However, these sprouts and their associated SCs disappear after the removal of the inducer. Last, induction of the active receptor is sufficient to rescue SCs in neonatal muscle from denervation-induced apoptosis. These findings show that the responses of SCs in muscle to denervation can be explained by induction of an autocrine/paracrine neuregulin signaling cascade suggested by previous molecular studies.
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9
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Shakiryanova D, Tully A, Levitan ES. Activity-dependent synaptic capture of transiting peptidergic vesicles. Nat Neurosci 2006; 9:896-900. [PMID: 16767091 DOI: 10.1038/nn1719] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 05/18/2006] [Indexed: 12/23/2022]
Abstract
Synapses require resources synthesized in the neuronal soma, but there are no known mechanisms to overcome delays associated with the synthesis and axonal transport of new proteins generated in response to activity, or to direct resources specifically to active synapses. Here, in vivo imaging of the Drosophila melanogaster neuromuscular junction reveals a cell-biological strategy that addresses these constraints. Peptidergic vesicles continually transit through resting terminals, but retrograde peptidergic vesicle flux is accessed following activity to rapidly boost neuropeptide content in synaptic boutons. The presence of excess transiting vesicles implies that synaptic neuropeptide stores are limited by the capture of peptidergic vesicles at the terminal, rather than by synthesis in the soma or delivery via the axon. Furthermore, activity-dependent capture from a pool of transiting vesicles provides a nerve terminal-based mechanism for directing distally and slowly generated resources quickly to active synapses. Finally, retrograde transport in the nerve terminal is regulated by activity.
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Affiliation(s)
- Dinara Shakiryanova
- Department of Pharmacology, University of Pittburgh, Pittsburgh, Pennsylvania 15261, USA
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10
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Mukhamedyarov MA, Grishin SN, Zefirov AL, Palotás A. Evidences for calcium-dependent inactivation of calcium current at the frog motor nerve terminal. Brain Res Bull 2006; 69:652-5. [PMID: 16716833 DOI: 10.1016/j.brainresbull.2006.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 03/04/2006] [Accepted: 03/20/2006] [Indexed: 11/25/2022]
Abstract
Assessment of calcium-dependent inactivation of calcium current in nerve terminals is not feasible due to technical reasons. Perineural measurement of calcium-flow, however, might be utilized as indirect means to evaluate synaptic currents. Using perineural recording from frog neuromuscular junction, supra-threshold stimuli applied to motor nerve in paired-pulse manner with varying inter-pulse intervals (5-50 ms) are demonstrated in this study to cause paired-pulse depression (PPD) of Ca(2+)-current. PPD of Ca(2+)-flow was reduced at lower extracellular Ca(2+) concentrations, in BAPTA-AM and EGTA-AM treated preparations and after replacing extracellular Ca(2+) with Sr(2+). Using perineural measurement of calcium current as an indirect model to investigate synaptic ionic activity, our findings demonstrate that PPD may be attributed to calcium-dependent inactivation of Ca(2+)-current, which may serve as negative feedback in response to massive Ca(2+) entry to motor nerve terminals. A putative sensor of Ca(2+)-current is also proposed in this study.
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Affiliation(s)
- Marat A Mukhamedyarov
- Department of Physiology, Kazan State Medical University, ul. Butlerov 49, R-420012 Kazan, Russia
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11
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Abstract
Rolling blackout (RBO) is a putative transmembrane lipase required for phospholipase C-dependent phosphatidylinositol 4,5-bisphosphate-diacylglycerol signaling in Drosophila neurons. Conditional temperature-sensitive (TS) rbo mutants display complete, reversible paralysis within minutes, demonstrating that RBO is acutely required for movement. RBO protein is localized predominantly in presynaptic boutons at neuromuscular junction (NMJ) synapses and throughout central synaptic neuropil, and rbo TS mutants display a complete, reversible block of both central and peripheral synaptic transmission within minutes. This phenotype appears limited to adults, because larval NMJs do not manifest the acute blockade. Electron microscopy of adult rbo TS mutant boutons reveals an increase in total synaptic vesicle (SV) content, with a concomitant shrinkage of presynaptic bouton size and an accumulation of docked SVs at presynaptic active zones within minutes. Genetic tests reveal a synergistic interaction between rbo and syntaxin1A TS mutants, suggesting that RBO is required in the mechanism of N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated SV exocytosis, or in a parallel pathway necessary for SV fusion. The rbo TS mutation does not detectably alter SNARE complex assembly, suggesting a downstream requirement in SV fusion. We conclude that RBO plays an essential role in neurotransmitter release, downstream of SV docking, likely mediating SV fusion.
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Affiliation(s)
- Fu-De Huang
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Brain Institute, Vanderbilt University, Nashville, Tennessee 37235-1634, USA
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12
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Abstract
Motoneuron populations possess a range of intrinsic excitability that plays an important role in establishing how motor units are recruited. The fact that this range collapses after axotomy and does not recover completely until after reinnervation occurs suggests that muscle innervation is needed to maintain or regulate adult motoneuron excitability, but the nature and identity of underlying mechanisms remain poorly understood. Here, we report the results of experiments in which we studied the effects on rat motoneuron excitability produced by manipulations of neuromuscular transmission and compared these with the effects of peripheral nerve axotomy. Inhibition of acetylcholine release from motor terminals for 5-6 d with botulinum toxin produced relatively minor changes in motoneuron excitability compared with the effect of axotomy. In contrast, the blockade of acetylcholine receptors with alpha-bungarotoxin over the same time interval produced changes in motoneuron excitability that were statistically equivalent to axotomy. Muscle fiber recordings showed that low levels of acetylcholine release persisted at motor terminals after botulinum toxin, but endplate currents were completely blocked for at least several hours after daily intramuscular injections of alpha-bungarotoxin. We conclude that the complete but transient blockade of endplate currents underlies the robust axotomy-like effects of alpha-bungarotoxin on motoneuron excitability, and the low level of acetylcholine release that remains after injections of botulinum toxin inhibits axotomy-like changes in motoneurons. The results suggest the existence of a retrograde signaling mechanism located at the motor endplate that enables expression of adult motoneuron excitability and depends on acetylcholine receptor activation for its normal operation.
