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Carpenter AW, Schoenfisch MH. Nitric oxide release: part II. Therapeutic applications. Chem Soc Rev 2012; 41:3742-52. [PMID: 22362384 DOI: 10.1039/c2cs15273h] [Citation(s) in RCA: 658] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A wide range of nitric oxide (NO)-releasing materials has emerged as potential therapeutics that exploit NO's vast biological roles. Macromolecular NO-releasing scaffolds are particularly promising due to their ability to store and deliver larger NO payloads in a more controlled and effective manner compared to low molecular weight NO donors. While a variety of scaffolds (e.g., particles, dendrimers, and polymers/films) have been cleverly designed, the ultimate clinical utility of most NO-releasing macromolecules remains unrealized. Although not wholly predictive of clinical success, in vitro and in vivo investigations have enabled a preliminary evaluation of the therapeutic potential of such materials. In this tutorial review, we review the application of macromolecular NO therapies for cardiovascular disease, cancer, bacterial infections, and wound healing.
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Affiliation(s)
- Alexis W Carpenter
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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302
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The Regulation of a Cell’s Ca2+ Signaling Toolkit: The Ca2+ Homeostasome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1-25. [DOI: 10.1007/978-94-007-2888-2_1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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303
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Akowuah GA, Ismail Z, Ahmad M. HPLC–TOF/MS profile and nitric oxide scavenging activity of Orthosiphon stamineus leaf extracts. Asian Pac J Trop Biomed 2012. [DOI: 10.1016/s2221-1691(12)60432-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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304
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Freire MAM, Faber J, Picanço-Diniz CW, Franca JG, Pereira A. Morphometric variability of nicotinamide adenine dinucleotide phosphate diaphorase neurons in the primary sensory areas of the rat. Neuroscience 2011; 205:140-53. [PMID: 22226695 DOI: 10.1016/j.neuroscience.2011.12.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 12/21/2022]
Abstract
Even though there is great regional variation in the distribution of inhibitory neurons in the mammalian isocortex, relatively little is known about their morphological differences across areal borders. To obtain a better understanding of particularities of inhibitory circuits in cortical areas that correspond to different sensory modalities, we investigated the morphometric differences of a subset of inhibitory neurons reactive to the enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) within the primary auditory (A1), somatosensory (S1), and visual (V1) areas of the rat. One hundred and twenty NADPH-d-reactive neurons from cortical layer IV (40 cells in each cortical area) were reconstructed using the Neurolucida system. We collected morphometric data on cell body area, dendritic field area, number of dendrites per branching order, total dendritic length, dendritic complexity (Sholl analysis), and fractal dimension. To characterize different cell groups based on morphology, we performed a cluster analysis based on the previously mentioned parameters and searched for correlations among these variables. Morphometric analysis of NADPH-d neurons allowed us to distinguish three groups of cells, corresponding to the three analyzed areas. S1 neurons have a higher morphological complexity than those found in both A1 and V1. The difference among these groups, based on cluster analysis, was mainly related to the size and complexity of dendritic branching. A principal component analysis (PCA) applied to the data showed that area of dendritic field and fractal dimension are the parameters mostly responsible for dataset variance among the three areas. Our results suggest that the nitrergic cortical circuitry of primary sensory areas of the rat is differentially specialized, probably reflecting peculiarities of both habit and behavior of the species.
