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Sample records for acetylcholine enhances neural

  1. Acetylcholine is released from taste cells, enhancing taste signalling

    PubMed Central

    Dando, Robin; Roper, Stephen D

    2012-01-01

    Acetylcholine (ACh), a candidate neurotransmitter that has been implicated in taste buds, elicits calcium mobilization in Receptor (Type II) taste cells. Using RT-PCR analysis and pharmacological interventions, we demonstrate that the muscarinic acetylcholine receptor M3 mediates these actions. Applying ACh enhanced both taste-evoked Ca2+ responses and taste-evoked afferent neurotransmitter (ATP) secretion from taste Receptor cells. Blocking muscarinic receptors depressed taste-evoked responses in Receptor cells, suggesting that ACh is normally released from taste cells during taste stimulation. ACh biosensors confirmed that, indeed, taste Receptor cells secrete acetylcholine during gustatory stimulation. Genetic deletion of muscarinic receptors resulted in significantly diminished ATP secretion from taste buds. The data demonstrate a new role for acetylcholine as a taste bud transmitter. Our results imply specifically that ACh is an autocrine transmitter secreted by taste Receptor cells during gustatory stimulation, enhancing taste-evoked responses and afferent transmitter secretion. PMID:22570381

  2. Acetylcholine is released from taste cells, enhancing taste signalling.

    PubMed

    Dando, Robin; Roper, Stephen D

    2012-07-01

    Acetylcholine (ACh), a candidate neurotransmitter that has been implicated in taste buds, elicits calcium mobilization in Receptor (Type II) taste cells. Using RT-PCR analysis and pharmacological interventions, we demonstrate that the muscarinic acetylcholine receptor M3 mediates these actions. Applying ACh enhanced both taste-evoked Ca2+ responses and taste-evoked afferent neurotransmitter (ATP) secretion from taste Receptor cells. Blocking muscarinic receptors depressed taste-evoked responses in Receptor cells, suggesting that ACh is normally released from taste cells during taste stimulation. ACh biosensors confirmed that, indeed, taste Receptor cells secrete acetylcholine during gustatory stimulation. Genetic deletion of muscarinic receptors resulted in significantly diminished ATP secretion from taste buds. The data demonstrate a new role for acetylcholine as a taste bud transmitter. Our results imply specifically that ACh is an autocrine transmitter secreted by taste Receptor cells during gustatory stimulation, enhancing taste-evoked responses and afferent transmitter secretion.

  3. Acetylcholine mediates behavioral and neural post-error control.

    PubMed

    Danielmeier, Claudia; Allen, Elena A; Jocham, Gerhard; Onur, Oezguer A; Eichele, Tom; Ullsperger, Markus

    2015-06-01

    Humans often commit errors when they are distracted by irrelevant information and no longer focus on what is relevant to the task at hand. Adjustments following errors are essential for optimizing goal achievement. The posterior medial frontal cortex (pMFC), a key area for monitoring errors, has been shown to trigger such post-error adjustments by modulating activity in visual cortical areas. However, the mechanisms by which pMFC controls sensory cortices are unknown. We provide evidence for a mechanism based on pMFC-induced recruitment of cholinergic projections to task-relevant sensory areas. Using fMRI in healthy volunteers, we found that error-related pMFC activity predicted subsequent adjustments in task-relevant visual brain areas. In particular, following an error, activity increased in those visual cortical areas involved in processing task-relevant stimulus features, whereas activity decreased in areas representing irrelevant, distracting features. Following treatment with the muscarinic acetylcholine receptor antagonist biperiden, activity in visual areas was no longer under control of error-related pMFC activity. This was paralleled by abolished post-error behavioral adjustments under biperiden. Our results reveal a prominent role of acetylcholine in cognitive control that has not been recognized thus far. Regaining optimal performance after errors critically depends on top-down control of perception driven by the pMFC and mediated by acetylcholine. This may explain the lack of adaptivity in conditions with reduced availability of cortical acetylcholine, such as Alzheimer's disease.

  4. Caffeine potentiates the enhancement by choline of striatal acetylcholine release

    NASA Technical Reports Server (NTRS)

    Johnson, D. A.; Ulus, I. H.; Wurtman, R. J.

    1992-01-01

    We investigated the effect of peripherally administered caffeine (50 mg/kg), choline (30, 60, or 120 mg/kg) or combinations of both drugs on the spontaneous release of acetylcholine (ACh) from the corpus striatum of anesthetized rats using in vivo microdialysis. Caffeine alone or choline in the 30 or 60 mg/kg dose failed to increase ACh in microdialysis samples; the 120 mg/kg choline dose significantly enhanced ACh during the 80 min following drug administration. Coadministration of caffeine with choline significantly increased ACh release after each of the choline doses tested. Peak microdialysate levels with the 120 mg/kg dose were increased 112% when caffeine was additionally administered, as compared with 54% without caffeine. These results indicate that choline administration can enhance spontaneous ACh release from neurons, and that caffeine, a drug known to block adenosine receptors on these neurons, can amplify the choline effect.

  5. Neural regulation of acetylcholine receptors in rat neonatal muscle.

    PubMed Central

    Bambrick, L L; Gordon, T

    1992-01-01

    1. The neuronal regulation of the developmental decline in skeletal muscle acetylcholine (ACh) receptors was studied by comparing the effects of sciatic nerve section or of neuromuscular blockade with botulinum toxin (BoTX) on this decline in neonatal and adult rats, using 125I-alpha-bungarotoxin (125I-BTX) as a ligand for the receptor alpha-subunit. 2. The decline in 125I-BTX binding site concentration in neonatal rat triceps surae muscle homogenates towards low, adult levels followed a simple exponential with a time constant of 8 days. This decline occurred while the muscle is still rapidly growing, before the postnatal increase in numbers of sodium channels. It also preceded the decline in muscle ACh receptor alpha-subunit mRNA, reported in other studies, suggesting that subunit levels are not regulated only by mRNA availability. 3. Muscle denervation in the first two weeks of life prevented this developmental decline. Denervation increased the concentration of 125I-BTX binding sites but the magnitude of this increase became progressively smaller as the muscle matured, showing that removal of innervation during adult life does not revert the muscle, in toto, to its pre-innervation state. 4. Blockade of neuromuscular activity with BoTX increased 125I-BTX binding sites to a lesser extent than muscle denervation during neonatal life. This lesser effect of BoTX blockade contrasts with the equal effects of BoTX blockade and denervation in the adult. PMID:1522519

  6. Dynamical State Transition by Neuromodulation Due to Acetylcholine in Neural Network Model for Oscillatory Phenomena in Thalamus

    NASA Astrophysics Data System (ADS)

    Omori, Toshiaki; Horiguchi, Tsuyoshi

    2004-12-01

    We propose a two-layered neural network model for oscillatory phenomena in the thalamic system and investigate an effect of neuromodulation due to the acetylcholine on the oscillatory phenomena by numerical simulations. The proposed model consists of a layer of the thalamic reticular neurons and that of the cholinergic neurons. We introduce a dynamics of concentration of the acetylcholine which depends on a state of the cholinergic neurons, and assume that the conductance of the thalamic reticular neurons is dynamically regulated by the acetylcholine. From the results obtained by numerical simulations, we find that a dynamical transition between a bursting state and a resting state occurs successively in the layer of the thalamic reticular neurons due to the acetylcholine. Therefore it turns out that the neuromodulation due to the acetylcholine is important for the dynamical state transition in the thalamic system.

  7. Clitoria ternatea root extract enhances acetylcholine content in rat hippocampus.

    PubMed

    Rai, K S; Murthy, K D; Karanth, K S; Nalini, K; Rao, M S; Srinivasan, K K

    2002-12-01

    Treatment with 100 mg/kg of Clitoria ternatea aqueous root extract (CTR), for 30 days in neonatal and young adult age groups of rat, significantly increased acetylcholine (ACh) content in their hippocampi as compared to age matched controls. Increase in ACh content in their hippocampus may be the neurochemical basis for their improved learning and memory. PMID:12490229

  8. Enhanced role of potassium channels in relaxations to acetylcholine in hypercholesterolemic rabbit carotid artery.

    PubMed

    Najibi, S; Cowan, C L; Palacino, J J; Cohen, R A

    1994-05-01

    The effect of hypercholesterolemia for 10 wk on endothelium-dependent relaxations to acetylcholine was studied in isolated rings of rabbit carotid artery and abdominal aorta contracted with phenylephrine or elevated potassium. In these arteries obtained from hypercholesterolemic rabbits, endothelium-dependent relaxations to acetylcholine were not significantly different from those of normal rabbits. In normal and hypercholesterolemic arteries, partial relaxation persisted in the presence of NG-nitro-L-arginine methyl ester (L-NAME), which blocked acetylcholine-induced increases in arterial guanosine 3',5'-cyclic monophosphate (cGMP). Combined treatment with L-NAME and the calcium-dependent potassium-channel inhibitor, charybdotoxin, blocked relaxations in both groups, suggesting that L-NAME-resistant relaxations are mediated by an endothelium-derived hyperpolarizing factor. Charybdotoxin alone or depolarizing potassium had no significant effect on normal carotid artery or normal and hypercholesterolemic abdominal aorta but significantly inhibited relaxations of the carotid artery from cholesterol-fed rabbits. The enhanced role of calcium-dependent potassium channels and the hyperpolarizing factor in relaxation of the hypercholesterolemic carotid artery suggested by these results was likely related to the fact that acetylcholine failed to stimulate cGMP only in that artery. These data suggest that endothelium-dependent relaxation in these rabbit arteries is mediated by nitric oxide-cGMP-dependent and -independent mechanisms. In hypercholesterolemia, the contribution of nitric oxide-cGMP in the carotid artery is reduced, but a hyperpolarizing factor and calcium-dependent potassium channels maintain normal acetylcholine-induced relaxation. PMID:7515589

  9. Spintronic characteristics of self-assembled neurotransmitter acetylcholine molecular complexes enable quantum information processing in neural networks and brain

    NASA Astrophysics Data System (ADS)

    Tamulis, Arvydas; Majauskaite, Kristina; Kairys, Visvaldas; Zborowski, Krzysztof; Adhikari, Kapil; Krisciukaitis, Sarunas

    2016-09-01

    Implementation of liquid state quantum information processing based on spatially localized electronic spin in the neurotransmitter stable acetylcholine (ACh) neutral molecular radical is discussed. Using DFT quantum calculations we proved that this molecule possesses stable localized electron spin, which may represent a qubit in quantum information processing. The necessary operating conditions for ACh molecule are formulated in self-assembled dimer and more complex systems. The main quantum mechanical research result of this paper is that the neurotransmitter ACh systems, which were proposed, include the use of quantum molecular spintronics arrays to control the neurotransmission in neural networks.

  10. NeuroD1 mediates nicotine-induced migration and invasion via regulation of the nicotinic acetylcholine receptor subunits in a subset of neural and neuroendocrine carcinomas.

    PubMed

    Osborne, Jihan K; Guerra, Marcy L; Gonzales, Joshua X; McMillan, Elizabeth A; Minna, John D; Cobb, Melanie H

    2014-06-01

    Cigarette smoking is a major risk factor for acquisition of small cell lung cancer (SCLC). A role has been demonstrated for the basic helix-loop-helix transcription factor NeuroD1 in the pathogenesis of neural and neuroendocrine lung cancer, including SCLC. In the present study we investigate the possible function of NeuroD1 in established tumors, as well as actions early on in pathogenesis, in response to nicotine. We demonstrate that nicotine up-regulates NeuroD1 in immortalized normal bronchial epithelial cells and a subset of undifferentiated carcinomas. Increased expression of NeuroD1 subsequently leads to regulation of expression and function of the nicotinic acetylcholine receptor subunit cluster of α3, α5, and β4. In addition, we find that coordinated expression of these subunits by NeuroD1 leads to enhanced nicotine-induced migration and invasion, likely through changes in intracellular calcium. These findings suggest that aspects of the pathogenesis of neural and neuroendocrine lung cancers may be affected by a nicotine- and NeuroD1-induced positive feedback loop.

  11. NeuroD1 mediates nicotine-induced migration and invasion via regulation of the nicotinic acetylcholine receptor subunits in a subset of neural and neuroendocrine carcinomas

    PubMed Central

    Osborne, Jihan K.; Guerra, Marcy L.; Gonzales, Joshua X.; McMillan, Elizabeth A.; Minna, John D.; Cobb, Melanie H.

    2014-01-01

    Cigarette smoking is a major risk factor for acquisition of small cell lung cancer (SCLC). A role has been demonstrated for the basic helix-loop-helix transcription factor NeuroD1 in the pathogenesis of neural and neuroendocrine lung cancer, including SCLC. In the present study we investigate the possible function of NeuroD1 in established tumors, as well as actions early on in pathogenesis, in response to nicotine. We demonstrate that nicotine up-regulates NeuroD1 in immortalized normal bronchial epithelial cells and a subset of undifferentiated carcinomas. Increased expression of NeuroD1 subsequently leads to regulation of expression and function of the nicotinic acetylcholine receptor subunit cluster of α3, α5, and β4. In addition, we find that coordinated expression of these subunits by NeuroD1 leads to enhanced nicotine-induced migration and invasion, likely through changes in intracellular calcium. These findings suggest that aspects of the pathogenesis of neural and neuroendocrine lung cancers may be affected by a nicotine- and NeuroD1-induced positive feedback loop. PMID:24719457

  12. Subtype-selective nicotinic acetylcholine receptor agonists enhance the responsiveness to citalopram and reboxetine in the mouse forced swim test.

    PubMed

    Andreasen, Jesper T; Nielsen, Elsebet Ø; Christensen, Jeppe K; Olsen, Gunnar M; Peters, Dan; Mirza, Naheed R; Redrobe, John P

    2011-10-01

    Nicotine increases serotonergic and noradrenergic neuronal activity and facilitates serotonin and noradrenaline release. Accordingly, nicotine enhances antidepressant-like actions of reuptake inhibitors selective for serotonin or noradrenaline in the mouse forced swim test and the mouse tail suspension test. Both high-affinity α4β2 and low-affinity α7 nicotinic acetylcholine receptor subtypes are implicated in nicotine-mediated release of serotonin and noradrenaline. The present study therefore investigated whether selective agonism of α4β2 or α7 nicotinic acetylcholine receptors would affect the mouse forced swim test activity of two antidepressants with distinct mechanisms of action, namely the selective serotonin reuptake inhibitor citalopram and the noradrenaline reuptake inhibitor reboxetine. Subthreshold and threshold doses of citalopram (3 and 10 mg/kg) or reboxetine (10 and 20 mg/kg) were tested alone and in combination with the novel α4β2-selective partial nicotinic acetylcholine receptor agonist, NS3956 (0.3 and 1.0 mg/kg) or the α7-selective nicotinic acetylcholine receptor agonist, PNU-282987 (10 and 30 mg/kg). Alone, NS3956 and PNU-282987 were devoid of activity in the mouse forced swim test, but both 1.0 mg/kg NS3956 and 30 mg/kg PNU-282987 enhanced the effect of citalopram and also reboxetine. The data suggest that the activity of citalopram and reboxetine in the mouse forced swim test can be enhanced by agonists at either α4β2 or α7 nicotinic acetylcholine receptors, suggesting that both nicotinic acetylcholine receptor subtypes may be involved in the nicotine-enhanced action of antidepressants.

  13. AzoCholine Enables Optical Control of Alpha 7 Nicotinic Acetylcholine Receptors in Neural Networks.

    PubMed

    Damijonaitis, Arunas; Broichhagen, Johannes; Urushima, Tatsuya; Hüll, Katharina; Nagpal, Jatin; Laprell, Laura; Schönberger, Matthias; Woodmansee, David H; Rafiq, Amir; Sumser, Martin P; Kummer, Wolfgang; Gottschalk, Alexander; Trauner, Dirk

    2015-05-20

    Nicotinic acetylcholine receptors (nAChRs) are essential for cellular communication in higher organisms. Even though a vast pharmacological toolset to study cholinergic systems has been developed, control of endogenous neuronal nAChRs with high spatiotemporal precision has been lacking. To address this issue, we have generated photoswitchable nAChR agonists and re-evaluated the known photochromic ligand, BisQ. Using electrophysiology, we found that one of our new compounds, AzoCholine, is an excellent photoswitchable agonist for neuronal α7 nAChRs, whereas BisQ was confirmed to be an agonist for the muscle-type nAChR. AzoCholine could be used to modulate cholinergic activity in a brain slice and in dorsal root ganglion neurons. In addition, we demonstrate light-dependent perturbation of behavior in the nematode, Caenorhabditis elegans. PMID:25741856

  14. The structural requirements for phorbol esters to enhance serotonin and acetylcholine release from rat brain cortex

    PubMed Central

    Iannazzo, L; Kotsonis, P; Majewski, H

    1999-01-01

    The effects of various phorbol-based protein kinase C (PKC) activators on the electrical stimulation-induced (S-I) release of serotonin and acetylcholine was studied in rat brain cortical slices pre-incubated with [3H]-serotonin or [3H]-choline to investigate possible structure-activity relationships. 4β-Phorbol 12,13-dibutyrate (4βPDB, 0.1–3.0 μM), enhanced S-I release of serotonin in a concentration-dependent manner whereas the structurally related inactive isomer 4α-phorbol 12, 13-dibutyrate (4αPDB) and phorbol 13-acetate (PA) were without effect. Another group of phorbol esters containing a common 13-ester substituent (phorbol 12,13-diacetate, PDA; phorbol 12-myristate 13-acetate, PMA; phorbol 12-methylaminobenzoate 13-acetate, PMBA) also enhanced S-I serotonin release with PMA being least potent. The deoxyphorbol monoesters, 12-deoxyphorbol 13-acetate (dPA), 12-deoxyphorbol 13-angelate (dPAng), 12-deoxyphorbol 13-phenylacetate (dPPhen) and 12-deoxyphorbol 13-isobutyrate (dPiB) enhanced S-I serotonin release but 12-deoxyphorbol 13-tetradecanoate (dPT) was without effect. The 20-acetate derivatives of dPPhen and dPAng were less effective in enhancing S-I serotonin release compared to the parent compounds. With acetylcholine release all phorbol esters tested had a far lesser effect when compared to their facilitatory action on serotonin release with only 4βPDB, PDA, dPA, dPAng and dPiB having significant effects. The effects of the phorbol esters on serotonin release were not correlated with their reported in vitro affinity and isozyme selectivity for PKC. A comparison across three transmitter systems (noradrenaline, dopamine, serotonin) suggests basic similarities in the structural requirements of phorbol esters to enhance transmitter release with short chain substituted mono- and diesters of phorbol being more potent facilitators of release than the long chain esters. Some compounds notably PDA, PMBA, dPPhen, dPPhenA had different potencies across

  15. Prenatal stress enhances stress- and corticotropin-releasing factor-induced stimulation of hippocampal acetylcholine release in adult rats.

    PubMed

    Day, J C; Koehl, M; Deroche, V; Le Moal, M; Maccari, S

    1998-03-01

    There is growing evidence that stressors occurring during pregnancy can impair biological and behavioral responses to stress in the adult offspring. For instance, prenatal stress enhances emotional reactivity, anxiety, and depressive-like behaviors associated with a prolonged stress-induced corticosterone secretion and a reduction in hippocampal corticosteroid receptors. Among the neurotransmitters involved in these hormonal and behavioral responses, acetylcholine may play a critical role. However, it is unknown whether prenatal stressful events also may influence the development of cholinergic systems. In the present study, hippocampal acetylcholine was measured, by in vivo microdialysis, in both male and female adult prenatally stressed rats, under basal conditions, after a mild stress (saline injection) or after intracerebroventricular administration of corticotropin-releasing factor (CRF; 0.1 nM). No difference in basal release of acetylcholine was observed between control and prenatally stressed rats of both genders. Mild stress was found to increase hippocampal acetylcholine release to a greater extent in prenatally stressed rats than in controls. In males, the CRF-induced increase in hippocampal acetylcholine release was larger in prenatally stressed rats, as compared with controls, during the first hour after the injection and in females during the third hour after the injection. These data indicate that prenatal stress has long-term effects on the development of forebrain cholinergic systems. The augmented increase in hippocampal acetylcholine release after the mild stress and CRF injection in prenatally stressed rats may be involved in some of the hormonal and behavioral abnormalities found in prenatally stressed rats. PMID:9465013

  16. Boosting visual cortex function and plasticity with acetylcholine to enhance visual perception

    PubMed Central

    Kang, Jun Il; Huppé-Gourgues, Frédéric; Vaucher, Elvire

    2014-01-01

    The cholinergic system is a potent neuromodulatory system that plays critical roles in cortical plasticity, attention and learning. In this review, we propose that the cellular effects of acetylcholine (ACh) in the primary visual cortex during the processing of visual inputs might induce perceptual learning; i.e., long-term changes in visual perception. Specifically, the pairing of cholinergic activation with visual stimulation increases the signal-to-noise ratio, cue detection ability and long-term facilitation in the primary visual cortex. This cholinergic enhancement would increase the strength of thalamocortical afferents to facilitate the treatment of a novel stimulus while decreasing the cortico-cortical signaling to reduce recurrent or top-down modulation. This balance would be mediated by different cholinergic receptor subtypes that are located on both glutamatergic and GABAergic neurons of the different cortical layers. The mechanisms of cholinergic enhancement are closely linked to attentional processes, long-term potentiation (LTP) and modulation of the excitatory/inhibitory balance. Recently, it was found that boosting the cholinergic system during visual training robustly enhances sensory perception in a long-term manner. Our hypothesis is that repetitive pairing of cholinergic and sensory stimulation over a long period of time induces long-term changes in the processing of trained stimuli that might improve perceptual ability. Various non-invasive approaches to the activation of the cholinergic neurons have strong potential to improve visual perception. PMID:25278848

  17. Enhancing neural-network performance via assortativity

    SciTech Connect

    Franciscis, Sebastiano de; Johnson, Samuel; Torres, Joaquin J.

    2011-03-15

    The performance of attractor neural networks has been shown to depend crucially on the heterogeneity of the underlying topology. We take this analysis a step further by examining the effect of degree-degree correlations - assortativity - on neural-network behavior. We make use of a method recently put forward for studying correlated networks and dynamics thereon, both analytically and computationally, which is independent of how the topology may have evolved. We show how the robustness to noise is greatly enhanced in assortative (positively correlated) neural networks, especially if it is the hub neurons that store the information.

  18. Enhancing neural-network performance via assortativity.

    PubMed

    de Franciscis, Sebastiano; Johnson, Samuel; Torres, Joaquín J

    2011-03-01

    The performance of attractor neural networks has been shown to depend crucially on the heterogeneity of the underlying topology. We take this analysis a step further by examining the effect of degree-degree correlations--assortativity--on neural-network behavior. We make use of a method recently put forward for studying correlated networks and dynamics thereon, both analytically and computationally, which is independent of how the topology may have evolved. We show how the robustness to noise is greatly enhanced in assortative (positively correlated) neural networks, especially if it is the hub neurons that store the information.

  19. Burst Firing Enhances Neural Output Correlation

    PubMed Central

    Chan, Ho Ka; Yang, Dong-Ping; Zhou, Changsong; Nowotny, Thomas

    2016-01-01

    Neurons communicate and transmit information predominantly through spikes. Given that experimentally observed neural spike trains in a variety of brain areas can be highly correlated, it is important to investigate how neurons process correlated inputs. Most previous work in this area studied the problem of correlation transfer analytically by making significant simplifications on neural dynamics. Temporal correlation between inputs that arises from synaptic filtering, for instance, is often ignored when assuming that an input spike can at most generate one output spike. Through numerical simulations of a pair of leaky integrate-and-fire (LIF) neurons receiving correlated inputs, we demonstrate that neurons in the presence of synaptic filtering by slow synapses exhibit strong output correlations. We then show that burst firing plays a central role in enhancing output correlations, which can explain the above-mentioned observation because synaptic filtering induces bursting. The observed changes of correlations are mostly on a long time scale. Our results suggest that other features affecting the prevalence of neural burst firing in biological neurons, e.g., adaptive spiking mechanisms, may play an important role in modulating the overall level of correlations in neural networks. PMID:27242499

  20. Activation of α7 nicotinic acetylcholine receptors persistently enhances hippocampal synaptic transmission and prevents Aß-mediated inhibition of LTP in the rat hippocampus.

    PubMed

    Ondrejcak, Tomas; Wang, Qinwen; Kew, James N C; Virley, David J; Upton, Neil; Anwyl, Roger; Rowan, Michael J

    2012-02-29

    Nicotinic acetylcholine receptors mediate fast cholinergic modulation of glutamatergic transmission and synaptic plasticity. Here we investigated the effects of subtype selective activation of the α7 nicotinic acetylcholine receptors on hippocampal transmission and the inhibition of synaptic long-term potentiation by the Alzheimer's disease associated amyloid ß-protein (Aß). The α7 nicotinic acetylcholine receptor agonist "compound A" ((R)-N-(1-azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl))thiophene-2-carboxamide) induced a rapid-onset persistent enhancement of synaptic transmission in the dentate gyrus in vitro. Consistent with a requirement for activation of α7 nicotinic acetylcholine receptors, the type II α7-selective positive allosteric modulator PheTQS ((3aR, 4S, 9bS)-4-(4-methylphenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide) potentiated, and the antagonist methyllycaconitine (MLA) prevented the persistent enhancement. Systemic injection of the agonist also induced a similar MLA-sensitive persistent enhancement of synaptic transmission in the CA1 area in vivo. Remarkably, although compound A did not affect control long-term potentiation (LTP) in vitro, it prevented the inhibition of LTP by Aß1-42 and this effect was inhibited by MLA. These findings strongly indicate that activation of α7 nicotinic acetylcholine receptors is sufficient to persistently enhance hippocampal synaptic transmission and to overcome the inhibition of LTP by Aß.

  1. Thymus cells in myasthenia gravis selectively enhance production of anti-acetylcholine-receptor antibody by autologous blood lymphocytes

    SciTech Connect

    Newsom-Davis, J.; Willcox, N.; Calder, L.

    1981-11-26

    We investigated the role of the thymus in 16 patients with myasthenia gravis without thymoma by studying the production of anti-acetylcholine-receptor antibody by thymic and blood lymphocytes cultured alone or together. In 10 responders (with the highest receptor-antibody titers in their plasma), cultured thymic cells spontaneously produced measurable receptor antibody. Receptor-antibody production by autologous blood lymphocytes was enhanced by the addition of responder's thymic cells, irradiated to abrogate antibody production and suppression (P<0.01). This enhancement was greater and more consistent than that by pokeweed mitogen; it depended on viable thymic cells, appeared to be selective for receptor antibody, and correlated with the ratio of thymic helper (OKT4-positive or OKT4+) to suppressor (OKT8+) T cells (P<0.01). These results suggest that myasthenic thymus contains cell-bound acetylcholine-receptor-like material or specific T cells (or both) that can aid receptor-antibody production. This may be relevant to the benefits of thymectomy in myasthenia and to the breakdown in self-tolerance in this and other autoimmune diseases.

  2. Chronic exposure to nicotine enhances insulin sensitivity through α7 nicotinic acetylcholine receptor-STAT3 pathway.

    PubMed

    Xu, Tian-Ying; Guo, Ling-Ling; Wang, Pei; Song, Jie; Le, Ying-Ying; Viollet, Benoit; Miao, Chao-Yu

    2012-01-01

    This study was to investigate the effect of nicotine on insulin sensitivity and explore the underlying mechanisms. Treatment of Sprague-Dawley rats with nicotine (3 mg/kg/day) for 6 weeks reduced 43% body weight gain and 65% blood insulin level, but had no effect on blood glucose level. Both insulin tolerance test and glucose tolerance test demonstrated that nicotine treatment enhanced insulin sensitivity. Pretreatment of rats with hexamethonium (20 mg/kg/day) to antagonize peripheral nicotinic receptors except for α7 nicotinic acetylcholine receptor (α7-nAChR) had no effect on the insulin sensitizing effect of nicotine. However, the insulin sensitizing effect but not the bodyweight reducing effect of nicotine was abrogated in α7-nAChR knockout mice. Further, chronic treatment with PNU-282987 (0.53 mg/kg/day), a selective α7-nAChR agonist, significantly enhanced insulin sensitivity without apparently modifying bodyweight not only in normal mice but also in AMP-activated kinase-α2 knockout mice, an animal model of insulin resistance with no sign of inflammation. Moreover, PNU-282987 treatment enhanced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in skeletal muscle, adipose tissue and liver in normal mice. PNU-282987 treatment also increased glucose uptake by 25% in C2C12 myotubes and this effect was total abrogated by STAT3 inhibitor, S3I-201. All together, these findings demonstrated that nicotine enhanced insulin sensitivity in animals with or without insulin resistance, at least in part via stimulating α7-nAChR-STAT3 pathway independent of inflammation. Our results contribute not only to the understanding of the pharmacological effects of nicotine, but also to the identifying of new therapeutic targets against insulin resistance.

  3. High school music classes enhance the neural processing of speech.

    PubMed

    Tierney, Adam; Krizman, Jennifer; Skoe, Erika; Johnston, Kathleen; Kraus, Nina

    2013-01-01

    Should music be a priority in public education? One argument for teaching music in school is that private music instruction relates to enhanced language abilities and neural function. However, the directionality of this relationship is unclear and it is unknown whether school-based music training can produce these enhancements. Here we show that 2 years of group music classes in high school enhance the neural encoding of speech. To tease apart the relationships between music and neural function, we tested high school students participating in either music or fitness-based training. These groups were matched at the onset of training on neural timing, reading ability, and IQ. Auditory brainstem responses were collected to a synthesized speech sound presented in background noise. After 2 years of training, the neural responses of the music training group were earlier than at pre-training, while the neural timing of students in the fitness training group was unchanged. These results represent the strongest evidence to date that in-school music education can cause enhanced speech encoding. The neural benefits of musical training are, therefore, not limited to expensive private instruction early in childhood but can be elicited by cost-effective group instruction during adolescence.

  4. High school music classes enhance the neural processing of speech

    PubMed Central

    Tierney, Adam; Krizman, Jennifer; Skoe, Erika; Johnston, Kathleen; Kraus, Nina

    2013-01-01

    Should music be a priority in public education? One argument for teaching music in school is that private music instruction relates to enhanced language abilities and neural function. However, the directionality of this relationship is unclear and it is unknown whether school-based music training can produce these enhancements. Here we show that 2 years of group music classes in high school enhance the neural encoding of speech. To tease apart the relationships between music and neural function, we tested high school students participating in either music or fitness-based training. These groups were matched at the onset of training on neural timing, reading ability, and IQ. Auditory brainstem responses were collected to a synthesized speech sound presented in background noise. After 2 years of training, the neural responses of the music training group were earlier than at pre-training, while the neural timing of students in the fitness training group was unchanged. These results represent the strongest evidence to date that in-school music education can cause enhanced speech encoding. The neural benefits of musical training are, therefore, not limited to expensive private instruction early in childhood but can be elicited by cost-effective group instruction during adolescence. PMID:24367339

  5. Selective Activation of M4 Muscarinic Acetylcholine Receptors Reverses MK-801-Induced Behavioral Impairments and Enhances Associative Learning in Rodents

    PubMed Central

    2015-01-01

    Positive allosteric modulators (PAMs) of the M4 muscarinic acetylcholine receptor (mAChR) represent a novel approach for the treatment of psychotic symptoms associated with schizophrenia and other neuropsychiatric disorders. We recently reported that the selective M4 PAM VU0152100 produced an antipsychotic drug-like profile in rodents after amphetamine challenge. Previous studies suggest that enhanced cholinergic activity may also improve cognitive function and reverse deficits observed with reduced signaling through the N-methyl-d-aspartate subtype of the glutamate receptor (NMDAR) in the central nervous system. Prior to this study, the M1 mAChR subtype was viewed as the primary candidate for these actions relative to the other mAChR subtypes. Here we describe the discovery of a novel M4 PAM, VU0467154, with enhanced in vitro potency and improved pharmacokinetic properties relative to other M4 PAMs, enabling a more extensive characterization of M4 actions in rodent models. We used VU0467154 to test the hypothesis that selective potentiation of M4 receptor signaling could ameliorate the behavioral, cognitive, and neurochemical impairments induced by the noncompetitive NMDAR antagonist MK-801. VU0467154 produced a robust dose-dependent reversal of MK-801-induced hyperlocomotion and deficits in preclinical models of associative learning and memory functions, including the touchscreen pairwise visual discrimination task in wild-type mice, but failed to reverse these stimulant-induced deficits in M4 KO mice. VU0467154 also enhanced the acquisition of both contextual and cue-mediated fear conditioning when administered alone in wild-type mice. These novel findings suggest that M4 PAMs may provide a strategy for addressing the more complex affective and cognitive disruptions associated with schizophrenia and other neuropsychiatric disorders. PMID:25137629

  6. Repeated administration of almonds increases brain acetylcholine levels and enhances memory function in healthy rats while attenuates memory deficits in animal model of amnesia.

    PubMed

    Batool, Zehra; Sadir, Sadia; Liaquat, Laraib; Tabassum, Saiqa; Madiha, Syeda; Rafiq, Sahar; Tariq, Sumayya; Batool, Tuba Sharf; Saleem, Sadia; Naqvi, Fizza; Perveen, Tahira; Haider, Saida

    2016-01-01

    Dietary nutrients may play a vital role in protecting the brain from age-related memory dysfunction and neurodegenerative diseases. Tree nuts including almonds have shown potential to combat age-associated brain dysfunction. These nuts are an important source of essential nutrients, such as tocopherol, folate, mono- and poly-unsaturated fatty acids, and polyphenols. These components have shown promise as possible dietary supplements to prevent or delay the onset of age-associated cognitive dysfunction. This study investigated possible protective potential of almond against scopolamine induced amnesia in rats. The present study also investigated a role of acetylcholine in almond induced memory enhancement. Rats in test group were orally administrated with almond suspension (400 mg/kg/day) for four weeks. Both control and almond-treated rats were then divided into saline and scopolamine injected groups. Rats in the scopolamine group were injected with scopolamine (0.5 mg/kg) five minutes before the start of each memory test. Memory was assessed by elevated plus maze (EPM), Morris water maze (MWM) and novel object recognition (NOR) task. Cholinergic function was determined in terms of hippocampal and frontal cortical acetylcholine content and acetylcholinesterase activity. Results of the present study suggest that almond administration for 28 days significantly improved memory retention. This memory enhancing effect of almond was also observed in scopolamine induced amnesia model. Present study also suggests a role of acetylcholine in the attenuation of scopolamine induced amnesia by almond.

  7. The role of nicotinic acetylcholine receptors in the primary reinforcing and reinforcement-enhancing effects of nicotine.

    PubMed

    Palmatier, Matthew I; Liu, Xiu; Caggiula, Anthony R; Donny, Eric C; Sved, Alan F

    2007-05-01

    The primary reinforcing effects of nicotine are mediated by the drugs action at central nervous system nicotinic acetylcholine receptors (nAChRs). Although previous studies have demonstrated that nicotine potently enhances responding for non-pharmacological stimuli, the role of nAChRs in this reinforcement-enhancing effect is not known. The two reinforcement-related effects of nicotine can be dissociated in a paradigm that provides concurrent access to drug infusions and a non-pharmacological visual stimulus (VS). The present study characterized the role of nAChRs in the primary reinforcing effect of nicotine and the reinforcement-enhancing effect of nicotine. For rats with access to VS (VS-Only), nicotine (NIC-Only), both reinforcers contingent upon one response (NIC+VS) or both reinforcers contingent upon separate responses (2-Lever), unit dose-response relationships (0, 30, 60, or 90 microg/kg/infusion, free base) were determined over a 22-day acquisition period. Expression of the two reinforcement-related effects of nicotine was manipulated by pharmacological antagonism of nAChRs (1 mg/kg mecamylamine, subcutaneous, 5-min before the session) or by substituting saline for nicotine infusions (ie extinction) over a series of seven test sessions. Unit dose manipulations yielded an inverse dose-response relationship for active lever responding in the NIC+VS group. The dose-response relationships for rats with independent access to each reinforcer (2-Lever group) were relatively flat. For the 2-Lever group, acute mecamylamine challenge blocked the reinforcement-enhancing effects of nicotine, VS-lever responding decreased to basal levels on the first day of mecamylamine treatment or saline substitution (to the level of the VS-Only group). In contrast, nicotine-lever responding decreased gradually over the 7-day testing period (similar to saline extinction). The two reinforcement-related effects of nicotine are mediated by nAChRs but can be dissociated by acute and

  8. Natural compounds endowed with cholinergic or anticholinergic activity. Enhancement of acetylcholine release by a quaternary derivative of L-hyoscyamine.

    PubMed

    Souccar, Caden; Salamanca, Ana Lucia V; Tanae, Mirtes M; Lima-Landman, Maria Teresa R; Lapa, Antonio José

    2010-01-01

    New compounds that target nicotinic receptors (nAChRs) have been sought to correct disorders affecting cholinergic transmission in central and peripheral synapses. A quaternary derivate of l-hyoscyamine, phenthonium (Phen), was shown by our group to enhance the spontaneous acetylcholine (ACh) release without altering the nerve-induced transmitter release at the neuromuscular junction. The effect was unrelated to membrane depolarization, and was not induced by an increase of calcium influx into the nerve terminal. Phen also presented a competitive antimuscarinic activity and blocked noncompetitively the neuromuscular transmission. In this work we re-examined the mechanisms underlying the facilitatory actions of Phen on [(3)H]-ACh release in isolated ganglia of the guinea pig ileal myenteric plexus. Exposure of the preparations to Phen (10-50 microM) increased the release of [(3)H]-ACh by 81 to 68% over the basal. The effect was not affected by the ganglionic nAChR antagonist hexamethonium (1 nM) at a concentration that inhibited the increase of [(3)H]-ACh release induced by the nicotinic agonist dimethylphenylpiperazinium (DMPP, 30 microM). Association of Phen (10 microM) with DMPP potentiated the facilitatory effect of Phen. [(3)H]-ACh release was not altered by the muscarinic antagonists atropine (1 nM) or pirenzepine (1 microM). However, both antagonists inhibited the release of [(3)H]-ACh induced by either the muscarinic M1 agonist McN-343 (10 microM) or Phen (20 microM). The facilitatory effect of Phen was not altered by CdCl(2) (50 mM), but it was potentiated in the presence of tetraethylammonium (40 mM). The results indicate that the facilitatory action of Phen appears to be mediated by an increase of the inwardly rectifying potassium channels conductance probably related to the compound antimuscarinic activity.

  9. Increases in cholinergic neurotransmission measured by using choline-sensitive microelectrodes: enhanced detection by hydrolysis of acetylcholine on recording sites?

    PubMed Central

    Giuliano, Chiara; Parikh, Vinay; Ward, Josh.R.; Chiamulera, Christian; Sarter, Martin

    2008-01-01

    Previous experiments demonstrated that second-based transient increases in choline concentrations measured by electrodes coated with choline oxidase (ChOx) and the amperometric detection of hydrogen peroxide validly indicate the depolarization-dependent release of acetylcholine (ACh) and its hydrolysis by endogenous acetylcholinesterase (AChE). Therefore, choline-sensitive microelectrodes have become valuable tools in neuropharmacological and behavioral research. The present experiments were designed to test the possibility that co-immobilization of ChOx plus AChE on recording sites increases the level of detection for evoked ACh release in the brain. If newly released ACh is not completely hydrolyzed by endogenous AChE and capable of reaching the extracellular space, currents recorded via sites equipped with both enzymes should be greater when compared with sites coated with ChOx only. Pairs of Platinum-recordings sites were coated either with AChE plus ChOx or ChOx alone. Potassium or nicotine-evoked currents were recorded throughout the entire dorsal-ventral extent of the medial prefrontal cortex (mPFC). The amplitudes of evoked cholinergic signals did not differ significantly between AChE+ChOx and ChOx-only coated recording sites. Additional experiments controlling for several potential confounds suggested that, in vivo, ACh levels ≥150 fmol were detected by recordings sites featuring dual enzyme coating. Collectively, these results indicate that co-coating of microelectrodes with AChE does not enhance the detection of cholinergic activity in the cortex compared with measurements via recording sites coated only with ChOx. PMID:18346819

  10. Loop 2 of Ophiophagus hannah toxin b binds with neuronal nicotinic acetylcholine receptors and enhances intracranial drug delivery.