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Affiliation(s)
- Stan T Nakanishi
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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13
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Boneva N, Hamra-Amitay Y, Wirguin I, Brenner T. Stimulated-single fiber electromyography monitoring of anti-sense induced changes in experimental autoimmune myasthenia gravis. Neurosci Res 2006; 55:40-4. [PMID: 16504322 DOI: 10.1016/j.neures.2006.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 12/28/2005] [Accepted: 01/19/2006] [Indexed: 11/26/2022]
Abstract
The neuromuscular weakness associated with myasthenia gravis (MG) can be transiently relieved by pharmacological inhibitors of acetylcholinesterase (AChE). Here, we expand the anticholinesterase repertoire to include 2'-O-methyl-protected antisense oligonucleotides targeted to AChE mRNA (EN101). Using stimulated-single fiber electromyography, we show that EN101 treatment of rats with experimental autoimmune myasthenia gravis (EAMG), improved the mean consecutive difference (MCD) and blocking for 24h. This treatment was more efficient than pyridostigmine and was accompanied by marked improvement in stamina and clinical profile.
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MESH Headings
- Acetylcholinesterase/genetics
- Animals
- Electric Stimulation/methods
- Electromyography
- Exercise Test/methods
- Female
- Monitoring, Physiologic
- Muscles/drug effects
- Muscles/physiopathology
- Muscles/radiation effects
- Myasthenia Gravis, Autoimmune, Experimental/chemically induced
- Myasthenia Gravis, Autoimmune, Experimental/drug therapy
- Myasthenia Gravis, Autoimmune, Experimental/physiopathology
- Neuromuscular Junction/drug effects
- Neuromuscular Junction/physiopathology
- Neuromuscular Junction/radiation effects
- Oligodeoxyribonucleotides
- Oligonucleotides, Antisense/therapeutic use
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred Lew
- Receptors, Cholinergic/immunology
- Time Factors
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Affiliation(s)
- Neli Boneva
- Laboratory of Neuroimmunology, Department of Neurology, and the Agnes Ginges Center for Human Neurogenetics, Hadassah University Hospital and Hebrew University Medical School, Jerusalem
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14
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Xing B, Ashleigh Long A, Harrison DA, Cooper RL. Developmental consequences of neuromuscular junctions with reduced presynaptic calcium channel function. Synapse 2005; 57:132-47. [PMID: 15945059 DOI: 10.1002/syn.20165] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evoked neurotransmitter release at the Drosophila neuromuscular junction (NMJ) is regulated by the amount of calcium influx at the presynaptic nerve terminal, as for most chemical synapses. Calcium entry occurs via voltage-gated calcium channels. The temperature-sensitive Drosophila mutant, cac(TS2), has a reduced amount of calcium entry during evoked stimulation. We have used this mutation to examine homeostatic regulatory mechanisms during development of the NMJ on muscle 6 within the developing larva. The amplitude of the excitatory postsynaptic potentials are reduced for both the Ib and Is motor neurons in 3rd instar larvae which have been raised at 33 degrees C from the 1st instar stage. Larvae raised at 25 degrees C and larvae pulsed at 33 degrees C from the late 2nd instar for various lengths of time show a reduced synaptic efficacy as a 3rd instar. The results indicate that the nerve terminal cannot fully compensate physiologically in the regulation of synaptic transmission during larval life for a reduced amount of evoked calcium entry. Morphological comparisons of Ib and Is terminals in relation to length and numbers of varicosities are significantly reduced in cac(TS2), which also suggests a lack in homeostatic ability. These findings are relevant since many deficits in synaptic transmission in various systems are compensated for either physiologically or structural over development, but not in this case for reduced calcium entry during evoked transmission.
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Affiliation(s)
- Bin Xing
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
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15
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Polo-Parada L, Plattner F, Bose C, Landmesser LT. NCAM 180 acting via a conserved C-terminal domain and MLCK is essential for effective transmission with repetitive stimulation. Neuron 2005; 46:917-31. [PMID: 15953420 DOI: 10.1016/j.neuron.2005.05.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 04/01/2005] [Accepted: 05/06/2005] [Indexed: 12/31/2022]
Abstract
NCAM 180 isoform null neuromuscular junctions are unable to effectively mobilize and exocytose synaptic vesicles and thus exhibit periods of total transmission failure during high-frequency repetitive stimulation. We have identified a highly conserved C-terminal (KENESKA) domain on NCAM that is required to maintain effective transmission and demonstrate that it acts via a pathway involving MLCK and probably myosin light chain (MLC) and myosin II. By perfecting a method of introducing peptides into adult NMJs, we tested the hypothesized role of proteins in this pathway by competitive disruption of protein-protein interactions. The effects of KENESKA and other peptides on MLCK and MLC activation and on failures in both wild-type and NCAM 180 null junctions supported this pathway, and serine phosphorylation of KENESKA was critical. We propose that this pathway is required to replenish synaptic vesicles utilized during high levels of exocytosis by facilitating myosin-driven delivery of synaptic vesicles to active zones or their subsequent exocytosis.
