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Esen O, Bailey SJ, Stashuk DW, Howatson G, Goodall S. Influence of nitrate supplementation on motor unit activity during recovery following a sustained ischemic contraction in recreationally active young males. Eur J Nutr 2024; 63:2379-2387. [PMID: 38809323 PMCID: PMC11377467 DOI: 10.1007/s00394-024-03440-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 05/21/2024] [Indexed: 05/30/2024]
Abstract
PURPOSE Dietary nitrate (NO3-) supplementation enhances muscle blood flow and metabolic efficiency in hypoxia, however, its efficacy on neuromuscular function and specifically, the effect on motor unit (MU) activity is less clear. We investigated whether NO3- supplementation affected MU activity following a 3 min sustained ischemic contraction and whether this is influenced by blood flow restriction (BFR) during the recovery period. METHOD In a randomized, double-blinded, cross-over design, 14 males (mean ± SD, 25 ± 6 years) completed two trials following 5 days of supplementation with NO3--rich (NIT) or NO3--depleted (PLA) beetroot juice to modify plasma nitrite (NO2-) concentration (482 ± 92 vs. 198 ± 48 nmol·L-1, p < 0.001). Intramuscular electromyography was used to assess MU potential (MUP) size (duration and area) and mean firing rates (MUFR) during a 3 min submaximal (25% MVC) isometric contraction with BFR. These variables were also assessed during a 90 s recovery period with the first half completed with, and the second half completed without, BFR. RESULTS The change in MUP area and MUFR, did not differ between conditions (all p > 0.05), but NIT elicited a reduction in MUP recovery time during brief isometric contractions (p < 0.001), and during recoveries with (p = 0.002) and without (p = 0.012) BFR. CONCLUSION These novel observations improve understanding of the effects of NO3- on the recovery of neuromuscular function post-exercise and might have implications for recovery of muscle contractile function. TRIAL REGISTRATION The study was registered on clinicaltrials.gov with ID of NCT05993715 on August 08, 2023.
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Affiliation(s)
- Ozcan Esen
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-Upon-Tyne, NE1 8ST, UK.
- Department of Health Professions, Manchester Metropolitan University, Manchester, UK.
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-Upon-Tyne, NE1 8ST, UK
- Water Research Group, North West University, Potchefstroom, South Africa
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-Upon-Tyne, NE1 8ST, UK
- Physical Activity, Sport and Recreation Research Focus Area, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
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Yakovleva O, Albova P, Sitdikova G. The Role of Nitric Oxide in Regulation of Exocytosis and Endocytosis of Synaptic Vesicles in Motor Nerve Endings of Mice in Alloxan Model of Diabetes Mellitus. BIONANOSCIENCE 2022. [DOI: 10.1007/s12668-022-00976-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Esen O, Faisal A, Zambolin F, Bailey SJ, Callaghan MJ. Effect of nitrate supplementation on skeletal muscle motor unit activity during isometric blood flow restriction exercise. Eur J Appl Physiol 2022; 122:1683-1693. [PMID: 35460359 PMCID: PMC9197866 DOI: 10.1007/s00421-022-04946-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/17/2022] [Indexed: 12/26/2022]
Abstract
Background Nitrate (NO3−) supplementation has been reported to lower motor unit (MU) firing rate (MUFR) during dynamic resistance exercise; however, its impact on MU activity during isometric and ischemic exercise is unknown. Purpose To assess the effect of NO3− supplementation on knee extensor MU activities during brief isometric contractions and a 3 min sustained contraction with blood flow restriction (BFR). Methods Sixteen healthy active young adults (six females) completed two trials in a randomized, double-blind, crossover design. Trials were preceded by 5 days of either NO3− (NIT) or placebo (PLA) supplementation. Intramuscular electromyography was used to determine the M. vastus lateralis MU potential (MUP) size, MUFR and near fibre (NF) jiggle (a measure of neuromuscular stability) during brief (20 s) isometric contractions at 25% maximal strength and throughout a 3 min sustained BFR isometric contraction. Results Plasma nitrite (NO2−) concentration was elevated after NIT compared to PLA (475 ± 93 vs. 198 ± 46 nmol L−1, p < 0.001). While changes in MUP area, NF jiggle and MUFR were similar between NIT and PLA trials (all p > 0.05), MUP duration was shorter with NIT compared to PLA during brief isometric contractions and the sustained ischemic contraction (p < 0.01). In addition, mean MUP duration, MUP area and NF jiggle increased, and MUFR decreased over the 3 min sustained BFR isometric contraction for both conditions (all p < 0.05). Conclusions These findings provide insight into the effect of NO3− supplementation on MUP properties and reveal faster MUP duration after short-term NO3− supplementation which may have positive implications for skeletal muscle contractile performance.