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Affiliation(s)
- M A M Freire
- Laboratory of Neurodegeneration and Infection, João de Barros Barreto Universitary Hospital, Federal University of Pará, 66073-000 Belém, PA, Brazil
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305
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Inkielewicz-Stepniak I, Radomski MW, Wozniak M. Fisetin prevents fluoride- and dexamethasone-induced oxidative damage in osteoblast and hippocampal cells. Food Chem Toxicol 2011; 50:583-9. [PMID: 22198064 DOI: 10.1016/j.fct.2011.12.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/07/2011] [Accepted: 12/10/2011] [Indexed: 01/03/2023]
Abstract
Fluoride intoxication and dexamethasone treatment produce deleterious effects in bone and brain. The aim of this study was to evaluate the effect of fluoride (F) and dexamethasone (Dex) co-exposure on oxidative stress and apoptosis in osteoblast-like MC3T3-E1 and hippocampal HT22 cell lines. Co-exposure to F and Dex resulted in a concentration-dependent decrease in cell viability, induction of apoptosis and increased generation of reactive oxygen species (ROS) and nitric oxide (NO) following 72 h of incubation. Fluoride-induced apoptosis in MC3T3-E1 and HT22 cells was attenuated by catalase and L-NNMA, indicating a role for H2O2 and NO as mediators of cytotoxicity. Dexamethasone-induced apoptosis was associated with H2O2 generation in both cell lines and it was attenuated during co-incubation with catalase. These data indicate that co-exposure to F and Dex amplifies their respective cytotoxicity in H2O2- and NO-dependent manner. As flavonoid fisetin prevented F- and Dex-induced cytotoxicity the potential role of this product in pharmacology and diet may be considered.
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306
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Silva M, Aguiar DC, Diniz CRA, Guimarães FS, Joca SRL. Neuronal NOS Inhibitor and Conventional Antidepressant Drugs Attenuate Stress-induced Fos Expression in Overlapping Brain Regions. Cell Mol Neurobiol 2011; 32:443-53. [DOI: 10.1007/s10571-011-9775-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/15/2011] [Indexed: 01/22/2023]
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307
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Sultana R. Ferulic acid ethyl ester as a potential therapy in neurodegenerative disorders. Biochim Biophys Acta Mol Basis Dis 2011; 1822:748-52. [PMID: 22064438 DOI: 10.1016/j.bbadis.2011.10.015] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 12/11/2022]
Abstract
Oxidative stress is involved in the onset, progression and pathogenesis of a number of diseases including neurodegenerative diseases. It is critical to develop a pharmacological approach to combat oxidative stress which may reduce the risk of diseases and help in promoting healthy life. In an attempt to reduce the side effects associated with allopathic medicines a number of studies are now focusing on developing treatment regimens from naturally occurring plant products. In this review, the protective role of ferulic acid (4-hydroxy-3-methoxycinnamic acid) (FA), a naturally occurring antioxidant compound found in fruit, some vegetables, and grains, and its ethyl ester derivative are discussed with respect to neurodegeneration. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.
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Affiliation(s)
- Rukhsana Sultana
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA.
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308
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Keilhoff G. nNOS deficiency-induced cell proliferation depletes the neurogenic reserve. Neurosci Lett 2011; 505:248-53. [PMID: 22027181 DOI: 10.1016/j.neulet.2011.10.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 09/30/2011] [Accepted: 10/12/2011] [Indexed: 12/23/2022]
Abstract
The consequences of nitric oxide synthase (NOS) gene knockout on proliferation, survival and differentiation of neuronal precursors in the subgranular (SGZ) and subventricular (SVZ) zones were analyzed. Comparative studies were performed in neonatal, adult and old (18-month) wild-type (WT), nNOS, eNOS, and iNOS knockout (KO) mice. Effects on brain cell proliferation were studied by sacrificing animals at 24h after injecting BrdU, while effects on survival and differentiation of dividing brain cells were studied by sacrificing other animals at three weeks after injections and double immunostaining with cell phenotype-specific antibodies. In the neonatal SGZ, cell proliferation was higher than at any other age, with a significantly decreased level in eNOS-KO mice. In the neonatal SVZ, cell proliferation in each of the three NOS-KO strains was significantly lower than in WT. In the adult, in both the SGZ and SVZ, all strains showed lower levels of cell proliferation than in neonates. Thereby, the significant highest cell proliferation was found in the SGZ and SVZ of nNOS-KO mice. In the SGZ and SVZ of old mice, in each strain, BrdU-positive cell counts were further reduced from adult levels, whereby cell proliferation of nNOS-KO mice attained the most massive reduction (in the SGZ almost to zero). In adult animals sacrificed 21 days after BrdU injections, values of BrdU-/NeuN-positive cells in all knockout animals were the same as WT, indicating that the initial cell proliferation changes were not sustained or translated into neuronal differentiation. The effect of nNOS-KO, inducing cell proliferation only temporarily, consists with the concept that neuronal stem cells have a finite proliferation capacity.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, University of Magdeburg, Leipziger Strasse 44, 39114 Magdeburg, Germany.