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Affiliation(s)
- Luis Polo-Parada
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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16
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Abstract
Ca2+ indicators of varying affinity and mobility were pressure injected into the presynaptic axon of the inhibitor of the crayfish neuromuscular junction (NMJ). Fluorescence transients recorded at a 2-kHz resolution were used to probe physiological parameters governing the decay of fluorescence transients within 100 ms after an action potential (early decay). Blocking Ca2+ extrusion or Ca2+ sequestration processes did not significantly alter early decay, arguing against a role for either mechanism. Fluorescence transients recorded with low mobility or fixed indicators exhibited early decay similar to that recorded with indicators of comparable affinity but high mobility, suggesting that early decay was not due to the rate of Ca2+-indicator diffusion. The extent of early decay correlated closely with the affinity, but not mobility, of the Ca2+ sensitive dyes tested. These results implicate intrinsic buffers with slow Ca2+ binding kinetics as the most likely determinants of early decay. However, computer simulations showed that intrinsic buffers with a slow binding rate are unlikely to be the only ones present in the system because the slow kinetics would be unable to buffer incoming Ca2+ during an action potential and would result in momentary indicator saturation. In fact, experimental data show that the peak amplitude of an action potential activated Ca+ transient is about 20% of the maximal fluorescence intensity activated by prolonged Ca2+ influx. We conclude that endogenous buffering at the crayfish NMJ includes both fast and slow components, the former being fast enough to compete with fast Ca2+ indicators, and the latter dictating the early decay.
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Affiliation(s)
- Jen-Wei Lin
- Department of Biology, Boston University, 5 Cummington St., Boston, Massachuetts 02215, USA.
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17
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Guerrero G, Agarwal G, Reiff DF, Ball RW, Borst A, Goodman CS, Isacoff EY. Heterogeneity in synaptic transmission along a Drosophila larval motor axon. Nat Neurosci 2005; 8:1188-96. [PMID: 16116446 PMCID: PMC1402256 DOI: 10.1038/nn1526] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Accepted: 07/25/2005] [Indexed: 11/09/2022]
Abstract
At the Drosophila melanogaster larval neuromuscular junction (NMJ), a motor neuron releases glutamate from 30-100 boutons onto the muscle it innervates. How transmission strength is distributed among the boutons of the NMJ is unknown. To address this, we created synapcam, a version of the Ca2+ reporter Cameleon. Synapcam localizes to the postsynaptic terminal and selectively reports Ca2+ influx through glutamate receptors (GluRs) with single-impulse and single-bouton resolution. GluR-based Ca2+ signals were uniform within a given connection (that is, a given bouton/postsynaptic terminal pair) but differed considerably among connections of an NMJ. A steep gradient of transmission strength was observed along axonal branches, from weak proximal connections to strong distal ones. Presynaptic imaging showed a matching axonal gradient, with higher Ca2+ influx and exocytosis at distal boutons. The results suggest that transmission strength is mainly determined presynaptically at the level of individual boutons, possibly by one or more factors existing in a gradient.
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Affiliation(s)
- Giovanna Guerrero
- Department of Molecular and Cell Biology, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
| | - Gautam Agarwal
- Helen Wills Neuroscience Institute, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
| | - Dierk F. Reiff
- Department of Systems and Computational Neurobiology, Max-Planck-Institute of Neurobiology, Am Klopfersptiz 18 A, 82152 Martinsried, Germany
| | - Robin W. Ball
- Helen Wills Neuroscience Institute, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
| | - Alexander Borst
- Department of Systems and Computational Neurobiology, Max-Planck-Institute of Neurobiology, Am Klopfersptiz 18 A, 82152 Martinsried, Germany
| | - Corey S. Goodman
- Department of Molecular and Cell Biology, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
- Helen Wills Neuroscience Institute, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
- Current address: Renovis, Inc., Two Corporate Drive, South San Francisco, California 94080, USA
| | - Ehud Y. Isacoff
- Department of Molecular and Cell Biology, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
- Helen Wills Neuroscience Institute, 279 Life Sciences Addition, University of California, Berkeley, California 94720-3200, USA
- Physical Bioscience and Material Science Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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18
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Abstract
Like other complex behaviors, the cyclical, rhythmic consummatory feeding behaviors of Aplysia-biting, swallowing, and rejection of unsuitable food-are produced by a complex neuromuscular system: the animal's buccal mass, with numerous pairs of antagonistic muscles, controlled by the firing of numerous motor neurons, all driven by the motor programs of a central pattern generator (CPG) in the buccal ganglia. In such a complex neuromuscular system, it has always been assumed that the activities of the various components must necessarily be tightly coupled and coordinated if successful functional behavior is to be produced. However, we have recently found that the CPG generates extremely variable motor programs from one cycle to the next, and so very variable motor neuron firing patterns and contractions of individual muscles. Here we show that this variability extends even to higher-level parameters of the operation of the neuromuscular system such as the coordination between entire antagonistic subsystems within the buccal neuromusculature. In motor programs elicited by stimulation of the esophageal nerve, we have studied the relationship between the contractions of the accessory radula closer (ARC) muscle, and the firing patterns of its motor neurons B15 and B16, with those of its antagonist, the radula opener (I7) muscle, and its motor neuron B48. There are two separate B15/B16-ARC subsystems, one on each side of the animal, and these are indeed very tightly coupled. Tight coupling can, therefore, be achieved in this neuromuscular system where required. Yet there is essentially no coupling at all between the contractions of the ARC muscles and those of the antagonistic radula opener muscle. We interpret this result in terms of a hypothesis that ascribes a higher-order benefit to such loose coupling in the neuromusculature. The variability, emerging in the successive feeding movements made by the animal, diversifies the range of movements and thereby implements a trial-and-error search through the space of movements that might be successful, an optimal strategy for the animal in an unknown, rapidly changing feeding environment.