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Affiliation(s)
- Ozcan Esen
- Department of Health Professions, Manchester Metropolitan University, Manchester, M15 6GX, UK.
- Manchester Metropolitan University Institute of Sport, Manchester, UK.
| | - Azmy Faisal
- Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, UK
- Manchester Metropolitan University Institute of Sport, Manchester, UK
- Faculty of Physical Education for Men, Alexandria University, Alexandria, Egypt
| | - Fabio Zambolin
- Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, UK
- Manchester Metropolitan University Institute of Sport, Manchester, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Michael J Callaghan
- Department of Health Professions, Manchester Metropolitan University, Manchester, M15 6GX, UK
- Manchester University Hospital Foundation Trust, Manchester, UK
- Arthritis Research UK Centre for Epidemiology, Centre for Musculoskeletal Research, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
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Nitric oxide and skeletal muscle contractile function. Nitric Oxide 2022; 122-123:54-61. [PMID: 35405336 PMCID: PMC10167965 DOI: 10.1016/j.niox.2022.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/23/2022] [Accepted: 04/05/2022] [Indexed: 11/21/2022]
Abstract
Nitric oxide (NO) is complex modulator of skeletal muscle contractile function, capable of increasing or decreasing force and power output depending on multiple factors. This review explores the effects and potential mechanisms for modulation of skeletal muscle contractile function by NO, from pharmacological agents in isolated muscle preparations to dietary nitrate supplementation in humans and animals. Pharmacological manipulation in vitro suggests that NO signaling diminishes submaximal isometric force, whereas dietary manipulation in vivo suggest that NO enhances submaximal force. The bases for these different responses are unknown but could reflect dose-dependent effects. Maximal isometric force is unaffected by physiologically relevant levels of NO, which do not induce overt protein oxidation. Pharmacological and dietary manipulation of NO signaling enhances the maximal rate of isometric force development, unloaded shortening velocity, and peak power. We hypothesize that these effects are mediated by post-translational modifications of myofibrillar proteins that modulate thick filament regulation of contraction (e.g., mechanosensing and strain-dependence of cross-bridge kinetics). NO effects on contractile function appear to have some level of fiber type and sex-specificity. The mechanisms behind NO-mediated changes in skeletal muscle function need to be explored through proteomics analysis and advanced biophysical assays to advance the development of small molecules and open intriguing therapeutic and ergogenic possibilities for aging, disease, and athletic performance.
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5
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Lukáčová N, Hricová L, Kisucká A, Papcunová Š, Bimbová K, Bačová M, Pavel J, Marsala M, Vanický I, Dzurjašková Z, Matéffy S, Lukáčová V, Stropkovská A, Gálik J. Is Innervation of the Neuromuscular Junction at the Diaphragm Modulated by sGC/cGMP Signaling? Front Physiol 2020; 11:700. [PMID: 32655417 PMCID: PMC7324717 DOI: 10.3389/fphys.2020.00700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 05/28/2020] [Indexed: 11/15/2022] Open
Abstract
We previously reported NO/sGC signaling in the upper respiratory pathway, receiving input from the respiratory neurons of the brainstem to phrenic motoneurons in the C3–C6 spinal cord. In order to assess whether innervation of the neuromuscular junction (NMJ) at the diaphragm is modulated by sGC/cGMP signaling, we performed unilateral 8-day continuous ligation of the phrenic nerve in rats. We examined sGCβ1 within the lower bulbospinal pathway (phrenic motoneurons, phrenic nerves and NMJs at the diaphragm) and the cGMP level in the contra- and ipsilateral hemidiaphragm. Additionally, we characterized the extent of phrenic nerve axonal degeneration and denervation at diaphragm NMJs. The results of our study show that continuous 8-day phrenic nerve ligation caused a marked increase in sGCβ1 (immunoreactivity and the protein level) in the ipsilateral phrenic motor pool. However, the protein sGCβ1 level in the phrenic nerve below its ligation and the cGMP level in the ipsilateral hemidiaphragm were evidently decreased. Using confocal analysis we discovered a reduction in sGCβ1-IR boutons/synaptic vesicles at the ipsilateral MNJs. These findings are consistent with the marked axonal loss (∼47%) and significant NMJs degeneration in the ipsilateral diaphragm muscle. The remarkable unilateral decrease in cGMP level in the diaphragm and the failure of EMG recordings in the ipsilateral hemidiaphragm muscle can be attributed to the fact that sGC is involved in transmitter release at the diaphragm NMJs via the sGC-cGMP pathway.