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309
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Steinert JR, Robinson SW, Tong H, Haustein MD, Kopp-Scheinpflug C, Forsythe ID. Nitric oxide is an activity-dependent regulator of target neuron intrinsic excitability. Neuron 2011; 71:291-305. [PMID: 21791288 PMCID: PMC3245892 DOI: 10.1016/j.neuron.2011.05.037] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2011] [Indexed: 02/07/2023]
Abstract
Activity-dependent changes in synaptic strength are well established as mediating long-term plasticity underlying learning and memory, but modulation of target neuron excitability could complement changes in synaptic strength and regulate network activity. It is thought that homeostatic mechanisms match intrinsic excitability to the incoming synaptic drive, but evidence for involvement of voltage-gated conductances is sparse. Here, we show that glutamatergic synaptic activity modulates target neuron excitability and switches the basis of action potential repolarization from Kv3 to Kv2 potassium channel dominance, thereby adjusting neuronal signaling between low and high activity states, respectively. This nitric oxide-mediated signaling dramatically increases Kv2 currents in both the auditory brain stem and hippocampus (>3-fold) transforming synaptic integration and information transmission but with only modest changes in action potential waveform. We conclude that nitric oxide is a homeostatic regulator, tuning neuronal excitability to the recent history of excitatory synaptic inputs over intervals of minutes to hours.
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Affiliation(s)
- Joern R Steinert
- Neurotoxicity at the Synaptic Interface, MRC Toxicology Unit, Hodgkin Building, University of Leicester, Leicester LE1 9HN, UK
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310
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A metronidazole-resistant isolate of Blastocystis spp. is susceptible to nitric oxide and downregulates intestinal epithelial inducible nitric oxide synthase by a novel parasite survival mechanism. Infect Immun 2011; 79:5019-26. [PMID: 21930763 DOI: 10.1128/iai.05632-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Blastocystis, one of the most common parasites colonizing the human intestine, is an extracellular, noninvasive, luminal protozoan with controversial pathogenesis. Blastocystis infections can be asymptomatic or cause intestinal symptoms of vomiting, diarrhea, and abdominal pain. Although chronic infections are frequently reported, Blastocystis infections have also been reported to be self-limiting in immunocompetent patients. Characterizing the host innate response to Blastocystis would lead to a better understanding of the parasite's pathogenesis. Intestinal epithelial cells produce nitric oxide (NO), primarily on the apical side, in order to target luminal pathogens. In this study, we show that NO production by intestinal cells may be a host defense mechanism against Blastocystis. Two clinically relevant isolates of Blastocystis, ST-7 (B) and ST-4 (WR-1), were found to be susceptible to a range of NO donors. ST-7 (B), a metronidazole-resistant isolate, was found to be more sensitive to nitrosative stress. Using the Caco-2 model of human intestinal epithelium, Blastocystis ST-7 (B) but not ST-4 (WR-1) exhibited dose-dependent inhibition of Caco-2 NO production, and this was associated with downregulation of inducible nitric oxide synthase (iNOS). Despite its higher susceptibility to NO, Blastocystis ST-7 (B) may have evolved unique strategies to evade this potential host defense by depressing host NO production. This is the first study to highlight a strain-to-strain variation in the ability of Blastocystis to evade the host antiparasitic NO response.