    PubMed

    Zhan, Changyou; Yan, Zhiqiang; Xie, Cao; Lu, Weiyue

    2010-12-01

    Three-finger snake neurotoxins have been widely investigated for their high binding affinities with nicotinic acetylcholine receptors (nAChRs), which are widely expressed in the central nervous system including the blood-brain barrier and thus mediate intracranial drug delivery. The loop 2 segments of three-finger snake neurotoxins are considered as the binding domain with nAChRs, and thus, they may have the potential to enhance drug or drug delivery system intracranial transport. In the present work, binding of the synthetic peptides to the neuronal nAChRs was assessed by measuring their ability to inhibit the binding of (125)I-α-bungarotoxin to the receptor. The loop 2 segment of Ophiophagus hannah toxin b (KC2S) showed high binding affinity, and the competitive binding IC(50) value was 32.51 nM. Furthermore, the brain targeting efficiency of KC2S had been investigated in vitro and in vivo. The specific uptake by brain capillary endothelial cells (BCECs) demonstrated that KC2S could be endocytosized after binding with nAChRs. In vivo, the qualitative and quantitative biodistribution results of fluorescent dyes (DiR or coumarin-6) indicated that KC2S modified poly(ethylene glycol)-poly(lactic acid) micelles (KC2S-PEG-PLA micelles) could enhance intracranial drug delivery. Furthermore, intravenous treatment with paclitaxel-encapsulated KC2S-PEG-PLA micelles (KC2S-PEG-PLA-PTX micelles) afforded robust inhibition of intracranial glioblastoma. The median survival time of KC2S-PEG-PLA-PTX-micelle-treated mice (47.5 days) was significantly longer than that of mice treated by mPEG-PLA-PTX micelles (41.5 days), Taxol (38.5 days), or saline (34 days). Compared with the short peptide derived from rabies virus glycoprotein (RVG29) that has been previously reported as an excellent brain targeting ligand, KC2S has a similar binding affinity with neuronal nAChRs but fewer amino acid residues. Thus, we concluded that the loop 2 segment of Ophiophagus hannah toxin b could bind

  11. Distinct enhancers at the Pax3 locus can function redundantly to regulate neural tube and neural crest expressions.

    PubMed

    Degenhardt, Karl R; Milewski, Rita C; Padmanabhan, Arun; Miller, Mayumi; Singh, Manvendra K; Lang, Deborah; Engleka, Kurt A; Wu, Meilin; Li, Jun; Zhou, Diane; Antonucci, Nicole; Li, Li; Epstein, Jonathan A

    2010-03-15

    Pax3 is a transcription factor expressed in somitic mesoderm, dorsal neural tube and pre-migratory neural crest during embryonic development. We have previously identified cis-acting enhancer elements within the proximal upstream genomic region of Pax3 that are sufficient to direct functional expression of Pax3 in neural crest. These elements direct expression of a reporter gene to pre-migratory neural crest in transgenic mice, and transgenic expression of a Pax3 cDNA using these elements is sufficient to rescue neural crest development in mice otherwise lacking endogenous Pax3. We show here that deletion of these enhancer sequences by homologous recombination is insufficient to abrogate neural crest expression of Pax3 and results in viable mice. We identify a distinct enhancer in the fourth intron that is also capable of mediating neural crest expression in transgenic mice and zebrafish. Our analysis suggests the existence of functionally redundant neural crest enhancer modules for Pax3.

  12. Positive allosteric modulation of alpha 7 nicotinic acetylcholine receptors enhances recognition memory and cognitive flexibility in rats.

    PubMed

    Nikiforuk, Agnieszka; Kos, Tomasz; Potasiewicz, Agnieszka; Popik, Piotr

    2015-08-01

    A wide body of preclinical and clinical data suggests that alpha 7 nicotinic acetylcholine receptors (α7-nAChRs) may represent useful targets for cognitive improvement in schizophrenia and Alzheimer׳s disease. A promising recent approach is based on the use of positive allosteric modulators (PAMs) of α7-nAChRs due to their several advantages over the direct agonists. Nevertheless, the behavioural effects of this class of compounds, particularly with regard to higher-order cognitive functions, have not been broadly characterised. The aim of the present study was to evaluate the procognitive efficacies of type I and type II α7-nAChRs PAMs, N-(4-chlorophenyl)-[[(4-chlorophenyl)amino]methylene]-3-methyl-5-isoxazoleacet-amide (CCMI) and N-(5-Chloro-2,4-dimethoxyphenyl)-N'-(5-methyl-3-isoxazolyl)urea (PNU-120596) in the novel object recognition task (NORT), attentional set-shifting task (ASST) and five-choice serial reaction time task (5-CSRTT) in rats. Additionally, the effects of galantamine, an acetylcholinesterase inhibitor that also allosterically modulates nAChRs, were assessed. We report that CCMI (0.3-3mg/kg), PNU-120596 (0.3-3mg/kg) and galantamine (1-3mg/kg) attenuated the delay-induced impairment in NORT performance and facilitated cognitive flexibility in the ASST. Methyllycaconitine (3mg/kg) blocked the actions of CCMI, PNU-120596 and galantamine in the NORT and ASST, suggesting that the procognitive effects of these compounds are α7-nAChRs-dependent. However, none of the compounds tested affected the rats' attentional performance in the 5-CSRTT. The present findings confirm and extend the observations indicating that the positive allosteric modulation of α7-nAChRs enhances recognition memory and cognitive flexibility in preclinical tasks. Therefore, the present study supports the utility of α7-nAChRs PAMs as a potential cognitive enhancing therapy. PMID:26003081

  13. Supervised learning in hierarchical neural networks for edge enhancement

    NASA Astrophysics Data System (ADS)

    Lu, Si W.; Szeto, Anthony

    1992-09-01

    Hierarchical artificial neural networks are designed to enhance edge measurement. The neural network comprises four subnets: the Edge Contour Detection subnet, the Maximum Detection subnet, the Gradient Adjustment subnet, and the Orientation Determination subnet. The interconnections between these subnets are fashioned in a hierarchical manner. In order for the neural network system to perform correctly and accurately, each of the neural subnets must be given suitable weights by learning. The learning is very difficult for the hierarchical neural networks because of the complicated hierarchical structure. In our learning algorithm the modularity is introduced for fast learning and good generalization, based on the analysis of the local concept and the distributed concept represented by the module. The amount of information which the nets need to learn is drastically reduced. Therefore, only a small number of training patterns are required to train the nets and still derive suitable weights for the nets to perform accurately and efficiently. The neural network is simulated on a MIPS M120-S machine running UNIX. For the test images degraded by random noise up to 20%, the true edges are detected and enhanced, the false edges are suppressed, the noise is eliminated, the weak edges are reinforced, and the missing edge elements are interpolated.

  14. Adaptive neural network for image enhancement

    NASA Astrophysics Data System (ADS)

    Perl, Dan; Marsland, T. A.

    1992-09-01

    ANNIE is a neural network that removes noise and sharpens edges in digital images. For noise removal, ANNIE makes a weighted average of the values of the pixels over a certain neighborhood. For edge sharpening, ANNIE detects edges and applies a correction around them. Although averaging is a simple operation and needs only a two-layer neural network, detecting edges is more complex and demands several hidden layers. Based on Marr's theory of natural vision, the edge detection method uses zero-crossings in the image filtered by the ∇2G operator (where ∇2 is the Laplacian operator and G stands for a two- dimensional Gaussian distribution), and uses two channels with different spatial frequencies. Edge detectors are tuned for vertical and horizontal orientations. Lateral inhibition implemented through one-step recursion achieves both edge relaxation and correlation of the two channels. Training by means of the quickprop algorithm determines the shapes of the weighted averaging filter and the edge correction filters, and the rules for edge relaxation and channel interaction. ANNIE uses pairs of pictures as training patterns: one picture is a reference for the output of the network and the same picture deteriorated by noise and/or blur is the input of the network.

  15. Noise-enhanced convolutional neural networks.

    PubMed

    Audhkhasi, Kartik; Osoba, Osonde; Kosko, Bart

    2016-06-01

    Injecting carefully chosen noise can speed convergence in the backpropagation training of a convolutional neural network (CNN). The Noisy CNN algorithm speeds training on average because the backpropagation algorithm is a special case of the generalized expectation-maximization (EM) algorithm and because such carefully chosen noise always speeds up the EM algorithm on average. The CNN framework gives a practical way to learn and recognize images because backpropagation scales with training data. It has only linear time complexity in the number of training samples. The Noisy CNN algorithm finds a special separating hyperplane in the network's noise space. The hyperplane arises from the likelihood-based positivity condition that noise-boosts the EM algorithm. The hyperplane cuts through a uniform-noise hypercube or Gaussian ball in the noise space depending on the type of noise used. Noise chosen from above the hyperplane speeds training on average. Noise chosen from below slows it on average. The algorithm can inject noise anywhere in the multilayered network. Adding noise to the output neurons reduced the average per-iteration training-set cross entropy by 39% on a standard MNIST image test set of handwritten digits. It also reduced the average per-iteration training-set classification error by 47%. Adding noise to the hidden layers can also reduce these performance measures. The noise benefit is most pronounced for smaller data sets because the largest EM hill-climbing gains tend to occur in the first few iterations. This noise effect can assist random sampling from large data sets because it allows a smaller random sample to give the same or better performance than a noiseless sample gives.

  16. A cortical neural prosthesis for restoring and enhancing memory

    NASA Astrophysics Data System (ADS)

    Berger, Theodore W.; Hampson, Robert E.; Song, Dong; Goonawardena, Anushka; Marmarelis, Vasilis Z.; Deadwyler, Sam A.

    2011-08-01

    A primary objective in developing a neural prosthesis is to replace neural circuitry in the brain that no longer functions appropriately. Such a goal requires artificial reconstruction of neuron-to-neuron connections in a way that can be recognized by the remaining normal circuitry, and that promotes appropriate interaction. In this study, the application of a specially designed neural prosthesis using a multi-input/multi-output (MIMO) nonlinear model is demonstrated by using trains of electrical stimulation pulses to substitute for MIMO model derived ensemble firing patterns. Ensembles of CA3 and CA1 hippocampal neurons, recorded from rats performing a delayed-nonmatch-to-sample (DNMS) memory task, exhibited successful encoding of trial-specific sample lever information in the form of different spatiotemporal firing patterns. MIMO patterns, identified online and in real-time, were employed within a closed-loop behavioral paradigm. Results showed that the model was able to predict successful performance on the same trial. Also, MIMO model-derived patterns, delivered as electrical stimulation to the same electrodes, improved performance under normal testing conditions and, more importantly, were capable of recovering performance when delivered to animals with ensemble hippocampal activity compromised by pharmacologic blockade of synaptic transmission. These integrated experimental-modeling studies show for the first time that, with sufficient information about the neural coding of memories, a neural prosthesis capable of real-time diagnosis and manipulation of the encoding process can restore and even enhance cognitive, mnemonic processes.

  17. A cortical neural prosthesis for restoring and enhancing memory.

    PubMed

    Berger, Theodore W; Hampson, Robert E; Song, Dong; Goonawardena, Anushka; Marmarelis, Vasilis Z; Deadwyler, Sam A

    2011-08-01

    A primary objective in developing a neural prosthesis is to replace neural circuitry in the brain that no longer functions appropriately. Such a goal requires artificial reconstruction of neuron-to-neuron connections in a way that can be recognized by the remaining normal circuitry, and that promotes appropriate interaction. In this study, the application of a specially designed neural prosthesis using a multi-input/multi-output (MIMO) nonlinear model is demonstrated by using trains of electrical stimulation pulses to substitute for MIMO model derived ensemble firing patterns. Ensembles of CA3 and CA1 hippocampal neurons, recorded from rats performing a delayed-nonmatch-to-sample (DNMS) memory task, exhibited successful encoding of trial-specific sample lever information in the form of different spatiotemporal firing patterns. MIMO patterns, identified online and in real-time, were employed within a closed-loop behavioral paradigm. Results showed that the model was able to predict successful performance on the same trial. Also, MIMO model-derived patterns, delivered as electrical stimulation to the same electrodes, improved performance under normal testing conditions and, more importantly, were capable of recovering performance when delivered to animals with ensemble hippocampal activity compromised by pharmacologic blockade of synaptic transmission. These integrated experimental-modeling studies show for the first time that, with sufficient information about the neural coding of memories, a neural prosthesis capable of real-time diagnosis and manipulation of the encoding process can restore and even enhance cognitive, mnemonic processes. PMID:21677369

  18. The potential transformation of our species by neural enhancement.

    PubMed

    Zehr, E Paul

    2015-01-01

    Neural enhancement represents recovery of function that has been lost due to injury or disease pathology. Restoration of functional ability is the objective. For example, a neuroprosthetic to replace a forearm and hand lost to the ravages of war or industrial accident. However, the same basic constructs used for neural enhancement after injury could amplify abilities that are already in the natural normal range. That is, neural enhancement technologies to restore function and improve daily abilities for independent living could be used to improve so-called normal function to ultimate function. Approaching that functional level by use and integration of technology takes us toward the concept of a new species. This new subspecies--homo sapiens technologicus--is one that uses technology not just to assist but to change its own inherent biological function. The author uses examples from prosthetics and neuroprosthetics to address the issue of the limitations of constructs on the accepted range of human performance ability and aims to provide a cautionary view toward reflection on where our science may take the entire species.

  19. The potential transformation of our species by neural enhancement.

    PubMed

    Zehr, E Paul

    2015-01-01

    Neural enhancement represents recovery of function that has been lost due to injury or disease pathology. Restoration of functional ability is the objective. For example, a neuroprosthetic to replace a forearm and hand lost to the ravages of war or industrial accident. However, the same basic constructs used for neural enhancement after injury could amplify abilities that are already in the natural normal range. That is, neural enhancement technologies to restore function and improve daily abilities for independent living could be used to improve so-called normal function to ultimate function. Approaching that functional level by use and integration of technology takes us toward the concept of a new species. This new subspecies--homo sapiens technologicus--is one that uses technology not just to assist but to change its own inherent biological function. The author uses examples from prosthetics and neuroprosthetics to address the issue of the limitations of constructs on the accepted range of human performance ability and aims to provide a cautionary view toward reflection on where our science may take the entire species. PMID:25575224

  20. The Potential Transformation of Our Species by Neural Enhancement

    PubMed Central

    Zehr, E. Paul

    2015-01-01

    ABSTRACT. Neural enhancement represents recovery of function that has been lost due to injury or disease pathology. Restoration of functional ability is the objective. For example, a neuroprosthetic to replace a forearm and hand lost to the ravages of war or industrial accident. However, the same basic constructs used for neural enhancement after injury could amplify abilities that are already in the natural normal range. That is, neural enhancement technologies to restore function and improve daily abilities for independent living could be used to improve so-called normal function to ultimate function. Approaching that functional level by use and integration of technology takes us toward the concept of a new species. This new subspecies—homo sapiens technologicus—is one that uses technology not just to assist but to change its own inherent biological function. The author uses examples from prosthetics and neuroprosthetics to address the issue of the limitations of constructs on the accepted range of human performance ability and aims to provide a cautionary view toward reflection on where our science may take the entire species. PMID:25575224

  1. GPS/INS Enhancement for Land Navigation using Neural Network

    NASA Astrophysics Data System (ADS)

    Kaygisiz, Burak H.; Erkmen, Ismet; Erkmen, Aydan M.

    2004-05-01

    We propose in this paper a method to enhance the performance of a coupled global positioning/inertial navigation system (GPS/INS) for land navigation applications during GPS signal loss. Our method is based on the use of an artificial neural network (ANN) to intelligently aid the GPS/INS coupled navigation system in the absence of GPS signals. The proposed enhanced GPS/INS is tested in the dynamic environment of a land vehicle navigating around a closed path on the METU campus and we provide the results. Our GPS/INS+ANN system performance is thus demonstrated with a land trial.

  2. Mental training enhances attentional stability: neural and behavioral evidence.

    PubMed

    Lutz, Antoine; Slagter, Heleen A; Rawlings, Nancy B; Francis, Andrew D; Greischar, Lawrence L; Davidson, Richard J

    2009-10-21

    The capacity to stabilize the content of attention over time varies among individuals, and its impairment is a hallmark of several mental illnesses. Impairments in sustained attention in patients with attention disorders have been associated with increased trial-to-trial variability in reaction time and event-related potential deficits during attention tasks. At present, it is unclear whether the ability to sustain attention and its underlying brain circuitry are transformable through training. Here, we show, with dichotic listening task performance and electroencephalography, that training attention, as cultivated by meditation, can improve the ability to sustain attention. Three months of intensive meditation training reduced variability in attentional processing of target tones, as indicated by both enhanced theta-band phase consistency of oscillatory neural responses over anterior brain areas and reduced reaction time variability. Furthermore, those individuals who showed the greatest increase in neural response consistency showed the largest decrease in behavioral response variability. Notably, we also observed reduced variability in neural processing, in particular in low-frequency bands, regardless of whether the deviant tone was attended or unattended. Focused attention meditation may thus affect both distracter and target processing, perhaps by enhancing entrainment of neuronal oscillations to sensory input rhythms, a mechanism important for controlling the content of attention. These novel findings highlight the mechanisms underlying focused attention meditation and support the notion that mental training can significantly affect attention and brain function.

  3. Enhanced memory performance thanks to neural network assortativity

    SciTech Connect

    Franciscis, S. de; Johnson, S.; Torres, J. J.

    2011-03-24

    The behaviour of many complex dynamical systems has been found to depend crucially on the structure of the underlying networks of interactions. An intriguing feature of empirical networks is their assortativity--i.e., the extent to which the degrees of neighbouring nodes are correlated. However, until very recently it was difficult to take this property into account analytically, most work being exclusively numerical. We get round this problem by considering ensembles of equally correlated graphs and apply this novel technique to the case of attractor neural networks. Assortativity turns out to be a key feature for memory performance in these systems - so much so that for sufficiently correlated topologies the critical temperature diverges. We predict that artificial and biological neural systems could significantly enhance their robustness to noise by developing positive correlations.

  4. Human neural stem cells promote proliferation of endogenous neural stem cells and enhance angiogenesis in ischemic rat brain

    PubMed Central

    Ryu, Sun; Lee, Seung-Hoon; Kim, Seung U.; Yoon, Byung-Woo

    2016-01-01

    Transplantation of human neural stem cells into the dentate gyrus or ventricle of rodents has been reportedly to enhance neurogenesis. In this study, we examined endogenous stem cell proliferation and angiogenesis in the ischemic rat brain after the transplantation of human neural stem cells. Focal cerebral ischemia in the rat brain was induced by middle cerebral artery occlusion. Human neural stem cells were transplanted into the subventricular zone. The behavioral performance of human neural stem cells-treated ischemic rats was significantly improved and cerebral infarct volumes were reduced compared to those in untreated animals. Numerous transplanted human neural stem cells were alive and preferentially localized to the ipsilateral ischemic hemisphere. Furthermore, 5-bromo-2′-deoxyuridine-labeled endogenous neural stem cells were observed in the subventricular zone and hippocampus, where they differentiated into cells immunoreactive for the neural markers doublecortin, neuronal nuclear antigen NeuN, and astrocyte marker glial fibrillary acidic protein in human neural stem cells-treated rats, but not in the untreated ischemic animals. The number of 5-bromo-2′-deoxyuridine-positive ⁄ anti-von Willebrand factor-positive proliferating endothelial cells was higher in the ischemic boundary zone of human neural stem cells-treated rats than in controls. Finally, transplantation of human neural stem cells in the brains of rats with focal cerebral ischemia promoted the proliferation of endogenous neural stem cells and their differentiation into mature neural-like cells, and enhanced angiogenesis. This study provides valuable insights into the effect of human neural stem cell transplantation on focal cerebral ischemia, which can be applied to the development of an effective therapy for stroke. PMID:27073384

  5. In vivo blockade of acetylcholinesterase increases intraovarian acetylcholine and enhances follicular development and fertility in the rat

    PubMed Central

    Blohberger, Jan; Tiszavari, Michelle; Mayerhofer, Artur; Lara, Hernan E.

    2016-01-01

    Growth and differentiation of ovarian follicles are regulated by systemic and local factors, which may include acetylcholine (ACh). Granulosa cells (GCs) of growing follicles and luteal cells produce ACh and in cultured GCs it exerts trophic actions via muscarinic receptors. However, such actions were not studied in vivo. After having established that rat ovarian GCs and luteal cells express the ACh-metabolizing enzyme ACh esterase (AChE), we examined the consequences of local application of an AChE inhibitor, huperzine A (HupA), by osmotic minipump delivery into the ovarian bursa of hemiovariectomized rats. Saline was used in the control group. Local delivery of HupA for 4 weeks increased ovarian ACh content. Estrus cyclicity was not changed indicating a locally restricted range of HupA action. The number of primordial and primary follicles was unaffected, but small secondary follicles significantly increased in the HupA group. Furthermore, a significant increase in the number of corpora lutea suggested increased ovulatory events. In support, as shown upon mating, HupA-treated females had significantly increased implantation sites and more pups. Thus the data are in support of a trophic role of ACh in follicular development and ovulation and point to an important role of ACh in female fertility. PMID:27440195

  6. Enhanced meta-analysis of acetylcholine binding protein structures reveals conformational signatures of agonism in nicotinic receptors

    PubMed Central

    Stober, Spencer T; Abrams, Cameron F

    2012-01-01

    The soluble acetylcholine binding protein (AChBP) is the default structural proxy for pentameric ligand-gated ion channels (LGICs). Unfortunately, it is difficult to recognize conformational signatures of LGIC agonism and antagonism within the large set of AChBP crystal structures in both apo and ligand-bound states, primarily because AChBP conformations in this set are nearly superimposable (root mean square deviation < 1.5 Å). We have undertaken a systematic, alignment-free approach to elucidate conformational differences displayed by AChBP that cleanly differentiate apo/antagonist-bound from agonist-bound states. Our approach uses statistical inference based on both crystallographic states and conformations sampled during long molecular dynamics simulations to select important inter-Cα distances and map their collective values onto functional states. We observe that binding of (nAChR) agonists to AChBP elicits clockwise rotation of the inner β-sheet with respect to the outer β-sheet, causing tilting of the cys-loop away from the five-fold axis, in a manner quite similar to that speculated for α-subunits of the heteromeric nAChR structure (Unwin, J Mol Biol 2005;346:967), making this motion potentially important in transmission of the gating signal to the transmembrane domain of a LGIC. The method is also successful at discriminating partial from full agonists and supports the hypothesis that a particularly controversial ligand, lobeline, is in fact an LGIC antagonist. PMID:22170867

  7. Neural activity associated with enhanced facial attractiveness by cosmetics use.

    PubMed

    Ueno, Aya; Ito, Ayahito; Kawasaki, Iori; Kawachi, Yousuke; Yoshida, Kazuki; Murakami, Yui; Sakai, Shinya; Iijima, Toshio; Matsue, Yoshihiko; Fujii, Toshikatsu

    2014-04-30

    Previous psychological studies have shown that make-up enhances facial attractiveness. Although neuroimaging evidence indicates that the orbitofrontal cortex (OFC) shows greater activity for faces of attractive people than for those of unattractive people, there is no direct evidence that the OFC also shows greater activity for the face of an individual wearing make-up than for the same face without make-up. Using functional magnetic resonance imaging (fMRI), we investigated neural activity while subjects viewed 144 photographs of the same faces with and without make-up (48 with make-up, 48 without make-up, and 48 scrambled photographs) and assigned these faces an attractiveness rating. The behavioral data showed that the faces with make-up were rated as more attractive than those without make-up. The imaging data revealed that the left OFC and the right hippocampus showed greater activity for faces with make-up than for those without make-up. Furthermore, the activities of the right anterior cingulate cortex, left hippocampus, and left OFC increased with increasing facial attractiveness resulting from cosmetics use. These results provide direct evidence of the neural underpinnings of cosmetically enhanced facial attractiveness.

  8. Neural regulation of MRNA for the alpha-subunit of acetylcholine receptors: Role of neuromuscular transmission. (Reannouncement with new availability information)

    SciTech Connect

    Lipsky, N.G.; Drachman, D.B.; Pestronk, A.; Shih, P.J.

    1989-12-31

    Levels of mRNA for acetylcholine receptor (AChR) subunits are relatively low in innervated skeletal muscles. Following denervation they rise rapidly, leading to increased AChR synthesis. The mechanism by which motor nerves normally regulate these mRNA levels is not yet known. In order to determine the possible role of synaptic transmission in this process, the authors have compared the effect of blockade of cholinergic ACh transmission with that of surgical denervation. Blockade of quantal ACh transmission was produced by injection of type A botulinum toxin into the soleus muscles of rats.

  9. Nicotinic acetylcholine receptors mediate donepezil-induced oligodendrocyte differentiation.

    PubMed

    Imamura, Osamu; Arai, Masaaki; Dateki, Minori; Ogata, Toru; Uchida, Ryuji; Tomoda, Hiroshi; Takishima, Kunio

    2015-12-01

    Oligodendrocytes are the myelin-forming cells of the central nervous system (CNS). Failure of myelin development and oligodendrocyte loss results in serious human disorders, including multiple sclerosis. Here, we show that donepezil, an acetlycholinesterase inhibitor developed for the treatment of Alzheimer's disease, can stimulate oligodendrocyte differentiation and maturation of neural stem cell-derived oligodendrocyte progenitor cells without affecting proliferation or cell viability. Transcripts for essential myelin-associated genes, such as PLP, MAG, MBP, CNPase, and MOG, in addition to transcription factors that regulate oligodendrocyte differentiation and myelination, were rapidly increased after treatment with donepezil. Furthermore, luciferase assays confirmed that both MAG and MBP promoters display increased activity upon donepezil-induced oligodendrocytes differentiation, suggesting that donepezil increases myelin gene expression mainly through enhanced transcription. We also found that the increase in the number of oligodendrocytes observed following donepezil treatment was significantly inhibited by the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine, but not by the muscarinic acetylcholine receptor antagonist scopolamine. Moreover, donepezil-induced myelin-related gene expression was suppressed by mecamylamine at both the mRNA and protein level. These results suggest that donepezil stimulates oligodendrocyte differentiation and myelin-related gene expression via nAChRs in neural stem cell-derived oligodendrocyte progenitor cells. We show that donepezil, a drug for the treatment of Alzheimer disease, can stimulate oligodendrocyte differentiation and maturation of oligodendrocyte progenitor cells. Transcripts for essential myelin-associated genes, such as PLP, MAG, MBP, CNPase and MOG in addition to transcripton factors that regulate oligodendrocyte differentiation and myelination were rapidly increased after treatment with donepezil

  10. Enhanced expression of FNDC5 in human embryonic stem cell-derived neural cells along with relevant embryonic neural tissues.

    PubMed

    Ghahrizjani, Fatemeh Ahmadi; Ghaedi, Kamran; Salamian, Ahmad; Tanhaei, Somayeh; Nejati, Alireza Shoaraye; Salehi, Hossein; Nabiuni, Mohammad; Baharvand, Hossein; Nasr-Esfahani, Mohammad Hossein

    2015-02-25

    Availability of human embryonic stem cells (hESCs) has enhanced the capability of basic and clinical research in the context of human neural differentiation. Derivation of neural progenitor (NP) cells from hESCs facilitates the process of human embryonic development through the generation of neuronal subtypes. We have recently indicated that fibronectin type III domain containing 5 protein (FNDC5) expression is required for appropriate neural differentiation of mouse embryonic stem cells (mESCs). Bioinformatics analyses have shown the presence of three isoforms for human FNDC5 mRNA. To differentiate which isoform of FNDC5 is involved in the process of human neural differentiation, we have used hESCs as an in vitro model for neural differentiation by retinoic acid (RA) induction. The hESC line, Royan H5, was differentiated into a neural lineage in defined adherent culture treated by RA and basic fibroblast growth factor (bFGF). We collected all cell types that included hESCs, rosette structures, and neural cells in an attempt to assess the expression of FNDC5 isoforms. There was a contiguous increase in all three FNDC5 isoforms during the neural differentiation process. Furthermore, the highest level of expression of the isoforms was significantly observed in neural cells compared to hESCs and the rosette structures known as neural precursor cells (NPCs). High expression levels of FNDC5 in human fetal brain and spinal cord tissues have suggested the involvement of this gene in neural tube development. Additional research is necessary to determine the major function of FDNC5 in this process.

  11. Enhanced acetylcholine induced relaxation in small mesenteric arteries from pregnant rats: an important role for endothelium-derived hyperpolarizing factor (EDHF)

    PubMed Central

    Gerber, R T; Anwar, M A; Poston, L

    1998-01-01

    Small mesenteric arteries from pregnant rats demonstrated greater sensitivity (pEC50 : P<0.001) and maximum relaxation (P<0.01) to acetylcholine (ACh) than those of control non-pregnant animals.Maximum relaxation, but not sensitivity, to ACh remained greater (P<0.01) in pregnant animals when evaluated in 25 mM KCl, which prevents relaxation dependent upon hyperpolarization. ACh induced relaxation in the presence of 25 mM KCl was completely inhibited in pregnant and non-pregnant groups by Nω-nitro L-arginine methyl ester (L-NAME, 100 μM), indomethacin (INDO, 10 μM) and oxadiazole quinoxalin (ODQ, 1 μM), suggesting pregnancy associated enhancement of dilator prostanoid and/or nitric oxide (NO) synthesis.ACh induced relaxation in 5 mM KCl was only partially inhibited by a combination of Nω-nitro L-arginine methyl ester (L-NAME, 100 μM), indomethacin (INDO, 10 μM) and oxadiazole quinoxalin (ODQ, 1 μM). The residual relaxation, which was greater in arteries from pregnant rats (maximum relaxation: P<0.01), was prevented by 25 mM KCl, indicating pregnancy associated enhanced synthesis/reduced degradation of a hyperpolarizing factor. Residual relaxation to ACh in 5 mM KCl was inhibited by the cytochrome P450 inhibitor, proadifen (1 μM) in the pregnant group (P<0.001).Relaxation to spermine NONOate was similar in pregnant and non-pregnant groups and totally inhibited by ODQ (in the presence of L-NAME).This study suggests that, in addition to enhanced endothelium dependent NO/dilator prostanoid synthesis, a hyperpolarizing factor may contribute to the vascular adaptation to pregnancy. PMID:9806327

  12. The melanin-concentrating hormone1 receptor antagonists, SNAP-7941 and GW3430, enhance social recognition and dialysate levels of acetylcholine in the frontal cortex of rats.

    PubMed

    Millan, Mark J; Gobert, Alain; Panayi, Fany; Rivet, Jean-Michel; Dekeyne, Anne; Brocco, Mauricette; Ortuno, Jean-Claude; Di Cara, Benjamin

    2008-12-01

    Melanin-concentrating hormone (MCH)1 receptors are widely expressed in limbic structures and cortex. Their inactivation is associated with anxiolytic and antidepressive properties but little information is available concerning cognition. This issue was addressed using the selective antagonists, SNAP-7941 and GW3430, in a social recognition paradigm in rats. The muscarinic blocker, scopolamine (1.25 mg/kg s.c.), reduced social recognition, an action dose-dependently blocked by SNAP-7941 and GW3430 (0.63-10.0 and 20.0-80.0 mg/kg i.p., respectively) which did not themselves display amnesic properties. Further, in a protocol where a spontaneous deficit was induced by a prolonged inter-session delay, SNAP-7941 and GW3430 dose-dependently enhanced social recognition. In dialysis studies, SNAP-7941 (0.63-40.0 mg/kg i.p.) and GW3430 (10.0-40.0 mg/kg i.p.) elevated extracellular levels of acetylcholine (ACh) in the frontal cortex (FCX) of freely moving rats. The SNAP-7941 effect was specific, as it did not increase levels of ACh in ventral and dorsal hippocampus: moreover, it did not modify levels of noradrenaline, dopamine, serotonin and glutamate in FCX. Active doses of SNAP-7941 and GW3430 corresponded to doses (2.5-40.0 and 10.0-80.0 mg/kg i.p., respectively) exerting anxiolytic properties in Vogel conflict and ultrasonic vocalization tests, and antidepressant actions in forced swim, isolation-induced aggression and marble-burying procedures. In contrast to SNAP-7941 and GW3430, the benzodiazepine, diazepam, decreased social recognition and dialysate levels of ACh, while the tricyclic, imipramine, reduced social recognition and failed to enhance cholinergic transmission. In conclusion, at anxiolytic and antidepressant doses, SNAP-7941 and GW3430 improve social recognition and elevate extracellular ACh levels in FCX. This profile differentiates MCH1 receptor antagonists from conventional anxiolytic and antidepressant agents.

  13. Nicotine enhances invasion and metastasis of human colorectal cancer cells through the nicotinic acetylcholine receptor downstream p38 MAPK signaling pathway.

    PubMed

    Xiang, Tao; Fei, Rushan; Wang, Zhe; Shen, Zhonglei; Qian, Jing; Chen, Wenbin

    2016-01-01

    Nicotine as a cigarette component is an established risk factor for colorectal cancer tumorigenesis. The downstream signaling pathways of nicotinic acetylcholine receptors (nAchRs) are believed to be responsible for the cellular effects. In the present study, we evaluated the effects and novel mechanisms for nicotine on the capacity for colorectal cancer cell invasion and metastasis. LOVO and SW620 colorectal cancer cells were stimulated with nicotine in vitro. A Transwell chamber model was applied to detect the capacity for tumor cell invasion. Assays for gelatin zymography and western blotting were applied to detect the activity and expression of metastasis-related matrix metalloproteinases (MMPs), respectively. Signal transduction was assessed by immunoblotting for the phosphorylation of relevant signal molecules and the application of pharmaceutical inhibitors. We showed that nicotine increased LOVO and SW620 colorectal cancer cell invasion along with enhanced activity and expression of MMP-1, -2 and -9. Nicotine increased phosphorylation of p38, ERK, Akt and PI3K p85 but had no effect on phosphorylation of JNK, or NF-κB. Of the pharmaceutical inhibitors of U0126 (ERK1/2 inhibitor), LY294002 (Akt activation inhibitor), SB239063 (p38 MAPK activation inhibitor) and hexamethonium (Hex) (nAchRs inhibitor), the cellular and molecular effects were reduced by the applications of SB239063 and Hex. We concluded that nicotine stimulates the invasion and metastasis of colon cancer cells in vitro via activation of the nAchRs and the p38 MAPK downstream signaling pathway. Therefore, p38 MAPK may have potential as a therapeutic target for smoking-related human colorectal cancer metastasis.

  14. Low-dimensional recurrent neural network-based Kalman filter for speech enhancement.

    PubMed

    Xia, Youshen; Wang, Jun

    2015-07-01

    This paper proposes a new recurrent neural network-based Kalman filter for speech enhancement, based on a noise-constrained least squares estimate. The parameters of speech signal modeled as autoregressive process are first estimated by using the proposed recurrent neural network and the speech signal is then recovered from Kalman filtering. The proposed recurrent neural network is globally asymptomatically stable to the noise-constrained estimate. Because the noise-constrained estimate has a robust performance against non-Gaussian noise, the proposed recurrent neural network-based speech enhancement algorithm can minimize the estimation error of Kalman filter parameters in non-Gaussian noise. Furthermore, having a low-dimensional model feature, the proposed neural network-based speech enhancement algorithm has a much faster speed than two existing recurrent neural networks-based speech enhancement algorithms. Simulation results show that the proposed recurrent neural network-based speech enhancement algorithm can produce a good performance with fast computation and noise reduction.

  15. Acetylcholine activity in selective striatal regions supports behavioral flexibility.

    PubMed

    Ragozzino, Michael E; Mohler, Eric G; Prior, Margaret; Palencia, Carlos A; Rozman, Suzanne

    2009-01-01

    Daily living often requires individuals to flexibly respond to new circumstances. There is considerable evidence that the striatum is part of a larger neural network that supports flexible adaptations. Cholinergic interneurons are situated to strongly influence striatal output patterns which may enable flexible adaptations. The present experiments investigated whether acetylcholine actions in different striatal regions support behavioral flexibility by measuring acetylcholine efflux during place reversal learning. Acetylcholine efflux selectively increased in the dorsomedial striatum, but not dorsolateral or ventromedial striatum during place reversal learning. In order to modulate the M2-class of autoreceptors, administration of oxotremorine sesquifumurate (100 nM) into the dorsomedial striatum, concomitantly impaired reversal learning and an increase in acetylcholine output. These effects were reversed by the m(2) muscarinic receptor antagonist, AF-DX-116 (20 nM). The effects of oxotremorine sesquifumurate and AF-DX-116 on acetylcholine efflux were selective to behaviorally-induced changes as neither treatment affected acetylcholine output in a resting condition. In contrast to reversal learning, acetylcholine efflux in the dorsomedial striatum did not change during place acquisition. The results reveal an essential role for cholinergic activity and define its locus of control to the dorsomedial striatum in cognitive flexibility.

  16. Lecozotan (SRA-333): a selective serotonin 1A receptor antagonist that enhances the stimulated release of glutamate and acetylcholine in the hippocampus and possesses cognitive-enhancing properties.

    PubMed

    Schechter, L E; Smith, D L; Rosenzweig-Lipson, S; Sukoff, S J; Dawson, L A; Marquis, K; Jones, D; Piesla, M; Andree, T; Nawoschik, S; Harder, J A; Womack, M D; Buccafusco, J; Terry, A V; Hoebel, B; Rada, P; Kelly, M; Abou-Gharbia, M; Barrett, J E; Childers, W

    2005-09-01

    Recent data has suggested that the 5-hydroxytryptamine (5-HT)(1A) receptor is involved in cognitive processing. A novel 5-HT(1A) receptor antagonist, 4-cyano-N-{2R-[4-(2,3-dihydrobenzo[1,4]-dioxin-5-yl)-piperazin-1-yl]-propyl}-N-pyridin-2-yl-benzamide HCl (lecozotan), which has been characterized in multiple in vitro and in vivo pharmacological assays as a drug to treat cognitive dysfunction, is reported. In vitro binding and intrinsic activity determinations demonstrated that lecozotan is a potent and selective 5-HT(1A) receptor antagonist. Using in vivo microdialysis, lecozotan (0.3 mg/kg s.c.) antagonized the decrease in hippocampal extracellular 5-HT induced by a challenge dose (0.3 mg/kg s.c.) of 8-hydroxy-2-dipropylaminotetralin (8-OH-DPAT) and had no effects alone at doses 10-fold higher. Lecozotan significantly potentiated the potassium chloride-stimulated release of glutamate and acetylcholine in the dentate gyrus of the hippocampus. Chronic administration of lecozotan did not induce 5-HT(1A) receptor tolerance or desensitization in a behavioral model indicative of 5-HT(1A) receptor function. In drug discrimination studies, lecozotan (0.01-1 mg/kg i.m.) did not substitute for 8-OH-DPAT and produced a dose-related blockade of the 5-HT(1A) agonist discriminative stimulus cue. In aged rhesus monkeys, lecozotan produced a significant improvement in task performance efficiency at an optimal dose (1 mg/kg p.o.). Learning deficits induced by the glutamatergic antagonist MK-801 [(-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] (assessed by perceptually complex and visual spatial discrimination) and by specific cholinergic lesions of the hippocampus (assessed by visual spatial discrimination) were reversed by lecozotan (2 mg/kg i.m.) in marmosets. The heterosynaptic nature of the effects of lecozotan imbues this compound with a novel mechanism of action directed at the biochemical pathologies underlying cognitive loss in Alzheimer's disease.