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Affiliation(s)
- Yuriy Zhurov
- Department of Physiology and Biophysics, Box 1218, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, New York 10029, USA
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19
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Abstract
Fidelity of synaptic transmission is essential at the neuromuscular junction (NMJ). To ensure that transmission does not fail, vertebrate motoneurons often release more neurotransmitter than is required for muscle contraction. This safety factor allows some loss of synaptic function without failure of muscle contraction. It is not known whether a similar mechanism operates at the invertebrate neuromuscular junction. In our study of the Drosophila NMJ, we find that glutamate receptor mutants can exhibit a substantial decrease in synaptic function while maintaining muscle contraction. The persistence of neuromuscular function in these mutants is not explained by synaptic facilitation, temporal summation of high frequency stimuli, or a hyperpolarizing shift in the activation range of muscle calcium channels. Instead, the attenuated synaptic response is sufficient to drive muscle contraction. Quantitative analysis of the decrease in synaptic transmission in these mutants implies that at the wild-type NMJ there is an approximately five- to ninefold excess in released transmitter. Hence, the presence of a synaptic safety factor is a conserved feature of neuromuscular organization in both invertebrates and vertebrates.
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Affiliation(s)
- Scott B Marrus
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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20
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Parnas H, Slutsky I, Rashkovan G, Silman I, Wess J, Parnas I. Depolarization initiates phasic acetylcholine release by relief of a tonic block imposed by presynaptic M2 muscarinic receptors. J Neurophysiol 2005; 93:3257-69. [PMID: 15703226 DOI: 10.1152/jn.01131.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of presynaptic muscarinic autoreceptors in the initiation of phasic acetylcholine (ACh) release at frog and mouse neuromuscular junctions was studied by measuring the dependency of the amount (m) of ACh release on the level of presynaptic depolarization. Addition of methoctramine (a blocker of M2 muscarinic receptors), or of acetylcholinesterase (AChE), increased release in a voltage-dependent manner; enhancement of release declined as the depolarizing pulse amplitude increased. In frogs and wild-type mice the slope of log m/log pulse amplitude (PA) was reduced from about 7 in the control to about 4 in the presence of methoctramine or AChE. In M2 muscarinic receptor knockout mice, the slope of log m/log PA was much smaller (about 4) and was not further reduced by addition of either methoctramine or AChE. The effect of a brief (0.1 ms), but strong (-1.2 microA) depolarizing prepulse on the dependency of m on PA was also studied. The depolarizing prepulse had effects similar to those of methoctramine and AChE. In particular, it enhanced release of test pulses in a voltage-dependent manner and reduced the slope of log m/log PA from about 7 to about 4. Methoctramine + AChE occluded the prepulse effects. In knockout mice, the depolarizing prepulse had no effects. The cumulative results suggest that initiation of phasic ACh release is achieved by depolarization-mediated relief of a tonic block imposed by presynaptic M2 muscarinic receptors.
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Affiliation(s)
- H Parnas
- Department of Neurobiology, The Hebrew University, Jerusalem 91904, Israel.
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21
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Shakiryanova D, Tully A, Hewes RS, Deitcher DL, Levitan ES. Activity-dependent liberation of synaptic neuropeptide vesicles. Nat Neurosci 2005; 8:173-8. [PMID: 15643430 DOI: 10.1038/nn1377] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Accepted: 10/26/2004] [Indexed: 11/08/2022]
Abstract
Despite the importance of neuropeptide release, which is evoked by long bouts of action potential activity and which regulates behavior, peptidergic vesicle movement has not been examined in living nerve terminals. Previous in vitro studies have found that secretory vesicle motion at many sites of release is constitutive: Ca(2+) does not affect the movement of small synaptic vesicles in nerve terminals or the movement of large dense core vesicles in growth cones and endocrine cells. However, in vivo imaging of a neuropeptide, atrial natriuretic factor, tagged with green fluorescent protein in larval Drosophila melanogaster neuromuscular junctions shows that peptidergic vesicle behavior in nerve terminals is sensitive to activity-induced Ca(2+) influx. Specifically, peptidergic vesicles are immobile in resting synaptic boutons but become mobile after seconds of stimulation. Vesicle movement is undirected, occurs without the use of axonal transport motors or F-actin, and aids in the depletion of undocked neuropeptide vesicles. Peptidergic vesicle mobilization and post-tetanic potentiation of neuropeptide release are sustained for minutes.
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Affiliation(s)
- Dinara Shakiryanova
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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22
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Abstract
Synaptic transmission is a critical mechanism for transferring information from the nervous system to the body. Environmental stress, such as extreme temperature, can disrupt synaptic transmission and result in death. Previous work on larval Drosophila has shown that prior heat-shock exposure protects synaptic transmission against failure during subsequent thermal stress. This induced thermoprotection has been ascribed to an up-regulation of the inducible heat-shock protein, Hsp70. However, the mechanisms mediating natural thermoprotection in the wild are unknown. We compared synaptic thermosensitivity between D. melanogaster and a desert species, D. arizonae. Synaptic thermosensitivity and the functional limits of the related locomotor behavior differed significantly between closely related, albeit ecologically distinct species. Locomotory behavior of wandering third instar D. arizonae larvae was less thermosensitive and the upper temperature limit of locomotory function exceeded that of D. melanogaster by 6 degrees C. Behavioral results corresponded with significantly lower synaptic thermosensitivity at the neuromuscular junction in D. arizonae. Prior heat-shock protected only D. melanogaster by increasing relative excitatory junctional potential (EJP) duration, the time required for EJP failure at 40 degrees C, and the incidence of EJP recovery following heat-induced failure. Hsp70 induction profiles following heat-shock demonstrate up-regulation of inducible Hsp70 in D. melanogaster but not in D. arizonae. However, expression of Hsp70 under control conditions is greater in D. arizonae. These results suggest that the mechanisms of natural thermoprotection involve an increase in baseline Hsp70 expression.