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311
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Montezuma K, Biojone C, Lisboa SF, Cunha FQ, Guimarães FS, Joca SRL. Inhibition of iNOS induces antidepressant-like effects in mice: pharmacological and genetic evidence. Neuropharmacology 2011; 62:485-91. [PMID: 21939674 DOI: 10.1016/j.neuropharm.2011.09.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 08/31/2011] [Accepted: 09/06/2011] [Indexed: 12/13/2022]
Abstract
Recent evidence has suggested that systemic administration of non-selective NOS inhibitors induces antidepressant-like effects in animal models. However, the precise involvement of the different NOS isoforms (neuronal-nNOS and inducible-iNOS) in these effects has not been clearly defined yet. Considering that mediators of the inflammatory response, that are able to induce iNOS expression, can be increased by exposure to stress, the aim of the present study was to investigate iNOS involvement in stress-induced behavioral consequences in the forced swimming test (FST), an animal model sensitive to antidepressant drugs. Therefore, we investigated the effects induced by systemic injection of aminoguanidine (preferential iNOS inhibitor), 1400W (selective iNOS inhibitor) or n-propyl-l-arginine (NPA, selective nNOS inhibitor) in mice submitted to the FST. We also investigated the behavior of mice with genetic deletion of iNOS (knockout) submitted to the FST. Aminoguanidine significantly decreased the immobility time (IT) in the FST. 1400W but not NPA, when administered at equivalent doses considering the magnitude of their Ki values for iNOS and nNOS, respectively, reduced the IT, thus suggesting that aminoguanidine-induced effects would be due to selective iNOS inhibition. Similarly, iNOS KO presented decreased IT in the FST when compared to wild-type mice. These results are the first to show that selective inhibition of iNOS or its knockdown induces antidepressant-like effects, therefore suggesting that iNOS-mediated NO synthesis is involved in the modulation of stress-induced behavioral consequences. Moreover, they further support NO involvement in the neurobiology of depression. This article is part of a Special Issue entitled 'Anxiety and Depression'.
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Affiliation(s)
- Karina Montezuma
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Brazil
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312
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Marcillac F, Brix B, Repond C, Jöhren O, Pellerin L. Nitric oxide induces the expression of the monocarboxylate transporter MCT4 in cultured astrocytes by a cGMP-independent transcriptional activation. Glia 2011; 59:1987-95. [PMID: 21901758 DOI: 10.1002/glia.21240] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/03/2011] [Indexed: 12/28/2022]
Abstract
The monocarboxylate transporter MCT4 is a proton-linked carrier particularly important for lactate release from highly glycolytic cells. In the central nervous system, MCT4 is exclusively expressed by astrocytes. Surprisingly, MCT4 expression in primary cultures of mouse cortical astrocytes is conspicuously low, suggesting that an external, nonastrocytic signal is necessary to obtain the observed pattern of expression in vivo. Here, we demonstrate that nitric oxide (NO), delivered by various NO donors, time- and dose-dependently induces MCT4 expression in cultured cortical astrocytes both at the mRNA and protein levels. In contrast, NO does not enhance the expression of MCT1, the other astrocytic monocarboxylate transporter. The transcriptional effect of NO is not mediated by a cGMP-dependent mechanism as shown by the absence of effect of a cGMP analog or of a selective guanylate cyclase inhibitor. NO causes an increase in astrocytic lactate transport capacity which requires the enhancement of MCT4 expression as both are prevented by the use of a specific siRNA against MCT4. In addition, cumulated lactate release by astrocytes over a period of 24 h was also enhanced by NO treatment. Our data suggest that NO represents a putative intercellular signal to control MCT4 expression in astrocytes and in doing so, to facilitate lactate transfer to other surrounding cell types in the central nervous system. © 2011 Wiley-Liss, Inc.