  17. Noise-enhanced categorization in a recurrently reconnected neural network

    SciTech Connect

    Monterola, Christopher; Zapotocky, Martin

    2005-03-01

    We investigate the interplay of recurrence and noise in neural networks trained to categorize spatial patterns of neural activity. We develop the following procedure to demonstrate how, in the presence of noise, the introduction of recurrence permits to significantly extend and homogenize the operating range of a feed-forward neural network. We first train a two-level perceptron in the absence of noise. Following training, we identify the input and output units of the feed-forward network, and thus convert it into a two-layer recurrent network. We show that the performance of the reconnected network has features reminiscent of nondynamic stochastic resonance: the addition of noise enables the network to correctly categorize stimuli of subthreshold strength, with optimal noise magnitude significantly exceeding the stimulus strength. We characterize the dynamics leading to this effect and contrast it to the behavior of a more simple associative memory network in which noise-mediated categorization fails.

  18. YAP/TAZ enhance mammalian embryonic neural stem cell characteristics in a Tead-dependent manner

    SciTech Connect

    Han, Dasol; Byun, Sung-Hyun; Park, Soojeong; Kim, Juwan; Kim, Inhee; Ha, Soobong; Kwon, Mookwang; Yoon, Keejung

    2015-02-27

    Mammalian brain development is regulated by multiple signaling pathways controlling cell proliferation, migration and differentiation. Here we show that YAP/TAZ enhance embryonic neural stem cell characteristics in a cell autonomous fashion using diverse experimental approaches. Introduction of retroviral vectors expressing YAP or TAZ into the mouse embryonic brain induced cell localization in the ventricular zone (VZ), which is the embryonic neural stem cell niche. This change in cell distribution in the cortical layer is due to the increased stemness of infected cells; YAP-expressing cells were colabeled with Sox2, a neural stem cell marker, and YAP/TAZ increased the frequency and size of neurospheres, indicating enhanced self-renewal- and proliferative ability of neural stem cells. These effects appear to be TEA domain family transcription factor (Tead)–dependent; a Tead binding-defective YAP mutant lost the ability to promote neural stem cell characteristics. Consistently, in utero gene transfer of a constitutively active form of Tead2 (Tead2-VP16) recapitulated all the features of YAP/TAZ overexpression, and dominant negative Tead2-EnR resulted in marked cell exit from the VZ toward outer cortical layers. Taken together, these results indicate that the Tead-dependent YAP/TAZ signaling pathway plays important roles in neural stem cell maintenance by enhancing stemness of neural stem cells during mammalian brain development. - Highlights: • Roles of YAP and Tead in vivo during mammalian brain development are clarified. • Expression of YAP promotes embryonic neural stem cell characteristics in vivo in a cell autonomous fashion. • Enhancement of neural stem cell characteristics by YAP depends on Tead. • Transcriptionally active form of Tead alone can recapitulate the effects of YAP. • Transcriptionally repressive form of Tead severely reduces stem cell characteristics.

  19. Neural Networks Based Approach to Enhance Space Hardware Reliability

    NASA Technical Reports Server (NTRS)

    Zebulum, Ricardo S.; Thakoor, Anilkumar; Lu, Thomas; Franco, Lauro; Lin, Tsung Han; McClure, S. S.

    2011-01-01

    This paper demonstrates the use of Neural Networks as a device modeling tool to increase the reliability analysis accuracy of circuits targeted for space applications. The paper tackles a number of case studies of relevance to the design of Flight hardware. The results show that the proposed technique generates more accurate models than the ones regularly used to model circuits.

  20. Inhibition of GSK-3β enhances neural differentiation in unrestricted somatic stem cells.

    PubMed

    Dastjerdi, Fatemeh Vahid; Zeynali, Bahman; Tafreshi, Azita Parvaneh; Shahraz, Anahita; Chavoshi, Mahin Sadat; Najafabadi, Irandokht Khaki; Vardanjani, Marzieh Mowlavi; Atashi, Amir; Soleimani, Masoud

    2012-11-01

    GSK-3β is a key molecule in several signalling pathways, including the Wnt/β-catenin signalling pathway. There is increasing evidence suggesting Wnt/β-catenin signalling is involved in the neural differentiation of embryonic, somatic and neural stem cells. However, a large body of evidence indicates that this pathway maintains stem cells in a proliferative state. To address this controversy, we have investigated whether the Wnt/β-catenin pathway is present and involved in the neural differentiation of newly introduced USSCs (unrestricted somatic stem cells). Our results indicate that the components of Wnt/β-catenin signalling are present in undifferentiated USSCs. We also show that the treatment of neurally induced USSCs with BIO (6-bromoindirubin-3'-oxime), a specific GSK-3β inhibitor and Wnt activator, for 5 and 10 days results in increased expression of a general neuronal marker (β-tubulin III). Moreover, the expression of pGSK-3β and stabilized β-catenin increased by BIO in neurally induced USSCs, indicates that the Wnt pathway is activated and functional in these cells. Thus, inhibition of GSK-3β in USSCs enhances their neural differentiation, which suggests a positive role of the Wnt/β-catenin signalling pathway towards neural fate.

  1. Neural control of muscle

    NASA Technical Reports Server (NTRS)

    Max, S. R.; Markelonis, G. J.

    1983-01-01

    Cholinergic innervation regulates the physiological and biochemical properties of skeletal muscle. The mechanisms that appear to be involved in this regulation include soluble, neurally-derived polypeptides, transmitter-evoked muscle activity and the neurotransmitter, acetylcholine, itself. Despite extensive research, the interacting neural mechanisms that control such macromolecules as acetylcholinesterase, the acetylcholine receptor and glucose 6-phosphate dehydrogenase remain unclear. It may be that more simplified in vitro model systems coupled with recent dramatic advances in the molecular biology of neurally-regulated proteins will begin to allow researchers to unravel the mechanisms controlling the expression and maintenance of these macromolecules.

  2. Musical Training during Early Childhood Enhances the Neural Encoding of Speech in Noise

    ERIC Educational Resources Information Center

    Strait, Dana L.; Parbery-Clark, Alexandra; Hittner, Emily; Kraus, Nina

    2012-01-01

    For children, learning often occurs in the presence of background noise. As such, there is growing desire to improve a child's access to a target signal in noise. Given adult musicians' perceptual and neural speech-in-noise enhancements, we asked whether similar effects are present in musically-trained children. We assessed the perception and…

  3. Repetition Priming and Repetition Suppression: A Case for Enhanced Efficiency Through Neural Synchronization

    PubMed Central

    Gotts, Stephen J.; Chow, Carson C.; Martin, Alex

    2012-01-01

    Stimulus repetition in identification tasks leads to improved behavioral performance ("repetition priming") but attenuated neural responses ("repetition suppression") throughout task-engaged cortical regions. While it's clear that this pervasive brain-behavior relationship reflects some form of improved processing efficiency, the exact form that it takes remains elusive. In this Discussion Paper, we review four different theoretical proposals that have the potential to link repetition suppression and priming, with a particular focus on a proposal that stimulus repetition affects improved efficiency through enhanced neural synchronization. We argue that despite exciting recent work on the role of neural synchronization in cognitive processes such as attention and perception, similar studies in the domain of learning and memory - and priming, in particular - have been lacking. We emphasize the need for new studies with adequate spatiotemporal resolution, formulate several novel predictions, and discuss our ongoing efforts to disentangle the current proposals. PMID:23144664

  4. Exposure to an Inflammatory Challenge Enhances Neural Sensitivity to Negative and Positive Social Feedback

    PubMed Central

    Muscatell, Keely A.; Moieni, Mona; Inagaki, Tristen K.; Dutcher, Janine M.; Jevtic, Ivana; Breen, Elizabeth C.; Irwin, Michael R.; Eisenberger, Naomi I.

    2016-01-01

    Inflammation, part of the body’s innate immune response, can lead to “sickness behaviors,” as well as alterations in social and affective experiences. Elevated levels of pro-inflammatory cytokines have been associated with increased neural sensitivity to social rejection and social threat, but also decreased neural sensitivity to rewards. However, recent evidence suggests that inflammation may actually enhance sensitivity to certain social rewards, such as those that signal support and care. Despite a growing interest in how inflammation influences neural reactivity to positive and negative social experiences, no known studies have investigated these processes in the same participants, using a similar task. To examine this issue, 107 participants were randomly assigned to receive either placebo or low-dose endotoxin, which safely triggers an inflammatory response. When levels of pro-inflammatory cytokines were at their peak, participants were scanned using fMRI while they received positive, negative, and neutral feedback from an “evaluator” (actually a confederate) about how they came across in an audio-recorded interview. In response to negative feedback (vs. neutral), participants in the endotoxin condition showed heightened neural activity in a number of threat-related neural regions (i.e., bilateral amygdala, dorsal anterior cingulate cortex) and a key mentalizing-related region (i.e., dorsomedial PFC), compared to placebo participants. Interestingly, when receiving positive feedback (vs. neutral), endotoxin led to greater neural activity in the ventral striatum and ventromedial PFC, regions often implicated in processing reward, compared to placebo. Together, these results reveal that individuals exposed to an inflammatory challenge are more “neurally sensitive” to both negative and positive social feedback, suggesting that inflammation may lead to a greater vigilance for both social threats and social rewards. PMID:27032568

  5. Exposure to an inflammatory challenge enhances neural sensitivity to negative and positive social feedback.

    PubMed

    Muscatell, Keely A; Moieni, Mona; Inagaki, Tristen K; Dutcher, Janine M; Jevtic, Ivana; Breen, Elizabeth C; Irwin, Michael R; Eisenberger, Naomi I

    2016-10-01

    Inflammation, part of the body's innate immune response, can lead to "sickness behaviors," as well as alterations in social and affective experiences. Elevated levels of pro-inflammatory cytokines have been associated with increased neural sensitivity to social rejection and social threat, but also decreased neural sensitivity to rewards. However, recent evidence suggests that inflammation may actually enhance sensitivity to certain social rewards, such as those that signal support and care. Despite a growing interest in how inflammation influences neural reactivity to positive and negative social experiences, no known studies have investigated these processes in the same participants, using a similar task. To examine this issue, 107 participants were randomly assigned to receive either placebo or low-dose endotoxin, which safely triggers an inflammatory response. When levels of pro-inflammatory cytokines were at their peak, participants were scanned using fMRI while they received positive, negative, and neutral feedback from an "evaluator" (actually a confederate) about how they came across in an audio-recorded interview. In response to negative feedback (vs. neutral), participants in the endotoxin condition showed heightened neural activity in a number of threat-related neural regions (i.e., bilateral amygdala, dorsal anterior cingulate cortex) and a key mentalizing-related region (i.e., dorsomedial PFC), compared to placebo participants. Interestingly, when receiving positive feedback (vs. neutral), endotoxin (vs. placebo) led to greater neural activity in the ventral striatum and ventromedial PFC, regions often implicated in processing reward, as well as greater activity in dorsomedial PFC. Together, these results reveal that individuals exposed to an inflammatory challenge are more "neurally sensitive" to both negative and positive social feedback, suggesting that inflammation may lead to a greater vigilance for both social threats and social rewards.

  6. Canonical Wnt signaling transiently stimulates proliferation and enhances neurogenesis in neonatal neural progenitor cultures

    SciTech Connect

    Hirsch, Cordula; Campano, Louise M.; Woehrle, Simon; Hecht, Andreas . E-mail: andreas.hecht@mol-med.uni-freiburg.de

    2007-02-01

    Canonical Wnt signaling triggers the formation of heterodimeric transcription factor complexes consisting of {beta}-catenin and T cell factors, and thereby controls the execution of specific genetic programs. During the expansion and neurogenic phases of embryonic neural development canonical Wnt signaling initially controls proliferation of neural progenitor cells, and later neuronal differentiation. Whether Wnt growth factors affect neural progenitor cells postnatally is not known. Therefore, we have analyzed the impact of Wnt signaling on neural progenitors isolated from cerebral cortices of newborn mice. Expression profiling of pathway components revealed that these cells are fully equipped to respond to Wnt signals. However, Wnt pathway activation affected only a subset of neonatal progenitors and elicited a limited increase in proliferation and neuronal differentiation in distinct subsets of cells. Moreover, Wnt pathway activation only transiently stimulated S-phase entry but did not support long-term proliferation of progenitor cultures. The dampened nature of the Wnt response correlates with the predominant expression of inhibitory pathway components and the rapid actuation of negative feedback mechanisms. Interestingly, in differentiating cell cultures activation of canonical Wnt signaling reduced Hes1 and Hes5 expression suggesting that during postnatal neural development, Wnt/{beta}-catenin signaling enhances neurogenesis from progenitor cells by interfering with Notch pathway activity.

  7. Design and expression of human alpha7 nicotinic acetylcholine receptor extracellular domain mutants with enhanced solubility and ligand-binding properties.

    PubMed

    Zouridakis, Marios; Zisimopoulou, Paraskevi; Eliopoulos, Elias; Poulas, Konstantinos; Tzartos, Socrates J

    2009-02-01

    In order to facilitate structural studies of the extracellular domain (ECD) of human alpha7 nicotinic acetylcholine receptor (nAChR), we designed several mutants, since the wild-type-ECD forms large oligomers and microaggregates, and expressed them in the yeast Pichia pastoris. Mutant design was based on a 3D model of human alpha7-nAChR-ECD, constructed using as templates the X-ray crystal structure of the homologous acetylcholine-binding protein (AChBP) and the electron microscopy structure of the Torpedo alpha-nAChR-ECD. At least one mutant, mut10, carrying six single-point mutations (Phe3Tyr, Val69Thr, Cys116Ser, Ile165Thr, Val177Thr, Phe187Tyr) and the replacement of its Cys-loop with the corresponding and more hydrophilic AChBP Cys-loop, was expressed with a 4-fold higher expression yield (1.2 mg/L) than the wild-type alpha7-ECD, existing exclusively as a soluble oligomeric, probably pentameric, form, at concentrations up to at least 10 mg/mL, as judged by gel filtration and dynamic light scattering. This mutant displayed a significantly improved (125)I-alpha-bungarotoxin-binding affinity (K(d)=24 nM) compared to the wild-type-ECD (K(d)=70 nM), the binding being inhibited by unlabelled alpha-bungarotoxin, d-tubocurarine or nicotine (K(i) of 21.5 nM, 127 microM and 17.5 mM, respectively). Circular dichroism studies of mut10 revealed (a) a similar secondary structure composition ( approximately 5% alpha-helix, approximately 45% beta-sheet) to that of the AChBP, Torpedo alpha-nAChR-ECD, and mouse alpha1-nAChR-ECD, (b) a well-defined tertiary structure and (c) binding of small cholinergic ligands at micromolar concentrations. Furthermore, electron microscopy showed well-assembled, probably pentameric, particles of mut10. Finally, since deglycosylation did not alter its solubility or ligand-binding properties, mut10, in either its glycosylated or deglycosylated form, is a promising alpha7-ECD mutant for structural studies, useful for the rational drug design to

  8. Mortality salience enhances racial in-group bias in empathic neural responses to others' suffering.

    PubMed

    Li, Xiaoyang; Liu, Yi; Luo, Siyang; Wu, Bing; Wu, Xinhuai; Han, Shihui

    2015-09-01

    Behavioral research suggests that mortality salience (MS) leads to increased in-group identification and in-group favoritism in prosocial behavior. What remains unknown is whether and how MS influences brain activity that mediates emotional resonance with in-group and out-group members and is associated with in-group favoritism in helping behavior. The current work investigated MS effects on empathic neural responses to racial in-group and out-group members' suffering. Experiments 1 and 2 respectively recorded event related potentials (ERPs) and blood oxygen level dependent signals to pain/neutral expressions of Asian and Caucasian faces from Chinese adults who had been primed with MS or negative affect (NA). Experiment 1 found that an early frontal/central activity (P2) was more strongly modulated by pain vs. neutral expressions of Asian than Caucasian faces, but this effect was not affected by MS vs. NA priming. However, MS relative to NA priming enhanced racial in-group bias in long-latency neural response to pain expressions over the central/parietal regions (P3). Experiment 2 found that MS vs. NA priming increased racial in-group bias in empathic neural responses to pain expression in the anterior and mid-cingulate cortex. Our findings indicate that reminding mortality enhances brain activity that differentiates between racial in-group and out-group members' emotional states and suggest a neural basis of in-group favoritism under mortality threat.

  9. Mortality salience enhances racial in-group bias in empathic neural responses to others' suffering.

    PubMed

    Li, Xiaoyang; Liu, Yi; Luo, Siyang; Wu, Bing; Wu, Xinhuai; Han, Shihui

    2015-09-01

    Behavioral research suggests that mortality salience (MS) leads to increased in-group identification and in-group favoritism in prosocial behavior. What remains unknown is whether and how MS influences brain activity that mediates emotional resonance with in-group and out-group members and is associated with in-group favoritism in helping behavior. The current work investigated MS effects on empathic neural responses to racial in-group and out-group members' suffering. Experiments 1 and 2 respectively recorded event related potentials (ERPs) and blood oxygen level dependent signals to pain/neutral expressions of Asian and Caucasian faces from Chinese adults who had been primed with MS or negative affect (NA). Experiment 1 found that an early frontal/central activity (P2) was more strongly modulated by pain vs. neutral expressions of Asian than Caucasian faces, but this effect was not affected by MS vs. NA priming. However, MS relative to NA priming enhanced racial in-group bias in long-latency neural response to pain expressions over the central/parietal regions (P3). Experiment 2 found that MS vs. NA priming increased racial in-group bias in empathic neural responses to pain expression in the anterior and mid-cingulate cortex. Our findings indicate that reminding mortality enhances brain activity that differentiates between racial in-group and out-group members' emotional states and suggest a neural basis of in-group favoritism under mortality threat. PMID:26074201

  10. Pten deletion in adult neural stem/progenitor cells enhances constitutive neurogenesis.

    PubMed

    Gregorian, Caroline; Nakashima, Jonathan; Le Belle, Janel; Ohab, John; Kim, Rachel; Liu, Annie; Smith, Kate Barzan; Groszer, Matthias; Garcia, A Denise; Sofroniew, Michael V; Carmichael, S Thomas; Kornblum, Harley I; Liu, Xin; Wu, Hong

    2009-02-11

    Here we show that conditional deletion of Pten in a subpopulation of adult neural stem cells in the subependymal zone (SEZ) leads to persistently enhanced neural stem cell self-renewal without sign of exhaustion. These Pten null SEZ-born neural stem cells and progenies can follow the endogenous migration, differentiation, and integration pathways and contribute to constitutive neurogenesis in the olfactory bulb. As a result, Pten deleted animals have increased olfactory bulb mass and enhanced olfactory function. Pten null cells in the olfactory bulb can establish normal connections with peripheral olfactory epithelium and help olfactory bulb recovery from acute damage. Following a focal stroke, Pten null progenitors give rise to greater numbers of neuroblasts that migrate to peri-infarct cortex. However, in contrast to the olfactory bulb, no significant long-term survival and integration can be observed, indicating that additional factors are necessary for long-term survival of newly born neurons after stroke. These data suggest that manipulating PTEN-controlled signaling pathways may be a useful step in facilitating endogenous neural stem/progenitor expansion for the treatment of disorders or lesions in regions associated with constitutive neurogenesis. PMID:19211894

  11. Crossmodal integration enhances neural representation of task-relevant features in audiovisual face perception.

    PubMed

    Li, Yuanqing; Long, Jinyi; Huang, Biao; Yu, Tianyou; Wu, Wei; Liu, Yongjian; Liang, Changhong; Sun, Pei

    2015-02-01

    Previous studies have shown that audiovisual integration improves identification performance and enhances neural activity in heteromodal brain areas, for example, the posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG). Furthermore, it has also been demonstrated that attention plays an important role in crossmodal integration. In this study, we considered crossmodal integration in audiovisual facial perception and explored its effect on the neural representation of features. The audiovisual stimuli in the experiment consisted of facial movie clips that could be classified into 2 gender categories (male vs. female) or 2 emotion categories (crying vs. laughing). The visual/auditory-only stimuli were created from these movie clips by removing the auditory/visual contents. The subjects needed to make a judgment about the gender/emotion category for each movie clip in the audiovisual, visual-only, or auditory-only stimulus condition as functional magnetic resonance imaging (fMRI) signals were recorded. The neural representation of the gender/emotion feature was assessed using the decoding accuracy and the brain pattern-related reproducibility indices, obtained by a multivariate pattern analysis method from the fMRI data. In comparison to the visual-only and auditory-only stimulus conditions, we found that audiovisual integration enhanced the neural representation of task-relevant features and that feature-selective attention might play a role of modulation in the audiovisual integration.

  12. Pten deletion in adult neural stem/progenitor cells enhances constitutive neurogenesis.

    PubMed

    Gregorian, Caroline; Nakashima, Jonathan; Le Belle, Janel; Ohab, John; Kim, Rachel; Liu, Annie; Smith, Kate Barzan; Groszer, Matthias; Garcia, A Denise; Sofroniew, Michael V; Carmichael, S Thomas; Kornblum, Harley I; Liu, Xin; Wu, Hong

    2009-02-11

    Here we show that conditional deletion of Pten in a subpopulation of adult neural stem cells in the subependymal zone (SEZ) leads to persistently enhanced neural stem cell self-renewal without sign of exhaustion. These Pten null SEZ-born neural stem cells and progenies can follow the endogenous migration, differentiation, and integration pathways and contribute to constitutive neurogenesis in the olfactory bulb. As a result, Pten deleted animals have increased olfactory bulb mass and enhanced olfactory function. Pten null cells in the olfactory bulb can establish normal connections with peripheral olfactory epithelium and help olfactory bulb recovery from acute damage. Following a focal stroke, Pten null progenitors give rise to greater numbers of neuroblasts that migrate to peri-infarct cortex. However, in contrast to the olfactory bulb, no significant long-term survival and integration can be observed, indicating that additional factors are necessary for long-term survival of newly born neurons after stroke. These data suggest that manipulating PTEN-controlled signaling pathways may be a useful step in facilitating endogenous neural stem/progenitor expansion for the treatment of disorders or lesions in regions associated with constitutive neurogenesis.

  13. Musical training during early childhood enhances the neural encoding of speech in noise.

    PubMed

    Strait, Dana L; Parbery-Clark, Alexandra; Hittner, Emily; Kraus, Nina

    2012-12-01

    For children, learning often occurs in the presence of background noise. As such, there is growing desire to improve a child's access to a target signal in noise. Given adult musicians' perceptual and neural speech-in-noise enhancements, we asked whether similar effects are present in musically-trained children. We assessed the perception and subcortical processing of speech in noise and related cognitive abilities in musician and nonmusician children that were matched for a variety of overarching factors. Outcomes reveal that musicians' advantages for processing speech in noise are present during pivotal developmental years. Supported by correlations between auditory working memory and attention and auditory brainstem response properties, we propose that musicians' perceptual and neural enhancements are driven in a top-down manner by strengthened cognitive abilities with training. Our results may be considered by professionals involved in the remediation of language-based learning deficits, which are often characterized by poor speech perception in noise. PMID:23102977

  14. Musical training during early childhood enhances the neural encoding of speech in noise

    PubMed Central

    Strait, Dana L.; Parbery-Clark, Alexandra; Hittner, Emily; Kraus, Nina

    2012-01-01

    For children, learning often occurs in the presence of background noise. As such, there is growing desire to improve a child’s access to a target signal in noise. Given adult musicians’ perceptual and neural speech-in-noise enhancements, we asked whether similar effects are present in musically-trained children. We assessed the perception and subcortical processing of speech in noise and related cognitive abilities in musician and nonmusician children that were matched for a variety of overarching factors. Outcomes reveal that musicians’ advantages for processing speech in noise are present during pivotal developmental years. Supported by correlations between auditory working memory and attention and auditory brainstem response properties, we propose that musicians’ perceptual and neural enhancements are driven in a top-down manner by strengthened cognitive abilities with training. Our results may be considered by professionals involved in the remediation of language-based learning deficits, which are often characterized by poor speech perception in noise. PMID:23102977

  15. Musical training during early childhood enhances the neural encoding of speech in noise.

    PubMed

    Strait, Dana L; Parbery-Clark, Alexandra; Hittner, Emily; Kraus, Nina

    2012-12-01

    For children, learning often occurs in the presence of background noise. As such, there is growing desire to improve a child's access to a target signal in noise. Given adult musicians' perceptual and neural speech-in-noise enhancements, we asked whether similar effects are present in musically-trained children. We assessed the perception and subcortical processing of speech in noise and related cognitive abilities in musician and nonmusician children that were matched for a variety of overarching factors. Outcomes reveal that musicians' advantages for processing speech in noise are present during pivotal developmental years. Supported by correlations between auditory working memory and attention and auditory brainstem response properties, we propose that musicians' perceptual and neural enhancements are driven in a top-down manner by strengthened cognitive abilities with training. Our results may be considered by professionals involved in the remediation of language-based learning deficits, which are often characterized by poor speech perception in noise.

  16. Dimethyloxalylglycine may be enhance the capacity of neural-like cells in treatment of Alzheimer disease.

    PubMed

    Ghasemi Moravej, Fahimeh; Vahabian, Mehrangiz; Soleimani Asl, Sara

    2016-06-01

    Although using differentiated stem cells is the best proposed option for the treatment of Alzheimer disease (AD), an efficient differentiation and cell therapy require enhanced cell survival and homing and decreased apoptosis. It seems that hypoxia preconditioning via Dimethyloxalylglycine (DMOG) may increase the capacity of MSC to induce neural like stem cells (NSCs). Furthermore, it can likely improve the viability of NSCs when transplanted into the brain of AD rats.

  17. Acetylcholine Receptor: An Allosteric Protein

    NASA Astrophysics Data System (ADS)

    Changeux, Jean-Pierre; Devillers-Thiery, Anne; Chemouilli, Phillippe

    1984-09-01

    The nicotine receptor for the neurotransmitter acetylcholine is an allosteric protein composed of four different subunits assembled in a transmembrane pentamer α 2β γ δ . The protein carries two acetylcholine sites at the level of the α subunits and contains the ion channel. The complete sequence of the four subunits is known. The membrane-bound protein undergoes conformational transitions that regulate the opening of the ion channel and are affected by various categories of pharmacologically active ligands.

  18. Effect of potassium and acetylcholine on canine intestinal smooth muscle.

    PubMed

    Hara, Y; Szurszewski, J H

    1986-03-01

    Mechanical and intracellular electrical activity were recorded simultaneously from small intestinal smooth muscle of the dog. Tonic and phasic contractions due to exogenous acetylcholine and elevated external K+ concentration were spike-dependent in longitudinal and inner circular muscle layers and spike-independent in the outer circular muscle layer. Voltage-tension curves were generated by graded depolarization of the membrane. In spike-dependent longitudinal and inner circular muscle layers the threshold voltage for initiation of spikes and contraction was approximately --53 mV. In spike-independent outer circular muscle layer the voltage threshold for contraction was approximately -42 mV. The resting membrane potential in longitudinal and inner circular muscle layers was close to the voltage threshold for initiation of spikes and contraction. In contrast, in the outer circular muscle it was approximately 20 mV more negative to the voltage threshold for contraction. In the outer circular muscle layer of whole-thickness preparations an increase in the amplitude of phasic contractions caused by acetylcholine was associated with an increase in the amplitude of the slow waves. Tone was related to the resting membrane potential. In preparations of isolated outer circular muscle acetylcholine caused depolarization of the membrane potential, slow waves and phasic contractions; comparable depolarization by increases in external K+ concentration did not induce slow waves or phasic contractions. Comparison of the effect of acetylcholine on outer circular muscle with the voltage-tension curve for this muscle layer showed that the top of the slow wave was associated with just the contractile force predicted by the voltage-tension curve. This suggests that acetylcholine altered the force of phasic contraction of the outer circular muscle through a voltage-dependent mechanism. In non-neural cells located on the serosal side of the outer circular muscle layer of the dog, cat

  19. Histamine H3 receptors regulate acetylcholine release from the guinea pig ileum myenteric plexus

    SciTech Connect

    Poli, E.; Coruzzi, G.; Bertaccini, G. )

    1991-01-01

    The effect of selective histamine H3-receptor agonists and antagonists on the acetylcholine release from peripheral nerves was evaluated in the guinea pig longitudinal muscle-myenteric plexus preparations, preloaded with ({sup 3}H)choline. In the presence of H1 and H2 blockade, histamine and (R)-{alpha}-methylhistamine inhibited the electrically-evoked acetylcholine release, being (R)-{alpha}-methylhistamine more active than histamine, but behaving as a partial agonist. The effect of histamine was completely reversed by selective H3-blocking drugs, thioperamide and impromidine, while only submaximal doses of (R)-{alpha}-methylhistamine were antagonized. Furthermore, thioperamide and impromidine enhanced the electrically-evoked acetylcholine release. On the contrary, the new H3-blocker, HST-7, was found substantially ineffective, both as histamine antagonist and as acetylcholine overflow enhancer. These data suggest that histamine exerts an inhibitory control on the acetylcholine release from intestinal cholinergic nerves through the activation of H3 receptors.

  20. Enhanced role for the opening of potassium channels in relaxant responses to acetylcholine after myocardial ischaemia and reperfusion in dog coronary arteries

    PubMed Central

    Chan, Elsa C H; Woodman, Owen L

    1999-01-01

    Anaesthetized dogs were subjected to 1 h occlusion of the left circumflex coronary artery followed by 2 h of reperfusion. Relaxant responses were examined in coronary artery rings removed proximal (nonischaemic) or distal (ischaemic) to the site of occlusion. Relaxant responses to acetylcholine (ACh) were similar in nonischaemic and ischaemic artery rings. In addition ACh-induced relaxation of nonischaemic and ischaemic artery rings was equally susceptible to inhibition of nitric oxide (NO) synthase using L-NG-nitroarginine (L-NOARG, 10−4 M), or to inhibition of soluble guanylate cyclase using 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, 10−5 M). In nonischaemic arteries, the relaxation to ACh was unaffected by high K+ (67 mM) but in ischaemic arteries, the maximum relaxation to ACh was significantly reduced from 113±6 to 60±2% (ANOVA, P<0.05). Tetraethylammonium (TEA, 10−3 M), an inhibitor of large conductance calcium activated potassium (BKCa) channels did not inhibit the response to ACh in nonischaemic arteries but in ischaemic arteries TEA significantly shifted the concentration response curve to ACh to the right (pEC50; nonischaemic, 7.07±0.25; ischaemic, 6.54±0.21, P<0.01, ANOVA) without decreasing the maximum relaxation. TEA did not affect the responses to sodium nitroprusside in either nonischaemic or ischaemic arteries. In conclusion, ischaemia/reperfusion did not change the sensitivity of endothelium-dependent relaxation to L-NOARG or ODQ indicating that ischaemia did not affect the contribution of NO or cyclic GMP to ACh-induced relaxation. However, in ischaemic arteries the opening of the BKCa channels contributed to relaxation caused by ACh whereas TEA had no effect in nonischaemic arteries. The factor responsible for the opening of this potassium channel was a factor other than NO and may be endothelium derived hyperpolarizing factor (EDHF). PMID:10193772

  1. Enzyme-linked DNA dendrimer nanosensors for acetylcholine

    NASA Astrophysics Data System (ADS)

    Walsh, Ryan; Morales, Jennifer M.; Skipwith, Christopher G.; Ruckh, Timothy T.; Clark, Heather A.

    2015-10-01

    It is currently difficult to measure small dynamics of molecules in the brain with high spatial and temporal resolution while connecting them to the bigger picture of brain function. A step towards understanding the underlying neural networks of the brain is the ability to sense discrete changes of acetylcholine within a synapse. Here we show an efficient method for generating acetylcholine-detecting nanosensors based on DNA dendrimer scaffolds that incorporate butyrylcholinesterase and fluorescein in a nanoscale arrangement. These nanosensors are selective for acetylcholine and reversibly respond to levels of acetylcholine in the neurophysiological range. This DNA dendrimer architecture has the potential to overcome current obstacles to sensing in the synaptic environment, including the nanoscale size constraints of the synapse and the ability to quantify the spatio-temporal fluctuations of neurotransmitter release. By combining the control of nanosensor architecture with the strategic placement of fluorescent reporters and enzymes, this novel nanosensor platform can facilitate the development of new selective imaging tools for neuroscience.

  2. Enzyme-linked DNA dendrimer nanosensors for acetylcholine

    PubMed Central

    Walsh, Ryan; Morales, Jennifer M.; Skipwith, Christopher G.; Ruckh, Timothy T.; Clark, Heather A.

    2015-01-01

    It is currently difficult to measure small dynamics of molecules in the brain with high spatial and temporal resolution while connecting them to the bigger picture of brain function. A step towards understanding the underlying neural networks of the brain is the ability to sense discrete changes of acetylcholine within a synapse. Here we show an efficient method for generating acetylcholine-detecting nanosensors based on DNA dendrimer scaffolds that incorporate butyrylcholinesterase and fluorescein in a nanoscale arrangement. These nanosensors are selective for acetylcholine and reversibly respond to levels of acetylcholine in the neurophysiological range. This DNA dendrimer architecture has the potential to overcome current obstacles to sensing in the synaptic environment, including the nanoscale size constraints of the synapse and the ability to quantify the spatio-temporal fluctuations of neurotransmitter release. By combining the control of nanosensor architecture with the strategic placement of fluorescent reporters and enzymes, this novel nanosensor platform can facilitate the development of new selective imaging tools for neuroscience. PMID:26442999

  3. ROCK inhibition enhances neurite outgrowth in neural stem cells by upregulating YAP expression in vitro.

    PubMed

    Jia, Xu-Feng; Ye, Fei; Wang, Yan-Bo; Feng, Da-Xiong

    2016-06-01

    Spontaneous axonal regeneration of neurons does not occur after spinal cord injury because of inhibition by myelin and other inhibitory factors. Studies have demonstrated that blocking the Rho/Rho-kinase (ROCK) pathway can promote neurite outgrowth in spinal cord injury models. In the present study, we investigated neurite outgrowth and neuronal differentiation in neural stem cells from the mouse subventricular zone after inhibition of ROCK in vitro. Inhibition of ROCK with Y-27632 increased neurite length, enhanced neuronal differentiation, and upregulated the expression of two major signaling pathway effectors, phospho-Akt and phospho-mitogen-activated protein kinase, and the Hippo pathway effector YAP. These results suggest that inhibition of ROCK mediates neurite outgrowth in neural stem cells by activating the Hippo signaling pathway. PMID:27482229

  4. ROCK inhibition enhances neurite outgrowth in neural stem cells by upregulating YAP expression in vitro

    PubMed Central

    Jia, Xu-feng; Ye, Fei; Wang, Yan-bo; Feng, Da-xiong

    2016-01-01

    Spontaneous axonal regeneration of neurons does not occur after spinal cord injury because of inhibition by myelin and other inhibitory factors. Studies have demonstrated that blocking the Rho/Rho-kinase (ROCK) pathway can promote neurite outgrowth in spinal cord injury models. In the present study, we investigated neurite outgrowth and neuronal differentiation in neural stem cells from the mouse subventricular zone after inhibition of ROCK in vitro. Inhibition of ROCK with Y-27632 increased neurite length, enhanced neuronal differentiation, and upregulated the expression of two major signaling pathway effectors, phospho-Akt and phospho-mitogen-activated protein kinase, and the Hippo pathway effector YAP. These results suggest that inhibition of ROCK mediates neurite outgrowth in neural stem cells by activating the Hippo signaling pathway. PMID:27482229

  5. Acetylcholine Mediates a Slow Synaptic Potential in Hippocampal Pyramidal Cells

    NASA Astrophysics Data System (ADS)

    Cole, A. E.; Nicoll, R. A.

    1983-09-01

    The hippocampal slice preparation was used to study the role of acetylcholine as a synaptic transmitter. Bath-applied acetylcholine had three actions on pyramidal cells: (i) depolarization associated with increased input resistance, (ii) blockade of calcium-activated potassium responses, and (iii) blockade of accommodation of cell discharge. All these actions were reversed by the muscarinic antagonist atropine. Stimulation of sites in the slice known to contain cholinergic fibers mimicked all the actions. Furthermore, these evoked synaptic responses were enhanced by the cholinesterase inhibitor eserine and were blocked by atropine. These findings provide electrophysiological support for the role of acetylcholine as a synaptic transmitter in the brain and demonstrate that nonclassical synaptic responses involving the blockade of membrane conductances exist in the brain.

  6. Upregulation of Nicotinic Acetylcholine Receptor alph4+beta2 through a Ligand-Independent PI3Kbeta Mechanism That Is Enhanced by TNFalpha and the Jak2/p38Mapk Pathways

    PubMed Central

    Rogers, Scott W.; Gahring, Lorise C.

    2015-01-01

    High affinity nicotine-binding sites in the mammalian brain are neuronal nicotinic acetylcholine receptors (nAChR) assembled from at least alpha4 and beta2 subunits into pentameric ion channels. When exposed to ligands such as nicotine, these receptors respond by undergoing upregulation, a correlate of nicotine addiction. Upregulation can be measured using HEK293 (293) cells that stably express alpha4 and beta2 subunits using quantification of [3H]epibatidine ([3H]Eb) binding to measure mature receptors. Treatment of these cells with choline also produces upregulation through a hemicholinium3 (HC3)-sensitive (choline kinase) and an HC3-insensitive pathway which are both independent of the mechanism used by nicotine for upregulation. In both cases, upregulation is significantly enhanced by the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) which signals through its receptor Tnfr1 to activate p38Mapk. Here we report that the inhibition of class1 phosphoinositide 3-kinases isoform PI3Kbeta using the selective antagonist PI828 is alone sufficient to produce upregulation and enhance both nicotine and choline HC3-sensitive mediated upregulation. Further, these processes are impacted upon by an AG-490 sensitive Jak2-associated pathway. Both PI3Kbeta (negative) and Jak2 (positive) modulation of upregulation converge through p38Mapk and both overlap with TNFalpha enhancement of this process. Upregulation through the PI3Kbeta pathway did not require Akt. Collectively these findings support upregulation of endogenous alpha4beta2 as a balance among cellular signaling networks that are highly responsive to multiple environmental, inflammatory and metabolic agents. The findings also suggest how illness and metabolic stress could alter the expression of this important nicotinic receptor and novel avenues to intercede in modifying its expression. PMID:26619345

  7. Musical intervention enhances infants' neural processing of temporal structure in music and speech.

    PubMed

    Zhao, T Christina; Kuhl, Patricia K

    2016-05-10

    Individuals with music training in early childhood show enhanced processing of musical sounds, an effect that generalizes to speech processing. However, the conclusions drawn from previous studies are limited due to the possible confounds of predisposition and other factors affecting musicians and nonmusicians. We used a randomized design to test the effects of a laboratory-controlled music intervention on young infants' neural processing of music and speech. Nine-month-old infants were randomly assigned to music (intervention) or play (control) activities for 12 sessions. The intervention targeted temporal structure learning using triple meter in music (e.g., waltz), which is difficult for infants, and it incorporated key characteristics of typical infant music classes to maximize learning (e.g., multimodal, social, and repetitive experiences). Controls had similar multimodal, social, repetitive play, but without music. Upon completion, infants' neural processing of temporal structure was tested in both music (tones in triple meter) and speech (foreign syllable structure). Infants' neural processing was quantified by the mismatch response (MMR) measured with a traditional oddball paradigm using magnetoencephalography (MEG). The intervention group exhibited significantly larger MMRs in response to music temporal structure violations in both auditory and prefrontal cortical regions. Identical results were obtained for temporal structure changes in speech. The intervention thus enhanced temporal structure processing not only in music, but also in speech, at 9 mo of age. We argue that the intervention enhanced infants' ability to extract temporal structure information and to predict future events in time, a skill affecting both music and speech processing.