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Affiliation(s)
- Nadežda Lukáčová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - L'udmila Hricová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Alexandra Kisucká
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Štefánia Papcunová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Katarína Bimbová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Mária Bačová
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Jaroslav Pavel
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Martin Marsala
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia.,Neuroregeneration Laboratory, Department of Anesthesiology, University of California, San Diego, La Jolla, CA, United States
| | - Ivo Vanický
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Zuzana Dzurjašková
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Stanislav Matéffy
- Diagnostic Center of Pathology in Prešov, Alpha Medical, s.r.o., Martin, Slovakia
| | - Viktória Lukáčová
- Faculty of Economics, Technical University of Košice, Košice, Slovakia
| | - Andrea Stropkovská
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
| | - Ján Gálik
- Institute of Neurobiology, Biomedical Research Center of the Slovak Academy of Sciences, Košice, Slovakia
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McCarthy CJ, Ikeda Y, Skennerton D, Chakrabarty B, Kanai AJ, Jabr RI, Fry CH. Characterisation of nerve-mediated ATP release from bladder detrusor muscle and its pathological implications. Br J Pharmacol 2019; 176:4720-4730. [PMID: 31430833 DOI: 10.1111/bph.14840] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 07/31/2019] [Accepted: 08/04/2019] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE This study aims to characterise the molecular mechanisms that determine variability of atropine resistance of nerve-mediated contractions in human and guinea pig detrusor smooth muscle. EXPERIMENTAL APPROACH Atropine resistance of nerve-mediated contractions and the role of P2X1 receptors, were assessed in isolated preparations from guinea pigs and also humans with or without overactive bladder syndrome, from which the mucosa was removed. Nerve-mediated ATP release was measured directly with amperometric ATP-sensitive electrodes. Ecto-ATPase activity of guinea pig and human detrusor samples was measured in vitro by measuring the concentration-dependent rate of ATP breakdown. The transcription of ecto-ATPase subtypes in human samples was measured by qPCR. KEY RESULTS Atropine resistance was greatest in guinea pig detrusor, absent in human tissue from normally functioning bladders, and intermediate in human overactive bladder. Greater atropine resistance correlated with reduction of contractions by the ATP-diphosphohydrolase apyrase, directly implicating ATP in their generation. E-NTPDase-1 was the most abundantly transcribed ecto-ATPase of those tested, and transcription was reduced in tissue from human overactive, compared to normal, bladders. E-NTPDase-1 enzymic activity was inversely related to the magnitude of atropine resistance. Nerve-mediated ATP release was continually measured and varied with stimulation frequency over the range of 1-16 Hz. CONCLUSION AND IMPLICATIONS Atropine resistance in nerve-mediated detrusor contractions is due to ATP release and its magnitude is inversely related to E-NTPDase-1 activity. ATP is released under different stimulation conditions compared with ACh, implying different routes for their release.