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Affiliation(s)
- Fabrice Marcillac
- Département de Physiologie, Université de Lausanne, CH-1005 Lausanne, Switzerland
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313
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Santos RM, Lourenço CF, Gerhardt GA, Cadenas E, Laranjinha J, Barbosa RM. Evidence for a pathway that facilitates nitric oxide diffusion in the brain. Neurochem Int 2011; 59:90-6. [DOI: 10.1016/j.neuint.2011.05.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/11/2011] [Accepted: 05/13/2011] [Indexed: 11/17/2022]
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314
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Abstract
The physiologically active form of vitamin D, 1,25-dihydroxyvitamin D(3), is a fat-soluble steroid hormone with a well established role in skeletal health. A growing body of evidence suggests low vitamin D levels also play a role in the pathogenesis of a wide range of non-skeletal, age-associated diseases including cancer, heart disease, type 2 diabetes mellitus and stroke. Low levels of serum 25-hydroxyvitamin D [25(OH)D], a stable marker of vitamin D status, are also associated with increased odds of prevalent cognitive dysfunction, Alzheimer's disease and all-cause dementia in a number of studies, raising the possibility that vitamin D plays a role in the aetiology of cognitive dysfunction and dementia. To date, the majority of human studies reporting associations between vitamin D and cognition or dementia have been cross-sectional or case-control designs that do not permit us to exclude the possibility that such associations are a result of disease progression rather than being causal. Animal and in vitro experiments have identified a number of neuroprotective mechanisms that might link vitamin D status to cognitive dysfunction and dementia, including vasoprotection and amyloid phagocytosis and clearance, but the clinical relevance of these mechanisms in humans is not currently clear. Two recent, large, prospective studies go some way to establish the temporal relationship with cognitive decline. The relative risk of cognitive decline was 60% higher (relative risk = 1.6, 95% CI 1.2, 2.0) in elderly Italian adults with severely deficient 25(OH)D levels (<25 nmol/L) when compared with those with sufficient levels (≥75 nmol/L). Similarly, the odds of cognitive decline were 41% higher (odds ratio = 1.4, 95% CI 0.9, 2.2) when elderly US men in the lowest quartile (≤49.7 nmol/L) were compared with those in the highest quartile (≥74.4 nmol/L). To our knowledge, no prospective studies have examined the association between 25(OH)D levels and incident dementia or neuroimaging abnormalities. The possible therapeutic benefits of vitamin D have attracted considerable interest as over 1 billion people worldwide are thought to have insufficient 25(OH)D levels and these levels can be increased using inexpensive and well tolerated dietary supplements. However, no large randomized controlled trials have yet examined the effect of vitamin D supplements on cognitive decline or incident dementia. Further studies are urgently needed to establish which mechanisms have clinical relevance in human populations and whether vitamin D supplements are effective at minimizing cognitive decline or preventing dementia.
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Affiliation(s)
- Andy P Dickens
- Peninsula Collaboration for Leadership in Applied Health Research and Care, Peninsula College of Medicine & Dentistry, University of Exeter, Exeter, UK
| | - Iain A Lang
- Peninsula Collaboration for Leadership in Applied Health Research and Care, Peninsula College of Medicine & Dentistry, University of Exeter, Exeter, UK
| | - Kenneth M Langa
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
,Institute for Social Research, University of Michigan, Ann Arbor, Michigan, USA
,Department of Veterans Affairs, VA Center for Practice Management and Outcomes Research, VA Ann Arbor Healthcare System, Michigan, Ann Arbor, USA
| | - Katarina Kos
- Institute of Biomedical and Clinical Science, Peninsula College of Medicine & Dentistry, University of Exeter, Exeter, UK
| | - David J Llewellyn
- Institute of Biomedical and Clinical Science, Peninsula College of Medicine & Dentistry, University of Exeter, Exeter, UK
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315
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Sardella T, Polgár E, Watanabe M, Todd A. A quantitative study of neuronal nitric oxide synthase expression in laminae I-III of the rat spinal dorsal horn. Neuroscience 2011; 192:708-20. [PMID: 21763759 PMCID: PMC3183229 DOI: 10.1016/j.neuroscience.2011.07.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/30/2011] [Accepted: 07/01/2011] [Indexed: 02/02/2023]