  8. Musical intervention enhances infants’ neural processing of temporal structure in music and speech

    PubMed Central

    Zhao, T. Christina; Kuhl, Patricia K.

    2016-01-01

    Individuals with music training in early childhood show enhanced processing of musical sounds, an effect that generalizes to speech processing. However, the conclusions drawn from previous studies are limited due to the possible confounds of predisposition and other factors affecting musicians and nonmusicians. We used a randomized design to test the effects of a laboratory-controlled music intervention on young infants’ neural processing of music and speech. Nine-month-old infants were randomly assigned to music (intervention) or play (control) activities for 12 sessions. The intervention targeted temporal structure learning using triple meter in music (e.g., waltz), which is difficult for infants, and it incorporated key characteristics of typical infant music classes to maximize learning (e.g., multimodal, social, and repetitive experiences). Controls had similar multimodal, social, repetitive play, but without music. Upon completion, infants’ neural processing of temporal structure was tested in both music (tones in triple meter) and speech (foreign syllable structure). Infants’ neural processing was quantified by the mismatch response (MMR) measured with a traditional oddball paradigm using magnetoencephalography (MEG). The intervention group exhibited significantly larger MMRs in response to music temporal structure violations in both auditory and prefrontal cortical regions. Identical results were obtained for temporal structure changes in speech. The intervention thus enhanced temporal structure processing not only in music, but also in speech, at 9 mo of age. We argue that the intervention enhanced infants’ ability to extract temporal structure information and to predict future events in time, a skill affecting both music and speech processing. PMID:27114512

  9. Musical intervention enhances infants' neural processing of temporal structure in music and speech.

    PubMed

    Zhao, T Christina; Kuhl, Patricia K

    2016-05-10

    Individuals with music training in early childhood show enhanced processing of musical sounds, an effect that generalizes to speech processing. However, the conclusions drawn from previous studies are limited due to the possible confounds of predisposition and other factors affecting musicians and nonmusicians. We used a randomized design to test the effects of a laboratory-controlled music intervention on young infants' neural processing of music and speech. Nine-month-old infants were randomly assigned to music (intervention) or play (control) activities for 12 sessions. The intervention targeted temporal structure learning using triple meter in music (e.g., waltz), which is difficult for infants, and it incorporated key characteristics of typical infant music classes to maximize learning (e.g., multimodal, social, and repetitive experiences). Controls had similar multimodal, social, repetitive play, but without music. Upon completion, infants' neural processing of temporal structure was tested in both music (tones in triple meter) and speech (foreign syllable structure). Infants' neural processing was quantified by the mismatch response (MMR) measured with a traditional oddball paradigm using magnetoencephalography (MEG). The intervention group exhibited significantly larger MMRs in response to music temporal structure violations in both auditory and prefrontal cortical regions. Identical results were obtained for temporal structure changes in speech. The intervention thus enhanced temporal structure processing not only in music, but also in speech, at 9 mo of age. We argue that the intervention enhanced infants' ability to extract temporal structure information and to predict future events in time, a skill affecting both music and speech processing. PMID:27114512

  10. Power system dynamic security enhancement using artificial neural networks and energy margin

    SciTech Connect

    Momoh, J.A.; Effiong, C.B.

    1996-11-01

    A framework for dynamic security enhancement based on area-wise preventive control is proposed. The power system is partitioned into areas for stability evaluation using the transient energy margin. Area vulnerability is evaluated based on the sensitivity of the energy margin w.r.t. controls in the given areas of the system. The areas of the system which contribute significantly to instability are labeled critical or weak areas and preventive control is applied in those areas of the system. The final control application is achieved by the use of artificial neural network (ANN) to compute the control inputs.

  11. Enhanced Migration of Neural Stem Cells by Microglia Grown on a Three-Dimensional Graphene Scaffold.

    PubMed

    Jiang, Ziyun; Song, Qin; Tang, Mingliang; Yang, Lingyan; Cheng, Yilin; Zhang, Min; Xu, Dongsheng; Cheng, Guosheng

    2016-09-28

    One of the key challenges in engineering neural tissues for cell-based therapies is to develop a biocompatible scaffold material to direct neural stem cell (NSC) behaviors. One great advantage for a scaffold would be to induce NSC migration toward pathological sites during regeneration and repair. In particular, the inflammatory responses in the pathological zone, which are mainly mediated by microglia in the central nervous system, affect the repair capacity of NSCs through NSC migration. Recently, graphene was used as a neural interface and scaffold material, but few studies have addressed the relationship between microglia and NSCs in a graphene culture system. In this study, we used a combination of immunofluorescence, Western blotting, enzyme-linked immunosorbent assays, and scanning electron microscopy to investigate how conditioned medium (CM) produced from microglia grown on two-dimensional graphene (2D-G) films or three-dimensional graphene (3D-G) foams govern NSC migration. The results revealed that the CM produced by microglia grown in 3D-G cultures could promote neurosphere formation, facilitate NSC migration from the neurospheres, and increase single cell polarization by activating the stromal cell-derived factor 1 α (SDF-1α)/CXC chemokine receptor 4 (CXCR4) signaling pathway and enhancing cell adhesion on the substrate. By contrast, the 2D-G CM failed to achieve these results. Our study suggests the great potential of 3D-G as a neural scaffold for NSC-based therapy in tissue engineering and regenerative medicine. PMID:27589088

  12. Differential effects of subtype-specific nicotinic acetylcholine receptor agonists on early and late hippocampal LTP.

    PubMed

    Kroker, Katja S; Rast, Georg; Rosenbrock, Holger

    2011-12-01

    Brain nicotinic acetylcholine receptors are involved in several neuropsychiatric disorders, e.g. Alzheimer's and Parkinson's diseases, Tourette's syndrome, schizophrenia, depression, autism, attention deficit hyperactivity disorder, and anxiety. Currently, approaches selectively targeting the activation of specific nicotinic acetylcholine receptors are in clinical development for treatment of memory impairment of Alzheimer's disease patients. These are α4β2 and α7 nicotinic acetylcholine receptor agonists which are believed to enhance cholinergic and glutamatergic neurotransmission, respectively. In order to gain a better insight into the mechanistic role of these two nicotinic acetylcholine receptors in learning and memory, we investigated the effects of the α4β2 nicotinic acetylcholine receptor agonist TC-1827 and the α7 nicotinic acetylcholine receptor partial agonist SSR180711 on hippocampal long-term potentiation (LTP), a widely accepted cellular experimental model of memory formation. Generally, LTP is distinguished in an early and a late form, the former being protein-synthesis independent and the latter being protein-synthesis dependent. TC-1827 was found to increase early LTP in a bell-shaped dose dependent manner, but did not affect late LTP. In contrast, the α7 nicotinic acetylcholine receptor partial agonist SSR180711 showed enhancing effects on both early and late LTP in a bell-shaped manner. Furthermore, SSR180711 not only increased early LTP, but also transformed it into late LTP, which was not observed with the α4β2 nicotinic acetylcholine receptor agonist. Therefore, based on these findings α7 nicotinic acetylcholine receptor (partial) agonists appear to exhibit stronger efficacy on memory improvement than α4β2 nicotinic acetylcholine receptor agonists. PMID:21968142

  13. Progranulin enhances neural progenitor cell proliferation through glycogen synthase kinase 3β phosphorylation.

    PubMed

    Nedachi, T; Kawai, T; Matsuwaki, T; Yamanouchi, K; Nishihara, M

    2011-06-30

    Progranulin (PGRN) is an estrogen-inducible growth factor thought to affect multiple processes in the CNS, including brain sexual differentiation, adult neurogenesis in the hippocampus, and development of neurodegenerative diseases. However, the precise physiological functions of PGRN in individual nerve cells are not fully understood. The aim of the present study was to enhance the understanding of PGRN function in the CNS by investigating the effects of PGRN on neural progenitor cells (NPCs). We found that significant amounts of endogenous PGRN were secreted from isolated NPCs in cultures. To assess the bioactivities of endogenous and exogenous PGRN, we studied NPCs derived from wild-type mice (WT-NPCs) and PGRN-deficient mice (KO-NPCs). We found that proliferation of KO-NPCs was significantly enhanced by PGRN treatment; however, PGRN treatment apparently did not affect proliferation of WT-NPCs perhaps because of the high levels of endogenous PGRN expression. NPC death and asymmetric cellular division of KO-NPCs and WT-NPCs, which results in production of neural stem cells, astrocytes, or oligodendrocytes, were not affected by PGRN treatment. We also investigated the signaling mechanism(s) that mediate PGRN-induced NPC proliferation and found that phosphorylation of serine 9 (S9) of glycogen synthase kinase 3-beta (GSK3β), which was dependent on phosphatidylinositol 3-kinase (PI3K) activity, was induced by PGRN treatment. In addition, a GSK3β-specific inhibitor enhanced NPC proliferation. Taken together, our observations indicate that PGRN enhanced NPC proliferation, at least in part, via inducing GSK3β phosphorylation. PMID:21540081

  14. Neural coordination can be enhanced by occasional interruption of normal firing patterns: a self-optimizing spiking neural network model.

    PubMed

    Woodward, Alexander; Froese, Tom; Ikegami, Takashi

    2015-02-01

    The state space of a conventional Hopfield network typically exhibits many different attractors of which only a small subset satisfies constraints between neurons in a globally optimal fashion. It has recently been demonstrated that combining Hebbian learning with occasional alterations of normal neural states avoids this problem by means of self-organized enlargement of the best basins of attraction. However, so far it is not clear to what extent this process of self-optimization is also operative in real brains. Here we demonstrate that it can be transferred to more biologically plausible neural networks by implementing a self-optimizing spiking neural network model. In addition, by using this spiking neural network to emulate a Hopfield network with Hebbian learning, we attempt to make a connection between rate-based and temporal coding based neural systems. Although further work is required to make this model more realistic, it already suggests that the efficacy of the self-optimizing process is independent from the simplifying assumptions of a conventional Hopfield network. We also discuss natural and cultural processes that could be responsible for occasional alteration of neural firing patterns in actual brains.

  15. A neural network for enhancing boundaries and surfaces in synthetic aperture radar images.

    PubMed

    Mingolla, Ennio; Ross, William; Grossberg, Stephen

    1999-04-01

    A neural network system for boundary segmentation and surface representation, inspired by a new local-circuit model of visual processing in the cerebral cortex, is used to enhance images of range data gathered by a synthetic aperture radar (SAR) sensor. Boundary segmentation is accomplished by an improved Boundary Contour System (BCS) model which completes coherent boundaries that retain their sensitivity to image contrasts and locations. A Feature Contour System (FCS) model compensates for local contrast variations and uses the compensated signals to diffusively fill-in surface regions within the BCS boundaries. Image noise pixels that are not supported by BCS boundaries are hereby eliminated. More generally, BCS/FCS processing normalizes input dynamic range, reduces noise, and enhances contrasts between surface regions. BCS/FCS processing hereby makes structures such as motor vehicles, roads, and buildings more salient to human observers than in original imagery. The new BCS model improves image enhancement with significant reductions in processing time and complexity over previous BCS applications. The new system also outperforms several established techniques for image enhancement.

  16. Simvastatin Enhances Spatial Memory and Long-Term Potentiation in Hippocampal CA1 via Upregulation of α7 Nicotinic Acetylcholine Receptor.

    PubMed

    Chen, Tingting; Wang, Conghui; Sha, Sha; Zhou, Libin; Chen, Lei; Chen, Ling

    2016-08-01

    Simvastatin (SV) has been reported to improve cognitive deficits in Alzheimer's disease. Here, we show that chronic administration of SV (20 mg/kg) for 30 days in adult mice (SV mice) enhanced spatial cognitive performance as assessed by Morris water maze and Y-maze. To explore mechanisms underlying SV-enhanced spatial cognition, we further examined synaptic properties and long-term potentiation (LTP) in hippocampal CA1, hippocampal α7nAChR expression, and Akt and ERK2 phosphorylation. In comparison with controls, the SV administration caused increase in presynaptic glutamate release and amplitude of NMDAr-dependent LTP (LTP-augmentation), and decrease in threshold of NMDAr-independent LTP induction (LTP-facilitation). The supplement of isoprenoid farnesyl pyrophosphate (FPP) by applying farnesol (FOH) could abolish the spatial cognitive potentiation, increased glutamate release, and LTP-augmentation/facilitation in SV mice. Expression of α7nAChR, but not α4β2nAChR, was increased in hippocampal pyramidal cells of SV mice with the reduction of transcription factor AP-2α, which were abolished by FOH. Levels of Akt and ERK2 phosphorylation in SV mice were elevated, which were suppressed by FOH or α7nAChR antagonist methyl-lycaconitine (MLA). In hippocampal slices obtained from SV mice, acute perfusion of MLA blocked the increased glutamate release, whereas FOH, PI3K inhibitor LY294002, or MEK inhibitor U0126 could not. In the slices of SV mice, the perfusion of MLA or U0126, but not FOH, abolished the LTP-augmentation and LTP-facilitation. By contrast, LY294002 prevented the LTP-facilitation but failed to affect the LTP-augmentation. The findings indicate that the administration of SV through reducing FPP increases α7nAChR expression and α7nAChR-related Akt and ERK2 phosphorylation, leading to LTP enhancement and spatial cognitive potentiation.

  17. Immersive audiomotor game play enhances neural and perceptual salience of weak signals in noise

    PubMed Central

    Whitton, Jonathon P.; Hancock, Kenneth E.; Polley, Daniel B.

    2014-01-01

    All sensory systems face the fundamental challenge of encoding weak signals in noisy backgrounds. Although discrimination abilities can improve with practice, these benefits rarely generalize to untrained stimulus dimensions. Inspired by recent findings that action video game training can impart a broader spectrum of benefits than traditional perceptual learning paradigms, we trained adult humans and mice in an immersive audio game that challenged them to forage for hidden auditory targets in a 2D soundscape. Both species learned to modulate their angular search vectors and target approach velocities based on real-time changes in the level of a weak tone embedded in broadband noise. In humans, mastery of this tone in noise task generalized to an improved ability to comprehend spoken sentences in speech babble noise. Neural plasticity in the auditory cortex of trained mice supported improved decoding of low-intensity sounds at the training frequency and an enhanced resistance to interference from background masking noise. These findings highlight the potential to improve the neural and perceptual salience of degraded sensory stimuli through immersive computerized games. PMID:24927596

  18. Immersive audiomotor game play enhances neural and perceptual salience of weak signals in noise.

    PubMed

    Whitton, Jonathon P; Hancock, Kenneth E; Polley, Daniel B

    2014-06-24

    All sensory systems face the fundamental challenge of encoding weak signals in noisy backgrounds. Although discrimination abilities can improve with practice, these benefits rarely generalize to untrained stimulus dimensions. Inspired by recent findings that action video game training can impart a broader spectrum of benefits than traditional perceptual learning paradigms, we trained adult humans and mice in an immersive audio game that challenged them to forage for hidden auditory targets in a 2D soundscape. Both species learned to modulate their angular search vectors and target approach velocities based on real-time changes in the level of a weak tone embedded in broadband noise. In humans, mastery of this tone in noise task generalized to an improved ability to comprehend spoken sentences in speech babble noise. Neural plasticity in the auditory cortex of trained mice supported improved decoding of low-intensity sounds at the training frequency and an enhanced resistance to interference from background masking noise. These findings highlight the potential to improve the neural and perceptual salience of degraded sensory stimuli through immersive computerized games. PMID:24927596

  19. Enhanced emotion regulation capacity and its neural substrates in those exposed to moderate childhood adversity

    PubMed Central

    Schweizer, Susanne; Walsh, Nicholas D.; Stretton, Jason; Dunn, Valerie J.; Goodyer, Ian M.; Dalgleish, Tim

    2016-01-01

    Individuals exposed to childhood adversities (CA) present with emotion regulation (ER) difficulties in later life, which have been identified as risk and maintenance factors for psychopathologies. However, it is unclear if CA negatively impacts on ER capacity per se or whether observed regulation difficulties are a function of the challenging circumstances in which ER is being deployed. In this longitudinal study, we aimed to clarify this association by investigating the behavioral and neural effects of exposure to common moderate CA (mCA) on a laboratory measure of ER capacity in late adolescence/young adulthood. Our population-derived samples of adolescents/young adults (N = 53) were administered a film-based ER-task during functional magnetic resonance imaging that allowed evaluation of ER across mCA-exposure. mCA-exposure was associated with enhanced ER capacity over both positive and negative affect. At the neural level, the better ER of negative material in those exposed to mCA was associated with reduced recruitment of ER-related brain regions, including the prefrontal cortex and temporal gyrus. In addition mCA-exposure was associated with a greater down-regulation of the amygdala during ER of negative material. The implications of these findings for our understanding of the effects of mCA on the emergence of resilience in adolescence are discussed. PMID:26341903

  20. Activation of nicotinic α(7) acetylcholine receptor enhances long term potentation in wild type mice but not in APP(swe)/PS1ΔE9 mice.

    PubMed

    Söderman, Andreas; Mikkelsen, Jens D; West, Mark J; Christensen, Ditte Z; Jensen, Morten S

    2011-01-10

    Amyloid β (Aβ) plays a central role in Alzheimer's disease (AD) and binds to the nicotinic α(7) receptor (α(7) nAChR). Little is known about the degree to which the binding of Aβ to the α(7) nAChR influences the role of this receptor in long-term potentiation (LTP), however. We have studied the effect of the partial α(7) nAChR agonist SSR180711 on hippocampal slice preparations from normal wild type (Wt) and APP(swe)/PS1ΔE9 transgenic (Tg) mice. In the hippocampal slices from the 6 months old Wt mice, the application of both nicotine (5μM) and SSR180711 (300nM) resulted in a significant enhancement of LTP expressed in area CA1. However, in the Tg mice the application of SSR180711 did not result in an increase in LTP beyond control levels. The amount of binding of the α(7) nAChR ligand 125-I-α-bungarotoxin was not different between in Tg and Wt mice. These findings indicate that the α(7) nAChR is functionally blocked in the hippocampal neurons, downstream of the α(7) nAChR, and that this is likely due to an interaction between the receptor and Aβ, which leads to changes in LTP.

  1. Comparation of enhanced green fluorescent protein gene transfected and wild-type porcine neural stem cells.

    PubMed

    Zheng, Yue-Mao; An, Zhi-Xing; Zhao, Xiao-E; Quan, Fu-Sheng; Zhao, Hui-Ying; Zhang, Ya-Rong; Liu, Jun; He, Xiao-Ying; He, Xiao-Ning

    2010-02-01

    The aim of this study was to transfect and express the enhanced green fluorescence protein (EGFP) gene into porcine neural stem cells (NSCs) to determine whether EGFP can be used as a marker to monitor NSCs. NSCs were isolated from embryonic day 30 fetal pig brain and transfected with EGFP gene using lipofection. Transfected and wild-type NSCs were induced to differentiate into cells of neuronal and myogenic lineages. Markers of passage three NSCs and their differentiated cells were tested by reverse transcription polymerase chain reaction. The results showed that EGFP could be expressed in NSCs and the differentiated cells. NSCs expressed Nestin, NogoA, DCX, Hes1, Oct4, CD-90 and Sox2. NSCs could differentiated into astrocyte (GFAP(+)), oligodendrocyte (GalC(+)), neuron (NF(+), NSE(+) and MAP2(+)) and myocyte (myf-6(+) and myoD(+)). We concluded that EGFP can be used as a marker in monitoring NSCs. PMID:19580981

  2. Comparation of enhanced green fluorescent protein gene transfected and wild-type porcine neural stem cells.

    PubMed

    Zheng, Yue-Mao; An, Zhi-Xing; Zhao, Xiao-E; Quan, Fu-Sheng; Zhao, Hui-Ying; Zhang, Ya-Rong; Liu, Jun; He, Xiao-Ying; He, Xiao-Ning

    2010-02-01

    The aim of this study was to transfect and express the enhanced green fluorescence protein (EGFP) gene into porcine neural stem cells (NSCs) to determine whether EGFP can be used as a marker to monitor NSCs. NSCs were isolated from embryonic day 30 fetal pig brain and transfected with EGFP gene using lipofection. Transfected and wild-type NSCs were induced to differentiate into cells of neuronal and myogenic lineages. Markers of passage three NSCs and their differentiated cells were tested by reverse transcription polymerase chain reaction. The results showed that EGFP could be expressed in NSCs and the differentiated cells. NSCs expressed Nestin, NogoA, DCX, Hes1, Oct4, CD-90 and Sox2. NSCs could differentiated into astrocyte (GFAP(+)), oligodendrocyte (GalC(+)), neuron (NF(+), NSE(+) and MAP2(+)) and myocyte (myf-6(+) and myoD(+)). We concluded that EGFP can be used as a marker in monitoring NSCs.

  3. Accelerated and enhanced effect of CCR5-transduced bone marrow neural stem cells on autoimmune encephalomyelitis

    PubMed Central

    Yang, Jingxian; Yan, Yaping; Ma, Cun-Gen; Kang, Tingguo; Zhang, Nan; Gran, Bruno; Xu, Hui; Li, Ke; Ciric, Bogoljub; Zangaladze, Andro; Curtis, Mark; Rostami, Abdolmohamad; Zhang, Guang-Xian

    2013-01-01

    The suppressive effect of neural stem cells (NSCs) on experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), has been reported. However, the migration of NSCs to inflammatory sites was relatively slow as was the onset of rather limited clinical benefit. Lack of, or low expression of particular chemokine receptors on NSCs could be an important factor underlying the slow migration of NSCs. To enhance the therapeutic effect of NSCs, in the present study we transduced bone marrow (BM)-derived NSCs with CCR5, a receptor for CCL3, CCL4, and CCL5, chemokines that are abundantly produced in CNS-inflamed foci of MS/EAE. After i.v. injection, CCR5-NSCs rapidly reached EAE foci in larger numbers, and more effectively suppressed CNS inflammatory infiltration, myelin damage, and clinical EAE than GFP-NSCs used as controls. CCR5-NSC-treated mice also exhibited augmented remyelination and neuron/oligodendrocyte repopulation compared to PBS- or GFP-NSC-treated mice. We inferred that the critical mechanism underlying enhanced effect of CCR5-transduced NSCs on EAE is the early migration of chemokine receptor-transduced NSCs into the inflamed foci. Such migration at an earlier stage of inflammation enables NSCs to exert more effective immunomodulation, to reduce the extent of early myelin/neuron damage by creating a less hostile environment for remyelinating cells, and possibly to participate in the remyelination/neural re-population process. These features of BM-derived transduced NSCs, combined with their easy availability (the subject’s own BM) and autologous properties, may lay the groundwork for an innovative approach to rapid and highly effective MS therapy. PMID:22526024

  4. Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model.

    PubMed

    Rajendran, Ranjith; Borghi, Elisa; Falleni, Monica; Perdoni, Federica; Tosi, Delfina; Lappin, David F; O'Donnell, Lindsay; Greetham, Darren; Ramage, Gordon; Nile, Christopher

    2015-08-01

    Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo. In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

  5. Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

    PubMed Central

    Rajendran, Ranjith; Borghi, Elisa; Falleni, Monica; Perdoni, Federica; Tosi, Delfina; Lappin, David F.; O'Donnell, Lindsay; Greetham, Darren; Ramage, Gordon

    2015-01-01

    Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo. In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections. PMID:26092919

  6. Music Training Enhances Rapid Neural Plasticity of N1 and P2 Source Activation for Unattended Sounds

    PubMed Central

    Seppänen, Miia; Hämäläinen, Jarmo; Pesonen, Anu-Katriina; Tervaniemi, Mari

    2012-01-01

    Neurocognitive studies have demonstrated that long-term music training enhances the processing of unattended sounds. It is not clear, however, whether music training also modulates rapid (within tens of minutes) neural plasticity for sound encoding. To study this phenomenon, we examined whether adult musicians display enhanced rapid neural plasticity compared to non-musicians. More specifically, we compared the modulation of P1, N1, and P2 responses to standard sounds between four unattended passive blocks. Among the standard sounds, infrequently presented deviant sounds were presented (the so-called oddball paradigm). In the middle of the experiment (after two blocks), an active task was presented. Source analysis for event-related potentials (ERPs) showed that N1 and P2 source activation was selectively decreased in musicians after 15 min of passive exposure to sounds and that P2 source activation was found to be re-enhanced after the active task in musicians. Additionally, ERP analysis revealed that in both musicians and non-musicians, P2 ERP amplitude was enhanced after 15 min of passive exposure but only at the frontal electrodes. Furthermore, in musicians, the N1 ERP was enhanced after the active discrimination task but only at the parietal electrodes. Musical training modulates the rapid neural plasticity reflected in N1 and P2 source activation for unattended regular standard sounds. Enhanced rapid plasticity of N1 and P2 is likely to reflect faster auditory perceptual learning in musicians. PMID:22435057

  7. Age-related differences in enhancement and suppression of neural activity underlying selective attention in matched young and old adults.

    PubMed

    Haring, A E; Zhuravleva, T Y; Alperin, B R; Rentz, D M; Holcomb, P J; Daffner, K R

    2013-03-01

    Selective attention reflects the top-down control of sensory processing that is mediated by enhancement or inhibition of neural activity. ERPs were used to investigate age-related differences in neural activity in an experiment examining selective attention to color under Attend and Ignore conditions, as well as under a Neutral condition in which color was task-irrelevant. We sought to determine whether differences in neural activity between old and young adult subjects were due to differences in age rather than executive capacity. Old subjects were matched to two groups of young subjects on the basis of neuropsychological test performance: one using age-appropriate norms and the other using test scores not adjusted for age. We found that old and young subject groups did not differ in the overall modulation of selective attention between Attend and Ignore conditions, as indexed by the size of the anterior Selection Positivity. However, in contrast to either young adult group, old subjects did not exhibit reduced neural activity under the Ignore relative to Neutral condition, but showed enhanced activity under the Attend condition. The onset and peak of the Selection Positivity occurred later for old than young subjects. In summary, older adults execute selective attention less efficiently than matched younger subjects, with slowed processing and failed suppression under Ignore. Increased enhancement under Attend may serve as a compensatory mechanism.

  8. Musicians' Enhanced Neural Differentiation of Speech Sounds Arises Early in Life: Developmental Evidence from Ages 3 to 30

    PubMed Central

    Strait, Dana L.; O'Connell, Samantha; Parbery-Clark, Alexandra; Kraus, Nina

    2014-01-01

    The perception and neural representation of acoustically similar speech sounds underlie language development. Music training hones the perception of minute acoustic differences that distinguish sounds; this training may generalize to speech processing given that adult musicians have enhanced neural differentiation of similar speech syllables compared with nonmusicians. Here, we asked whether this neural advantage in musicians is present early in life by assessing musically trained and untrained children as young as age 3. We assessed auditory brainstem responses to the speech syllables /ba/ and /ga/ as well as auditory and visual cognitive abilities in musicians and nonmusicians across 3 developmental time-points: preschoolers, school-aged children, and adults. Cross-phase analyses objectively measured the degree to which subcortical responses differed to these speech syllables in musicians and nonmusicians for each age group. Results reveal that musicians exhibit enhanced neural differentiation of stop consonants early in life and with as little as a few years of training. Furthermore, the extent of subcortical stop consonant distinction correlates with auditory-specific cognitive abilities (i.e., auditory working memory and attention). Results are interpreted according to a corticofugal framework for auditory learning in which subcortical processing enhancements are engendered by strengthened cognitive control over auditory function in musicians. PMID:23599166

  9. Nicotinic Acetylcholine Receptor (nAChR) Dependent Chorda Tympani Taste Nerve Responses to Nicotine, Ethanol and Acetylcholine.

    PubMed

    Ren, Zuo Jun; Mummalaneni, Shobha; Qian, Jie; Baumgarten, Clive M; DeSimone, John A; Lyall, Vijay

    2015-01-01

    Nicotine elicits bitter taste by activating TRPM5-dependent and TRPM5-independent but neuronal nAChR-dependent pathways. The nAChRs represent common targets at which acetylcholine, nicotine and ethanol functionally interact in the central nervous system. Here, we investigated if the nAChRs also represent a common pathway through which the bitter taste of nicotine, ethanol and acetylcholine is transduced. To this end, chorda tympani (CT) taste nerve responses were monitored in rats, wild-type mice and TRPM5 knockout (KO) mice following lingual stimulation with nicotine free base, ethanol, and acetylcholine, in the absence and presence of nAChR agonists and antagonists. The nAChR modulators: mecamylamine, dihydro-β-erythroidine, and CP-601932 (a partial agonist of the α3β4* nAChR), inhibited CT responses to nicotine, ethanol, and acetylcholine. CT responses to nicotine and ethanol were also inhibited by topical lingual application of 8-chlorophenylthio (CPT)-cAMP and loading taste cells with [Ca2+]i by topical lingual application of ionomycin + CaCl2. In contrast, CT responses to nicotine were enhanced when TRC [Ca2+]i was reduced by topical lingual application of BAPTA-AM. In patch-clamp experiments, only a subset of isolated rat fungiform taste cells exposed to nicotine responded with an increase in mecamylamine-sensitive inward currents. We conclude that nAChRs expressed in a subset of taste cells serve as common receptors for the detection of the TRPM5-independent bitter taste of nicotine, acetylcholine and ethanol.

  10. Acetylcholine Synthesis in Synaptosomes: Mode of Transfer of Mitochondrial Acetyl Coenzyme A

    NASA Astrophysics Data System (ADS)

    Benjamin, A. M.; Quastel, J. H.

    1981-09-01

    Labeled acetylcholine derived from labeled pyruvate in a synaptosomal preparation from rat brain, incubated with nicotinamide adenine dinucleotide as well as coenzyme A, is stimulated by calcium ions in the absence but not in the presence of Triton X-100. Whereas citrate is taken up by cholinergic synaptosomes because it suppresses the formation of acetylcholine from pyruvate, it is not itself converted into acetylcholine. The evidence suggests that there is a calcium-dependent transfer of mitochondrial acetyl coenzyme A into the cholinergic synaptoplasm, which is apparently devoid of the citrate cleavage enzyme, and is there converted into acetylcholine. The permeability of the inner mitochondrial membrane to coenzyme A and acetyl coenzyme A seems to be enhanced by calcium ions, and this effect may be mediated by mitochondrial phospholipase A2.

  11. The neural mechanisms underlying the aging-related enhancement of positive affects: electrophysiological evidences

    PubMed Central

    Meng, Xianxin; Yang, Jiemin; Cai, AYan; Ding, XinSheng; Liu, Wenwen; Li, Hong; Yuan, JiaJin

    2015-01-01

    Background: Previous studies reported that old adults, relative to young adults, showed improvement of emotional stability and increased experiences of positive affects. Methods: In order to better understand the neural underpinnings behind the aging-related enhancement of positive affects, it is necessary to investigate whether old and young adults differ in the threshold of eliciting positive or negative emotional reactions. However, no studies have examined emotional reaction differences between old and young adults by manipulating the intensity of emotional stimuli to date. To clarify this issue, the present study examined the impact of aging on the brain’s susceptibility to affective pictures of varying emotional intensities. We recorded event-related potentials (ERP) for highly negative (HN), mildly negative (MN) and neutral pictures in the negative experimental block; and for highly positive (HP), mildly positive (MP) and neutral pictures in the positive experimental block, when young and old adults were required to count the number of pictures, irrespective of the emotionality of the pictures. Results: Event-related potentials results showed that LPP (late positive potentials) amplitudes were larger for HN and MN stimuli compared to neutral stimuli in young adults, but not in old adults. By contrast, old adults displayed larger LPP amplitudes for HP and MP relative to neutral stimuli, while these effects were absent for young adults. In addition, old adults reported more frequent perception of positive stimuli and less frequent perception of negative stimuli than young adults. The post-experiment stimulus assessment showed more positive ratings of Neutral and MP stimuli, and reduced arousal ratings of HN stimuli in old compared to young adults. Conclusion: These results suggest that old adults are more resistant to the impact of negative stimuli, while they are equipped with enhanced attentional bias for positive stimuli. The implications of these results

  12. Nicotinic Acetylcholine Receptors in Sensory Cortex

    ERIC Educational Resources Information Center

    Metherate, Raju

    2004-01-01

    Acetylcholine release in sensory neocortex contributes to higher-order sensory function, in part by activating nicotinic acetylcholine receptors (nAChRs). Molecular studies have revealed a bewildering array of nAChR subtypes and cellular actions; however, there is some consensus emerging about the major nAChR subtypes and their functions in…

  13. The Hippo pathway member YAP enhances human neural crest cell fate and migration

    PubMed Central

    Hindley, Christopher J.; Condurat, Alexandra Larisa; Menon, Vishal; Thomas, Ria; Azmitia, Luis M.; Davis, Jason A.; Pruszak, Jan

    2016-01-01

    The Hippo/YAP pathway serves as a major integrator of cell surface-mediated signals and regulates key processes during development and tumorigenesis. The neural crest is an embryonic tissue known to respond to multiple environmental cues in order to acquire appropriate cell fate and migration properties. Using multiple in vitro models of human neural development (pluripotent stem cell-derived neural stem cells; LUHMES, NTERA2 and SH-SY5Y cell lines), we investigated the role of Hippo/YAP signaling in neural differentiation and neural crest development. We report that the activity of YAP promotes an early neural crest phenotype and migration, and provide the first evidence for an interaction between Hippo/YAP and retinoic acid signaling in this system. PMID:26980066

  14. [Intern(euron)al affairs : The role of specific neocortical interneuron classes in the interaction between acetylcholine and GABAergic anesthetics].

    PubMed

    Liebig, L; Grasshoff, C; Hentschke, H

    2016-08-01

    Acetylcholine is a neuromodulator which is released throughout the central nervous system and plays an essential role in consciousness and cognitive processes including attention and learning. Due to its 'activating' effect on the neuronal and behavioral level its interaction with anesthetics has long been of interest to anesthesiologists. It is widely held that a reduction of the release of acetylcholine by general anesthetics constitutes part of the anesthetic effect. This notion is backed by numerous human and animal studies, but is also in seeming contradiction to findings that acetylcholine activates specific classes of inhibitory neurons: if acetylcholine excites elements within the neuronal network responsible for the release of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), its withdrawal should diminish, not enhance, the effect of anesthetics.Focusing on cortical circuits, we present an overview of recent advances in cellular neurophysiology, particularly the interactions between inhibitory neuron classes, which provide insights on the interaction between acetylcholine and GABA.

  15. Genome-Wide Definition of Promoter and Enhancer Usage during Neural Induction of Human Embryonic Stem Cells.

    PubMed

    Poletti, Valentina; Delli Carri, Alessia; Malagoli Tagliazucchi, Guidantonio; Faedo, Andrea; Petiti, Luca; Mazza, Emilia Maria Cristina; Peano, Clelia; De Bellis, Gianluca; Bicciato, Silvio; Miccio, Annarita; Cattaneo, Elena; Mavilio, Fulvio

    2015-01-01

    Genome-wide mapping of transcriptional regulatory elements is an essential tool for understanding the molecular events orchestrating self-renewal, commitment and differentiation of stem cells. We combined high-throughput identification of transcription start sites with genome-wide profiling of histones modifications to map active promoters and enhancers in embryonic stem cells (ESCs) induced to neuroepithelial-like stem cells (NESCs). Our analysis showed that most promoters are active in both cell types while approximately half of the enhancers are cell-specific and account for most of the epigenetic changes occurring during neural induction, and most likely for the modulation of the promoters to generate cell-specific gene expression programs. Interestingly, the majority of the promoters activated or up-regulated during neural induction have a "bivalent" histone modification signature in ESCs, suggesting that developmentally-regulated promoters are already poised for transcription in ESCs, which are apparently pre-committed to neuroectodermal differentiation. Overall, our study provides a collection of differentially used enhancers, promoters, transcription starts sites, protein-coding and non-coding RNAs in human ESCs and ESC-derived NESCs, and a broad, genome-wide description of promoter and enhancer usage and of gene expression programs characterizing the transition from a pluripotent to a neural-restricted cell fate.

  16. Immunodeficiency reduces neural stem/progenitor cell apoptosis and enhances neurogenesis in the cerebral cortex after stroke.

    PubMed

    Saino, Orie; Taguchi, Akihiko; Nakagomi, Takayuki; Nakano-Doi, Akiko; Kashiwamura, Shin-Ichiro; Doe, Nobutaka; Nakagomi, Nami; Soma, Toshihiro; Yoshikawa, Hiroo; Stern, David M; Okamura, Haruki; Matsuyama, Tomohiro

    2010-08-15

    Acute inflammation in the poststroke period exacerbates neuronal damage and stimulates reparative mechanisms, including neurogenesis. However, only a small fraction of neural stem/progenitor cells survives. In this report, by using a highly reproducible model of cortical infarction in SCID mice, we examined the effects of immunodeficiency on reduction of brain injury, survival of neural stem/progenitor cells, and functional recovery. Subsequently, the contribution of T lymphocytes to neurogenesis was evaluated in mice depleted for each subset of T lymphocyte. SCID mice revealed the reduced apoptosis and enhanced proliferation of neural stem/progenitor cells induced by cerebral cortex after stroke compared with the immunocompetent wild-type mice. Removal of T lymphocytes, especially the CD4(+) T-cell population, enhanced generation of neural stem/progenitor cells, followed by accelerated functional recovery. In contrast, removal of CD25(+) T cells, a cell population including regulatory T lymphocytes, impaired functional recovery through, at least in part, suppression of neurogenesis. Our findings demonstrate a key role of T lymphocytes in regulation of poststroke neurogenesis and indicate a potential novel strategy for cell therapy in repair of the central nervous system. PMID:20623538

  17. Human Adult Dental Pulp Stem Cells Enhance Poststroke Functional Recovery Through Non-Neural Replacement Mechanisms

    PubMed Central

    Leong, Wai Khay; Henshall, Tanya L.; Arthur, Agnes; Kremer, Karlea L.; Lewis, Martin D.; Helps, Stephen C.; Field, John; Hamilton-Bruce, Monica A.; Warming, Scott; Manavis, Jim; Vink, Robert; Gronthos, Stan

    2012-01-01

    Human adult dental pulp stem cells (DPSCs), derived from third molar teeth, are multipotent and have the capacity to differentiate into neurons under inductive conditions both in vitro and following transplantation into the avian embryo. In this study, we demonstrate that the intracerebral transplantation of human DPSCs 24 hours following focal cerebral ischemia in a rodent model resulted in significant improvement in forelimb sensorimotor function at 4 weeks post-treatment. At this time, 2.3 ± 0.7% of engrafted cells had survived in the poststroke brain and demonstrated targeted migration toward the stroke lesion. In the peri-infarct striatum, transplanted DPSCs differentiated into astrocytes in preference to neurons. Our data suggest that the dominant mechanism of action underlying DPSC treatment that resulted in enhanced functional recovery is unlikely to be due to neural replacement. Functional improvement is more likely to be mediated through DPSC-dependent paracrine effects. This study provides preclinical evidence for the future use of human DPSCs in cell therapy to improve outcome in stroke patients. PMID:23197777

  18. Long-term enhancement (LTE) of postsynaptic potentials following neural conditioning, in mammalian sympathetic ganglia.