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Affiliation(s)
- Amy E M Newman
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6.
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Brezina V, Horn CC, Weiss KR. Modeling neuromuscular modulation in Aplysia. III. Interaction of central motor commands and peripheral modulatory state for optimal behavior. J Neurophysiol 2004; 93:1523-56. [PMID: 15469963 DOI: 10.1152/jn.00475.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent work in computational neuroethology has emphasized that "the brain has a body": successful adaptive behavior is not simply commanded by the nervous system, but emerges from interactions of nervous system, body, and environment. Here we continue our study of these issues in the accessory radula closer (ARC) neuromuscular system of Aplysia. The ARC muscle participates in the animal's feeding behaviors, a set of cyclical, rhythmic behaviors driven by a central pattern generator (CPG). Patterned firing of the ARC muscle's two motor neurons, B15 and B16, releases not only ACh to elicit the muscle's contractions but also peptide neuromodulators that then shape the contractions through a complex network of actions on the muscle. These actions are dynamically complex: some are fast, but some are slow, so that they are temporally uncoupled from the motor neuron firing pattern in the current cycle. Under these circumstances, how can the nervous system, through just the narrow channel of the firing patterns of the motor neurons, control the contractions, movements, and behavior in the periphery? In two earlier papers, we developed a realistic mathematical model of the B15/B16-ARC neuromuscular system and its modulation. Here we use this model to study the functional performance of the system in a realistic behavioral task. We run the model with two kinds of inputs: a simple set of regular motor neuron firing patterns that allows us to examine the entire space of patterns, and the real firing patterns of B15 and B16 previously recorded in a 2 1/2-h-long meal of 749 cycles in an intact feeding animal. These real patterns are extremely irregular. Our main conclusions are the following. 1) The modulation in the periphery is necessary for superior functional performance. 2) The components of the modulatory network interact in nonlinear, context- and task-dependent combinations for best performance overall, although not necessarily in any particular cycle. 3) Both the fast and the slow dynamics of the modulatory state make important contributions. 4) The nervous system controls different components of the periphery to different degrees. To some extent the periphery operates semiautonomously. However, the structure of the peripheral modulatory network ensures robust performance under all circumstances, even with the irregular motor neuron firing patterns and even when the parameters of the functional task are randomly varied from cycle to cycle to simulate a variable feeding environment. In the variable environment, regular firing patterns, which are fine-tuned to one particular task, fail to provide robust performance. We propose that the CPG generates the irregular firing patterns, which nevertheless are guaranteed to give robust performance overall through the actions of the peripheral modulatory network, as part of a trial-and-error feeding strategy in a variable, uncertain environment.
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Affiliation(s)
- Vladimir Brezina
- Department of Physiology and Biophysics and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, Box 1218, 1 Gustave L. Levy Place, New York, NY 10029, USA.
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Nicolau RA, Martinez MS, Rigau J, Tomàs J. Neurotransmitter release changes induced by low power 830 nm diode laser irradiation on the neuromuscular junctions of the mouse. Lasers Surg Med 2004; 35:236-41. [PMID: 15389739 DOI: 10.1002/lsm.20087] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND OBJECTIVE Treating patients with a Gallium-Aluminum-Arsenide (GaAlAs) infrared (IR) diode laser reduces muscle spasm and increases mobility in the muscles. The effect of low intensity laser irradiation on nerve function, growth, and repair mechanisms is a contentious area of research. We have addressed one aspect of this controversy by systematically examining the influence of 830 nm laser radiation on neurotransmitter release in neuromuscular junctions (NMJ) of the mouse diaphragm. STUDY DESIGN/MATERIALS AND METHODS Thirty adult mice were studied. Diode laser GaAlAs 830 nm (4 and 12 J/cm2) was used. Neurotransmitter release was studied by conventional intracellular recording techniques on curarized muscles or high magnesium media. The quantal content, amplitude, and latency of the end-plate potentials (EPPs) were analyzed. Frequency and amplitude were evaluated for the miniature end-plate potentials (MEPPs). Facilitation of the neurotransmitter release was also evaluated by paired pulse stimulation. RESULTS AND CONCLUSIONS The irradiated (12 J/cm2) muscles showed a significant reduction in quantal content (P = 0.01) and EPP amplitude (P = 0.04), but the latency, spontaneous transmitter release (MEPPs) and paired pulse facilitation did not change. No alterations were observed in NMJ irradiated with 4 J/cm2. We conclude that 830 nm diode laser irradiation (at a dose of 12 J/cm2) can affect the evoked neurotransmitter release in the mouse motor endplates.
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Affiliation(s)
- Renata Amadei Nicolau
- Institute for Research and Development (IP&D), Universidade do Vale do Paraíba (Univap)-SJC, Brazil.