Abstract
Nitric oxide produced by neuronal nitric oxide synthase (nNOS) in the spinal cord is required for development of hyperalgesia in inflammatory and neuropathic pain states. nNOS is expressed by some dorsal horn neurons, and an early study that used a histochemical method to identify these cells suggested that they were mainly inhibitory interneurons. We have carried out a quantitative analysis of nNOS-immunoreactivity in laminae I-III of the rat dorsal horn, to determine the proportion of inhibitory and excitatory neurons and axonal boutons that express the protein. nNOS was present in ∼5% of neurons in laminae I and III, and 18% of those in lamina II. Although most cells with strong nNOS immunostaining were GABA-immunoreactive, two-thirds of the nNOS-positive cells in lamina II and half of those in lamina III were not GABAergic, and some of these expressed protein kinase Cγ (PKCγ). We estimate that nNOS is present in 17-19% of the inhibitory interneurons in laminae I-II, and 6% of those in lamina III. However, our results suggest that nNOS is also expressed at a relatively low level by a significant proportion (∼17%) of excitatory interneurons in lamina II. nNOS was seldom seen in boutons that contained vesicular glutamate transporter 2, which is expressed by excitatory interneurons, but was co-localised with the vesicular GABA transporter (VGAT, a marker for GABAergic and glycinergic axons). nNOS was detected in 13% of VGAT boutons in lamina I and in 7-8% of those in laminae II-III. However, it was only found in 2-4% of the VGAT boutons that were presynaptic to PKCγ-expressing interneurons in this region. These results indicate that nNOS is more widely expressed than previously thought, being present in both inhibitory and excitatory neurons. They provide further evidence that axons of neurochemically defined populations of inhibitory interneuron are selective in their post-synaptic targets.
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Affiliation(s)
- T.C.P. Sardella
- Institute of Neuroscience and Psychology, West Medical Building, University Avenue, University of Glasgow, Glasgow, G12 8QQ, UK
| | - E. Polgár
- Institute of Neuroscience and Psychology, West Medical Building, University Avenue, University of Glasgow, Glasgow, G12 8QQ, UK
| | - M. Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - A.J. Todd
- Institute of Neuroscience and Psychology, West Medical Building, University Avenue, University of Glasgow, Glasgow, G12 8QQ, UK
- Corresponding author. Tel: +44-141-330-5868; fax: +44-141-330-2868
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316
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Kuo CS, Kwan CY, Gong CL, Tsai MF, Nishibe S, Tatsuzaki J, Leung YM. Apocynum venetum leaf aqueous extract inhibits voltage-gated sodium channels of mouse neuroblastoma N2A cells. JOURNAL OF ETHNOPHARMACOLOGY 2011; 136:149-155. [PMID: 21530630 DOI: 10.1016/j.jep.2011.04.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/11/2011] [Accepted: 04/13/2011] [Indexed: 05/30/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Apocynum venetum Linn. (Apocynaceae family), also called Luobuma, is a shrub which grows widely in the Xinjiang Autonomous Region of China. Its leaves are used in herbal tea for the treatment of hypertension, anxiety and depression. Animal studies have also shown that Apocynum venetum leaf extract (AVLE) also exerts anti-depressant and anti-anxiety activities. The effects of AVLE on neuronal tissues in vitro are not fully understood. MATERIALS AND METHODS Using the whole-cell voltage-clamp method, we studied the effects of AVLE on ion channels in cultured mouse neuroblastoma N2A cells. RESULTS AVLE inhibited voltage-gated inward Na(+) current in a reversible and concentration-dependent manner (half-inhibitory concentration was 18 μg/ml and maximum inhibition at 100 μg/ml). AVLE specifically promoted steady-state inactivation of Na(+) channels but did not affect voltage-dependence of activation. The inhibitory effect was not use-dependent and was not affected by 300μM L-NAME, suggesting that NO was not involved in the action of AVLE in neuronal cells. AVLE also had a mild inhibitory effect on voltage-gated K(+) channels, but did not affect ATP-sensitive K(+) channels. CONCLUSIONS Since voltage-gated Na(+) and K(+) channels are associated with neuronal excitability and therefore affect neurotransmission, the modulation of neuronal ion channels by AVLE may exert neuropharmacological effects. In particular, the inhibition of voltage-gated Na(+) currents by AVLE may in part account for the psychopharmacological effects of this herbal remedy.