    PubMed

    Libet, B; Mochida, S

    1988-11-15

    Orthodromic, preganglionic conditioning stimulation can consistently induce long-term enhancement (LTE) (greater than 3 h) of the muscarinically mediated slow excitatory postsynaptic potential and the slow inhibitory postsynaptic potential. This was shown for superior cervical ganglia of rabbit and rat. Effective conditioning stimuli are in a physiologically observed range (3/s for 7 min, 5/s for 4 min, 10/s for 2 min, 20/s for 1 min). LTE was producible both homosynaptically and heterosynaptically. LTE can thus be associative, with conditioning synaptic input in one line inducing long-term changes in postsynaptic responses to another (heterosynaptic) input. The dopamine antagonist butaclamol depressed LTE, particularly that following the initial postconditioning period of 30 min. Adrenergic antagonists had no effect. This pharmacological evidence, coupled with the heterosynaptic induction of LTE, supports the view that neurally induced LTE may be at least partly mediated by endogenous dopamine. Another non-cholinergic but non-adrenergic transmitter (possibly a peptide) might contribute to the LTE seen in the initial 30 min postconditioning. The present, orthodromically induced LTE is clearly different from the long-term potentiation widely studied in hippocampus, etc., in the modes of induction and synaptic mediation.

  19. Alpha cells secrete acetylcholine as a non-neuronal paracrine signal priming human beta cell function

    PubMed Central

    Rodriguez-Diaz, Rayner; Dando, Robin; Jacques-Silva, M. Caroline; Fachado, Alberto; Molina, Judith; Abdulreda, Midhat; Ricordi, Camillo; Roper, Stephen D.; Berggren, Per-Olof; Caicedo, Alejandro

    2011-01-01

    Acetylcholine is a neurotransmitter that plays a major role in the function of the insulin secreting pancreatic beta cell1,2. Parasympathetic innervation of the endocrine pancreas, the islets of Langerhans, has been shown to provide cholinergic input to the beta cell in several species1,3,4, but the role of autonomic innervation in human beta cell function is at present unclear. Here we show that, in contrast to mouse islets, cholinergic innervation of human islets is sparse. Instead, we find that the alpha cells of the human islet provide paracrine cholinergic input to surrounding endocrine cells. Human alpha cells express the vesicular acetylcholine transporter and release acetylcholine when stimulated with kainate or a lowering in glucose concentration. Acetylcholine secretion by alpha cells in turn sensitizes the beta cell response to increases in glucose concentration. Our results demonstrate that in human islets acetylcholine is a paracrine signal that primes the beta cell to respond optimally to subsequent increases in glucose concentration. We anticipate these results to revise models about neural input and cholinergic signaling in the endocrine pancreas. Cholinergic signaling within the islet represents a potential therapeutic target in diabetes5, highlighting the relevance of this advance to future drug development. PMID:21685896

  20. Enhanced Neural Responses to Imagined Primary Rewards Predict Reduced Monetary Temporal Discounting.

    PubMed

    Hakimi, Shabnam; Hare, Todd A

    2015-09-23

    The pervasive tendency to discount the value of future rewards varies considerably across individuals and has important implications for health and well-being. Here, we used fMRI with human participants to examine whether an individual's neural representation of an imagined primary reward predicts the degree to which the value of delayed monetary payments is discounted. Because future rewards can never be experienced at the time of choice, imagining or simulating the benefits of a future reward may play a critical role in decisions between alternatives with either immediate or delayed benefits. We found that enhanced ventromedial prefrontal cortex response during imagined primary reward receipt was correlated with reduced discounting in a separate monetary intertemporal choice task. Furthermore, activity in enhanced ventromedial prefrontal cortex during reward imagination predicted temporal discounting behavior both between- and within-individual decision makers with 62% and 73% mean balanced accuracy, respectively. These results suggest that the quality of reward imagination may impact the degree to which future outcomes are discounted. Significance statement: We report a novel test of the hypothesis that an important factor influencing the discount rate for future rewards is the quality with which they are imagined or estimated in the present. Previous work has shown that temporal discounting is linked to individual characteristics ranging from general intelligence to the propensity for addiction. We demonstrate that individual differences in a neurobiological measure of primary reward imagination are significantly correlated with discounting rates for future monetary payments. Moreover, our neurobiological measure of imagination can be used to accurately predict choice behavior both between and within individuals. These results suggest that improving reward imagination may be a useful therapeutic target for individuals whose high discount rates promote

  1. Enhanced proliferation of PC12 neural cells on untreated, nanotextured glass coverslips.

    PubMed

    Islam, Muhymin; Atmaramani, Rahul; Mukherjee, Siddhartha; Ghosh, Santaneel; Iqbal, Samir M

    2016-10-14

    Traumatic injury to the central nervous system is a significant health problem. There is no effective treatment available partly because of the complexity of the system. Implementation of multifunctional micro- and nano-device based combinatorial therapeutics can provide biocompatible and tunable approaches to perform on-demand release of specific drugs. This can help the damaged cells to improve neuronal survival, regeneration of axons, and their reconnection to appropriate targets. Nano-topological features induced rapid cell growth is especially important towards the design of effective platforms to facilitate damaged neural circuit reconstruction. In this study, for the first time, feasibility of neuron-like PC12 cell growth on untreated and easy to prepare nanotextured surfaces has been carried out. The PC12 neuron-like cells were cultured on micro reactive ion etched  nanotextured glass coverslips. The effect of nanotextured topology as physical cue for the growth of PC12 cells was observed exclusively, eliminating the possible influence(s) of the enhanced concentration of coated materials on the surface. The cell density was observed to increase by almost 200% on nanotextured coverslips compared to plain coverslips. The morphology study indicated that PC12 cell attachment and growth on the nanotextured substrates did not launch any apoptotic machinery of the cell. Less than 5% cells deformed and depicted condensed nuclei with apoptotic bodies on nanotextured surfaces which is typical for the normal cell handling and culture. Enhanced PC12 cell proliferation by such novel and easy to prepare substrates is not only attractive for neurite outgrowth and guidance, but may be used to increase the affinity of similar cancerous cells (ex: B35 neuroblastoma) and rapid proliferation thereafter-towards the development of combinatorial theranostics to diagnose and treat aggressive cancers like neuroblastoma. PMID:27587351

  2. Enhanced proliferation of PC12 neural cells on untreated, nanotextured glass coverslips.

    PubMed

    Islam, Muhymin; Atmaramani, Rahul; Mukherjee, Siddhartha; Ghosh, Santaneel; Iqbal, Samir M

    2016-10-14

    Traumatic injury to the central nervous system is a significant health problem. There is no effective treatment available partly because of the complexity of the system. Implementation of multifunctional micro- and nano-device based combinatorial therapeutics can provide biocompatible and tunable approaches to perform on-demand release of specific drugs. This can help the damaged cells to improve neuronal survival, regeneration of axons, and their reconnection to appropriate targets. Nano-topological features induced rapid cell growth is especially important towards the design of effective platforms to facilitate damaged neural circuit reconstruction. In this study, for the first time, feasibility of neuron-like PC12 cell growth on untreated and easy to prepare nanotextured surfaces has been carried out. The PC12 neuron-like cells were cultured on micro reactive ion etched  nanotextured glass coverslips. The effect of nanotextured topology as physical cue for the growth of PC12 cells was observed exclusively, eliminating the possible influence(s) of the enhanced concentration of coated materials on the surface. The cell density was observed to increase by almost 200% on nanotextured coverslips compared to plain coverslips. The morphology study indicated that PC12 cell attachment and growth on the nanotextured substrates did not launch any apoptotic machinery of the cell. Less than 5% cells deformed and depicted condensed nuclei with apoptotic bodies on nanotextured surfaces which is typical for the normal cell handling and culture. Enhanced PC12 cell proliferation by such novel and easy to prepare substrates is not only attractive for neurite outgrowth and guidance, but may be used to increase the affinity of similar cancerous cells (ex: B35 neuroblastoma) and rapid proliferation thereafter-towards the development of combinatorial theranostics to diagnose and treat aggressive cancers like neuroblastoma.

  3. Minocycline-Preconditioned Neural Stem Cells Enhance Neuroprotection after Ischemic Stroke in Rats

    PubMed Central

    Sakata, Hiroyuki; Niizuma, Kuniyasu; Yoshioka, Hideyuki; Kim, Gab Seok; Jung, Joo Eun; Katsu, Masataka; Narasimhan, Purnima; Maier, Carolina M.; Nishiyama, Yasuhiro; Chan, Pak H.

    2012-01-01

    Transplantation of neural stem cells (NSCs) offers a novel therapeutic strategy for stroke; however, massive grafted-cell death following transplantation, possibly due to a hostile host-brain environment, lessens the effectiveness of this approach. Here, we have investigated whether reprogramming NSCs with minocycline, a broadly-used antibiotic also known to possess cytoprotective properties, enhances survival of grafted cells and promotes neuroprotection in ischemic stroke. NSCs harvested from the subventricular zone of fetal rats were preconditioned with minocycline in vitro and transplanted into rat brains 6 h after transient middle cerebral artery occlusion. Histological and behavioral tests were examined from days 0–28 after stroke. For in vitro experiments, NSCs were subjected to oxygen-glucose deprivation and reoxygenation. Cell viability and antioxidant gene expression were analyzed. Minocycline preconditioning protected the grafted NSCs from ischemic reperfusion injury via up-regulation of Nrf2 and Nrf2-regulated antioxidant genes. Additionally, preconditioning with minocycline induced the NSCs to release paracrine factors, including brain-derived neurotrophic factor, nerve growth factor, glial cell-derived neurotrophic factor, and vascular endothelial growth factor. Moreover, transplantation of the minocycline-preconditioned NSCs significantly attenuated infarct size and improved neurological performance, compared with non-preconditioned NSCs. Minocycline-induced neuroprotection was abolished by transfecting the NSCs with Nrf2-small interfering RNA before transplantation. Thus, preconditioning with minocycline, which reprograms NSCs to tolerate oxidative stress after ischemic reperfusion injury and to express higher levels of paracrine factors through Nrf2 up-regulation, is a simple and safe approach to enhance the effectiveness of transplantation therapy in ischemic stroke. PMID:22399769

  4. Enhanced proliferation of PC12 neural cells on untreated, nanotextured glass coverslips

    NASA Astrophysics Data System (ADS)

    Islam, Muhymin; Atmaramani, Rahul; Mukherjee, Siddhartha; Ghosh, Santaneel; Iqbal, Samir M.

    2016-10-01

    Traumatic injury to the central nervous system is a significant health problem. There is no effective treatment available partly because of the complexity of the system. Implementation of multifunctional micro- and nano-device based combinatorial therapeutics can provide biocompatible and tunable approaches to perform on-demand release of specific drugs. This can help the damaged cells to improve neuronal survival, regeneration of axons, and their reconnection to appropriate targets. Nano-topological features induced rapid cell growth is especially important towards the design of effective platforms to facilitate damaged neural circuit reconstruction. In this study, for the first time, feasibility of neuron-like PC12 cell growth on untreated and easy to prepare nanotextured surfaces has been carried out. The PC12 neuron-like cells were cultured on micro reactive ion etched nanotextured glass coverslips. The effect of nanotextured topology as physical cue for the growth of PC12 cells was observed exclusively, eliminating the possible influence(s) of the enhanced concentration of coated materials on the surface. The cell density was observed to increase by almost 200% on nanotextured coverslips compared to plain coverslips. The morphology study indicated that PC12 cell attachment and growth on the nanotextured substrates did not launch any apoptotic machinery of the cell. Less than 5% cells deformed and depicted condensed nuclei with apoptotic bodies on nanotextured surfaces which is typical for the normal cell handling and culture. Enhanced PC12 cell proliferation by such novel and easy to prepare substrates is not only attractive for neurite outgrowth and guidance, but may be used to increase the affinity of similar cancerous cells (ex: B35 neuroblastoma) and rapid proliferation thereafter—towards the development of combinatorial theranostics to diagnose and treat aggressive cancers like neuroblastoma.

  5. Using Neural Net Technology To Enhance the Efficiency of a Computer Adaptive Testing Application.

    ERIC Educational Resources Information Center

    Van Nelson, C.; Henriksen, Larry W.

    The potential for computer adaptive testing (CAT) has been well documented. In order to improve the efficiency of this process, it may be possible to utilize a neural network, or more specifically, a back propagation neural network. The paper asserts that in order to accomplish this end, it must be shown that grouping examinees by ability as…

  6. Spaced Learning Enhances Subsequent Recognition Memory by Reducing Neural Repetition Suppression

    ERIC Educational Resources Information Center

    Xue, Gui; Mei, Leilei; Chen, Chuansheng; Lu, Zhong-Lin; Poldrack, Russell; Dong, Qi

    2011-01-01

    Spaced learning usually leads to better recognition memory as compared with massed learning, yet the underlying neural mechanisms remain elusive. One open question is whether the spacing effect is achieved by reducing neural repetition suppression. In this fMRI study, participants were scanned while intentionally memorizing 120 novel faces, half…

  7. Substance P, like acetylcholine, augments one type of Ca2+ current in isolated smooth muscle cells.

    PubMed

    Clapp, L H; Vivaudou, M B; Singer, J J; Walsh, J V

    1989-03-01

    Electrophysiological recordings from freshly-dissociated smooth muscle cells from toad stomach revealed that substance P enhances one of two types of Ca2+ currents. That is, substance P enhances the slowly inactivating, high-threshold current but not the fast inactivating, low-threshold current. Acetylcholine has the same effect, but the acetylcholine action is blocked by atropine whereas the substance P action is not, indicating that the two agents act at different receptor sites. Thus, substance P, like acetylcholine, has a dual excitatory action on the smooth muscle cells employed in these studies, enhancing a specific type of Ca2+ current, as demonstrated here, and suppressing a voltage-sensitive K+ conductance, as previously described [Sims, S.M., Walsh, J.V., Jr. & Singer, J.J. (1986) Am. J. Physiol. 251, C580-C587].

  8. Acetylcholine: future research and perspectives.

    PubMed

    Van der Zee, E A; Platt, B; Riedel, G

    2011-08-10

    Ever since the initial description of chemical transmission in the early part of the 20th century and the identification of acetylcholine (ACh) as the first such transmitter, interests grew to define the multiple facets of its functions. This multitude is only partially covered here, but even in the areas preselected for this special issue, research on the cholinergic system is still thriving. Notwithstanding an impressive amount of knowledge that has been accumulated, partly triggered by the cholinergic hypothesis of Alzheimer's disease (AD [1]), the different reviews in this issue not only summarise our current state of the art, they also highlight that this field has still large potential for future development. Taken from these reviews, we here pinpoint several topics fit for future attention.

  9. Nicotinic acetylcholine receptors and cancer

    PubMed Central

    DANG, NINGNING; MENG, XIANGUANG; SONG, HAIYAN

    2016-01-01

    Nicotine, the primary addictive constituent of cigarettes, is believed to contribute to cancer promotion and progression through the activation of nicotinic acetylcholine receptors (nAChRs), which are membrane ligand-gated cation channels. nAChRs activation can be triggered by the neurotransmitter Ach, or certain other biological compounds, such as nicotine. In recent years, genome-wide association studies have indicated that allelic variation in the α5-α3-β4 nAChR cluster on chromosome 15q24-15q25.1 is associated with lung cancer risk. The role of nAChRs in other types of cancer has also been reported. The present review highlights the role of nAChRs in types of human cancer. PMID:27123240

  10. Enhanced differentiation of neural progenitor cells into neurons of the mesencephalic dopaminergic subtype on topographical patterns.

    PubMed

    Tan, Kenneth K B; Tann, Jason Y; Sathe, Sharvari R; Goh, Seok Hong; Ma, Dongliang; Goh, Eyleen L K; Yim, Evelyn K F

    2015-03-01

    Parkinson's disease (PD) is a neurodegenerative disease attributed to the loss of midbrain dopaminergic (DA) neurons. The current lack of predictive models for this disease has been hampered by the acquirement of robust cells, posing a major barrier to drug development. Differentiation of stem cells into subtype specific cells may be guided by appropriate topographical cues but the role of topography has hitherto not been well understood. We used a Multi-Architecture (MARC) chip with various topographical structures and identified three topographies, which generate DA neurons from murine hippocampal neural progenitor cells with the highest percentage of neuronal (β-III-tubulin positive) and dopaminergic (tyrosine hydroxylase positive) populations. Analysis on single pattern structures showed that 2 μm gratings with 2 μm spacing and 2 μm height (2 μm gratings) and 2 μm gratings with hierarchical structure produced cells with the highest gene expression of TH and PITX3, with the longest neurite and highest percentage of alignment. Quantitative image analysis showed the 2 μm gratings produced cells with the highest expression of pituitary homeobox 3 (PITX3), LIM homeobox transcription factor 1 alpha (LMX1a), aldehyde dehydrogenase 1 family member A1 (ALDH1a1) and microtubule associated protein 2 (MAP2), as compared to nano-gratings and unpatterned controls. These patterns also enhance DA neuron differentiation on different substrate rigidities, as seen on both poly-dimethylsiloxane (PDMS) and tissue culture polystyrene (TCPS) substrates. These results show the use of topographical influence for neuronal subtype specification, which could be translated into a wide range of clinical applications for PD. PMID:25591959

  11. Solar energetic particle flux enhancement as a predictor of geomagnetic activity in a neural network-based model

    NASA Astrophysics Data System (ADS)

    Valach, F.; Revallo, M.; Bochníček, J.; Hejda, P.

    2009-04-01

    Coronal mass ejections (CMEs) are believed to be the principal cause of increased geomagnetic activity. They are regarded as being in context of a series of related solar energetic events, such as X-ray flares (XRAs) accompanied by solar radio bursts (RSPs) and also by solar energetic particle (SEP) flux. Two types of the RSP events are known to be geoeffective, namely, the RSP of type II, interpreted as the signature of shock initiation in the solar corona, and type IV, representing material moving upward in the corona. The SEP events causing geomagnetic response are known to be produced by CME-driven shocks. In this paper, we use the method of the artificial neural network in order to quantify the geomagnetic response of particular solar events. The data concerning XRAs and RSPs II and/or IV together with their heliographic positions are taken as the input for the neural network. There is a key question posed in our study: can the successfulness of the neural network prediction scheme based solely on the solar disc observations (XRA and RSP) be improved by additional information concerning the SEP flux? To resolve this problem, we chose the SEP events possessing significant enhancement in the 10-h window, commencing 12 h after the generation of XRAs. In particular, we consider the flux of high-energy protons with energies over 10 MeV. We have used a chi-square test to demonstrate that supplying such extra input data improves the neural network prediction scheme.

  12. The conformation of acetylcholine at its target site in the membrane-embedded nicotinic acetylcholine receptor

    PubMed Central

    Williamson, P. T. F.; Verhoeven, A.; Miller, K. W.; Meier, B. H.; Watts, A.

    2007-01-01

    The conformation of the neurotransmitter acetylcholine bound to the fully functional nicotinic acetylcholine receptor embedded in its native membrane environment has been characterized by using frequency-selective recoupling solid-state NMR. Six dipolar couplings among five resolved 13C-labeled atoms of acetylcholine were measured. Bound acetylcholine adopts a bent conformation characterized with a quaternary ammonium-to-carbonyl distance of 5.1 Å. In this conformation, and with its orientation constrained to that previously determined by us, the acetylcholine could be docked satisfactorily in the agonist pocket of the agonist-bound, but not the agonist-free, crystal structure of a soluble acetylcholine-binding protein from Lymnaea stagnali. The quaternary ammonium group of the acetylcholine was determined to be within 3.9 Å of five aromatic residues and its acetyl group close to residues C187/188 of the principle and residue L112 of the complementary subunit. The observed >CO chemical shift is consistent with H bonding to the nicotinic acetylcholine receptor residues γY116 and δT119 that are homologous to L112 in the soluble acetylcholine-binding protein. PMID:17989232

  13. Synergistic combination of near-infrared irradiation and targeted gold nanoheaters for enhanced photothermal neural stimulation.

    PubMed

    Eom, Kyungsik; Im, Changkyun; Hwang, Seoyoung; Eom, Seyoung; Kim, Tae-Seong; Jeong, Hae Sun; Kim, Kyung Hwan; Byun, Kyung Min; Jun, Sang Beom; Kim, Sung June

    2016-04-01

    Despite a potential of infrared neural stimulation (INS) for modulating neural activities, INS suffers from limited light confinement and bulk tissue heating. Here, a novel methodology for an advanced optical stimulation is proposed by combining near-infrared (NIR) stimulation with gold nanorods (GNRs) targeted to neuronal cell membrane. We confirmed experimentally that in vitro and in vivo neural activation is associated with a local heat generation based on NIR stimulation and GNRs. Compared with the case of NIR stimulation without an aid of GNRs, combination with cell-targeted GNRs allows photothermal stimulation with faster neural response, lower delivered energy, higher stimulation efficiency and stronger behavior change. Since the suggested method can reduce a requisite radiant exposure level and alleviate a concern of tissue damage, it is expected to open up new possibilities for applications to optical neuromodulations for diverse excitable tissues and treatments of neurological disorders. PMID:27446678

  14. Synergistic combination of near-infrared irradiation and targeted gold nanoheaters for enhanced photothermal neural stimulation

    PubMed Central

    Eom, Kyungsik; Im, Changkyun; Hwang, Seoyoung; Eom, Seyoung; Kim, Tae-Seong; Jeong, Hae Sun; Kim, Kyung Hwan; Byun, Kyung Min; Jun, Sang Beom; Kim, Sung June

    2016-01-01

    Despite a potential of infrared neural stimulation (INS) for modulating neural activities, INS suffers from limited light confinement and bulk tissue heating. Here, a novel methodology for an advanced optical stimulation is proposed by combining near-infrared (NIR) stimulation with gold nanorods (GNRs) targeted to neuronal cell membrane. We confirmed experimentally that in vitro and in vivo neural activation is associated with a local heat generation based on NIR stimulation and GNRs. Compared with the case of NIR stimulation without an aid of GNRs, combination with cell-targeted GNRs allows photothermal stimulation with faster neural response, lower delivered energy, higher stimulation efficiency and stronger behavior change. Since the suggested method can reduce a requisite radiant exposure level and alleviate a concern of tissue damage, it is expected to open up new possibilities for applications to optical neuromodulations for diverse excitable tissues and treatments of neurological disorders. PMID:27446678

  15. Galantamine-induced amyloid-{beta} clearance mediated via stimulation of microglial nicotinic acetylcholine receptors.

    PubMed

    Takata, Kazuyuki; Kitamura, Yoshihisa; Saeki, Mana; Terada, Maki; Kagitani, Sachiko; Kitamura, Risa; Fujikawa, Yasuhiro; Maelicke, Alfred; Tomimoto, Hidekazu; Taniguchi, Takashi; Shimohama, Shun

    2010-12-17

    Reduction of brain amyloid-β (Aβ) has been proposed as a therapeutic target for Alzheimer disease (AD), and microglial Aβ phagocytosis is noted as an Aβ clearance system in brains. Galantamine is an acetylcholinesterase inhibitor approved for symptomatic treatment of AD. Galantamine also acts as an allosterically potentiating ligand (APL) for nicotinic acetylcholine receptors (nAChRs). APL-binding site is located close to but distinct from that for acetylcholine on nAChRs, and FK1 antibody specifically binds to the APL-binding site without interfering with the acetylcholine-binding site. We found that in human AD brain, microglia accumulated on Aβ deposits and expressed α7 nAChRs including the APL-binding site recognized with FK1 antibody. Treatment of rat microglia with galantamine significantly enhanced microglial Aβ phagocytosis, and acetylcholine competitive antagonists as well as FK1 antibody inhibited the enhancement. Thus, the galantamine-enhanced microglial Aβ phagocytosis required the combined actions of an acetylcholine competitive agonist and the APL for nAChRs. Indeed, depletion of choline, an acetylcholine-competitive α7 nAChR agonist, from the culture medium impeded the enhancement. Similarly, Ca(2+) depletion or inhibition of the calmodulin-dependent pathways for the actin reorganization abolished the enhancement. These results suggest that galantamine sensitizes microglial α7 nAChRs to choline and induces Ca(2+) influx into microglia. The Ca(2+)-induced intracellular signaling cascades may then stimulate Aβ phagocytosis through the actin reorganization. We further demonstrated that galantamine treatment facilitated Aβ clearance in brains of rodent AD models. In conclusion, we propose a further advantage of galantamine in clinical AD treatment and microglial nAChRs as a new therapeutic target. PMID:20947502

  16. Hybrid artificial neural network segmentation and classification of dynamic contrast-enhanced MR imaging (DEMRI) of osteosarcoma.

    PubMed

    Glass, J O; Reddick, W E

    1998-11-01

    The evaluation of pediatric osteosarcoma has suffered from the lack of an accurate imaging measure of response. One major problem is that osteosarcoma do not shrink in response to chemotherapy; instead, viable tumor is replaced by necrotic tissue. Currently available techniques that use dynamic contrast-enhanced magnetic resonance imaging to quantitatively evaluate tumor response fail to assess the percentage of necrosis. At present, histopathologic evaluation of resected tissue is the only means of measuring the percentage of necrosis in treated osteosarcoma. The current study presents a non-invasive method to visualize necrotic and viable tumor and quantitatively assess the response of osteosarcoma. Our technique uses a hybrid neural network consisting of a Kohonen self-organizing map to segment dynamic contrast-enhanced magnetic resonance images and a multi-layer backpropagation neural network to classify the segmented images. Because the hybrid neural network is completely automated, our technique removes both inter- and intra-operator error. An analysis comparing the percentage of necrosis from our technique to the histopathologic analysis revealed a highly significant Spearman correlation coefficient of 0.617 with p < 0.001.

  17. (R)-3'-(3-methylbenzo[b]thiophen-5-yl)spiro[1-azabicyclo[2,2,2]octane-3,5'-oxazolidin]-2'-one, a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist displays cognitive enhancing properties.

    PubMed

    Tatsumi, Ryo; Fujio, Masakazu; Takanashi, Shin-ichi; Numata, Atsushi; Katayama, Jiro; Satoh, Hiroyuki; Shiigi, Yasuyuki; Maeda, Jun-ichi; Kuriyama, Makoto; Horikawa, Takashi; Murozono, Takahiro; Hashimoto, Kenji; Tanaka, Hiroshi

    2006-07-13

    Recent studies have suggested that the alpha7 nicotinic acetylcholine receptors play important roles in learning and memory. Herein, we describe our research of the structure-activity relationships (SAR) in a series of (S)-spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin]-2'-ones bearing various bicyclic moieties to discover novel alpha7 receptor agonists. Through a number of SAR studies on the series, we have found out that inhibition of CYP 2D6 isozyme, which was a primary obstacle for the previously identified compound, was avoidable by the introduction of bicyclic moieties. Chemical optimization of the series led to the identification of a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist 23. This compound not only possessed high binding affinity (K(i) = 3 nmol/L) toward the alpha7 receptor but also showed agonistic activity even at a concentration of 0.1 micromol/L. In addition, compound 23 improved cognition in several rat models, which might suggest the potential of the alpha7 receptor partial agonist for the treatment of neurological disorders including cognitive dysfunction.

  18. Brain injury expands the numbers of neural stem cells and progenitors in the SVZ by enhancing their responsiveness to EGF

    PubMed Central

    Alagappan, Dhivyaa; Lazzarino, Deborah A; Felling, Ryan J; Balan, Murugabaskar; Kotenko, Sergei V; Levison, Steven W

    2009-01-01

    There is an increase in the numbers of neural precursors in the SVZ (subventricular zone) after moderate ischaemic injuries, but the extent of stem cell expansion and the resultant cell regeneration is modest. Therefore our studies have focused on understanding the signals that regulate these processes towards achieving a more robust amplification of the stem/progenitor cell pool. The goal of the present study was to evaluate the role of the EGFR [EGF (epidermal growth factor) receptor] in the regenerative response of the neonatal SVZ to hypoxic/ischaemic injury. We show that injury recruits quiescent cells in the SVZ to proliferate, that they divide more rapidly and that there is increased EGFR expression on both putative stem cells and progenitors. With the amplification of the precursors in the SVZ after injury there is enhanced sensitivity to EGF, but not to FGF (fibroblast growth factor)-2. EGF-dependent SVZ precursor expansion, as measured using the neurosphere assay, is lost when the EGFR is pharmacologically inhibited, and forced expression of a constitutively active EGFR is sufficient to recapitulate the exaggerated proliferation of the neural stem/progenitors that is induced by hypoxic/ischaemic brain injury. Cumulatively, our results reveal that increased EGFR signalling precedes that increase in the abundance of the putative neural stem cells and our studies implicate the EGFR as a key regulator of the expansion of SVZ precursors in response to brain injury. Thus modulating EGFR signalling represents a potential target for therapies to enhance brain repair from endogenous neural precursors following hypoxic/ischaemic and other brain injuries. PMID:19570028

  19. Enhanced neural activity in frontal and cerebellar circuits after cognitive training in children with attention-deficit/hyperactivity disorder.

    PubMed

    Hoekzema, Elseline; Carmona, Susanna; Tremols, Virginia; Gispert, Joan Domingo; Guitart, Marc; Fauquet, Jordi; Rovira, Mariana; Bielsa, Anna; Soliva, Juan Carlos; Tomas, Xavier; Bulbena, Antonio; Ramos-Quiroga, Antoni; Casas, Miguel; Tobeña, Adolf; Vilarroya, Oscar

    2010-12-01

    The brain is a plastic entity that can undergo dynamic changes throughout the lifespan as a result of training. Attention-deficit/hyperactivity disorder (ADHD) is commonly treated with psychostimulant medication, and the prevalence of ADHD medication prescription is a topic of heated scientific debate. In addition, cognitive training is frequently provided to patients with ADHD. Although psychostimulant effects have been thoroughly investigated, no previous studies have assessed the neural effects of cognitive training in ADHD. We applied fMRI-paradigms of response inhibition and selective attention to chart the effects of a 10-day cognitive training program in 19 unmedicated ADHD children receiving either cognitive or control training. The two resulting longitudinal datasets were analyzed using whole-brain random-effects general linear models. Although we observed no increases of activity in the control group, both fMRI-datasets revealed enhanced activity after cognitive training in neural structures closely related to ADHD pathophysiology. On the inhibition paradigm, our results indicated increases in orbitofrontal, superior frontal, middle temporal, and inferior frontal cortex. The attentional task was characterized by increased activity in the cerebellum, which correlated with improvement on in-scanner measures of attention. Our findings provide preliminary evidence that cognitive training enhances activity in neural structures typically affected by the disorder. Similar results have been obtained following methylphenidate administration, suggesting that training of cognitive functions may mimic the effects of psychostimulant medication on the brain. These findings postulate a neural account for the potency of cognitive training in ADHD, and hold clinical implications, supporting the inclusion of training programs in standard ADHD-treatment. PMID:20336653

  20. Fuzzy wavelet plus a quantum neural network as a design base for power system stability enhancement.

    PubMed

    Ganjefar, Soheil; Tofighi, Morteza; Karami, Hamidreza

    2015-11-01

    In this study, we introduce an indirect adaptive fuzzy wavelet neural controller (IAFWNC) as a power system stabilizer to damp inter-area modes of oscillations in a multi-machine power system. Quantum computing is an efficient method for improving the computational efficiency of neural networks, so we developed an identifier based on a quantum neural network (QNN) to train the IAFWNC in the proposed scheme. All of the controller parameters are tuned online based on the Lyapunov stability theory to guarantee the closed-loop stability. A two-machine, two-area power system equipped with a static synchronous series compensator as a series flexible ac transmission system was used to demonstrate the effectiveness of the proposed controller. The simulation and experimental results demonstrated that the proposed IAFWNC scheme can achieve favorable control performance. PMID:26363960

  1. Neural Basis of Repetition Priming during Mathematical Cognition: Repetition Suppression or Repetition Enhancement?

    ERIC Educational Resources Information Center

    Salimpoor, Valorie N.; Chang, Catie; Menon, Vinod

    2010-01-01

    We investigated the neural basis of repetition priming (RP) during mathematical cognition. Previous studies of RP have focused on repetition suppression as the basis of behavioral facilitation, primarily using word and object identification and classification tasks. More recently, researchers have suggested associative stimulus-response learning…

  2. Self-Powered Electrical Stimulation for Enhancing Neural Differentiation of Mesenchymal Stem Cells on Graphene-Poly(3,4-ethylenedioxythiophene) Hybrid Microfibers.

    PubMed

    Guo, Weibo; Zhang, Xiaodi; Yu, Xin; Wang, Shu; Qiu, Jichuan; Tang, Wei; Li, Linlin; Liu, Hong; Wang, Zhong Lin

    2016-05-24

    Engineered conductive scaffolds toward neural regeneration should have the ability to regulate mesenchymal stems cell (MSC) differentiation into neural lineage through an electrical stimulation-assisted culture process. In this work, a self-powered electrical stimulation-assisted neural differentiation system for MSCs was realized by combining a high effective triboelectric nanogenerator (TENG) to supply pulsed electric simulation signals and a poly(3,4-ethylenedioxythiophene) (PEDOT)-reduced graphene oxide (rGO) hybrid microfiber (80 μm in diameter) as a scaffold. The conductive PEDOT endows the rGO-PEDOT hybrid microfiber with an enhanced electrical conductivity and maintains a good cytocompatibility. MSCs cultured on this highly conductive rGO-PEDOT hybrid microfiber possess enhanced proliferation ability and good neural differentiation tendency. Importantly, by inducing electric pulses generated by the TENG as the electrical stimulation signal, which are triggered by human walking steps, neural differentiation of MSCs is dramatically improved. This study illustrates the customizability of the rGO-PEDOT hybrid microfiber for neural tissue engineering scaffolding applications, underlines the potential of a self-powered TENG electrical stimulation system for accelerating MSC differentiation into neural cells without bio/chemical cues, and suggests the TENG's practical use as a wearable stimulation system to assist nerve regeneration for a walking person. PMID:27144593

  3. Effects of extracellular acetylcholine on muscarinic receptor binding assessed by [125I]dexetimide and a simple probe.

    PubMed

    Sánchez-Roa, P M; Wagner, H N; Villemagne, V L; London, E D; Lever, J R

    1998-10-01

    New pharmacologic approaches to enhance brain cholinergic function focus on increasing intrasynaptic acetylcholine. We examined the usefulness of a simple probe and [125I]dexetimide to evaluate in vivo the effects of extracellular acetylcholine on muscarinic receptor binding in the mouse brain. After radiotracer injection continuous time/activity curves were generated over 330 min. [125I]Dexetimide reached a plateau at 90 min post-injection. To increase extracellular acetylcholine, the anticholinesterase physostigmine was administered at 120 min, producing a reversible decrease in [125I]dexetimide specific binding (23%) for 30 min. These findings demonstrate that dynamic changes in extracellular acetylcholine can be evaluated by displacement of [125I]dexetimide binding in vivo using a simple probe system. PMID:9822886

  4. Extremely low-frequency electromagnetic fields enhance the proliferation and differentiation of neural progenitor cells cultured from ischemic brains.

    PubMed

    Cheng, Yannan; Dai, Yiqin; Zhu, Ximin; Xu, Haochen; Cai, Ping; Xia, Ruohong; Mao, Lizhen; Zhao, Bing-Qiao; Fan, Wenying

    2015-10-21

    In the mammalian brain, neurogenesis persists throughout the embryonic period and adulthood in the subventricular zone of the lateral ventricle and the granular zone (dentate gyrus) of the hippocampus. Newborn neural progenitor cells (NPCs) in the two regions play a critical role in structural and functional plasticity and neural regeneration after brain injury. Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) could promote osteogenesis, angiogenesis, and cardiac stem cells' differentiation, which indicates that ELF-EMF might be an effective tool for regenerative therapy. The present studies were carried out to examine the effects of ELF-EMF on hippocampal NPCs cultured from embryonic and adult ischemic brains. We found that exposure to ELF-EMF (50 Hz, 0.4 mT) significantly enhanced the proliferation capability both in embryonic NPCs and in ischemic NPCs. Neuronal differentiation was also enhanced after 7 days of cumulative ELF-EMF exposure, whereas glial differentiation was not influenced markedly. The expression of phosphorylated Akt increased during the proliferation process when ischemic NPCs were exposed to ELF-EMF. However, blockage of the Akt pathway abolished the ELF-EMF-induced proliferation of ischemic NPCs. These data show that ELF-EMF promotes neurogenesis of ischemic NPCs and suggest that this effect may occur through the Akt pathway.Video abstract, Supplemental Digital Content 1, http://links.lww.com/WNR/A347.

  5. A neural network approach for enhancing information extraction from multispectral image data

    USGS Publications Warehouse

    Liu, J.; Shao, G.; Zhu, H.; Liu, S.

    2005-01-01

    A back-propagation artificial neural network (ANN) was applied to classify multispectral remote sensing imagery data. The classification procedure included four steps: (i) noisy training that adds minor random variations to the sampling data to make the data more representative and to reduce the training sample size; (ii) iterative or multi-tier classification that reclassifies the unclassified pixels by making a subset of training samples from the original training set, which means the neural model can focus on fewer classes; (iii) spectral channel selection based on neural network weights that can distinguish the relative importance of each channel in the classification process to simplify the ANN model; and (iv) voting rules that adjust the accuracy of classification and produce outputs of different confidence levels. The Purdue Forest, located west of Purdue University, West Lafayette, Indiana, was chosen as the test site. The 1992 Landsat thematic mapper imagery was used as the input data. High-quality airborne photographs of the same Lime period were used for the ground truth. A total of 11 land use and land cover classes were defined, including water, broadleaved forest, coniferous forest, young forest, urban and road, and six types of cropland-grassland. The experiment, indicated that the back-propagation neural network application was satisfactory in distinguishing different land cover types at US Geological Survey levels II-III. The single-tier classification reached an overall accuracy of 85%. and the multi-tier classification an overall accuracy of 95%. For the whole test, region, the final output of this study reached an overall accuracy of 87%. ?? 2005 CASI.

  6. An enhanced non-uniformity correction algorithm for IRFPA based on neural network

    NASA Astrophysics Data System (ADS)

    Wang, BingJian; Liu, ShangQian; Bai, LiPing

    2008-04-01

    Influenced by detector materials' non-uniformity, growth and etching techniques, etc., every detector's responsivity of infrared focal plane arrays (IRFPA) is different, which results in non-uniformity of IRFPA. And non-uniformity of IRFPA generates fixed pattern noises (FPN) that are superposed on infrared image. And it may degrade the infrared image quality, which greatly limits the application of IRFPA. Non-uniformity correction (NUC) is an important technique for IRFPA. The traditional non-uniformity correction algorithm based on neural network and its modified algorithms are analyzed in this paper. And a new improved non-uniformity correction algorithm based on neural network is proposed in this paper. In this algorithm, the desired image is estimated by using three successive images in an infrared sequence. And blurring effect caused by motion is avoided by applying implicit motion detection and edge detection. So the estimation image is closer to real image than the estimation image estimated by other algorithms, which results in fast convergence speed of correction parameters. A comparison is made to these algorithms in this paper. And experimental results show that the algorithm proposed in this paper can correct the non-uniformity of IRFPA effectively and it prevails over other algorithms based on neural network.

  7. Enhanced growth of neural networks on conductive cellulose-derived nanofibrous scaffolds.

    PubMed

    Kuzmenko, Volodymyr; Kalogeropoulos, Theodoros; Thunberg, Johannes; Johannesson, Sara; Hägg, Daniel; Enoksson, Peter; Gatenholm, Paul

    2016-01-01

    The problem of recovery from neurodegeneration needs new effective solutions. Tissue engineering is viewed as a prospective approach for solving this problem since it can help to develop healthy neural tissue using supportive scaffolds. This study presents effective and sustainable tissue engineering methods for creating biomaterials from cellulose that can be used either as scaffolds for the growth of neural tissue in vitro or as drug screening models. To reach this goal, nanofibrous electrospun cellulose mats were made conductive via two different procedures: carbonization and addition of multi-walled carbon nanotubes. The resulting scaffolds were much more conductive than untreated cellulose material and were used to support growth and differentiation of SH-SY5Y neuroblastoma cells. The cells were evaluated by scanning electron microscopy and confocal microscopy methods over a period of 15 days at different time points. The results showed that the cellulose-derived conductive scaffolds can provide support for good cell attachment, growth and differentiation. The formation of a neural network occurred within 10 days of differentiation, which is a promising length of time for SH-SY5Y neuroblastoma cells.