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25
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Bolton DAE, Cauraugh JH, Hausenblas HA. Electromyogram-triggered neuromuscular stimulation and stroke motor recovery of arm/hand functions: a meta-analysis. J Neurol Sci 2004; 223:121-7. [PMID: 15337612 DOI: 10.1016/j.jns.2004.05.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Revised: 03/16/2004] [Accepted: 05/05/2004] [Indexed: 12/14/2022]
Abstract
Debate persists about the effectiveness of poststroke behavioral interventions for progress toward motor recovery. The current meta-analysis assessed the effect of electromyogram (EMG)-triggered neuromuscular stimulation on arm and hand functions. Computer searches of PubMed and Cochran databases, as well as hand searches of reference lists identified seven EMG-triggered neuromuscular stimulation studies. Outcome measures focused on arm and hand motor capability functions. In addition, the quality of each study was rated on three guidelines: randomization, double blind, and dropouts. After adjusting data for consistency in the arm/hand outcome measures and to avoid bias, five active stimulation studies were included in the analysis. Rehabilitation treatment in each study focused on wrist extension. The total number of individuals in the treatment groups was 47 whereas the control groups had 39 subjects. The meta-analysis revealed a significant overall mean effect size (delta=0.82, S.D.=0.59). A homogeneity test indicated that the pooled standardized effect sizes estimated the same treatment effect. A fail-safe test for null effect findings revealed that 15 studies were required to reduce the large effect (0.82) to a small effect (0.20). These improved wrist extension motor capabilities findings support EMG-triggered neuromuscular stimulation as an effective poststroke protocol.
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Affiliation(s)
- David A E Bolton
- Motor Behavior Laboratory, P.O. Box 118206, University of Florida, Gainesville, FL 32611, USA
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26
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Nicolau RA, Martinez MS, Rigau J, Tomàs J. Effect of low power 655 nm diode laser irradiation on the neuromuscular junctions of the mouse diaphragm. Lasers Surg Med 2004; 34:277-84. [PMID: 15022258 DOI: 10.1002/lsm.20006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVES Low level laser therapy (LLLT) in specific wavelengths and fluence maintains the electrophysiological activity of injured peripheral nerve in rats, preventing scar formation (at injury site) as well as degenerative changes in the corresponding motor neurons of the spinal cord, thus accelerating regeneration of the injured nerve. We studied the effect of LLLT on the neurotransmitter release in neuromuscular junctions of the mouse diaphragm. STUDY DESIGN/MATERIALS AND METHODS Thirty-nine diaphragm muscles were studied. LLLT with GaAlAs 655 nm (1-12 J/cm(2)) was used. Neurotransmitter release was studied by conventional intracellular recording techniques on curarised or high magnesium media. Quantal content, amplitude, latency and rise time were analysed for end-plate potentials (EPPs). Frequency and amplitude were evaluated for the miniature end-plate potentials (MEPPs). Short-term plasticity of the neurotransmitter release (fast facilitation) was also evaluated by paired pulse stimulation. RESULTS AND CONCLUSIONS This study showed that LLLT (655 nm) in these doses has no detectable physiological effect on the motor end-plate neurotransmitter release in mice.
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Affiliation(s)
- Renata Amadei Nicolau
- Institute for Research and Development, Universidade do Vale do Paralba (Univap)-SJC, Brazil.
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27
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Kiskin NI, Chillingworth R, McCray JA, Piston D, Ogden D. The efficiency of two-photon photolysis of a "caged" fluorophore, o-1-(2-nitrophenyl)ethylpyranine, in relation to photodamage of synaptic terminals. Eur Biophys J 2002; 30:588-604. [PMID: 11908850 DOI: 10.1007/s00249-001-0187-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Localized photolysis of caged neurotransmitters with the two-photon effect for investigations at synaptic preparations was evaluated by determining the toxicity to synaptic transmission of pulsed near-IR laser light focused into the terminals of the snake neuromuscular junction, and measuring the extent of photolysis of a conventional caging group with similar irradiation in microcuvette experiments. Photodamage was seen in synaptic terminals as a large, irreversible increase of spontaneous synaptic activity with laser flashes of 5 ms at 1 Hz at average powers > 5 mW and was due to multiphoton absorption. Localized photolysis due to two-photon absorption was investigated for a representative caged fluorophore, the 1-(2-nitrophenyl)ethyl ether of pyranine (NPE-HPTS). Irradiation of NPE-HPTS at 5 mW with the same optical arrangement produced very low rates of photolysis. NPE-HPTS photolysis mechanisms were investigated at high laser powers by measuring (1) the kinetics of two-photon fluorescence generated by two-photon photolysis in the focal volume and (2) the rates of HPTS accumulation inside closed 2-10 microm radius vesicles, measured with one-photon excitation during two-photon photolysis by repetitive 10 micros laser exposures. The two-photon crosssection of NPE-HPTS photolysis calculated from the rates is 0.02-0.04 GM (10(-50) cm4 x s/photon) and limits the efficiency of photolysis at 5 mW. With free diffusional exchange, 50% steady-state cage depletion in the focal volume was estimated to occur only at high laser powers of ca. 72 mW, masked in experiments by multiphoton bleaching. Based on these results, the two-photon photolysis cross-section needed for 50% steady-state photolysis of a caged neurotransmitter at 5 mW is calculated as 31 GM, much higher than in existing caged compounds.
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Abstract
Effects of a constant magnetic field (CMF) of 0.65 T on muscle tension over 9 h were studied in the neuromuscular preparation of the bullfrog sartorius muscle. Tension was developed every 30 min by stimulation of the sciatic nerve (nerve stimulation) or of the sartorius muscle itself (muscle stimulation). In sciatic nerve stimulation, tension decreased rapidly for the first 3-4 h at a similar rate in both test (exposed to CMF) and control muscles. However, the rate of decrease became smaller and almost leveled off after 3-4 h in the test muscles, whereas tension continued to decrease monotonically in control muscles. The slope of the decrease for these later periods was significantly different between the test and the control conditions. Accordingly, tension was larger in test than in control muscles. In muscle stimulation, tension decreased monotonically from the start of experiments in control muscles, while tension in test muscles maintained their initial values for almost 3 h. Thereafter they started to decrease with a similar rate to the control. Hence, tension was always larger in test than in control muscles. A similar pattern of temporal change was observed for the rate of rise of the maximum tension for nerve or muscle stimulation. However, a significant difference was detected only in the case of muscle stimulation. The present results showed that a strong CMF of 0.65 T had biological effects on tension development of the bullfrog sartorius muscle by stimulation of the sciatic nerve as well as by stimulation of muscle itself. The presence of a small AC magnetic field component leaves open the possibility of an AC, rather than a CMF effect.