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Affiliation(s)
- Carly J McCarthy
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Facultad de Ciencias Biomédicas, Austral University, Buenos Aires, Argentina.,Department of Surgery, University College London, London, UK
| | - Youko Ikeda
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University College London, London, UK
| | | | - Basu Chakrabarty
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Anthony J Kanai
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rita I Jabr
- School of Biosciences and Medicine, University of Surrey, Surrey, UK
| | - Christopher H Fry
- Department of Surgery, University College London, London, UK.,School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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Murcia V, Johnson L, Baldasare M, Pouliot B, McKelvey J, Barbery B, Lozier J, Bell WE, Turner JE. Effects of Estrogen, Nitric Oxide, and Dopamine on Behavioral Locomotor Activities in the Embryonic Zebrafish: A Pharmacological Study. TOXICS 2016; 4:toxics4040024. [PMID: 29051426 PMCID: PMC5606654 DOI: 10.3390/toxics4040024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/01/2016] [Accepted: 09/14/2016] [Indexed: 11/30/2022]
Abstract
Nitric oxide (NO) has been shown to affect motor function. Specifically, NO has been shown to act through regulation of dopamine (DA) release, transporter function, and the elicitation of neuroprotection/neurodegeneration of neurons. Recently, zebrafish have been proposed to be a new model for the study of various types of motor dysfunctions, since neurotoxin damage to their nigrostriatal-like neurons exhibit motor anomalies similar to those of mammalian models and human patients. Results from this study demonstrate that when NO synthesis is inhibited in zebrafish, using a neuronal NO synthase inhibitor (nNOSI), a condition called ‘listless’ occurs, where the fish lack swimming abilities, are rigid, and have difficulty maintaining balance. Additionally, co-treatment with either NO or estrogen (E2), an upstream regulator of NO synthase, can rescue fish from the ‘listless’ phenotype caused by exposure to the neurotoxin 6-hydroxydopamine (6 OHDA). In turn, NO deprived zebrafish were rescued from the ‘listless’ phenotype when co-treated with L-DOPA, a precursor to DA. Interestingly, the longer fish are exposed to a 6 OHDA + nNOSI co-treatment, the slower the recovery after washout, compared to a single treatment of each. Most significantly, NO involvement in the motor homeostasis of the embryonic zebrafish was shown to be expressed through the NO-cGMP-dependent pathway, and response to nNOSI treatments is developmentally regulated. In conclusion, these results indicate that there is a link between E2, NO, and DA systems that regulate motor functions in the embryonic zebrafish.
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Affiliation(s)
- Vania Murcia
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Luke Johnson
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Meredith Baldasare
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Bridgette Pouliot
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - John McKelvey
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Brandon Barbery
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Julie Lozier
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - Wade E Bell
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
| | - James E Turner
- Department of Biology, Center for Molecular, Cellular, and Biological Chemistry, Virginia Military Institute, Lexington, VA 24450, USA.
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8
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Skeletal muscle calpain acts through nitric oxide and neural miRNAs to regulate acetylcholine release in motor nerve terminals. J Neurosci 2013; 33:7308-7324. [PMID: 23616539 DOI: 10.1523/jneurosci.0224-13.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cholinergic overactivity in diseases of neuromuscular transmission elicits a retrograde signal resembling homeostatic synaptic plasticity that downregulates transmitter release. Understanding this compensatory pathway could provide insights into novel therapeutic avenues and molecular mechanisms underlying learning and memory. Here we identify nitric oxide as a possible source of this signal in pathological human and mouse muscle samples and link this signaling pathway to changes in synaptic function in the neuromuscular junction. We further show that neuronal nitric oxide synthase is regulated by cholinergic excess through activation of skeletal muscle calpain and its effect on Cdk5 and CaMKII, leading to direct modulation of presynaptic function. Finally, we show that this signaling pathway acts through specific miRNA control of presynaptic vesicle protein expression. The control of presynaptic miRNA levels by postsynaptic activity represents a novel mechanism for the modulation of synaptic activity in normal or pathological conditions.