  8. Metabolism of acetylcholine in human erythrocytes

    SciTech Connect

    Chapman, E.S.

    1990-01-01

    In order to examine the possible role of erythrocyte acetylcholinesterase in the maintenance of membrane phospholipid content and membrane fluidity, experiments were performed to monitor the activity of the enzyme and follow the fate of one of its hydrolytic products, choline. Intact human erythrocytes were incubated with acetylcholine (choline methyl-{sup 14}C). The incubation resulted in the hydrolysis of acetylcholine to acetate and choline; the reaction was catalyzed by membrane acetylcholinesterase. The studies demonstrate the further metabolism of choline. Experiments were carried out to determine rate of hydrolysis of acetylcholine, uptake of choline, identification of intracellular metabolites of choline, and identification of radiolabeled membrane components. Erythrocytes at a 25% hematocrit were incubated in an isoosmotic bicarbonate buffer pH 7.4, containing glucose, adenosine, streptomycin and penicillin with 0.3 {mu}Ci of acetylcholine (choline methyl-{sup 14}C), for 24 hours. Aliquots of the erythrocyte suspension were taken throughout for analysis. Erythrocytes were washed free of excess substrate, lysed, and the hemolysate was extracted for choline and its metabolites. Blank samples containing incubation buffer and radiolabeled acetylcholine only, and erythrocyte hemolysate extracts were analyzed for choline content, the difference between blank samples and hemolysate extracts was the amount of choline originating from acetylcholine and attributable to acetylcholinesterase activity. The conversion of choline to {sup 14}C-betaine is noted after several minutes of incubation; at 30 minutes, more than 80% of {sup 14}C-choline is taken up and after several hours, detectable levels of radiolabeled S-adenosylmethionine were present in the hemolysate extract.

  9. Effects of acetylcholine on neuronal properties in entorhinal cortex

    PubMed Central

    Heys, James G.; Schultheiss, Nathan W.; Shay, Christopher F.; Tsuno, Yusuke; Hasselmo, Michael E.

    2012-01-01

    The entorhinal cortex (EC) receives prominent cholinergic innervation from the medial septum and the vertical limb of the diagonal band of Broca (MSDB). To understand how cholinergic neurotransmission can modulate behavior, research has been directed toward identification of the specific cellular mechanisms in EC that can be modulated through cholinergic activity. This review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory. In particular, the study of stellate cells (SCs) in medial entorhinal has resulted in discovery of correlations between physiological properties of these neurons and properties of the unique spatial representation that is demonstrated through unit recordings of neurons in medial entorhinal cortex (mEC) from awake-behaving animals. A separate line of investigation has demonstrated persistent firing behavior among neurons in EC that is enhanced by cholinergic activity and could underlie working memory. There is also evidence that acetylcholine plays a role in modulation of synaptic transmission that could also enhance mnemonic function in EC. Finally, the local circuits of EC demonstrate a variety of interneuron physiology, which is also subject to cholinergic modulation. Together these effects alter the dynamics of EC to underlie the functional role of acetylcholine in memory. PMID:22837741

  10. The enhancement of neural stem cell survival and growth by coculturing with expanded Sertoli cells in vitro.

    PubMed

    Shi, Bingyang; Deng, Lei; Shi, Xiaolin; Dai, Sheng; Zhang, Hu; Wang, Yonghong; Bi, Jingxiu; Guo, Meijin

    2012-01-01

    Sertoli cells (SCs) have been described as the "nurse cells" of testis to provide essential growth factors and to create a proper environment for the development of other cells (e.g., germinal and neural stem cell). However, the physiological functions of the SCs obtained from different culture conditions are different in a coculturing system, and thus the optimal SC culturing condition should be investigated in vitro. In this paper, primary Sertoli cells were isolated from a 12-day-old mouse and expanded in two different culture conditions: a two dimensional (2D) plastic tissue disc and a three dimensional (3D) microcarrier culture system. They were then cocultured with neural stem cells (NSCs) isolated from 14-day-old mouse embryos. The metabolic activities of SCs(2D) (SCs in 2D) and SCs(3D) (SCs in 3D) and the amount of proteins secreted from two culturing systems were compared. The results show that the metabolic activity and the amount of secreted proteins from SCs(3D) were higher than both from SCs(2D). Three coculturing groups: NSCs+SC(2D), NSCs+SC(3D), and NSCs +SC-conditioned medium (SCCM, control group) were also compared regarding cell morphology and the numbers of neurons, neural outgrowths and neurospheres. The quantity of neurons, neural outgrowths and neurospheres were the highest in the NSCs+SC(3D) group. SCs cultured in the 3D system had a strong trophic effect on NSCs and enhanced their survival and growth. Besides, the mRNA of trophic and nutritive factors such as Glial-cell-line-derived neurotrophic factor (GDNF) and Interleukin-1 α (IL-1 α) secreted by the SCs from both 2D and 3D culture system were analyzed by real time-PCR and gel assay. The mRNA transcription of GDNF and IL-1α is more apparent in the 3D culture system than that from the 2D one. The coculturing system of NSCs+SC(3D) is a promising candidate for future neural stem cell transplantation.

  11. Potentiation of acetylcholine action by huperzine-A and physostigmine on some vertebrate effectors, including human iris sphincter muscle.

    PubMed

    Patil, Kaustubha D; Buerki, Robin A; Patil, Popat N

    2003-04-01

    The main objective of this investigation was to compare the acetylcholine potentiating action of huperzine-A with acetylcholinesterase inhibitor physostigmine on the frog rectus abdominus muscle, rat phrenic nerve diaphragm preparation, guinea pig ileum and human iris sphincter muscle. In vitro on the frog rectus abdominus muscle, microM of each alkaloid, incubated for 10 min, shifted the acetylcholine concentration response curve to the left. At EC(50) level, physostigmine potentiated acetylcholine response by 4-fold. The potentiation by huperzine-A was 40-fold. The acetylcholine maximum effect, relative to the control, increased to approximately 130% by each alkaloid. Neurally mediated twitch contraction of the rat diaphragm, a skeletal muscle at 1 microM was also potentiated more by huperzine-A than that by physostigmine. Neuromuscular block by (+)-tubocurarine was reversed more easily by huperzine-A than that by physostigmine. On guinea pig ileum, a 30 nM concentration of each alkaloid incubated for 5 min potentiated acetylcholine (10 nM) by 42%, and 33% for huperzine-A and physostigmine respectively. The difference in potentiation between the alkaloids was not significant. At 300 nM of each alkaloid, intrinsic indirect contractions were observed on the ileum, where the rate of contraction by huperzine-A was faster than that by physostigmine. On the iris sphincter, huperzine-A and physostigmine produced a concentration-dependent effect. Maximum effect after each alkaloid was achieved at 30 microM. Potentiation of acetylcholine response by 0.3 microM huperzine-A after a 10-min incubation was greater than that achieved by physostigmine at an equivalent concentration on the contralateral iris sphincter. In summary, huperzine-A exhibits greater acetylcholine potentiating activity on vertebrate muscles than that produced by physostigmine. The results are discussed in relation to the potential therapeutic value of huperzine-A.

  12. Modulation of AMPA receptor mediated current by nicotinic acetylcholine receptor in layer I neurons of rat prefrontal cortex

    PubMed Central

    Tang, Bo; Luo, Dong; Yang, Jie; Xu, Xiao-Yan; Zhu, Bing-Lin; Wang, Xue-Feng; Yan, Zhen; Chen, Guo-Jun

    2015-01-01

    Layer I neurons in the prefrontal cortex (PFC) exhibit extensive synaptic connections with deep layer neurons, implying their important role in the neural circuit. Study demonstrates that activation of nicotinic acetylcholine receptors (nAChRs) increases excitatory neurotransmission in this layer. Here we found that nicotine selectively increased the amplitude of AMPA receptor (AMPAR)-mediated current and AMPA/NMDA ratio, while without effect on NMDA receptor-mediated current. The augmentation of AMPAR current by nicotine was inhibited by a selective α7-nAChR antagonist methyllycaconitine (MLA) and intracellular calcium chelator BAPTA. In addition, nicotinic effect on mEPSC or paired-pulse ratio was also prevented by MLA. Moreover, an enhanced inward rectification of AMPAR current by nicotine suggested a functional role of calcium permeable and GluA1 containing AMPAR. Consistently, nicotine enhancement of AMPAR current was inhibited by a selective calcium-permeable AMPAR inhibitor IEM-1460. Finally, the intracellular inclusion of synthetic peptide designed to block GluA1 subunit of AMPAR at CAMKII, PKC or PKA phosphorylation site, as well as corresponding kinase inhibitor, blocked nicotinic augmentation of AMPA/NMDA ratio. These results have revealed that nicotine increases AMPAR current by modulating the phosphorylation state of GluA1 which is dependent on α7-nAChR and intracellular calcium. PMID:26370265

  13. Performance enhancement at the cost of potential brain plasticity: neural ramifications of nootropic drugs in the healthy developing brain

    PubMed Central

    Urban, Kimberly R.; Gao, Wen-Jun

    2014-01-01

    Cognitive enhancement is perhaps one of the most intriguing and controversial topics in neuroscience today. Currently, the main classes of drugs used as potential cognitive enhancers include psychostimulants (methylphenidate (MPH), amphetamine), but wakefulness-promoting agents (modafinil) and glutamate activators (ampakine) are also frequently used. Pharmacologically, substances that enhance the components of the memory/learning circuits—dopamine, glutamate (neuronal excitation), and/or norepinephrine—stand to improve brain function in healthy individuals beyond their baseline functioning. In particular, non-medical use of prescription stimulants such as MPH and illicit use of psychostimulants for cognitive enhancement have seen a recent rise among teens and young adults in schools and college campuses. However, this enhancement likely comes with a neuronal, as well as ethical, cost. Altering glutamate function via the use of psychostimulants may impair behavioral flexibility, leading to the development and/or potentiation of addictive behaviors. Furthermore, dopamine and norepinephrine do not display linear effects; instead, their modulation of cognitive and neuronal function maps on an inverted-U curve. Healthy individuals run the risk of pushing themselves beyond optimal levels into hyperdopaminergic and hypernoradrenergic states, thus vitiating the very behaviors they are striving to improve. Finally, recent studies have begun to highlight potential damaging effects of stimulant exposure in healthy juveniles. This review explains how the main classes of cognitive enhancing drugs affect the learning and memory circuits, and highlights the potential risks and concerns in healthy individuals, particularly juveniles and adolescents. We emphasize the performance enhancement at the potential cost of brain plasticity that is associated with the neural ramifications of nootropic drugs in the healthy developing brain. PMID:24860437

  14. Short-term Music Training Enhances Complex, Distributed Neural Communication during Music and Linguistic Tasks.

    PubMed

    Carpentier, Sarah M; Moreno, Sylvain; McIntosh, Anthony R

    2016-10-01

    Musical training is frequently associated with benefits to linguistic abilities, and recent focus has been placed on possible benefits of bilingualism to lifelong executive functions; however, the neural mechanisms for such effects are unclear. The aim of this study was to gain better understanding of the whole-brain functional effects of music and second-language training that could support such previously observed cognitive transfer effects. We conducted a 28-day longitudinal study of monolingual English-speaking 4- to 6-year-old children randomly selected to receive daily music or French language training, excluding weekends. Children completed passive EEG music note and French vowel auditory oddball detection tasks before and after training. Brain signal complexity was measured on source waveforms at multiple temporal scales as an index of neural information processing and network communication load. Comparing pretraining with posttraining, musical training was associated with increased EEG complexity at coarse temporal scales during the music and French vowel tasks in widely distributed cortical regions. Conversely, very minimal decreases in complexity at fine scales and trends toward coarse-scale increases were displayed after French training during the tasks. Spectral analysis failed to distinguish between training types and found overall theta (3.5-7.5 Hz) power increases after all training forms, with spatially fewer decreases in power at higher frequencies (>10 Hz). These findings demonstrate that musical training increased diversity of brain network states to support domain-specific music skill acquisition and music-to-language transfer effects.

  15. No Evidence That Gratitude Enhances Neural Performance Monitoring or Conflict-Driven Control.

    PubMed

    Saunders, Blair; He, Frank F H; Inzlicht, Michael

    2015-01-01

    It has recently been suggested that gratitude can benefit self-regulation by reducing impulsivity during economic decision making. We tested if comparable benefits of gratitude are observed for neural performance monitoring and conflict-driven self-control. In a pre-post design, 61 participants were randomly assigned to either a gratitude or happiness condition, and then performed a pre-induction flanker task. Subsequently, participants recalled an autobiographical event where they had felt grateful or happy, followed by a post-induction flanker task. Despite closely following existing protocols, participants in the gratitude condition did not report elevated gratefulness compared to the happy group. In regard to self-control, we found no association between gratitude--operationalized by experimental condition or as a continuous predictor--and any control metric, including flanker interference, post-error adjustments, or neural monitoring (the error-related negativity, ERN). Thus, while gratitude might increase economic patience, such benefits may not generalize to conflict-driven control processes.

  16. No Evidence That Gratitude Enhances Neural Performance Monitoring or Conflict-Driven Control

    PubMed Central

    Saunders, Blair; He, Frank F. H.; Inzlicht, Michael

    2015-01-01

    It has recently been suggested that gratitude can benefit self-regulation by reducing impulsivity during economic decision making. We tested if comparable benefits of gratitude are observed for neural performance monitoring and conflict-driven self-control. In a pre-post design, 61 participants were randomly assigned to either a gratitude or happiness condition, and then performed a pre-induction flanker task. Subsequently, participants recalled an autobiographical event where they had felt grateful or happy, followed by a post-induction flanker task. Despite closely following existing protocols, participants in the gratitude condition did not report elevated gratefulness compared to the happy group. In regard to self-control, we found no association between gratitude—operationalized by experimental condition or as a continuous predictor—and any control metric, including flanker interference, post-error adjustments, or neural monitoring (the error-related negativity, ERN). Thus, while gratitude might increase economic patience, such benefits may not generalize to conflict-driven control processes. PMID:26633830

  17. Short-term Music Training Enhances Complex, Distributed Neural Communication during Music and Linguistic Tasks

    PubMed Central

    Carpentier, Sarah M.; Moreno, Sylvain; McIntosh, Anthony R.

    2016-01-01

    Musical training is frequently associated with benefits to linguistic abilities, and recent focus has been placed on possible benefits of bilingualism to lifelong executive functions; however, the neural mechanisms for such effects are unclear. The aim of this study was to gain better understanding of the whole-brain functional effects of music and second-language training that could support such previously observed cognitive transfer effects. We conducted a 28-day longitudinal study of monolingual English-speaking 4- to 6-year-old children randomly selected to receive daily music or French language training, excluding weekends. Children completed passive EEG music note and French vowel auditory oddball detection tasks before and after training. Brain signal complexity was measured on source waveforms at multiple temporal scales as an index of neural information processing and network communication load. Comparing pretraining with posttraining, musical training was associated with increased EEG complexity at coarse temporal scales during the music and French vowel tasks in widely distributed cortical regions. Conversely, very minimal decreases in complexity at fine scales and trends toward coarse-scale increases were displayed after French training during the tasks. Spectral analysis failed to distinguish between training types and found overall theta (3.5–7.5 Hz) power increases after all training forms, with spatially fewer decreases in power at higher frequencies (>10 Hz). These findings demonstrate that musical training increased diversity of brain network states to support domain-specific music skill acquisition and music-to-language transfer effects. PMID:27243611

  18. Enhanced neural responses to rule violation in children with autism: a comparison to social exclusion.

    PubMed

    Bolling, Danielle Z; Pitskel, Naomi B; Deen, Ben; Crowley, Michael J; McPartland, James C; Kaiser, Martha D; Wyk, Brent C Vander; Wu, Jia; Mayes, Linda C; Pelphrey, Kevin A

    2011-07-01

    The present study aimed to explore the neural correlates of two characteristic deficits in autism spectrum disorders (ASD); social impairment and restricted, repetitive behavior patterns. To this end, we used comparable experiences of social exclusion and rule violation to probe potentially atypical neural networks in ASD. In children and adolescents with and without ASD, we used the interactive ball-toss game (Cyberball) to elicit social exclusion and a comparable game (Cybershape) to elicit a non-exclusive rule violation. Using functional magnetic resonance imaging (fMRI), we identified group differences in brain responses to social exclusion and rule violation. Though both groups reported equal distress following exclusion, the right insula and ventral anterior cingulate cortex were hypoactive during exclusion in children with ASD. In rule violation, right insula and dorsal prefrontal cortex were hyperactive in ASD. Right insula showed a dissociation in activation; it was hypoactive to social exclusion and hyperactive to rule violation in the ASD group. Further probed, different regions of right insula were modulated in each game, highlighting differences in regional specificity for which subsequent analyses revealed differences in patterns of functional connectivity. These results demonstrate neurobiological differences in processing social exclusion and rule violation in children with ASD.

  19. Short-term Music Training Enhances Complex, Distributed Neural Communication during Music and Linguistic Tasks.

    PubMed

    Carpentier, Sarah M; Moreno, Sylvain; McIntosh, Anthony R

    2016-10-01

    Musical training is frequently associated with benefits to linguistic abilities, and recent focus has been placed on possible benefits of bilingualism to lifelong executive functions; however, the neural mechanisms for such effects are unclear. The aim of this study was to gain better understanding of the whole-brain functional effects of music and second-language training that could support such previously observed cognitive transfer effects. We conducted a 28-day longitudinal study of monolingual English-speaking 4- to 6-year-old children randomly selected to receive daily music or French language training, excluding weekends. Children completed passive EEG music note and French vowel auditory oddball detection tasks before and after training. Brain signal complexity was measured on source waveforms at multiple temporal scales as an index of neural information processing and network communication load. Comparing pretraining with posttraining, musical training was associated with increased EEG complexity at coarse temporal scales during the music and French vowel tasks in widely distributed cortical regions. Conversely, very minimal decreases in complexity at fine scales and trends toward coarse-scale increases were displayed after French training during the tasks. Spectral analysis failed to distinguish between training types and found overall theta (3.5-7.5 Hz) power increases after all training forms, with spatially fewer decreases in power at higher frequencies (>10 Hz). These findings demonstrate that musical training increased diversity of brain network states to support domain-specific music skill acquisition and music-to-language transfer effects. PMID:27243611

  20. The Synapse Project: Engagement in mentally challenging activities enhances neural efficiency

    PubMed Central

    McDonough, Ian M.; Haber, Sara; Bischof, Gérard N.; Park, Denise C.

    2015-01-01

    Purpose: Correlational and limited experimental evidence suggests that an engaged lifestyle is associated with the maintenance of cognitive vitality in old age. However, the mechanisms underlying these engagement effects are poorly understood. We hypothesized that mental effort underlies engagement effects and used fMRI to examine the impact of high-challenge activities (digital photography and quilting) compared with low-challenge activities (socializing or performing low-challenge cognitive tasks) on neural function at pretest, posttest, and one year after the engagement program. Methods: In the scanner, participants performed a semantic-classification task with two levels of difficulty to assess the modulation of brain activity in response to task demands. Results: The High-Challenge group, but not the Low-Challenge group, showed increased modulation of brain activity in medial frontal, lateral temporal, and parietal cortex—regions associated with attention and semantic processing—some of which were maintained a year later. This increased modulation stemmed from decreases in brain activity during the easy condition for the High-Challenge group and was associated with time committed to the program, age, and cognition. Conclusions: Sustained engagement in cognitively demanding activities facilitated cognition by increasing neural efficiency. Mentally-challenging activities may be neuroprotective and an important element to maintaining a healthy brain into late adulthood. PMID:26484698

  1. Effects of nicotine, methamphetamine and cocaine on extracellular levels of acetylcholine in the interpeduncular nucleus of rats.

    PubMed

    Hussain, Rifat J; Taraschenko, Olga D; Glick, Stanley D

    2008-08-01

    There is increasing evidence that the cholinergic habenulo-interpeduncular pathway and the dopaminergic mesolimbic pathway may jointly mediate the reinforcing properties of addictive drugs. However, the effects of addictive drug on the functioning of the habenulo-interpeduncular pathway have not been well-characterized. Thus, several drugs of abuse (i.e., nicotine, cocaine, amphetamine) have been shown to alter the morphology of the habenulo-interpeduncular pathway, causing selective degeneration of the cholinergic neurons in this area. On the other hand, morphine was shown to alter the neurochemistry of the habenulo-interpeduncular pathway, inducing biphasic changes in acetylcholine release in the interpeduncular nucleus. In order to determine the effects of cocaine, amphetamine and nicotine on cholinergic neurotransmission in the habenulo-interpeduncular pathway, levels of acetylcholine were assessed during microdialysis in freely moving rats. Nicotine (0.1 and 0.4 mg/kg s.c.) produced a dose-dependent decrease in extracellular levels of acetylcholine, while methamphetamine (1 and 4 mg/kg i.p.) produced an increase in acetylcholine release in the interpeduncular nucleus. Cocaine (5 and 20 mg/kg i.p.) produced a biphasic effect on extracellular acetylcholine release, i.e., a low dose enhanced the release of acetylcholine and a high dose decreased its release. These results suggest that the habenulo-intepeduncular pathway may be a common target for drugs of abuse and, by modulating the mesolimbic pathway, may mediate unique aspects of the rewarding effects of different drugs.

  2. The neural transfer effect of working memory training to enhance hedonic processing in individuals with social anhedonia

    PubMed Central

    Li, Xu; Li, Zhi; Li, Ke; Zeng, Ya-wei; Shi, Hai-song; Xie, Wen-lan; Yang, Zhuo-ya; Lui, Simon S. Y.; Cheung, Eric F. C.; Leung, Ada W. S.; Chan, Raymond C. K.

    2016-01-01

    Anhedonia, the diminished ability to experience pleasure, is a challenging negative symptom in patients with schizophrenia and can be observed in at-risk individuals with schizotypy. Deficits in hedonic processing have been postulated to be related to decreased motivation to engage in potentially rewarding events. It remains unclear whether non-pharmacological interventions, such as cognitive training, could improve anhedonia. The present study aimed to examine the neural mechanism for alleviating hedonic deficits with working memory (WM) training in individuals with social anhedonia. Fifteen individuals with social anhedonia were recruited and received 20 sessions of training on a dual n-back task, five sessions a week. Functional imaging paradigms of the Monetary Incentive Delay (MID) and the Affective Incentive Delay (AID) tasks were administered both before and after the training to evaluate the neural transfer effects on hedonic processing ability. Enhanced brain activations related to anticipation were observed at the anterior cingulate cortex, the left dorsal striatum and the left precuneus with the AID task, and at the dorsolateral prefrontal cortex and the supramarginal gyrus with the MID task. The present findings support that WM training may improve monetary-based and affective-based hedonic processing in individuals with social anhedonia. PMID:27752140

  3. Mechanism underlying H2O2-induced inhibition of acetylcholine-induced contraction in rabbit tracheal smooth muscle.

    PubMed

    Saito, Michihiro; Watanabe, Yoshimasa; Itoh, Takeo

    2007-02-28

    The mechanism underlying the inhibition by H2O2 of acetylcholine-induced contraction was investigated in epithelium-denuded strips of rabbit trachea. Acetylcholine (10 microM) generated a phasic, followed by a tonic increase in both the intracellular Ca2+ concentration ([Ca2+]i) and force. Although the acetylcholine-induced tonic contraction was around 9 times the high K+ (80 mM)-induced one, the two stimulants induced similar [Ca2+]i increases (around 0.2 microM), indicating that acetylcholine generates tonic contraction via increases in both [Ca2+]i and myofilament Ca2+-sensitivity. H2O2 (30 microM) (a) enhanced the acetylcholine-induced tonic (not phasic) increase in [Ca2+]i but attenuated both phases of the acetylcholine-induced contraction and (b) enhanced the high K+-induced increase in [Ca2+]i but did not modify the high K+-induced contraction. In beta-escin-skinned strips, application of acetylcholine in the presence of GTP enhanced the contraction induced by 0.3 microM Ca2+ so that its amplitude became similar to that induced by 1 microM Ca2+. H2O2 (30 microM) attenuated the contraction induced by 0.3 microM Ca2+ (alone or in the presence of acetylcholine) but not those induced by higher concentrations of Ca2+ alone (0.5 microM and 1 microM). These results indicate that H2O2 acts directly on contractile proteins in rabbit tracheal smooth muscle to inhibit the contraction induced by low concentrations of Ca2+ (<0.5 microM). An action of H2O2 that increases [Ca2+]i (and thereby masks this reactive-oxygen-induced inhibition of myofilament Ca2+-sensitivity) is apparent in the presence of high K+ but not of acetylcholine. Thus, in rabbit tracheal smooth muscle H2O2 downregulates myofilament Ca2+-sensitivity more potently during acetylcholine-induced contraction than during high-K+-induced contraction, leading to an effective inhibition of the former contraction.

  4. Extracellular matrix-regulated neural differentiation of human multipotent marrow progenitor cells enhances functional recovery after spinal cord injury

    PubMed Central

    Deng, Win-Ping; Yang, Chi-Chiang; Yang, Liang-Yo; Chen, Chun-Wei D.; Chen, Wei-Hong; Yang, Charn-Bing; Chen, Yu-Hsin; Lai, Wen-Fu T.; Renshaw, Perry F.

    2015-01-01

    BACKGROUND CONTEXT Recent advanced studies have demonstrated that cytokines and extracellular matrix (ECM) could trigger various types of neural differentiation. However, the efficacy of differentiation and in vivo transplantation has not yet thoroughly been investigated. PURPOSE To highlight the current understanding of the effects of ECM on neural differentiation of human bone marrow-derived multipotent progenitor cells (MPCs), regarding state-of-art cure for the animal with acute spinal cord injury (SCI), and explore future treatments aimed at neural repair. STUDY DESIGN A selective overview of the literature pertaining to the neural differentiation of the MSCs and experimental animals aimed at improved repair of SCI. METHODS Extracellular matrix proteins, tenascin-cytotactin (TN-C), tenascin-restrictin (TN-R), and chondroitin sulfate (CS), with the cytokines, nerve growth factor (NGF)/brain-derived neurotrophic factor (BDNF)/retinoic acid (RA) (NBR), were incorporated to induce transdifferentiation of human MPCs. Cells were treated with NBR for 7 days, and then TN-C, TN-R, or CS was added for 2 days. The medium was changed every 2 days. Twenty-four animals were randomly assigned to four groups with six animals in each group: one experimental and three controls. Animals received two (bilateral) injections of vehicle, MPCs, NBR-induced MPCs, or NBR/TN-C-induced MPCs into the lesion sites after SCI. Functional assessment was measured using the Basso, Beattie, and Bresnahan locomotor rating score. Data were analyzed using analysis of variance followed by Student-Newman-Keuls (SNK) post hoc tests. RESULTS Results showed that MPCs with the transdifferentiation of human MPCs to neurons were associated with increased messenger-RNA (mRNA) expression of neuronal markers including nestin, microtubule-associated protein (MAP) 2, glial fibrillary acidic protein, βIII tubulin, and NGF. Greater amounts of neuronal morphology appeared in cultures incorporated with TN-C and TN

  5. Neural Network based Control of SG based Standalone Generating System with Energy Storage for Power Quality Enhancement

    NASA Astrophysics Data System (ADS)

    Nayar, Priya; Singh, Bhim; Mishra, Sukumar

    2016-09-01

    An artificial intelligence based control algorithm is used in solving power quality problems of a diesel engine driven synchronous generator with automatic voltage regulator and governor based standalone system. A voltage source converter integrated with a battery energy storage system is employed to mitigate the power quality problems. An adaptive neural network based signed regressor control algorithm is used for the estimation of the fundamental component of load currents for control of a standalone system with load leveling as an integral feature. The developed model of the system performs accurately under varying load conditions and provides good dynamic response to the step changes in loads. The real time performance is achieved using MATLAB along with simulink/simpower system toolboxes and results adhere to an IEEE-519 standard for power quality enhancement.

  6. Enhancer Analysis Unveils Genetic Interactions between TLX and SOX2 in Neural Stem Cells and In Vivo Reprogramming.

    PubMed

    Islam, Mohammed M; Smith, Derek K; Niu, Wenze; Fang, Sanhua; Iqbal, Nida; Sun, Guoqiang; Shi, Yanhong; Zhang, Chun-Li

    2015-11-10

    The orphan nuclear receptor TLX is a master regulator of postnatal neural stem cell (NSC) self-renewal and neurogenesis; however, it remains unclear how TLX expression is precisely regulated in these tissue-specific stem cells. Here, we show that a highly conserved cis-element within the Tlx locus functions to drive gene expression in NSCs. We demonstrate that the transcription factors SOX2 and MYT1 specifically interact with this genomic element to directly regulate Tlx enhancer activity in vivo. Knockdown experiments further reveal that SOX2 dominantly controls endogenous expression of TLX, whereas MYT1 only plays a modulatory role. Importantly, TLX is essential for SOX2-mediated in vivo reprogramming of astrocytes and itself is also sufficient to induce neurogenesis in the adult striatum. Together, these findings unveil functional genetic interactions among transcription factors that are critical to NSCs and in vivo cell reprogramming. PMID:26607952

  7. Programming Hippocampal Neural Stem/Progenitor Cells into Oligodendrocytes Enhances Remyelination in the Adult Brain after Injury.

    PubMed

    Braun, Simon M G; Pilz, Gregor-Alexander; Machado, Raquel A C; Moss, Jonathan; Becher, Burkhard; Toni, Nicolas; Jessberger, Sebastian

    2015-06-23

    Demyelinating diseases are characterized by a loss of oligodendrocytes leading to axonal degeneration and impaired brain function. Current strategies used for the treatment of demyelinating disease such as multiple sclerosis largely rely on modulation of the immune system. Only limited treatment options are available for treating the later stages of the disease, and these treatments require regenerative therapies to ameliorate the consequences of oligodendrocyte loss and axonal impairment. Directed differentiation of adult hippocampal neural stem/progenitor cells (NSPCs) into oligodendrocytes may represent an endogenous source of glial cells for cell-replacement strategies aiming to treat demyelinating disease. Here, we show that Ascl1-mediated conversion of hippocampal NSPCs into mature oligodendrocytes enhances remyelination in a diphtheria-toxin (DT)-inducible, genetic model for demyelination. These findings highlight the potential of targeting hippocampal NSPCs for the treatment of demyelinated lesions in the adult brain.

  8. Enhancer Analysis Unveils Genetic Interactions between TLX and SOX2 in Neural Stem Cells and In Vivo Reprogramming

    PubMed Central

    Islam, Mohammed M.; Smith, Derek K.; Niu, Wenze; Fang, Sanhua; Iqbal, Nida; Sun, Guoqiang; Shi, Yanhong; Zhang, Chun-Li

    2015-01-01

    Summary The orphan nuclear receptor TLX is a master regulator of postnatal neural stem cell (NSC) self-renewal and neurogenesis; however, it remains unclear how TLX expression is precisely regulated in these tissue-specific stem cells. Here, we show that a highly conserved cis-element within the Tlx locus functions to drive gene expression in NSCs. We demonstrate that the transcription factors SOX2 and MYT1 specifically interact with this genomic element to directly regulate Tlx enhancer activity in vivo. Knockdown experiments further reveal that SOX2 dominantly controls endogenous expression of TLX, whereas MYT1 only plays a modulatory role. Importantly, TLX is essential for SOX2-mediated in vivo reprogramming of astrocytes and itself is also sufficient to induce neurogenesis in the adult striatum. Together, these findings unveil functional genetic interactions among transcription factors that are critical to NSCs and in vivo cell reprogramming. PMID:26607952

  9. Endogenous Repair Signaling after Brain Injury and Complementary Bioengineering Approaches to Enhance Neural Regeneration

    PubMed Central

    Addington, Caroline P; Roussas, Adam; Dutta, Dipankar; Stabenfeldt, Sarah E

    2015-01-01

    Traumatic brain injury (TBI) affects 5.3 million Americans annually. Despite the many long-term deficits associated with TBI, there currently are no clinically available therapies that directly address the underlying pathologies contributing to these deficits. Preclinical studies have investigated various therapeutic approaches for TBI: two such approaches are stem cell transplantation and delivery of bioactive factors to mitigate the biochemical insult affiliated with TBI. However, success with either of these approaches has been limited largely due to the complexity of the injury microenvironment. As such, this review outlines the many factors of the injury microenvironment that mediate endogenous neural regeneration after TBI and the corresponding bioengineering approaches that harness these inherent signaling mechanisms to further amplify regenerative efforts. PMID:25983552

  10. Variations in prestimulus neural activity predict the emotion-enhanced memory effect.

    PubMed

    Yick, Yee Ying; Buratto, Luciano G; Schaefer, Alexandre

    2016-08-01

    Here, we report evidence that electrophysiological neural activity preceding the onset of emotional pictures can predict whether they will be remembered or forgotten 24 h later, whereas the same effect was not observed for neutral pictures. In contrast to previous research, we observed this effect using a paradigm in which participants could not predict the emotional or the neutral content of the pictures before their onset. These effects were obtained alongside significant behavioural effects of superior recognition memory for emotional compared with neutral items. These findings suggest that the preferential encoding of emotional events in memory is determined by fluctuations in the availability of processing resources just before event onset. This explanation argues in favour of mediational models of emotional memory, which contend that emotional information is preferentially encoded because it mobilizes a greater amount of processing resources than neutral information. PMID:27295027

  11. Hybrid optical fiber sensor and artificial neural network system for bioethanol quality control and productivity enhancement

    NASA Astrophysics Data System (ADS)

    Gusken, Edmilton; Salgado, Ricardo M.; Rossell, Carlos E. V.; Ohishi, Takaaki; Suzuki, Carlos K.

    2008-04-01

    Bioethanol is produced by bio-chemical process that converts sugar or biomass feedstock into ethanol. After bio-chemical process, the solution is distilled under controlled conditions of pressure and temperature, in order to obtain an ethanol-water solution. However, the ethanol concentration analysis is generally performed off-line and, sometimes, a re-distillation process becomes necessary. In this research, an optical apparatus based on Fresnel reflection has been used in combination with artificial neural networks for determination of bioethanol concentration in hydro-alcoholic solution at any temperature. The volumetric concentration and temperature effect was investigated. This intelligent system can effectively detect and update in real-time the correction of distillation parameters to reduce losses of bioethanol and also to improve the quality in a production plant.

  12. Rhomboid Enhancer Activity Defines a Subset of Drosophila Neural Precursors Required for Proper Feeding, Growth and Viability.

    PubMed

    Gresser, Amy L; Gutzwiller, Lisa M; Gauck, Mackenzie K; Hartenstein, Volker; Cook, Tiffany A; Gebelein, Brian

    2015-01-01

    Organismal growth regulation requires the interaction of multiple metabolic, hormonal and neuronal pathways. While the molecular basis for many of these are well characterized, less is known about the developmental origins of growth regulatory structures and the mechanisms governing control of feeding and satiety. For these reasons, new tools and approaches are needed to link the specification and maturation of discrete cell populations with their subsequent regulatory roles. In this study, we characterize a rhomboid enhancer element that selectively labels four Drosophila embryonic neural precursors. These precursors give rise to the hypopharyngeal sensory organ of the peripheral nervous system and a subset of neurons in the deutocerebral region of the embryonic central nervous system. Post embryogenesis, the rhomboid enhancer is active in a subset of cells within the larval pharyngeal epithelium. Enhancer-targeted toxin expression alters the morphology of the sense organ and results in impaired larval growth, developmental delay, defective anterior spiracle eversion and lethality. Limiting the duration of toxin expression reveals differences in the critical periods for these effects. Embryonic expression causes developmental defects and partially penetrant pre-pupal lethality. Survivors of embryonic expression, however, ultimately become viable adults. In contrast, post-embryonic toxin expression results in fully penetrant lethality. To better define the larval growth defect, we used a variety of assays to demonstrate that toxin-targeted larvae are capable of locating, ingesting and clearing food and they exhibit normal food search behaviors. Strikingly, however, following food exposure these larvae show a rapid decrease in consumption suggesting a satiety-like phenomenon that correlates with the period of impaired larval growth. Together, these data suggest a critical role for these enhancer-defined lineages in regulating feeding, growth and viability.

  13. Rhomboid Enhancer Activity Defines a Subset of Drosophila Neural Precursors Required for Proper Feeding, Growth and Viability.

    PubMed

    Gresser, Amy L; Gutzwiller, Lisa M; Gauck, Mackenzie K; Hartenstein, Volker; Cook, Tiffany A; Gebelein, Brian

    2015-01-01

    Organismal growth regulation requires the interaction of multiple metabolic, hormonal and neuronal pathways. While the molecular basis for many of these are well characterized, less is known about the developmental origins of growth regulatory structures and the mechanisms governing control of feeding and satiety. For these reasons, new tools and approaches are needed to link the specification and maturation of discrete cell populations with their subsequent regulatory roles. In this study, we characterize a rhomboid enhancer element that selectively labels four Drosophila embryonic neural precursors. These precursors give rise to the hypopharyngeal sensory organ of the peripheral nervous system and a subset of neurons in the deutocerebral region of the embryonic central nervous system. Post embryogenesis, the rhomboid enhancer is active in a subset of cells within the larval pharyngeal epithelium. Enhancer-targeted toxin expression alters the morphology of the sense organ and results in impaired larval growth, developmental delay, defective anterior spiracle eversion and lethality. Limiting the duration of toxin expression reveals differences in the critical periods for these effects. Embryonic expression causes developmental defects and partially penetrant pre-pupal lethality. Survivors of embryonic expression, however, ultimately become viable adults. In contrast, post-embryonic toxin expression results in fully penetrant lethality. To better define the larval growth defect, we used a variety of assays to demonstrate that toxin-targeted larvae are capable of locating, ingesting and clearing food and they exhibit normal food search behaviors. Strikingly, however, following food exposure these larvae show a rapid decrease in consumption suggesting a satiety-like phenomenon that correlates with the period of impaired larval growth. Together, these data suggest a critical role for these enhancer-defined lineages in regulating feeding, growth and viability. PMID

  14. Centered Kernel Alignment Enhancing Neural Network Pretraining for MRI-Based Dementia Diagnosis

    PubMed Central

    Cárdenas-Peña, David; Collazos-Huertas, Diego; Castellanos-Dominguez, German

    2016-01-01

    Dementia is a growing problem that affects elderly people worldwide. More accurate evaluation of dementia diagnosis can help during the medical examination. Several methods for computer-aided dementia diagnosis have been proposed using resonance imaging scans to discriminate between patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI) and healthy controls (NC). Nonetheless, the computer-aided diagnosis is especially challenging because of the heterogeneous and intermediate nature of MCI. We address the automated dementia diagnosis by introducing a novel supervised pretraining approach that takes advantage of the artificial neural network (ANN) for complex classification tasks. The proposal initializes an ANN based on linear projections to achieve more discriminating spaces. Such projections are estimated by maximizing the centered kernel alignment criterion that assesses the affinity between the resonance imaging data kernel matrix and the label target matrix. As a result, the performed linear embedding allows accounting for features that contribute the most to the MCI class discrimination. We compare the supervised pretraining approach to two unsupervised initialization methods (autoencoders and Principal Component Analysis) and against the best four performing classification methods of the 2014 CADDementia challenge. As a result, our proposal outperforms all the baselines (7% of classification accuracy and area under the receiver-operating-characteristic curve) at the time it reduces the class biasing. PMID:27148392

  15. Enhancement of cognitive and neural functions through complex reasoning training: evidence from normal and clinical populations.