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Affiliation(s)
- Y Satow
- Gifu College of Medical Technology, Seki City, Gifu, Japan
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29
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Hegstrom CD, Breedlove SM. Short day lengths affect perinatal development of the male reproductive system in the Siberian hamster, Phodopus sungorus. J Biol Rhythms 1999; 14:402-8. [PMID: 10511007 DOI: 10.1177/074873099129000803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Siberian hamster, Phodopus sungorus, breeds seasonally. In the laboratory, seasonal breeding can be controlled by photoperiod, which affects the duration of nightly melatonin secretion. Winterlike, short day lengths induce gonadal regression in adult animals, and pups born and maintained in short days undergo pubertal gonadal development later than animals born into long days. However, to date there have been no reports of gestational photoperiod affecting fetal development of reproductive systems. The spinal nucleus of the bulbocavernosus (SNB) and its target muscles, the bulbocavernosus (BC) and levator ani (LA), compose a sexually dimorphic, androgen-sensitive neuromuscular system involved in male reproduction. The SNB neuromuscular system was studied in male Siberian hamsters maintained from conception in short-day (8 h light, 16 h dark; 8L:16D) versus long-day (16L:8D) conditions. On the day of birth, and at postnatal (PN) days 2 and 18, the BC/LA muscles of hamsters gestated and raised in the short photoperiod were significantly reduced relative to those of their long-day counterparts. Testes weights were not significantly different between groups until day 18. Thus, photoperiod exposure during gestation and after birth affects perinatal development of the SNB system in this species, and these effects can be seen as early as the day of birth. Because photoperiod did not significantly affect testes weights until PN18, these results suggest that either perinatal photoperiod affects fetal androgen production without affecting testes weight or it influences BC/LA development independently from androgen.
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Affiliation(s)
- C D Hegstrom
- Department of Psychology, University of California, Berkeley 94720-1650, USA
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30
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Abstract
A comparative study between crotoxin and gamma irradiated crotoxin was performed on the indirectly evoked twitches and tetani of sciatic nerve-extensor digitorum longus muscle of rats. Crotoxin (3 to 14 microg/ml) decreased the amplitude of twitches and induced a slight tetanic fade, and irradiated crotoxin did not significantly affect either twitch amplitude or tetanic tension. Since gamma radiation reduced the neurotoxicity of crotoxin it may be useful for the production of anticrotalic serum.
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Affiliation(s)
- M Gallacci
- Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, Sao Paulo, Brazil
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31
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Tereshin SI. [The role of the central nervous system in realizing the action of UHF electromagnetic oscillations in the centimeter range on the function of the excited tissues in cold-blooded animals]. Vopr Kurortol Fizioter Lech Fiz Kult 1994:9-12. [PMID: 8017051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Experiments with male frogs carried out in autumn-winter revealed that the effect of UHF centimeter band electromagnetic field on excitable tissues depends on these tissues functioning. Such an exposure had the most marked effect on animals with destroyed central nervous system and on isolated tissues. On the whole this exposure reduced muscular tissue threshold excitability and resulted in variously directed shifts of these thresholds in nervous tissue. Changes in tissue accommodation capacity under the effect of such electromagnetic field varied in nature and in direction.
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32
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Langenfeld-Oster B, Dorlöchter M, Wernig A. Regular and photodamage-enhanced remodelling in vitally stained frog and mouse neuromuscular junctions. J Neurocytol 1993; 22:517-30. [PMID: 7691996 DOI: 10.1007/bf01189040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Repeated in vivo observations of vitally stained neuromuscular junctions allow direct monitoring of ongoing structural changes, although, normally occurring changes (remodelling) and those inflicted by the illumination itself (photodamage) need to be dissociated. In frog cutaneus pectoris muscles, stained in vivo with 4Di-2ASP twice within four to five weeks, growth only was observed in 14 out of 92 junctions (in 18 muscles), retraction only in 19, and both features simultaneously in 22 junctions, while 37 junctions showed no changes. The summed growth in a junction amounted to 5-42 microns, retraction to 5-52 microns, while overall changes in synaptic length were absent. This and the simultaneous occurrence of both, growth and retraction within a single junction, indicates junctional remodelling. Similar amounts of remodelling were observed in junctions illuminated for 180, 60 or 10-30 s, indicating that within this range and with the given optical system, blue light and 4Di-2ASP fluorescence were not harmful. Remodelling was not induced by the experimental procedure per se, since in in vitro preparations signs of sprouting (and retraction) were equally frequent in junctions of totally untreated muscles, in junctions vitally stained four to five weeks previously or vitally stained but not light-exposed in the same muscle. In endplates of mouse gluteus maximus muscles double stained with 4Di-2ASP and rhodamine-alpha-bungarotoxin, unusually large (> 10 microns) terminal sprouts and retraction with gain loss of ACh-receptors became prominent 9-29 days following illumination for more than 60 s. Frequently also, muscle fibre damage with local contracture and acute loss of stainability of axon terminals occurred; often followed by muscle fibre denervation. In contrast, no such changes occurred after lower illumination intensities (12% emission filter for green) or shorter exposure times (< 60 s); even at a fourth exposure performed within 53 days. Previously reported smaller changes indicating regular remodelling were not investigated here.