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Affiliation(s)
- Chang-Shin Kuo
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung 40402, Taiwan
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317
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Kopp-Scheinpflug C, Steinert JR, Forsythe ID. Modulation and control of synaptic transmission across the MNTB. Hear Res 2011; 279:22-31. [PMID: 21397677 DOI: 10.1016/j.heares.2011.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/04/2011] [Accepted: 02/27/2011] [Indexed: 12/13/2022]
Abstract
The aim of this review is to consider the various forms and functions of transmission across the calyx of Held/MNTB synapse and how its modulation might contribute to auditory processing. The calyx of Held synapse is the largest synapse in the mammalian brain which uses the conventional excitatory synaptic transmitter, glutamate. It is sometimes portrayed as the 'ultimate' in synaptic signalling: it is a synaptic relay in which a single axon forms one synaptic terminal onto one specific target neuron. Questions that are often raised are: "Why does such a large and secure synapse need any form of modulation? Surely it is built simply to guarantee firing an action potential in the target neuron? If this synapse is so secure, why is a synapse needed at all?" Investigating these questions explains some general limitations of transmission at synapses and provides insight into the ionic basis of neuronal function by bringing together in vivo and in vitro approaches. We will start by defining the firing behaviour of MNTB neurons in vitro (in response to synaptic stimulation or current injection) and in vivo (in response to sound) and examining the reasons for different types of firing under the two conditions. Then we will consider some of the mechanisms by which transmission can be regulated. We will finish by discussing the following hypothesis: modulation and adaptation of presynaptic and postsynaptic conductances at the calyx of Held relay synapse are aimed at maximising the security of sound onset encoding while providing secondary information on frequency spectrum, harmonic envelope and duration of sound throughout the later part of the response.
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Affiliation(s)
- Cornelia Kopp-Scheinpflug
- Neurotoxicity at the Synaptic Interface, MRC Toxicology Unit, Hodgkin Bldg, University of Leicester, Leicester LE1 9HN, UK
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318
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Schofield BR, Motts SD, Mellott JG. Cholinergic cells of the pontomesencephalic tegmentum: connections with auditory structures from cochlear nucleus to cortex. Hear Res 2010; 279:85-95. [PMID: 21195150 DOI: 10.1016/j.heares.2010.12.019] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 02/01/2023]
Abstract
Acetylcholine (ACh) is a neuromodulator that is likely to play a role in plasticity as well as other phenomena at many sites in the auditory system. The auditory cortex receives cholinergic innervation from the basal forebrain, whereas the cochlea receives cholinergic innervation from the superior olivary complex. Much of the remainder of the auditory pathways receives innervation from the pedunculopontine and laterodorsal tegmental nuclei, two nuclei referred to collectively as the pontomesencephalic tegmentum (PMT). The PMT provides the major source of ACh to the auditory thalamus and the midbrain, and is a substantial source (in addition to the superior olivary complex) of ACh in the cochlear nucleus. Individual cholinergic cells in the PMT often have axon branches that innervate multiple auditory nuclei, including nuclei on both sides of the brain as well as nuclei at multiple levels of the auditory system. The auditory cortex has direct axonal projections to the PMT cells, including cholinergic cells that project to the inferior colliculus or cochlear nucleus. The divergent projections of PMT cholinergic cells suggest widespread effects on the auditory pathways. These effects are likely to include plasticity as well as novelty detection, sensory gating, reward behavior, arousal and attention. Descending projections from the forebrain, including the auditory cortex, are likely to provide a high level of cognitive input to these cholinergic effects. Dysfunction associated with the cholinergic system may play a role in disorders such as tinnitus and schizophrenia.
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Affiliation(s)
- Brett R Schofield
- Department of Anatomy and Neurobiology, Northeastern Ohio Universities College of Medicine, PO Box 95, Rootstown, OH 44272, USA.