    PubMed

    Chapman, Sandra B; Mudar, Raksha A

    2014-01-01

    Public awareness of cognitive health is fairly recent compared to physical health. Growing evidence suggests that cognitive training offers promise in augmenting cognitive brain performance in normal and clinical populations. Targeting higher-order cognitive functions, such as reasoning in particular, may promote generalized cognitive changes necessary for supporting the complexities of daily life. This data-driven perspective highlights cognitive and brain changes measured in randomized clinical trials that trained gist reasoning strategies in populations ranging from teenagers to healthy older adults, individuals with brain injury to those at-risk for Alzheimer's disease. The evidence presented across studies support the potential for Gist reasoning training to strengthen cognitive performance in trained and untrained domains and to engage more efficient communication across widespread neural networks that support higher-order cognition. The meaningful benefits of Gist training provide compelling motivation to examine optimal dose for sustained benefits as well as to explore additive benefits of meditation, physical exercise, and/or improved sleep in future studies.

  16. Enhancement of cognitive and neural functions through complex reasoning training: evidence from normal and clinical populations

    PubMed Central

    Chapman, Sandra B.; Mudar, Raksha A.

    2014-01-01

    Public awareness of cognitive health is fairly recent compared to physical health. Growing evidence suggests that cognitive training offers promise in augmenting cognitive brain performance in normal and clinical populations. Targeting higher-order cognitive functions, such as reasoning in particular, may promote generalized cognitive changes necessary for supporting the complexities of daily life. This data-driven perspective highlights cognitive and brain changes measured in randomized clinical trials that trained gist reasoning strategies in populations ranging from teenagers to healthy older adults, individuals with brain injury to those at-risk for Alzheimer's disease. The evidence presented across studies support the potential for Gist reasoning training to strengthen cognitive performance in trained and untrained domains and to engage more efficient communication across widespread neural networks that support higher-order cognition. The meaningful benefits of Gist training provide compelling motivation to examine optimal dose for sustained benefits as well as to explore additive benefits of meditation, physical exercise, and/or improved sleep in future studies. PMID:24808834

  17. Role of the nicotinic acetylcholine receptor in Alzheimer's disease pathology and treatment.

    PubMed

    Lombardo, Sylvia; Maskos, Uwe

    2015-09-01

    Alzheimer's Disease (AD) is the major form of senile dementia, characterized by neuronal loss, extracellular deposits, and neurofibrillary tangles. It is accompanied by a loss of cholinergic tone, and acetylcholine (ACh) levels in the brain, which were hypothesized to be responsible for the cognitive decline observed in AD. Current medication is restricted to enhancing cholinergic signalling for symptomatic treatment of AD patients. The nicotinic acetylcholine receptor family (nAChR) and the muscarinic acetylcholine receptor family (mAChR) are the target of ACh in the brain. Both families of receptors are affected in AD. It was demonstrated that amyloid beta (Aβ) interacts with nAChRs. Here we discuss how Aβ activates or inhibits nAChRs, and how this interaction contributes to AD pathology. We will discuss the potential role of nAChRs as therapeutic targets. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'. PMID:25514383

  18. Perfection of a synaptic receptor: kinetics and energetics of the acetylcholine receptor.

    PubMed

    Jackson, M B

    1989-04-01

    The energetics and kinetics of activation of the acetylcholine receptor are evaluated in the context of optimizing rapid synaptic transmission. Physiological needs are used as the basis for estimating optimal values for the closed-to-open channel equilibrium constants of the liganded and unliganded receptor. An estimate is made of the maximum energy that can be derived from the binding of acetylcholine to a perfectly designed receptor binding site. Application of the principle of detailed balance shows that with only one ligand binding site the receptor will not be able to derive enough energy from acetylcholine binding to drive a sufficiently large change in the channel conformational equilibrium. This then provides a rationale for the existence of a second binding site, rather than the often invoked advantage of cooperativity. With two binding sites there is a considerable excess of binding energy and consequently considerable flexibility in how binding energy can be utilized. It is shown that the receptor must have at least one binding site that binds acetylcholine weakly when the channel is closed. This is essential to rapid response termination. However, making the other binding site bind more tightly can enhance and accelerate the activation of the receptor. To optimize both response activation and termination the best solution is to make the two binding sites different in their binding affinities. This qualitatively reproduces an experimental observation. PMID:2538836

  19. External Imaging of Cerebral Muscarinic Acetylcholine Receptors

    NASA Astrophysics Data System (ADS)

    Eckelman, William C.; Reba, Richard C.; Rzeszotarski, Waclaw J.; Gibson, Raymond E.; Hill, Thomas; Holman, B. Leonard; Budinger, Thomas; Conklin, James J.; Eng, Robert; Grissom, Michael P.

    1984-01-01

    A radioiodinated ligand that binds to muscarinic acetylcholine receptors was shown to distribute in the brain by a receptor-mediated process. With single-photon-emission imaging techniques, radioactivity was detected in the cerebrum but not in the cerebellum, whereas with a flow-limited radiotracer, radioactivity was detected in cerebrum and cerebellum. Single-photon-emission computed tomography showed good definition of the caudate putamen and cortex in man.

  20. External imaging of cerebral muscarinic acetylcholine receptors

    SciTech Connect

    Eckelman, W.C.; Reba, R.C.; Rzeszotarski, W.J.; Gibson, R.E.; Hill, T.; Holman, B.L.; Budinger, T.; Conklin, J.J.; Eng, R.; Grissom, M.P.

    1984-01-20

    A radioiodinated ligand that binds to muscarinic acetylcholine receptors was shown to distribute in the brain by a receptor-mediated process. With single-photon-emission imaging techniques, radioactivity was detected in the cerebrum but not in the cerebellum, whereas with a flow-limited radiotracer, radioactivity was detected in cerebrum and cerebellum. Single-photon-emission computed tomography showed good definition of the caudate putamen and cortex in man.

  1. Vital staining of nerve structures with fluorescent dyes and optical determination of acetylcholine in the somatic muscle of the earthworm Lumbricus terrestris.

    PubMed

    Volkov, M E

    2012-11-01

    Experiments with fluorescent dyes showed that high concentrations of K(+) ions in the medium depolarize the membrane and enhance exo-endocytosis in nerve structures, which is accompanied by an increase in acetylcholine concentration in the somatic muscle of earthworm. In the presence of BAPTA and without Ca(2+) exo-endocytosis is sharply decelerated, the level of acetylcholine in the muscle decreases, but remains relatively high. PMID:23330101

  2. Retinoic acid-loaded polymeric nanoparticles enhance vascular regulation of neural stem cell survival and differentiation after ischaemia

    NASA Astrophysics Data System (ADS)

    Ferreira, R.; Fonseca, M. C.; Santos, T.; Sargento-Freitas, J.; Tjeng, R.; Paiva, F.; Castelo-Branco, M.; Ferreira, L. S.; Bernardino, L.

    2016-04-01

    Stroke is one of the leading causes of death and disability worldwide. However, current therapies only reach a small percentage of patients and may cause serious side effects. We propose the therapeutic use of retinoic acid-loaded nanoparticles (RA-NP) to safely and efficiently repair the ischaemic brain by creating a favourable pro-angiogenic environment that enhances neurogenesis and neuronal restitution. Our data showed that RA-NP enhanced endothelial cell proliferation and tubule network formation and protected against ischaemia-induced death. To evaluate the effect of RA-NP on vascular regulation of neural stem cell (NSC) survival and differentiation, endothelial cell-conditioned media (EC-CM) were collected. EC-CM from healthy RA-NP-treated cells reduced NSC death and promoted proliferation while EC-CM from ischaemic RA-NP-treated cells decreased cell death, increased proliferation and neuronal differentiation. In parallel, human endothelial progenitor cells (hEPC), which are part of the endogenous repair response to vascular injury, were collected from ischaemic stroke patients. hEPC treated with RA-NP had significantly higher proliferation, which further highlights the therapeutic potential of this formulation. To conclude, RA-NP protected endothelial cells from ischaemic death and stimulated the release of pro-survival, proliferation-stimulating factors and differentiation cues for NSC. RA-NP were shown to be up to 83-fold more efficient than free RA and to enhance hEPC proliferation. These data serve as a stepping stone to use RA-NP as vasculotrophic and neurogenic agents for vascular disorders and neurodegenerative diseases with compromised vasculature.

  3. [Sites of synthesis of acetylcholine receptors in denervated muscles].

    PubMed

    Giacobini Robecchi, M G; Garelli, M; Filogamo, G

    1980-09-01

    Muscle fibres binding with 125I alpha-bungarotoxine from Bungarus Multicinctus, after treatment with saponine, shows (in electron microscope autoradiography) intracellular binding sites identifying sites of acetylcholine receptor synthesis. In innervated muscle, the acetylcholine receptor is located only at the neuromuscular junction. In denervated muscle the receptor is distributed along the whole sarcolemma; in this situation the acetylcholine receptor is synthesized "ex novo" in the membrane system over the whole length of the muscle fibre. PMID:7214035

  4. Construction of a 3D rGO-collagen hybrid scaffold for enhancement of the neural differentiation of mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Guo, Weibo; Wang, Shu; Yu, Xin; Qiu, Jichuan; Li, Jianhua; Tang, Wei; Li, Zhou; Mou, Xiaoning; Liu, Hong; Wang, Zhonglin

    2016-01-01

    The cell-material interface is one of the most important considerations in designing a high-performance tissue engineering scaffold because the surface of the scaffold can determine the fate of stem cells. A conductive surface is required for a scaffold to direct stem cells toward neural differentiation. However, most conductive polymers are toxic and not amenable to biological degradation, which restricts the design of neural tissue engineering scaffolds. In this study, we used a bioactive three-dimensional (3D) porcine acellular dermal matrix (PADM), which is mainly composed of type I collagen, as a basic material and successfully assembled a layer of reduced graphene oxide (rGO) nanosheets on the surface of the PADM channels to obtain a porous 3D, biodegradable, conductive and biocompatible PADM-rGO hybrid neural tissue engineering scaffold. Compared with the PADM scaffold, assembling the rGO into the scaffold did not induce a significant change in the microstructure but endowed the PADM-rGO hybrid scaffold with good conductivity. A comparison of the neural differentiation of rat bone-marrow-derived mesenchymal stem cells (MSCs) was performed by culturing the MSCs on PADM and PADM-rGO scaffolds in neuronal culture medium, followed by the determination of gene expression and immunofluorescence staining. The results of both the gene expression and protein level assessments suggest that the rGO-assembled PADM scaffold may promote the differentiation of MSCs into neuronal cells with higher protein and gene expression levels after 7 days under neural differentiation conditions. This study demonstrated that the PADM-rGO hybrid scaffold is a promising scaffold for neural tissue engineering; this scaffold can not only support the growth of MSCs at a high proliferation rate but also enhance the differentiation of MSCs into neural cells.The cell-material interface is one of the most important considerations in designing a high-performance tissue engineering scaffold

  5. Feeding with powdered diet after weaning affects sex difference in acetylcholine release in the hippocampus in rats.

    PubMed

    Takase, K; Mitsushima, D; Masuda, J; Mogi, K; Funabashi, T; Endo, Y; Kimura, F

    2005-01-01

    We have reported in the past that female rats fed a powdered diet showed better spatial learning and memory functions than female rats a fed pelleted diet. In the present study, we examined the effects of feeding with powdered diet on acetylcholine release in the hippocampus in both sexes of rats. After weaning (3 weeks of age), rats were fed either standard pelleted diet or powdered diet, and after maturation (9-12 weeks of age), they were used in an in vivo microdialysis study, in which no eserine (a cholinesterase inhibitor) was added to the perfusate. The dialysate was collected from the dorsal hippocampus at 20-min intervals under freely moving conditions for more than 24 h. Acetylcholine in the dialysate was measured by high performance liquid chromatography. As we reported previously, the acetylcholine release showed a clear daily rhythm in both sexes, and males showed significantly greater acetylcholine release in the hippocampus than females in rats fed pelleted diet. Conversely, in rats fed powdered diet, no sex difference in the acetylcholine release was observed, since feeding with powdered diet significantly increased the acetylcholine release only in females. To further examine the number of cholinergic neurons in the medial septum and horizontal limb of the diagonal band of Broca, immunocytochemistry for choline acetyltransferase was performed in both sexes of rats fed either standard pelleted diet or powdered diet. However, neither sex nor feeding conditions affect the number of choline acetyltransferase immunoreactive cells in the areas. These results suggest that powdered diet after weaning enhances spontaneous acetylcholine release in the hippocampus in female rats without changes in the number of cholinergic neurons in the areas. It is possible that this effect of feeding contributes to improve the performance in spatial learning and memory functions in female rats fed powdered diet.

  6. Immunocytochemical Detection of Acetylcholine in the Rat Central Nervous System

    NASA Astrophysics Data System (ADS)

    Geffard, M.; McRae-Degueurce, A.; Souan, Marie Laure

    1985-07-01

    A specific antibody to acetylcholine was raised and used as a marker for cholinergic neurons in the rat central nervous system. The acetylcholine conjugate was obtained by a two-step immunogen synthesis procedure. An enzyme-linked immunosorbent assay was used to test the specificity and affinity of the antibody in vitro; the results indicated high affinity. A chemical perfusion mixture of allyl alcohol and glutaraldehyde was used to fix the acetylcholine in the nervous tissue. Peroxidase-antiperoxidase immunocytochemistry showed many acetylcholine-immunoreactive cells and fibers in sections from the medial septum region.

  7. Construction of a 3D rGO-collagen hybrid scaffold for enhancement of the neural differentiation of mesenchymal stem cells.

    PubMed

    Guo, Weibo; Wang, Shu; Yu, Xin; Qiu, Jichuan; Li, Jianhua; Tang, Wei; Li, Zhou; Mou, Xiaoning; Liu, Hong; Wang, Zhonglin

    2016-01-28

    The cell-material interface is one of the most important considerations in designing a high-performance tissue engineering scaffold because the surface of the scaffold can determine the fate of stem cells. A conductive surface is required for a scaffold to direct stem cells toward neural differentiation. However, most conductive polymers are toxic and not amenable to biological degradation, which restricts the design of neural tissue engineering scaffolds. In this study, we used a bioactive three-dimensional (3D) porcine acellular dermal matrix (PADM), which is mainly composed of type I collagen, as a basic material and successfully assembled a layer of reduced graphene oxide (rGO) nanosheets on the surface of the PADM channels to obtain a porous 3D, biodegradable, conductive and biocompatible PADM-rGO hybrid neural tissue engineering scaffold. Compared with the PADM scaffold, assembling the rGO into the scaffold did not induce a significant change in the microstructure but endowed the PADM-rGO hybrid scaffold with good conductivity. A comparison of the neural differentiation of rat bone-marrow-derived mesenchymal stem cells (MSCs) was performed by culturing the MSCs on PADM and PADM-rGO scaffolds in neuronal culture medium, followed by the determination of gene expression and immunofluorescence staining. The results of both the gene expression and protein level assessments suggest that the rGO-assembled PADM scaffold may promote the differentiation of MSCs into neuronal cells with higher protein and gene expression levels after 7 days under neural differentiation conditions. This study demonstrated that the PADM-rGO hybrid scaffold is a promising scaffold for neural tissue engineering; this scaffold can not only support the growth of MSCs at a high proliferation rate but also enhance the differentiation of MSCs into neural cells. PMID:26750302

  8. Construction of a 3D rGO-collagen hybrid scaffold for enhancement of the neural differentiation of mesenchymal stem cells.

    PubMed

    Guo, Weibo; Wang, Shu; Yu, Xin; Qiu, Jichuan; Li, Jianhua; Tang, Wei; Li, Zhou; Mou, Xiaoning; Liu, Hong; Wang, Zhonglin

    2016-01-28

    The cell-material interface is one of the most important considerations in designing a high-performance tissue engineering scaffold because the surface of the scaffold can determine the fate of stem cells. A conductive surface is required for a scaffold to direct stem cells toward neural differentiation. However, most conductive polymers are toxic and not amenable to biological degradation, which restricts the design of neural tissue engineering scaffolds. In this study, we used a bioactive three-dimensional (3D) porcine acellular dermal matrix (PADM), which is mainly composed of type I collagen, as a basic material and successfully assembled a layer of reduced graphene oxide (rGO) nanosheets on the surface of the PADM channels to obtain a porous 3D, biodegradable, conductive and biocompatible PADM-rGO hybrid neural tissue engineering scaffold. Compared with the PADM scaffold, assembling the rGO into the scaffold did not induce a significant change in the microstructure but endowed the PADM-rGO hybrid scaffold with good conductivity. A comparison of the neural differentiation of rat bone-marrow-derived mesenchymal stem cells (MSCs) was performed by culturing the MSCs on PADM and PADM-rGO scaffolds in neuronal culture medium, followed by the determination of gene expression and immunofluorescence staining. The results of both the gene expression and protein level assessments suggest that the rGO-assembled PADM scaffold may promote the differentiation of MSCs into neuronal cells with higher protein and gene expression levels after 7 days under neural differentiation conditions. This study demonstrated that the PADM-rGO hybrid scaffold is a promising scaffold for neural tissue engineering; this scaffold can not only support the growth of MSCs at a high proliferation rate but also enhance the differentiation of MSCs into neural cells.

  9. Menthol Binding and Inhibition of α7-Nicotinic Acetylcholine Receptors

    PubMed Central

    Ashoor, Abrar; Nordman, Jacob C.; Veltri, Daniel; Yang, Keun-Hang Susan; Al Kury, Lina; Shuba, Yaroslav; Mahgoub, Mohamed; Howarth, Frank C.; Sadek, Bassem; Shehu, Amarda; Kabbani, Nadine; Oz, Murat

    2013-01-01

    Menthol is a common compound in pharmaceutical and commercial products and a popular additive to cigarettes. The molecular targets of menthol remain poorly defined. In this study we show an effect of menthol on the α7 subunit of the nicotinic acetylcholine (nACh) receptor function. Using a two-electrode voltage-clamp technique, menthol was found to reversibly inhibit α7-nACh receptors heterologously expressed in Xenopus oocytes. Inhibition by menthol was not dependent on the membrane potential and did not involve endogenous Ca2+-dependent Cl− channels, since menthol inhibition remained unchanged by intracellular injection of the Ca2+ chelator BAPTA and perfusion with Ca2+-free bathing solution containing Ba2+. Furthermore, increasing ACh concentrations did not reverse menthol inhibition and the specific binding of [125I] α-bungarotoxin was not attenuated by menthol. Studies of α7- nACh receptors endogenously expressed in neural cells demonstrate that menthol attenuates α7 mediated Ca2+ transients in the cell body and neurite. In conclusion, our results suggest that menthol inhibits α7-nACh receptors in a noncompetitive manner. PMID:23935840

  10. Voluntary enhancement of neural signatures of affiliative emotion using FMRI neurofeedback.

    PubMed

    Moll, Jorge; Weingartner, Julie H; Bado, Patricia; Basilio, Rodrigo; Sato, João R; Melo, Bruno R; Bramati, Ivanei E; de Oliveira-Souza, Ricardo; Zahn, Roland

    2014-01-01

    In Ridley Scott's film "Blade Runner", empathy-detection devices are employed to measure affiliative emotions. Despite recent neurocomputational advances, it is unknown whether brain signatures of affiliative emotions, such as tenderness/affection, can be decoded and voluntarily modulated. Here, we employed multivariate voxel pattern analysis and real-time fMRI to address this question. We found that participants were able to use visual feedback based on decoded fMRI patterns as a neurofeedback signal to increase brain activation characteristic of tenderness/affection relative to pride, an equally complex control emotion. Such improvement was not observed in a control group performing the same fMRI task without neurofeedback. Furthermore, the neurofeedback-driven enhancement of tenderness/affection-related distributed patterns was associated with local fMRI responses in the septohypothalamic area and frontopolar cortex, regions previously implicated in affiliative emotion. This demonstrates that humans can voluntarily enhance brain signatures of tenderness/affection, unlocking new possibilities for promoting prosocial emotions and countering antisocial behavior.

  11. Neural stem cell transplantation enhances mitochondrial biogenesis in a transgenic mouse model of Alzheimer's disease-like pathology.

    PubMed

    Zhang, Wei; Gu, Guo-Jun; Shen, Xing; Zhang, Qi; Wang, Gang-Min; Wang, Pei-Jun

    2015-03-01

    Mitochondrial dysfunction, especially a defect in mitochondrial biogenesis, is an early and prominent feature of Alzheimer's disease (AD). Previous studies demonstrated that the number of mitochondria is significantly reduced in susceptible hippocampal neurons from AD patients. Neural stem cell (NSC) transplantation in AD-like mice can compensate for the neuronal loss resulting from amyloid-beta protein deposition. The effects of NSC transplantation on mitochondrial biogenesis and cognitive function in AD-like mice, however, are poorly understood. In this study, we injected NSCs or vehicle into 12-month-old amyloid precursor protein (APP)/PS1 transgenic mice, a mouse model of AD-like pathology. The effects of NSC transplantation on cognitive function, the amount of mitochondrial DNA, the expression of mitochondrial biogenesis factors and mitochondria-related proteins, and mitochondrial morphology were investigated. Our results show that in NSC-injected APP/PS1 (Tg-NSC) mice, the cognitive function, number of mitochondria, and expression of mitochondria-related proteins, specifically the mitochondrial fission factors (dynamin-related protein 1 [Drp1] and fission 1 [Fis1]) and the mitochondrial fusion factor optic atrophy 1 (OPA1), were significantly increased compared with those in age-matched vehicle-injected APP/PS1 (Tg-Veh) mice, whereas the expression of mitochondrial fusion factors mitofusion 1 (Mfn1) and Mfn2 was significantly decreased. These data indicate that NSC transplantation may enhance mitochondria biogenesis and further rescue cognitive deficits in AD-like mice. PMID:25582749

  12. Promotion of cell migration by neural cell adhesion molecule (NCAM) is enhanced by PSA in a polysialyltransferase-specific manner.

    PubMed

    Guan, Feng; Wang, Xin; He, Fa

    2015-01-01

    Neural cell adhesion molecule 140 (NCAM-140) is a glycoprotein and always highly polysialylated in cancer. Functions of polysialic acid (PSA) that binds to N-glycan termini on NCAM remain unclear. ldlD-14 cells, a CHO cell mutant deficient in UDP-Gal 4-epimerase, are useful for structural and functional studies of Gal-containing glycoproteins because their abnormal glycosylation can be converted to normal status by exogenous addition of galactose (Gal). We cloned the genes for NCAM-140 and for polysialyltransferases STX and PST (responsible for PSA synthesis) from normal murine mammary gland epithelial (NMuMG) cells and transfected them into ldlD-14 and human breast cancer cells MCF-7. The effect of PSA on NCAM-mediated cell proliferation, motility, migration and adhesion was studied. We found that NCAM-140 significantly promoted cell proliferation, motility and migration, while polysialylation of NCAM-140 catalyzed by STX, but not by PST, enhanced NCAM-mediated cell migration, but not cell proliferation or motility. In addition, PSA catalyzed by different polysialyltransferases affected the adhesion of NCAM to different extracellular matrix (ECM) components. PMID:25885924

  13. Enhancing glass ionomer cement features by using the HA/YSZ nanocomposite: a feed forward neural network modelling.

    PubMed

    Rajabzadeh, Ghadir; Salehi, Sahar; Nemati, Ali; Tavakoli, Razeih; Solati Hashjin, Mehran

    2014-01-01

    Despite brilliant properties of glass ionomer cement (GIC), its weak mechanical property poses an obstacle for its use in medical applications. The present research aims to formulate hydroxyapatite/yttria-stabilized zirconia (HA/YSZ) in the composition of GIC to enhance mechanical properties and to improve fluoride release of GIC. HA/YSZ was synthesized via a sol-gel method and characterized by applying X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photo-emission spectroscopy (XPS) and simultaneous thermal analysis (STA) along with transmission electron microscopy (TEM) methods. The synthesized nanocomposite was mixed with GIC at a fixed composition of 5wt%. The effect of different weight percentages of YSZ:HA on GIC was investigated by measuring the compressive strength, diametral tensile strength, microhardness and fluoride release. The results showed that, after 1 and 7 days of setting, the 20wt% nanohydroxyapatite/80wt% stabilized zirconia cement exhibited higher compressive strength (1857-245MPa), higher diametral tensile strength (11-14MPa) and greater microhardness (104-106MPa) as compared with the pure GIC (65-88MPa in compressive strength, 5-9.5MPa in diametral tensile strength and 70-89MPa in microhardness). The reinforced cement, also, exhibited higher fluoride release compared with pure GIC. The artificial neural network (ANN) was trained for modeling the system. Results obtained by ANN have proved to be completely in accordance with expectations.

  14. Neural Correlates of Enhanced Visual Short-Term Memory for Angry Faces: An fMRI Study

    PubMed Central

    Jackson, Margaret C.; Wolf, Claudia; Johnston, Stephen J.; Raymond, Jane E.; Linden, David E. J.

    2008-01-01

    Background Fluid and effective social communication requires that both face identity and emotional expression information are encoded and maintained in visual short-term memory (VSTM) to enable a coherent, ongoing picture of the world and its players. This appears to be of particular evolutionary importance when confronted with potentially threatening displays of emotion - previous research has shown better VSTM for angry versus happy or neutral face identities. Methodology/Principal Findings Using functional magnetic resonance imaging, here we investigated the neural correlates of this angry face benefit in VSTM. Participants were shown between one and four to-be-remembered angry, happy, or neutral faces, and after a short retention delay they stated whether a single probe face had been present or not in the previous display. All faces in any one display expressed the same emotion, and the task required memory for face identity. We find enhanced VSTM for angry face identities and describe the right hemisphere brain network underpinning this effect, which involves the globus pallidus, superior temporal sulcus, and frontal lobe. Increased activity in the globus pallidus was significantly correlated with the angry benefit in VSTM. Areas modulated by emotion were distinct from those modulated by memory load. Conclusions/Significance Our results provide evidence for a key role of the basal ganglia as an interface between emotion and cognition, supported by a frontal, temporal, and occipital network. PMID:18958158

  15. Neural stem cell transplantation enhances mitochondrial biogenesis in a transgenic mouse model of Alzheimer's disease-like pathology.

    PubMed

    Zhang, Wei; Gu, Guo-Jun; Shen, Xing; Zhang, Qi; Wang, Gang-Min; Wang, Pei-Jun

    2015-03-01

    Mitochondrial dysfunction, especially a defect in mitochondrial biogenesis, is an early and prominent feature of Alzheimer's disease (AD). Previous studies demonstrated that the number of mitochondria is significantly reduced in susceptible hippocampal neurons from AD patients. Neural stem cell (NSC) transplantation in AD-like mice can compensate for the neuronal loss resulting from amyloid-beta protein deposition. The effects of NSC transplantation on mitochondrial biogenesis and cognitive function in AD-like mice, however, are poorly understood. In this study, we injected NSCs or vehicle into 12-month-old amyloid precursor protein (APP)/PS1 transgenic mice, a mouse model of AD-like pathology. The effects of NSC transplantation on cognitive function, the amount of mitochondrial DNA, the expression of mitochondrial biogenesis factors and mitochondria-related proteins, and mitochondrial morphology were investigated. Our results show that in NSC-injected APP/PS1 (Tg-NSC) mice, the cognitive function, number of mitochondria, and expression of mitochondria-related proteins, specifically the mitochondrial fission factors (dynamin-related protein 1 [Drp1] and fission 1 [Fis1]) and the mitochondrial fusion factor optic atrophy 1 (OPA1), were significantly increased compared with those in age-matched vehicle-injected APP/PS1 (Tg-Veh) mice, whereas the expression of mitochondrial fusion factors mitofusion 1 (Mfn1) and Mfn2 was significantly decreased. These data indicate that NSC transplantation may enhance mitochondria biogenesis and further rescue cognitive deficits in AD-like mice.

  16. Artificial Neural Network classification of operator workload with an assessment of time variation and noise-enhancement to increase performance

    PubMed Central

    Casson, Alexander J.

    2014-01-01

    Workload classification—the determination of whether a human operator is in a high or low workload state to allow their working environment to be optimized—is an emerging application of passive Brain-Computer Interface (BCI) systems. Practical systems must not only accurately detect the current workload state, but also have good temporal performance: requiring little time to set up and train the classifier, and ensuring that the reported performance level is consistent and predictable over time. This paper investigates the temporal performance of an Artificial Neural Network based classification system. For networks trained on little EEG data good classification accuracies (86%) are achieved over very short time frames, but substantial decreases in accuracy are found as the time gap between the network training and the actual use is increased. Noise-enhanced processing, where artificially generated noise is deliberately added to the testing signals, is investigated as a potential technique to mitigate this degradation without requiring the network to be re-trained using more data. Small stochastic resonance effects are demonstrated whereby the classification process gets better in the presence of more noise. The effect is small and does not eliminate the need for re-training, but it is consistent, and this is the first demonstration of such effects for non-evoked/free-running EEG signals suitable for passive BCI. PMID:25520608

  17. Effects of arterial infusions of adrenalin and acetylcholine on luteal secretion of progesterone and oxytocin in goats.

    PubMed

    Cooke, R G; Payne, J H

    1998-07-15

    The effects of close intra-arterial infusion of acetylcholine and adrenalin on ovarian secretion of progesterone and oxytocin were examined on Day 10 of the estrous cycle in goats (estrus = Day 0). Acetylcholine (15 micrograms/min) was without effect, but adrenalin (10 micrograms/min) significantly (P < 0.001) raised both progesterone and oxytocin concentrations in ovarian vein plasma. These results show that luteal hormone secretion is enhanced in the goat by beta-adrenergic stimulation and suggest that, as in the sheep and cow, there may be neuroendocrine involvement in the regulation of caprine luteal function. PMID:10734492

  18. pH-dependent hydrolysis of acetylcholine: Consequences for non-neuronal acetylcholine.

    PubMed

    Wessler, Ignaz; Michel-Schmidt, Rosmarie; Kirkpatrick, Charles James

    2015-11-01

    Acetylcholine is inactivated by acetylcholinesterase and butyrylcholinesterase and thereby its cellular signalling is stopped. One distinguishing difference between the neuronal and non-neuronal cholinergic system is the high expression level of the esterase activity within the former and a considerably lower level within the latter system. Thus, any situation which limits the activity of both esterases will affect the non-neuronal cholinergic system to a much greater extent than the neuronal one. Both esterases are pH-dependent with an optimum at pH above 7, whereas at pH values below 6 particularly the specific acetylcholinesterase is more or less inactive. Thus, acetylcholine is prevented from hydrolysis at such low pH values. The pH of the surface of the human skin is around 5 and therefore non-neuronal acetylcholine released from keratinocytes can be detected in a non-invasive manner. Several clinical conditions like metabolic acidosis, inflammation, fracture-related haematomas, cardiac ischemia and malignant tumours are associated with local or systemic pH values below 7. Thus, the present article describes some consequences of an impaired inactivation of extracellular non-neuronal acetylcholine.

  19. Serotonin selectively enhances perception and sensory neural responses to stimuli generated by same-sex conspecifics

    PubMed Central

    Deemyad, Tara; Metzen, Michael G.; Pan, Yingzhou; Chacron, Maurice J.

    2013-01-01

    Centrifugal serotonergic fibers innervating sensory brain areas are seen ubiquitously across systems and species but their function remains unclear. Here we examined the functional role of serotonergic innervation onto electrosensory neurons in weakly electric fish by eliciting endogenous release through electrical stimulation as well as exogenous focal application of serotonin in the vicinity of the cell being recorded from. Both approaches showed that the function of serotonergic input onto electrosensory pyramidal neurons is to render them more excitable by reducing the spike afterhyperpolarization amplitude and thereby promoting burst firing. Further, serotonergic input selectively improved neuronal responses to stimuli that occur during interactions between same-sex conspecifics but not to stimuli associated with either prey or that occur during interactions between opposite-sex conspecifics. Finally, we tested whether serotonin-mediated enhanced pyramidal neuron responses to stimuli associated with same-sex conspecifics actually increase perception by the animal. Our behavioral experiments show that exogenous injection and endogenous release of serotonin both increase the magnitude of behavioral responses to stimuli associated with same-sex conspecifics as well as simultaneously decrease aggressive behaviors. Thus, our data indicate that the serotonergic system inhibits aggressive behavior toward same-sex conspecifics, while at the same time increasing perception of stimuli associated with these individuals. This function is likely to be conserved across systems and species. PMID:24218585

  20. Neural Inhibition of Dopaminergic Signaling Enhances Immunity in a Cell-Non-autonomous Manner.

    PubMed

    Cao, Xiou; Aballay, Alejandro

    2016-09-12

    The innate immune system is the front line of host defense against microbial infections, but its rapid and uncontrolled activation elicits microbicidal mechanisms that have deleterious effects [1, 2]. Increasing evidence indicates that the metazoan nervous system, which responds to stimuli originating from both the internal and the external environment, functions as a modulatory apparatus that controls not only microbial killing pathways but also cellular homeostatic mechanisms [3-5]. Here we report that dopamine signaling controls innate immune responses through a D1-like dopamine receptor, DOP-4, in Caenorhabditis elegans. Chlorpromazine inhibition of DOP-4 in the nervous system activates a microbicidal PMK-1/p38 mitogen-activated protein kinase signaling pathway that enhances host resistance against bacterial infections. The immune inhibitory function of dopamine originates in CEP neurons and requires active DOP-4 in downstream ASG neurons. Our findings indicate that dopamine signaling from the nervous system controls immunity in a cell-non-autonomous manner and identifies the dopaminergic system as a potential therapeutic target for not only infectious diseases but also a range of conditions that arise as a consequence of malfunctioning immune responses.

  1. Situation-based social anxiety enhances the neural processing of faces: evidence from an intergroup context.

    PubMed

    Ofan, Renana H; Rubin, Nava; Amodio, David M

    2014-08-01

    Social anxiety is the intense fear of negative evaluation by others, and it emerges uniquely from a social situation. Given its social origin, we asked whether an anxiety-inducing social situation could enhance the processing of faces linked to the situational threat. While past research has focused on how individual differences in social anxiety relate to face processing, we tested the effect of manipulated social anxiety in the context of anxiety about appearing racially prejudiced in front of a peer. Visual processing of faces was indexed by the N170 component of the event-related potential. Participants viewed faces of Black and White males, along with nonfaces, either in private or while being monitored by the experimenter for signs of prejudice in a 'public' condition. Results revealed a difference in the N170 response to Black and Whites faces that emerged only in the public condition and only among participants high in dispositional social anxiety. These results provide new evidence that anxiety arising from the social situation modulates the earliest stages of face processing in a way that is specific to a social threat, and they shed new light on how anxiety effects on perception may contribute to the regulation of intergroup responses.

  2. Role of acetylcholine receptors in proliferation and differentiation of P19 embryonal carcinoma cells

    SciTech Connect

    Resende, R.R.; Alves, A.S.; Britto, L.R.G; Ulrich, H.

    2008-04-15

    Coordinated proliferation and differentiation of progenitor cells is the base for production of appropriate numbers of neurons and glia during neuronal development in order to establish normal brain functions. We have used murine embryonal carcinoma P19 cells as an in vitro model for early differentiation to study participation of nicotinic (nAChR) and muscarinic acetylcholine (mAChR) receptors in the proliferation of neural progenitor cells and their differentiation to neurons. We have previously shown that functional nicotinic acetylcholine receptors (nAChRs) already expressed in embryonic cells mediate elevations in cytosolic free calcium concentration ([Ca{sup 2+}]{sub i}) via calcium influx through nAChR channels whereas intracellular stores contribute to nAChR- and mAChR-mediated calcium fluxes in differentiated cells [Resende et al., Cell Calcium 43 (2008) 107-121]. In the present study, we have demonstrated that nicotine provoked inhibition of proliferation in embryonic cells as determined by BrdU labeling. However, in neural progenitor cells nicotine stimulated proliferation which was reversed in the presence of inhibitors of calcium mobilization from intracellular stores, indicating that liberation of intracellular calcium contributed to this proliferation induction. Muscarine induced proliferation stimulation in progenitor cells by activation of G{alpha}{sub q/11}-coupled M{sub 1}, M{sub 3} and M{sub 5} receptors and intracellular calcium stores, whereas G{alpha}{sub i/o}-protein coupled M{sub 2} receptor activity mediated neuronal differentiation.

  3. Biosynthesis of Acetylcholine in Turtle Photoreceptors

    PubMed Central

    Lam, Dominic M. K.

    1972-01-01

    For determination of possible neurotransmitters synthesized by photoreceptor cells, turtle retinas were dissociated into single cells with proteolytic enzymes. These cells were partially separated by velocity sedimentation to yield a fraction rich in photoreceptors. Individual photoreceptor cells were then sucked into a micropipette and incubated with labeled precursors of known or suspected neurotransmitters. After incubation, the radioactive products were analyzed by high-voltage electrophoresis. Of all the chemicals tested, turtle photoreceptor cells synthesized only acetylcholine, suggesting that these cells may be cholinergic. Images PMID:4505678

  4. Activation of muscarinic receptors by non-neuronal acetylcholine.

    PubMed

    Wessler, Ignaz Karl; Kirkpatrick, Charles James

    2012-01-01

    The biological role of acetylcholine and the cholinergic system is revisited based particularly on scientific research early and late in the last century. On the one hand, acetylcholine represents the classical neurotransmitter, whereas on the other hand, acetylcholine and the pivotal components of the cholinergic system (high-affinity choline uptake, choline acetyltransferase and its end product acetylcholine, muscarinic and nicotinic receptors and esterase) are expressed by more or less all mammalian cells, i.e. by the majority of cells not innervated by neurons at all. Moreover, it has been demonstrated that acetylcholine and "cholinergic receptors" are expressed in non-neuronal organisms such as plants and protists. Acetylcholine is even synthesized by bacteria and algae representing an extremely old signalling molecule on the evolutionary timescale. The following article summarizes examples, in which non-neuronal acetylcholine is released from primitive organisms as well as from mammalian non-neuronal cells and binds to muscarinic receptors to modulate/regulate phenotypic cell functions via auto-/paracrine pathways. The examples demonstrate that non-neuronal acetylcholine and the non-neuronal cholinergic system are vital for various types of cells such as epithelial, endothelial and immune cells.

  5. Exercise and neuromodulators: choline and acetylcholine in marathon runners

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Sabounjian, L. A.; Wurtman, R. J.

    1992-01-01

    Certain neurotransmitters (i.e., acetylcholine, catecholamines, and serotonin) are formed from dietary constituents (i.e., choline, tyrosine and tryptophan). Changing the consumption of these precursors alters release of their respective neurotransmitter products. The neurotransmitter acetylcholine is released from the neuromuscular junction and from brain. It is formed from choline, a common constituent in fish, liver, and eggs. Choline is also incorporated into cell membranes; membranes may likewise serve as an alternative choline source for acetylcholine synthesis. In trained athletes, running a 26 km marathon reduced plasma choline by approximately 40%, from 14.1 to 8.4 uM. Changes of similar magnitude have been shown to reduce acetylcholine release from the neuromuscular junction in vivo. Thus, the reductions in plasma choline associated with strenuous exercise may reduce acetylcholine release, and could thereby affect endurance or performance.