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Serov SI, Tereshin SI. [The effect of electromagnetic oscillations in the decimeter range on the function of nerve and muscle tissues (experimental research)]. Vopr Kurortol Fizioter Lech Fiz Kult 1990:48-50. [PMID: 2219817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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LaCourse JR, Vogt MC, Miller WT, Selikowitz SM. Spectral analysis interpretation of electrosurgical generator nerve and muscle stimulation. IEEE Trans Biomed Eng 1988; 35:505-9. [PMID: 3209211 DOI: 10.1109/10.4578] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Abstract
Morphological and physiological techniques were used to study the effects of radiation-induced hypomyelinating neuropathy on the innervation of skeletal muscle in the mouse. The right sciatic nerve was crushed focally and 3 days later the hind limb exposed to 20Gy X-rays. After reinnervation of original end-plate sites there was extensive formation of ultraterminal sprouts and of new end-plates characterized by small nerve terminals and rudimentary postsynaptic folds. In vitro examination of soleus nerve-muscle preparations showed reduced frequency of spontaneous miniature end-plate potentials and low quantal content of evoked potentials. The findings indicate that hypomyelinating neuropathy may cause reduction in quantal release of neurotransmitter.
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Abstract
The actions on amphibian embryos of UV-irradiation, exposure to Li+ or exposure to ouabain show interesting parallels with their effects on spontaneous release at the presynaptic terminals of the neuromuscular junction. It is suggested that these treatments serve to raise intracellular Ca2+ ([Ca2+]i) in these examples, and that UV-promoted abnormalities in embryogenesis are a consequence of changes in [Ca2+]i at critical stages in development.
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Trivedi HD, Kelkar VV, Jindal MN, Dave KC. Some photoresponses of isolated tissue preparations to ultraviolet light in the presence of photosensitizers. Indian J Physiol Pharmacol 1978; 22:136-41. [PMID: 212363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Responses of isolated tissue preparations to ultraviolet (UV) light were studied with and without the presence of photosensitizers like eosin, fluorescein and sodium nitrite. Exposure to UV light in the presence of sodium nitrite induced consistent relaxation of rat duodenum. The photorelaxation was found to be related to the concentration of sodium nitrite. Adrenergic or cholinergic mechanisms do not seem to be involved. The isolated rat duodenum preparation exhibited quantitatively consistent photoresponse for 3 to 4 hr at its normal tone obviating the need for additional spasmogens as needed with other preparations. The preparation is a suitable test model for the study of photobiologic response evoked by UV light.
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Rakhishev AR. [Reaction of the peripheral nervous system elements to the action of laser irradiation]. Arkh Anat Gistol Embriol 1976; 70:5-13. [PMID: 1259603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of light of the helium neon laser LG-75 with the output power 25mvt and the generated wave length 6328 A upon reparative processes in the neuromuscular apparatus was studied in rats in dynamics after neurotomy of the ischiatic nerve. Neurohistological (staining after Bielschowski-Gross, Spielmeier, Weigert-Pal) and electrophysiological (chronaximetry, "force-duration" index, electromyography) methods were used. The material was processed in a computer. A stimulating effect of the applied low-energy laser radiation on the regeneration of the ischiatic nerve was established.
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Faes MH, Aubert C, Rosselle N, Van der Schueren G. [Modifications of the localization of acetylcholinesterase at the neuromuscular junction after irradiation with 60 Co]. Arch Int Physiol Biochim 1971; 79:269-77. [PMID: 4108435 DOI: 10.3109/13813457109085308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Ul'ianitskaia AE. [The effect of ionizing radiation on the functional state of the neuromuscular synapses of frogs]. Radiobiologiia 1970; 10:54-8. [PMID: 4316447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Ul'ianitskaia AE. [Physiological analysis of the role of the synapse in disorders of neuromuscular apparatus disorders in irradiation]. Radiobiologiia 1968; 8:403-7. [PMID: 5742402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Znamenskiĭ VV. [A study of changes in the neuromuscular apparatus of the rat in chronic exposure to Mn54 and external gamma irradiation]. Gig Tr Prof Zabol 1968; 12:46-50. [PMID: 5729188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Popova MF. [On the radiotolerance of regenerating muscle tissue]. Arkh Anat Gistol Embriol 1966; 50:41-8. [PMID: 5966886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Tuzhilkova TN. [Relationship between neural and muscular elements in the process of posttraumatic regeneration of irradiated muscles]. Radiobiologiia 1966; 6:391-393. [PMID: 5983926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Pierson MB, Bachofer CS. Alterations in muscle activity during gamma-irradiation. Radiat Res 1965; 26:403-12. [PMID: 5846635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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SCHLIEP HJ. [Radiation-induced immediate effects on the nerves and muscles of Annelida]. Arztl Forsch 1962; 16:I/263-5. [PMID: 14498568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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ROSEN D, DAWSON KB. Search for immediate effects of x-radiation on frog nerve-muscle preparations. Radiat Res 1960; 12:357-70. [PMID: 14438869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
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PSHENNIKOVA MG. [Electrophysiological analysis of the distribution of non-impulse effects in nerve-muscle preparation structures from roentgen-irradiation regions]. Biofizika 1958; 3:680-8. [PMID: 13618300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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PONS H, DELONS P, DELONS E. [Neuromuscular excitability and isonizing radiations]. Toulouse Med 1958; 59:33-8. [PMID: 13543854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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