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Yakovleva OV, Shafigullin MU, Sitdikova GF. The role of nitric oxide in the regulation of neurotransmitter release and processes of exo- and endocytosis of synaptic vesicles in mouse motor nerve endings. NEUROCHEM J+ 2013. [DOI: 10.1134/s1819712413020104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Garcia-Pascual A, Labadía A, Garcia-Flores M, Sancho M, Triguero D. Refractoriness of urethral striated muscle contractility to nitric oxide-dependent cyclic GMP production. Nitric Oxide 2010; 23:26-33. [PMID: 20362065 DOI: 10.1016/j.niox.2010.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 03/18/2010] [Accepted: 03/26/2010] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to investigate the role of cyclic GMP (cGMP) in the effects of nitric oxide (NO) on urethral striated muscle and its involvement in contractile function. The localization of cGMP, neuronal NO synthase (nNOS), vimentin, and neuronal markers was assessed by immunofluorescence in the sheep and rat urethra and the expression of nNOS was determined in Western blots. Nerve-mediated contractile responses to electrical field stimulation (EFS) were recorded in the sheep urethra. The scant nitrergic innervation of the striated muscle layer suggests that autonomic control of its activity is unlikely. The striated fiber itself may be the source of high levels NO produced by sarcolemmal and/or cytosolic mu or alpha variant of nNOS. This endogenous NO may provoke high basal production of soluble guanylate cyclase (GC) dependent cGMP, mainly in non-NO producing muscle fibers, which is not further enhanced by NO donors. cGMP co-localizes with neurofilament and PGP 9.5 at muscle endplates. Modulators of the cGMP pathway did not affect nerve-mediated contractile activity induced by EFS, suggesting that cGMP is not a significant mediator of neuromuscular transmission. In addition, NO donors did increase the accumulation of cGMP in dense networks of vimentin immunoreactive interstitial cells of Cajal (ICC), whose function is not yet known. These data suggest that there is a strong but non-regulated production of cGMP under resting conditions, which does not seem to affect contractile function. Modulation of cholinergic neurotransmission by NO through cGMP-independent mechanisms cannot be discarded.
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11
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Nieoczym D, Łuszczki JJ, Czuczwar SJ, Wlaź P. Effect of sildenafil on the anticonvulsant action of classical and second-generation antiepileptic drugs in maximal electroshock-induced seizures in mice. Epilepsia 2010; 51:1552-9. [PMID: 20067503 DOI: 10.1111/j.1528-1167.2009.02485.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE The goal of the present study was to evaluate the effects of sildenafil on the threshold for electrically induced seizures in mice. In addition, interactions between sildenafil and classical and second-generation antiepileptic drugs (AEDs), that is, carbamazepine (CBZ), phenobarbital (PB), phenytoin (PHT), valproate (VPA), lamotrigine (LTG), topiramate (TPM), and oxcarbazepine (OXC) were evaluated. METHODS Two electroconvulsive tests were used: maximal electroshock seizure threshold (MEST) and maximal electroshock seizure (MES) tests in mice. Acute adverse effects of the studied combinations were investigated in the chimney test, step-through passive avoidance task, and grip-strength test. Total brain and free plasma concentrations of AEDs were also determined. RESULTS Sildenafil raised the threshold for electroconvulsions in a dose-dependent manner. It also increased the anticonvulsant activity of CBZ, VPA, and TPM in the MES test, whereas the activity of the remaining AEDs was not significantly changed. Sildenafil increased total brain and free (protein unbound) plasma CBZ concentrations and total brain VPA concentration. Neither sildenafil nor its coadministration with the studied AEDs affected motor coordination and long-term memory in mice. Interestingly, sildenafil dose-dependently enhanced the skeletal muscle strength in mice, although combinations of sildenafil with AEDs were ineffective in this respect. CONCLUSIONS Sildenafil significantly raised the threshold for electroconvulsions in mice without any impairment of motor performance and long-term memory, but it enhanced muscle strength. Treatment of patients on CBZ or VPA with sildenafil may not be recommended due to pharmacokinetic interactions. Coadministration of sildenafil with other AEDs, especially with TPM, seems to be a reasonable choice.