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319
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Zhang J, Boghossian AA, Barone PW, Rwei A, Kim JH, Lin D, Heller DA, Hilmer AJ, Nair N, Reuel NF, Strano MS. Single molecule detection of nitric oxide enabled by d(AT)15 DNA adsorbed to near infrared fluorescent single-walled carbon nanotubes. J Am Chem Soc 2010; 133:567-81. [PMID: 21142158 DOI: 10.1021/ja1084942] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the selective detection of single nitric oxide (NO) molecules using a specific DNA sequence of d(AT)(15) oligonucleotides, adsorbed to an array of near-infrared fluorescent semiconducting single-walled carbon nanotubes (AT(15)-SWNT). While SWNT suspended with eight other variant DNA sequences show fluorescence quenching or enhancement from analytes such as dopamine, NADH, L-ascorbic acid, and riboflavin, d(AT)(15) imparts SWNT with a distinct selectivity toward NO. In contrast, the electrostatically neutral polyvinyl alcohol enables no response to nitric oxide, but exhibits fluorescent enhancement to other molecules in the tested library. For AT(15)-SWNT, a stepwise fluorescence decrease is observed when the nanotubes are exposed to NO, reporting the dynamics of single-molecule NO adsorption via SWNT exciton quenching. We describe these quenching traces using a birth-and-death Markov model, and the maximum likelihood estimator of adsorption and desorption rates of NO is derived. Applying the method to simulated traces indicates that the resulting error in the estimated rate constants is less than 5% under our experimental conditions, allowing for calibration using a series of NO concentrations. As expected, the adsorption rate is found to be linearly proportional to NO concentration, and the intrinsic single-site NO adsorption rate constant is 0.001 s(-1) μM NO(-1). The ability to detect nitric oxide quantitatively at the single-molecule level may find applications in new cellular assays for the study of nitric oxide carcinogenesis and chemical signaling, as well as medical diagnostics for inflammation.
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Affiliation(s)
- Jingqing Zhang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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320
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Haustein MD, Read DJ, Steinert JR, Pilati N, Dinsdale D, Forsythe ID. Acute hyperbilirubinaemia induces presynaptic neurodegeneration at a central glutamatergic synapse. J Physiol 2010; 588:4683-93. [PMID: 20937712 DOI: 10.1113/jphysiol.2010.199778] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
There is a well-established link between hyperbilirubinaemia and hearing loss in paediatrics, but the cellular mechanisms have not been elucidated. Here we used the Gunn rat model of hyperbilirubinaemia to investigate bilirubin-induced hearing loss. In vivo auditory brainstem responses revealed that Gunn rats have severe auditory deficits within 18 h of exposure to high bilirubin levels. Using an in vitro preparation of the auditory brainstem from these rats, extracellular multi-electrode array recording from the medial nucleus of the trapezoid body (MNTB) showed longer latency and decreased amplitude of evoked field potentials following bilirubin exposure, suggestive of transmission failure at this synaptic relay. Whole-cell patch-clamp recordings confirmed that the electrophysiological properties of the postsynaptic MNTB neurons were unaffected by bilirubin, with no change in action potential waveforms or current-voltage relationships. However, stimulation of the trapezoid body was unable to elicit large calyceal EPSCs in MNTB neurons of hyperbilirubinaemic rats, indicative of damage at a presynaptic site. Multi-photon imaging of anterograde-labelled calyceal projections revealed axonal staining and presynaptic profiles around MNTB principal neuron somata. Following induction of hyperbilirubinaemia the giant synapses were largely destroyed. Electron microscopy confirmed loss of presynaptic calyceal terminals and supported the electrophysiological evidence for healthy postsynaptic neurons. MNTB neurons express high levels of neuronal nitric oxide synthase (nNOS). Nitric oxide has been implicated in mechanisms of bilirubin toxicity elsewhere in the brain, and antagonism of nNOS by 7-nitroindazole protected hearing during bilirubin exposure. We conclude that bilirubin-induced deafness is caused by degeneration of excitatory synaptic terminals in the auditory brainstem.
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Affiliation(s)
- Martin D Haustein
- Neurotoxicity at the Synaptic Interface, MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK.
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