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Affiliation(s)
- Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology, Maria Curie-Skłodowska University, Lublin, Poland
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12
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Tegenge MA, Stern M, Bicker G. Nitric oxide and cyclic nucleotide signal transduction modulates synaptic vesicle turnover in human model neurons. J Neurochem 2009; 111:1434-46. [PMID: 19807845 DOI: 10.1111/j.1471-4159.2009.06421.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The human Ntera2 (NT2) teratocarcinoma cell line can be induced to differentiate into post-mitotic neurons. Here, we report that the human NT2 neurons generated by a spherical aggregate cell culture method express increasing levels of typical pre-synaptic proteins (synapsin and synaptotagmin I) along the neurite depending on the length of in vitro culture. By employing an antibody directed against the luminal domain of synaptotagmin I and the fluorescent dye N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl)pyridinium dibromide, we show that depolarized NT2 neurons display calcium-dependent exo-endocytotic synaptic vesicle recycling. NT2 neurons express the neuronal isoform of neuronal nitric oxide synthase and soluble guanylyl cyclase (sGC), the major receptor for nitric oxide (NO). We tested whether NO signal transduction modulates synaptic vesicle turnover in human NT2 neurons. NO donors and cylic guanosine-monophosphate analogs enhanced synaptic vesicle recycling while a sGC inhibitor blocked the effect of NO donors. Two NO donors, sodium nitroprusside, and and N-Ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino) ethanamine evoked vesicle exocytosis which was partially blocked by the sGC inhibitor. The activator of adenylyl cyclase, forskolin, and a cAMP analog induced synaptic vesicle recycling and exocytosis via a parallel acting protein kinase A pathway. Our data from NT2 neurons suggest that NO/cyclic nucleotide signaling pathways may facilitate neurotransmitter release in human brain cells.
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Affiliation(s)
- Million Adane Tegenge
- Division of Cell Biology, Institute of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany
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13
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Akula KK, Dhir A, Kulkarni SK. Nitric oxide signaling pathway in the anti-convulsant effect of adenosine against pentylenetetrazol-induced seizure threshold in mice. Eur J Pharmacol 2008; 587:129-34. [PMID: 18457833 DOI: 10.1016/j.ejphar.2008.03.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/06/2008] [Accepted: 03/19/2008] [Indexed: 10/22/2022]
Abstract
The present study was performed to examine the involvement of nitric oxide (NO) signaling pathway in the anti-convulsant effect of adenosine against pentylenetetrazol seizure threshold in mice. Minimal dose of pentylenetetrazol (i.v., mg/kg) needed to induce different phases (myoclonic jerks, generalized clonus and tonic extension) of convulsions was recorded as an index of seizure threshold. Adenosine (100 or 200 mg/kg i.p.) produced a significant increase in the seizure threshold for convulsions induced by pentylenetetrazol i.v. infusion. The anti-convulsant effect of adenosine (100 mg/kg i.p.) was prevented by either L-arginine (50 mg/kg i.p.) [substrate for nitric oxide synthase (NOS)] or sodium nitroprusside (3 mg/kg i.p.) [a NO donor]. On the other hand, N(G)-nitro-L-arginine methyl ester (L-NAME, 2.5 mg/kg i.p.) [a non-selective NOS inhibitor] or 7-nitroindazole (7-NI) (25 mg/kg i.p.) [a specific neuronal nitric oxide synthase (nNOS) inhibitor] potentiated the anti-convulsant action of sub-effective dose of adenosine (50 mg/kg i.p.). Aminoguanidine (100 mg/kg i.p.) [a specific inducible NOS (iNOS) inhibitor] pre-treatment was not effective in inducing anti-convulsant effect with sub-effective dose of adenosine (50 mg/kg i.p.). Furthermore, the increase in seizure threshold elicited by adenosine (100 mg/kg i.p.) was also inhibited by concomitant administration with sildenafil (5 mg/kg i.p.) [phosphodiesterase 5 inhibitor]. In contrast, treatment of mice with methylene blue (1 mg/kg i.p.) [a direct inhibitor of both nitric oxide synthase (NOS) and soluble guanylate cyclase (sGC)] failed to induce anti-convulsant action with adenosine (50 mg/kg i.p.) against pentylenetetrazol i.v. infusion. The results demonstrated that the anti-convulsant action of adenosine in the pentylenetetrazol i.v. seizure threshold paradigm may possibly involve an interaction with the L-arginine-NO-cGMP pathway which may be secondary to the activation of adenosine receptors.
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Affiliation(s)
- Kiran Kumar Akula
- Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh-160014, India
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Tuning adenosine A1 and A2A receptors activation mediates l-citrulline-induced inhibition of [3H]-acetylcholine release depending on nerve stimulation pattern. Neurochem Int 2008; 52:834-45. [DOI: 10.1016/j.neuint.2007.09.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 09/20/2007] [Accepted: 09/24/2007] [Indexed: 11/21/2022]
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