  6. Molecular properties of muscarinic acetylcholine receptors

    PubMed Central

    HAGA, Tatsuya

    2013-01-01

    Muscarinic acetylcholine receptors, which comprise five subtypes (M1-M5 receptors), are expressed in both the CNS and PNS (particularly the target organs of parasympathetic neurons). M1-M5 receptors are integral membrane proteins with seven transmembrane segments, bind with acetylcholine (ACh) in the extracellular phase, and thereafter interact with and activate GTP-binding regulatory proteins (G proteins) in the intracellular phase: M1, M3, and M5 receptors interact with Gq-type G proteins, and M2 and M4 receptors with Gi/Go-type G proteins. Activated G proteins initiate a number of intracellular signal transduction systems. Agonist-bound muscarinic receptors are phosphorylated by G protein-coupled receptor kinases, which initiate their desensitization through uncoupling from G proteins, receptor internalization, and receptor breakdown (down regulation). Recently the crystal structures of M2 and M3 receptors were determined and are expected to contribute to the development of drugs targeted to muscarinic receptors. This paper summarizes the molecular properties of muscarinic receptors with reference to the historical background and bias to studies performed in our laboratories. PMID:23759942

  7. Homology modeling of human muscarinic acetylcholine receptors.

    PubMed

    Thomas, Trayder; McLean, Kimberley C; McRobb, Fiona M; Manallack, David T; Chalmers, David K; Yuriev, Elizabeth

    2014-01-27

    We have developed homology models of the acetylcholine muscarinic receptors M₁R-M₅R, based on the β₂-adrenergic receptor crystal as the template. This is the first report of homology modeling of all five subtypes of acetylcholine muscarinic receptors with binding sites optimized for ligand binding. The models were evaluated for their ability to discriminate between muscarinic antagonists and decoy compounds using virtual screening using enrichment factors, area under the ROC curve (AUC), and an early enrichment measure, LogAUC. The models produce rational binding modes of docked ligands as well as good enrichment capacity when tested against property-matched decoy libraries, which demonstrates their unbiased predictive ability. To test the relative effects of homology model template selection and the binding site optimization procedure, we generated and evaluated a naïve M₂R model, using the M₃R crystal structure as a template. Our results confirm previous findings that binding site optimization using ligand(s) active at a particular receptor, i.e. including functional knowledge into the model building process, has a more pronounced effect on model quality than target-template sequence similarity. The optimized M₁R-M₅R homology models are made available as part of the Supporting Information to allow researchers to use these structures, compare them to their own results, and thus advance the development of better modeling approaches.

  8. Pharmacological approaches to targeting muscarinic acetylcholine receptors.

    PubMed

    Matera, Carlo; Tata, Ada M

    2014-01-01

    The presence of cholinergic system markers and muscarinic receptor subtypes in several tissues also of nonneuronal type has been largely demonstrated. Acetylcholine, synthesized in the nervous system, can locally contribute to modulate cell proliferation, survival and apoptosis. Considering that the cholinergic system functions are impaired in a number of disorders, the identification of new drugs regulating these functions appears of great clinical relevance. The possible involvement of muscarinic acetylcholine receptors in different pathologies has been proposed in recent years and is becoming an important area of study. However, the lack of selective muscarinic receptor ligands has for long time limited the therapeutic treatment based on muscarinic receptors as targets. To date, some muscarinic ligands such as xanomeline (patent, US5980933) or cevimeline (patents US4855290, US5571918) have been developed for the treatment of several pathologies (Alzheimer's and Sjogren's diseases). The present review will be focused on the potential effects produced by muscarinic receptor activation in different pathologies, including tumors. In fact, the potential use of muscarinic ligands in therapeutic protocols in cancer therapy will be discussed, considering that several muscarinic antagonists, already used in the treatment of genitourinary diseases (e.g. darifenacin, patent, US5096890, US6106864), have also been demonstrated to arrest the tumor growth in vivo. Moreover, the contribution of muscarinic receptors to analgesia is also reviewed. Finally, some of the most significant achievements in the field of bitopic/dualsteric ligands will be discussed and the molecules patented so far will be presented.

  9. Eating breakfast enhances the efficiency of neural networks engaged during mental arithmetic in school-aged children.

    PubMed

    Pivik, R T; Tennal, Kevin B; Chapman, Stephen D; Gu, Yuyuan

    2012-06-25

    To determine the influence of a morning meal on complex mental functions in children (8-11 y), time-frequency analyses were applied to electroencephalographic (EEG) activity recorded while children solved simple addition problems after an overnight fast and again after having either eaten or skipped breakfast. Power of low frequency EEG activity [2 Hertz (Hz) bands in the 2-12 Hz range] was determined from recordings over frontal and parietal brain regions associated with mathematical thinking during mental calculation of correctly answered problems. Analyses were adjusted for background variables known to influence or reflect the development of mathematical skills, i.e., age and measures of math competence and math fluency. Relative to fed children, those who continued to fast showed greater power increases in upper theta (6-8 Hz) and both alpha bands (8-10 Hz; 10-12 Hz) across sites. Increased theta suggests greater demands on working memory. Increased alpha may facilitate task-essential activity by suppressing non-task-essential activity. Fasting children also had greater delta (2-4 Hz) and greater lower-theta (4-6 Hz) power in left frontal recordings-indicating a region-specific emphasis on both working memory for mental calculation (theta) and activation of processes that suppress interfering activity (delta). Fed children also showed a significant increase in correct responses while children who continued to fast did not. Taken together the findings suggest that neural network activity involved in processing numerical information is functionally enhanced and performance is improved in children who have eaten breakfast, whereas greater mental effort is required for this mathematical thinking in children who skip breakfast. PMID:22504496

  10. Inhibition of glycogen synthase kinase-3 enhances the differentiation and reduces the proliferation of adult human olfactory epithelium neural precursors

    SciTech Connect

    Manceur, Aziza P.; Tseng, Michael; Holowacz, Tamara; Witterick, Ian; Weksberg, Rosanna; McCurdy, Richard D.; Warsh, Jerry J.; Audet, Julie

    2011-09-10

    The olfactory epithelium (OE) contains neural precursor cells which can be easily harvested from a minimally invasive nasal biopsy, making them a valuable cell source to study human neural cell lineages in health and disease. Glycogen synthase kinase-3 (GSK-3) has been implicated in the etiology and treatment of neuropsychiatric disorders and also in the regulation of murine neural precursor cell fate in vitro and in vivo. In this study, we examined the impact of decreased GSK-3 activity on the fate of adult human OE neural precursors in vitro. GSK-3 inhibition was achieved using ATP-competitive (6-bromoindirubin-3'-oxime and CHIR99021) or substrate-competitive (TAT-eIF2B) inhibitors to eliminate potential confounding effects on cell fate due to off-target kinase inhibition. GSK-3 inhibitors decreased the number of neural precursor cells in OE cell cultures through a reduction in proliferation. Decreased proliferation was not associated with a reduction in cell survival but was accompanied by a reduction in nestin expression and a substantial increase in the expression of the neuronal differentiation markers MAP1B and neurofilament (NF-M) after 10 days in culture. Taken together, these results suggest that GSK-3 inhibition promotes the early stages of neuronal differentiation in cultures of adult human neural precursors and provide insights into the mechanisms by which alterations in GSK-3 signaling affect adult human neurogenesis, a cellular process strongly suspected to play a role in the etiology of neuropsychiatric disorders.

  11. Schizophrenia and the alpha7 nicotinic acetylcholine receptor.

    PubMed

    Martin, Laura F; Freedman, Robert

    2007-01-01

    In addition to the devastating symptoms of psychosis, many people with schizophrenia also suffer from cognitive impairment. These cognitive symptoms lead to marked dysfunction and can impact employability, treatment adherence, and social skills. Deficits in P50 auditory gating are associated with attentional impairment and may contribute to cognitive symptoms and perceptual disturbances. This nicotinic cholinergic-mediated inhibitory process represents a potential new target for therapeutic intervention in schizophrenia. This chapter will review evidence implicating the nicotinic cholinergic, and specifically, the alpha7 nicotinic receptor system in the pathology of schizophrenia. Impaired auditory sensory gating has been linked to the alpha7 nicotinic receptor gene on the chromosome 15q14 locus. A majority of persons with schizophrenia are heavy smokers. Although nicotine can acutely reverse diminished auditory sensory gating in people with schizophrenia, this effect is lost on a chronic basis due to receptor desensitization. The alpha7 nicotinic agonist 3-(2,4 dimethoxy)benzylidene-anabaseine (DMXBA) can also enhance auditory sensory gating in animal models. DMXBA is well tolerated in humans and a new study in persons with schizophrenia has found that DMXBA enhances both P50 auditory gating and cognition. alpha7 Nicotinic acetylcholine receptor agonists appear to be viable candidates for the treatment of cognitive disturbances in schizophrenia.

  12. Topographical studies of the nicotinic acetylcholine receptor. [Torpedo californica

    SciTech Connect

    Middlemas, D.S.

    1987-01-01

    All four subunits of the nicotinic acetylcholine receptor in membrane vesicles isolated from Torpedo californica have been labeled with the photoactivated hydrophobic probe, (/sup 3/H)adamantanediazirine, which selectively labels regions of integral membrane proteins in contact with the hydrocarbon core of the lipid bilayer. All four subunits of the acetylcholine receptor in membrane vesicles isolated from Torpedo californica have been labeled with (/sup 3/H)cholesteryl diazoacetate. As this probe incorporates into lipid bilayers analogously to cholesterol, this result indicates that acetylcholine receptor interacts with cholesterol. Since the photogenerated carbene is situated near the lipid-water interface, this probe has potential as a topographic tool for mapping membrane protein structure. The labeling studies with both (/sup 3/H)adamantanediazirine and (/sup 3/H)cholesteryl diazoacetate support the concept that the acetylcholine receptor is a pseudosymmetric complex of homologous subunits, all of which interact with and span the membrane. The synthesis of the fluorine-containing agonists for the Torpedo californica nicotinic acetylcholine receptor, fluoroacetylcholine bromide and p-fluorophenyltrimethylammonium iodide, are described. It is demonstrated that both are agonists using a cation flux assay with acetylcholine receptor enriched membrane vesicles. The affinity cleavage reagent, p-thiocyanophenyltrimethylammonium iodide, specifically cleaves a peptide bond of the nicotinic acetylcholine receptor in membrane vesicles isolated from Torpedo californica. It is demonstrated that this reagent is an agonist using a cation flux assay. The cleavage is blocked by stoichiometric quantities of ..cap alpha..-bungarotoxin.

  13. Suitability of Nicotinic Acetylcholine Receptor α7 and Muscarinic Acetylcholine Receptor 3 Antibodies for Immune Detection

    PubMed Central

    Rommel, Frank R.; Raghavan, Badrinarayanan; Paddenberg, Renate; Kummer, Wolfgang; Tumala, Susanne; Lochnit, Günter; Gieler, Uwe

    2015-01-01

    Recent evidence reveals a crucial role for acetylcholine and its receptors in the regulation of inflammation, particularly of nicotinic acetylcholine receptor α7 (Chrna7) and muscarinic acetylcholine receptor 3 (Chrm3). Immunohistochemistry is a key tool for their cellular localization in functional tissues. We evaluated nine different commercially available antibodies on back skin tissue from wild-type (Wt) and gene-deficient (KO) mice. In the immunohistochemical analysis, we focused on key AChR-ligand sensitive skin cells (mast cells, nerve fibers and keratinocytes). All five antibodies tested for Chrm3 and the first three Chrna7 antibodies stained positive in both Wt and respective KO skin. With the 4th antibody (ab23832) nerve fibers were unlabeled in the KO mice. By western blot analysis, this antibody detected bands in both Wt and Chrna7 KO skin and brain. qRT-PCR revealed mRNA amplification with a primer set for the undeleted region in both Wt and KO mice, but none with a primer set for the deleted region in KO mice. By 2D electrophoresis, we found β-actin and β-enolase cross reactivity, which was confirmed by double immunolabeling. In view of the present results, the tested antibodies are not suitable for immunolocalization in skin and suggest thorough control of antibody specificity is required if histomorphometry is intended. PMID:25673288

  14. Acetylcholine receptors in the human retina

    SciTech Connect

    Hutchins, J.B.; Hollyfield, J.G.

    1985-11-01

    Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand TH-propylbenzilylcholine mustard (TH-PrBCM) to label muscarinic receptors. TH- or SVI-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic receptors are apparently present in the inner plexiform layer of the retina. Autoradiographic grain densities are reduced in the presence of saturating concentrations of atropine, quinuclidinyl benzilate or scopolamine; this indicates that TH-PrBCM binding is specific for a population of muscarinic receptors in the human retina. Binding sites for radiolabeled alpha-BTx are found predominantly in the inner plexiform layer of the retina. Grain densities are reduced in the presence of d-tubocurarine, indicating that alpha-BTx may bind to a pharmacologically relevant nicotinic ACh receptor. This study provides evidence for cholinergic neurotransmission in the human retina.

  15. Action of acetylcholine on smooth muscle.

    PubMed

    Bolton, T B; Lim, S P

    1991-01-01

    Contraction of smooth muscle by acetylcholine is mediated by activation of muscarinic receptors of which M2 and M3 subtypes are present in longitudinal muscle of guinea pig intestine. In single cells, muscarinic receptor activation evokes calcium release from stores which raises the internal free calcium concentration and causes opening of calcium-activated potassium channels. The rise in internal calcium suppresses the voltage-dependent inward calcium current. A third important effect is the opening of channels which cause depolarization of the membrane and so increase action potential discharge and contraction in the whole muscle. These channels were studied by voltage-clamp of single cells from longitudinal muscle of rabbit small intestine. They were found to be permeable to Na and K but not detectably permeable to Cl. They can pass Ca but the amount entering the cell is not sufficient to raise the internal calcium concentration appreciably.

  16. Conotoxins Targeting Nicotinic Acetylcholine Receptors: An Overview

    PubMed Central

    Lebbe, Eline K. M.; Peigneur, Steve; Wijesekara, Isuru; Tytgat, Jan

    2014-01-01

    Marine snails of the genus Conus are a large family of predatory gastropods with an unparalleled molecular diversity of pharmacologically active compounds in their venom. Cone snail venom comprises of a rich and diverse cocktail of peptide toxins which act on a wide variety of ion channels such as voltage-gated sodium- (NaV), potassium- (KV), and calcium- (CaV) channels as well as nicotinic acetylcholine receptors (nAChRs) which are classified as ligand-gated ion channels. The mode of action of several conotoxins has been the subject of investigation, while for many others this remains unknown. This review aims to give an overview of the knowledge we have today on the molecular pharmacology of conotoxins specifically interacting with nAChRs along with the structure–function relationship data. PMID:24857959

  17. Neural mechanisms of selective auditory attention are enhanced by computerized training: Electrophysiological evidence from language-impaired and typically developing children

    PubMed Central

    Stevens, Courtney; Fanning, Jessica; Coch, Donna; Sanders, Lisa; Neville, Helen

    2008-01-01

    Recent proposals suggest that some interventions designed to improve language skills might also target or train selective attention. The present study examined whether six weeks of high-intensity (100 min/day) training with a computerized intervention program designed to improve language skills would also influence neural mechanisms of selective auditory attention previously shown to be deficient in children with specific language impairment (SLI). Twenty children received computerized training, including 8 children diagnosed with SLI and 12 children with typically developing language. An additional 13 children with typically developing language received no specialized training (NoTx control group) but were tested and retested after a comparable time period to control for maturational and test-retest effects. Before and after training (or a comparable delay period for the NoTx control group), children completed standardized language assessments and an event-related brain potential (ERP) measure of selective auditory attention. Relative to the NoTx control group, children receiving training showed increases in standardized measures of receptive language. In addition, children receiving training showed larger increases in the effects of attention on neural processing following training relative to the NoTx control group. The enhanced effect of attention on neural processing represented a large effect size (Cohen’s d = 0.8), and was specific to changes in signal enhancement of attended stimuli. These findings indicate that the neural mechanisms of selective auditory attention, previously shown to be deficient in children with SLI, can be remediated through training and can accompany improvements on standardized measures of language. Section Cognitive and Behavioral Neuroscience PMID:18353284

  18. Acetylcholine receptor channel imaged in the open state

    NASA Astrophysics Data System (ADS)

    Unwin, Nigel

    1995-01-01

    The structure of the open-channel form of the acetylcholine receptor has been determined from electron images of Torpedo ray postsynaptic membranes activated by brief (<5ms) mixing with droplets containing acetylcholine. Comparison with the closed-channel form shows that acetylcholine initiates small rotations of the subunits in the extracellular domain, which trigger a change in configuration of α-helices lining the membrane-spanning pore. The open pore tapers towards the intracellular membrane face, where it is shaped by a 'barrel' of α-helices having a pronounced right-handed twist.

  19. Enhanced robust fractional order proportional-plus-integral controller based on neural network for velocity control of permanent magnet synchronous motor.

    PubMed

    Zhang, Bitao; Pi, YouGuo

    2013-07-01

    The traditional integer order proportional-integral-differential (IO-PID) controller is sensitive to the parameter variation or/and external load disturbance of permanent magnet synchronous motor (PMSM). And the fractional order proportional-integral-differential (FO-PID) control scheme based on robustness tuning method is proposed to enhance the robustness. But the robustness focuses on the open-loop gain variation of controlled plant. In this paper, an enhanced robust fractional order proportional-plus-integral (ERFOPI) controller based on neural network is proposed. The control law of the ERFOPI controller is acted on a fractional order implement function (FOIF) of tracking error but not tracking error directly, which, according to theory analysis, can enhance the robust performance of system. Tuning rules and approaches, based on phase margin, crossover frequency specification and robustness rejecting gain variation, are introduced to obtain the parameters of ERFOPI controller. And the neural network algorithm is used to adjust the parameter of FOIF. Simulation and experimental results show that the method proposed in this paper not only achieve favorable tracking performance, but also is robust with regard to external load disturbance and parameter variation.

  20. [Probable mechanism of recognition of cholinergic ligands by acetylcholine receptors].

    PubMed

    Demushkin, V P; Kotelevtsev, Iu V; Pliashkevich, Iu G; Khramtsov, N V

    1982-01-01

    Dryding's models were used for the conformational analysis of compounds affecting muscarin-specific acetylcholine receptor and nicotin-specific acetylcholine receptor. Ammonium group and ether oxygen (3.6 A apart from the ammonium group) specifically oriented to each other were shown to be necessary structural elements to reveal muscarin-type cholinergic activity. Ammonium group along with carbonyl oxygen or its substituent (5 A distance) are the necessary structural units providing nicotin-type cholinergic activity. The presence of two hydrophobic substituents (one in the ammonium area and the other neighbouring the second active grouping) is the additional factor. The developed principles were justified by the use of a series of synthetic samples. The compounds were obtained likely favouring affinitive modification of acetylcholine receptor (dissociation constants of acetylcholine receptor complexes equalling to 10(-4)--10(-7) M-1). PMID:7070378

  1. New Insights on Plant Cell Elongation: A Role for Acetylcholine

    PubMed Central

    Di Sansebastiano, Gian-Pietro; Fornaciari, Silvia; Barozzi, Fabrizio; Piro, Gabriella; Arru, Laura

    2014-01-01

    We investigated the effect of auxin and acetylcholine on the expression of the tomato expansin gene LeEXPA2, a specific expansin gene expressed in elongating tomato hypocotyl segments. Since auxin interferes with clathrin-mediated endocytosis, in order to regulate cellular and developmental responses we produced protoplasts from tomato elongating hypocotyls and followed the endocytotic marker, FM4-64, internalization in response to treatments. Tomato protoplasts were observed during auxin and acetylcholine treatments after transient expression of chimerical markers of volume-control related compartments such as vacuoles. Here we describe the contribution of auxin and acetylcholine to LeEXPA2 expression regulation and we support the hypothesis that a possible subcellular target of acetylcholine signal is the vesicular transport, shedding some light on the characterization of this small molecule as local mediator in the plant physiological response. PMID:24642879

  2. New insights on plant cell elongation: a role for acetylcholine.

    PubMed

    Di Sansebastiano, Gian-Pietro; Fornaciari, Silvia; Barozzi, Fabrizio; Piro, Gabriella; Arru, Laura

    2014-01-01

    We investigated the effect of auxin and acetylcholine on the expression of the tomato expansin gene LeEXPA2, a specific expansin gene expressed in elongating tomato hypocotyl segments. Since auxin interferes with clathrin-mediated endocytosis, in order to regulate cellular and developmental responses we produced protoplasts from tomato elongating hypocotyls and followed the endocytotic marker, FM4-64, internalization in response to treatments. Tomato protoplasts were observed during auxin and acetylcholine treatments after transient expression of chimerical markers of volume-control related compartments such as vacuoles. Here we describe the contribution of auxin and acetylcholine to LeEXPA2 expression regulation and we support the hypothesis that a possible subcellular target of acetylcholine signal is the vesicular transport, shedding some light on the characterization of this small molecule as local mediator in the plant physiological response. PMID:24642879

  3. Monitoring substrate and products in a bioprocess with FTIR spectroscopy coupled to artificial neural networks enhanced with a genetic-algorithm-based method for wavelength selection.

    PubMed

    Franco, Vanina G; Perín, Juan C; Mantovani, Víctor E; Goicoechea, Héctor C

    2006-01-15

    An experiment was developed as a simple alternative to existing analytical methods for the simultaneous quantitation of glucose (substrate) and glucuronic acid (main product) in the bioprocesses Kombucha by using FTIR spectroscopy coupled to multivariate calibration (partial least-squares, PLS-1 and artificial neural networks, ANNs). Wavelength selection through a novel ranked regions genetic algorithm (RRGA) was used to enhance the predictive ability of the chemometric models. Acceptable results were obtained by using the ANNs models considering the complexity of the sample and the speediness and simplicity of the method. The accuracy on the glucuronic acid determination was calculated by analysing spiked real fermentation samples (recoveries ca. 115%).

  4. Cocaine inhibition of nicotinic acetylcholine receptors influences dopamine release

    PubMed Central

    Acevedo-Rodriguez, Alexandra; Zhang, Lifen; Zhou, Fuwen; Gong, Suzhen; Gu, Howard; De Biasi, Mariella; Zhou, Fu-Ming; Dani, John A.

    2014-01-01

    Nicotinic acetylcholine receptors (nAChRs) potently regulate dopamine (DA) release in the striatum and alter cocaine's ability to reinforce behaviors. Since cocaine is a weak nAChR inhibitor, we hypothesized that cocaine may alter DA release by inhibiting the nAChRs in DA terminals in the striatum and thus contribute to cocaine's reinforcing properties primarily associated with the inhibition of DA transporters. We found that biologically relevant concentrations of cocaine can mildly inhibit nAChR-mediated currents in midbrain DA neurons and consequently alter DA release in the dorsal and ventral striatum. At very high concentrations, cocaine also inhibits voltage-gated Na channels in DA neurons. Furthermore, our results show that partial inhibition of nAChRs by cocaine reduces evoked DA release. This diminution of DA release via nAChR inhibition more strongly influences release evoked at low or tonic stimulation frequencies than at higher (phasic) stimulation frequencies, particularly in the dorsolateral striatum. This cocaine-induced shift favoring phasic DA release may contribute to the enhanced saliency and motivational value of cocaine-associated memories and behaviors. PMID:25237305

  5. Cocaine inhibition of nicotinic acetylcholine receptors influences dopamine release.

    PubMed

    Acevedo-Rodriguez, Alexandra; Zhang, Lifen; Zhou, Fuwen; Gong, Suzhen; Gu, Howard; De Biasi, Mariella; Zhou, Fu-Ming; Dani, John A

    2014-01-01

    Nicotinic acetylcholine receptors (nAChRs) potently regulate dopamine (DA) release in the striatum and alter cocaine's ability to reinforce behaviors. Since cocaine is a weak nAChR inhibitor, we hypothesized that cocaine may alter DA release by inhibiting the nAChRs in DA terminals in the striatum and thus contribute to cocaine's reinforcing properties primarily associated with the inhibition of DA transporters. We found that biologically relevant concentrations of cocaine can mildly inhibit nAChR-mediated currents in midbrain DA neurons and consequently alter DA release in the dorsal and ventral striatum. At very high concentrations, cocaine also inhibits voltage-gated Na channels in DA neurons. Furthermore, our results show that partial inhibition of nAChRs by cocaine reduces evoked DA release. This diminution of DA release via nAChR inhibition more strongly influences release evoked at low or tonic stimulation frequencies than at higher (phasic) stimulation frequencies, particularly in the dorsolateral striatum. This cocaine-induced shift favoring phasic DA release may contribute to the enhanced saliency and motivational value of cocaine-associated memories and behaviors. PMID:25237305

  6. Effects of acetylcholine and electrical stimulation on glial cell line-derived neurotrophic factor production in skeletal muscle cells.

    PubMed

    Vianney, John-Mary; Miller, Damon A; Spitsbergen, John M

    2014-11-01

    Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor required for survival of neurons in the central and peripheral nervous system. Specifically, GDNF has been characterized as a survival factor for spinal motor neurons. GDNF is synthesized and secreted by neuronal target tissues, including skeletal muscle in the peripheral nervous system; however, the mechanisms by which GDNF is synthesized and released by skeletal muscle are not fully understood. Previous results suggested that cholinergic neurons regulate secretion of GDNF by skeletal muscle. In the current study, GDNF production by skeletal muscle myotubes following treatment with acetylcholine was examined. Acetylcholine receptors on myotubes were identified with labeled alpha-bungarotoxin and were blocked using unlabeled alpha-bungarotoxin. The question of whether electrical stimulation has a similar effect to that of acetylcholine was also investigated. Cells were stimulated with voltage pulses; at 1 and 5 Hz frequencies for times ranging from 30 min to 48 h. GDNF content in myotubes and GDNF in conditioned culture medium were quantified by enzyme-linked immunosorbant assay. Results suggest that acetylcholine and short-term electrical stimulation reduce GDNF secretion, while treatment with carbachol or long-term electrical stimulation enhances GDNF production by skeletal muscle.

  7. Modal gating of muscle nicotinic acetylcholine receptors

    NASA Astrophysics Data System (ADS)

    Vij, Ridhima

    Many ion channels exhibit multiple patterns of kinetic activity in single-channel currents. This behavior is rare in WT mouse muscle nicotinic acetylcholine receptors (AChRs), where A2C↔A2O gating events are well-described by single exponentials. Also, single-channel open probability (PO) is essentially homogeneous at a given agonist concentration in the WT receptors. Here I report that perturbations of almost all the residues in loop C (alpha188-alpha199, at the agonist binding site) generate heterogeneity in PO ('modes'). Such unsettled activity was apparent with an alanine substitution at all positions in loop C (except alphaY190 and alphaY198) and with different side chain substitutions at alphaP197 for both adult- and fetal-type AChRs. I used single channel electrophysiology along with site-directed mutagenesis to study modal gating in AChRs consequent to mutations/deletions in loop C. The multiple patterns of kinetic activity arose from the difference in agonist affinity rather than in intrinsic AChR gating. Out of the four different agonists used to study the modal behavior, acetylcholine (ACh) showed a higher degree of kinetic heterogeneity compared to others. The time constant for switching between modes was long (~mins), suggesting that they arise from alternative, stable protein conformations. By studying AChRs having only 1 functional binding site, I attempted to find the source of the affinity difference, which was traced mainly to the alphadelta agonist site. Affinity at the neurotransmitter binding site is mainly determined by a core of five aromatic residues (alphaY93, alphaW149, alphaY190, alphaY198 and deltaW57). Phenylalanine substitutions at all aromatic residues except alphaY93 resulted in elimination of modes. Modes were also eliminated by alanine mutation at deltaW57 on the complementary side but not at other aromatics. Also, by substituting four gamma subunit residues into the delta subunit on the complementary beta sheet, I found that

  8. Ionophoretically applied acetylcholine and vagal stimulation in the arrested sinus venosus of the toad, Bufo marinus.

    PubMed Central

    Bramich, N J; Brock, J A; Edwards, F R; Hirst, G D

    1994-01-01

    1. The effects of acetylcholine (ACh), applied by ionophoresis, on the isolated arrested sinus venosus of the toad, Bufo marinus, were examined. 2. At each position where ACh was applied across the surface of sinus venosus preparations, a hyperpolarization was produced. These responses were abolished by hyoscine, indicating that muscarinic cholinoceptors are widely distributed over the surface of these muscle cells. 3. Vagal stimulation produced hyperpolarizations which were mimicked, to some extent, by ionophoretically applied ACh. 4. The responses to ionophoretically applied ACh were abolished by adding barium ions to the perfusion fluid, whereas responses to vagal stimulation persisted. 5. The responses to ionophoretically applied ACh were consistently slower than those to vagal stimulation. It is argued that the pathways activated by neural and applied ACh have different kinetics of activation. PMID:7965847

  9. The Oncogenic Functions of Nicotinic Acetylcholine Receptors

    PubMed Central

    Zhao, Yue

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) are ion channels that are expressed in the cell membrane of all mammalian cells, including cancer cells. Recent findings suggest that nAChRs not only mediate nicotine addiction in the brain but also contribute to the development and progression of cancers directly induced by nicotine and its derived carcinogenic nitrosamines whereas deregulation of the nAChRs is observed in many cancers, and genome-wide association studies (GWAS) indicate that SNPs nAChRs associate with risks of lung cancers and nicotine addiction. Emerging evidences suggest nAChRs are posited at the central regulatory loops of numerous cell growth and prosurvival signal pathways and also mediate the synthesis and release of stimulatory and inhibitory neurotransmitters induced by their agonists. Thus nAChRs mediated cell signaling plays an important role in stimulating the growth and angiogenic and neurogenic factors and mediating oncogenic signal transduction during cancer development in a cell type specific manner. In this review, we provide an integrated view of nAChRs signaling in cancer, heightening on the oncogenic properties of nAChRs that may be targeted for cancer treatment. PMID:26981122

  10. The Oncogenic Functions of Nicotinic Acetylcholine Receptors.

    PubMed

    Zhao, Yue

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) are ion channels that are expressed in the cell membrane of all mammalian cells, including cancer cells. Recent findings suggest that nAChRs not only mediate nicotine addiction in the brain but also contribute to the development and progression of cancers directly induced by nicotine and its derived carcinogenic nitrosamines whereas deregulation of the nAChRs is observed in many cancers, and genome-wide association studies (GWAS) indicate that SNPs nAChRs associate with risks of lung cancers and nicotine addiction. Emerging evidences suggest nAChRs are posited at the central regulatory loops of numerous cell growth and prosurvival signal pathways and also mediate the synthesis and release of stimulatory and inhibitory neurotransmitters induced by their agonists. Thus nAChRs mediated cell signaling plays an important role in stimulating the growth and angiogenic and neurogenic factors and mediating oncogenic signal transduction during cancer development in a cell type specific manner. In this review, we provide an integrated view of nAChRs signaling in cancer, heightening on the oncogenic properties of nAChRs that may be targeted for cancer treatment. PMID:26981122

  11. The mechanism of acetylcholine receptor in binding MuSK in myasthenia gravis and the role of HSP90 molecular chaperone.

    PubMed

    Chen, Rongbo; Chen, Siqia; Liao, Juan; Chen, Xiaopu; Xu, Xiaoling

    2016-01-01

    As an autoimmune disease, myasthenia gravis is caused by the dysfunction of neural transmission. Acetylcholine is known to exert its function after entering into synaptic cleft through binding onto postsynaptic membrane. The role of acetylcholine in binding MuSK in myasthenia gravis, however, remains unknown. A total of 38 myasthenia gravis patients and 27 healthy controls were included in this study for the detection of the expression of MuSK using immunofluorescent method. Expression of both MuSK and interleukin-6 (IL-6) were measured by Western blot, followed by the correlation analysis between heat shock protein 90 (HSP90) and IL-6 which were measured by enzyme-linked immunosorbent assay (ELISA). In myasthenia gravis patients, MuSK was co-localized with acetylcholine at the postsynaptic membrane. Such accumulation of MuSK, however, did not occur in normal people. Meanwhile we also observed elevated expression of IL-6 in myasthenia gravis patients (p<0.05). ELISA assay showed higher expression of HSP90 in patients. Further signaling pathway screening revealed the activation of IL-6-mediated pathways including STAT3 and SPH2. In conclusion, MuSK was co-localized with acetylcholine in myasthenia gravis patients, with elevated expression. HSP90 in disease people can activate IL-6 mediated signaling pathways.

  12. Intracoronary Acetylcholine Provocation Testing for Assessment of Coronary Vasomotor Disorders.

    PubMed

    Ong, Peter; Athanasiadis, Anastasios; Sechtem, Udo

    2016-01-01

    Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the catheterization laboratory which was introduced more than 30 years ago. Due to the short half-life of acetylcholine it can only be applied directly into the coronary arteries. Several studies have demonstrated the safety and clinical usefulness of this test. However, acetylcholine testing is only rarely applied in the U.S. or Europe. Nevertheless, it has been shown that 62% of Caucasian patients with stable angina and unobstructed coronary arteries on coronary angiography suffer from coronary vasomotor disorders that can be diagnosed with acetylcholine testing. In recent years it has been appreciated that the ACH-test not only assesses the presence of epicardial spasm but that it can also be useful for the detection of coronary microvascular spam. In such cases no epicardial spasm is seen after injection of acetylcholine but ischemic ECG shifts are present together with a reproduction of the patient's symptoms during the test. This article describes the experience with the ACH-test and its implementation in daily clinical routine. PMID:27583694

  13. The Role of Acetylcholine in Cocaine Addiction

    PubMed Central

    Williams, Mark J; Adinoff, Bryon

    2008-01-01

    Central nervous system cholinergic neurons arise from several discrete sources, project to multiple brain regions, and exert specific effects on reward, learning, and memory. These processes are critical for the development and persistence of addictive disorders. Although other neurotransmitters, including dopamine, glutamate, and serotonin, have been the primary focus of drug research to date, a growing preclinical literature reveals a critical role of acetylcholine (ACh) in the experience and progression of drug use. This review will present and integrate the findings regarding the role of ACh in drug dependence, with a primary focus on cocaine and the muscarinic ACh system. Mesostriatal ACh appears to mediate reinforcement through its effect on reward, satiation, and aversion, and chronic cocaine administration produces neuroadaptive changes in the striatum. ACh is further involved in the acquisition of conditional associations that underlie cocaine self-administration and context-dependent sensitization, the acquisition of associations in conditioned learning, and drug procurement through its effects on arousal and attention. Long-term cocaine use may induce neuronal alterations in the brain that affect the ACh system and impair executive function, possibly contributing to the disruptions in decision making that characterize this population. These primarily preclinical studies suggest that ACh exerts a myriad of effects on the addictive process and that persistent changes to the ACh system following chronic drug use may exacerbate the risk of relapse during recovery. Ultimately, ACh modulation may be a potential target for pharmacological treatment interventions in cocaine-addicted subjects. However, the complicated neurocircuitry of the cholinergic system, the multiple ACh receptor subtypes, the confluence of excitatory and inhibitory ACh inputs, and the unique properties of the striatal cholinergic interneurons suggest that a precise target of cholinergic

  14. The Advantage of Ambiguity? Enhanced Neural Responses to Multi-Stable Percepts Correlate with the Degree of Perceived Instability

    PubMed Central

    Dyson, Benjamin J.

    2011-01-01

    Artwork can often pique the interest of the viewer or listener as a result of the ambiguity or instability contained within it. Our engagement with uncertain sensory experiences might have its origins in early cortical responses, in that perceptually unstable stimuli might preclude neural habituation and maintain activity in early sensory areas. To assess this idea, participants engaged with an ambiguous visual stimulus wherein two squares alternated with one another, in terms of simultaneously opposing vertical and horizontal locations relative to fixation (i.e., stroboscopic alternating motion; von Schiller, 1933). At each trial, participants were invited to interpret the movement of the squares in one of five ways: traditional vertical or horizontal motion, novel clockwise or counter-clockwise motion, and, a free-view condition in which participants were encouraged to switch the direction of motion as often as possible. Behavioral reports of perceptual stability showed clockwise and counter-clockwise motion to possess an intermediate level of stability compared to relatively stable vertical and horizontal motion, and, relatively unstable motion perceived during free-view conditions. Early visual evoked components recorded at parietal–occipital sites such as C1, P1, and N1 modulated as a function of visual intention. Both at a group and individual level, increased perceptual instability was related to increased negativity in all three of these early visual neural responses. Engagement with increasingly ambiguous input may partly result from the underlying exaggerated neural response to it. The study underscores the utility of combining neuroelectric recording with the presentation of perceptually multi-stable yet physically identical stimuli, in revealing brain activity associated with the purely internal process of interpreting and appreciating the sensory world that surrounds us. PMID:21897812

  15. FN-DFE: Fuzzy-Neural Data Fusion Engine for Enhanced State-Awareness of Resilient Hybrid Energy System

    SciTech Connect

    Ondrej Linda; Dumidu Wijayasekara; Milos Manic; Craig Rieger

    2014-11-01

    Resiliency and improved state-awareness of modern critical infrastructures, such as energy production and industrial systems, is becoming increasingly important. As control systems become increasingly complex, the number of inputs and outputs increase. Therefore, in order to maintain sufficient levels of state-awareness, a robust system state monitoring must be implemented that correctly identifies system behavior even when one or more sensors are faulty. Furthermore, as intelligent cyber adversaries become more capable, incorrect values may be fed to the operators. To address these needs, this paper proposes a Fuzzy-Neural Data Fusion Engine (FN-DFE) for resilient state-awareness of control systems. The designed FN-DFE is composed of a three-layered system consisting of: 1) traditional threshold based alarms, 2) anomalous behavior detector using self-organizing fuzzy logic system, and 3) artificial neural network based system modeling and prediction. The improved control system state-awareness is achieved via fusing input data from multiple sources and combining them into robust anomaly indicators. In addition, the neural network based signal predictions are used to augment the resiliency of the system and provide coherent state-awareness despite temporary unavailability of sensory data. The proposed system was integrated and tested with a model of the Idaho National Laboratory’s (INL) hybrid energy system facility know as HYTEST. Experimental results demonstrate that the proposed FN-DFE provides timely plant performance monitoring and anomaly detection capabilities. It was shown that the system is capable of identifying intrusive behavior significantly earlier than conventional threshold based alarm systems.

  16. Endoplasmic reticulum stress contributes to acetylcholine receptor degradation by promoting endocytosis in skeletal muscle cells.

    PubMed

    Du, Ailian; Huang, Shiqian; Zhao, Xiaonan; Zhang, Yun; Zhu, Lixun; Ding, Ji; Xu, Congfeng

    2016-01-15

    After binding by acetylcholine released from a motor neuron, a nicotinic acetylcholine receptor at the neuromuscular junction produces a localized end-plate potential, which leads to muscle contraction. Improper turnover and renewal of acetylcholine receptors contributes to the pathogenesis of myasthenia gravis. In the present study, we demonstrate that endoplasmic reticulum (ER) stress contributes to acetylcholine receptor degradation in C2C12 myocytes. We further show that ER stress promotes acetylcholine receptor endocytosis and lysosomal degradation, which was dampened by blocking endocytosis or treating with lysosome inhibitor. Knockdown of ER stress proteins inhibited acetylcholine receptor endocytosis and degradation, while rescue assay restored its endocytosis and degradation, confirming the effects of ER stress on promoting endocytosis-mediated degradation of junction acetylcholine receptors. Thus, our studies identify ER stress as a factor promoting acetylcholine receptor degradation through accelerating endocytosis in muscle cells. Blocking ER stress and/or endocytosis might provide a novel therapeutic approach for myasthenia gravis.

  17. Vitamin E isomer δ-tocopherol enhances the efficiency of neural stem cell differentiation via L-type calcium channel.

    PubMed

    Deng, Sihao; Hou, Guoqiang; Xue, Zhiqin; Zhang, Longmei; Zhou, Yuye; Liu, Chao; Liu, Yanqing; Li, Zhiyuan

    2015-01-12

    The effects of the vitamin E isomer δ-tocopherol on neural stem cell (NSC) differentiation have not been investigated until now. Here we investigated the effects of δ-tocopherol on NSC neural differentiation, maturation and its possible mechanisms. Neonatal rat NSCs were grown in suspended neurosphere cultures, and were identified by their expression of nestin protein and their capacity for self-renewal. Treatment with a low concentration of δ-tocopherol induced a significant increase in the percentage of β-III-tubulin-positive cells. δ-Tocopherol also stimulated morphological maturation of neurons in culture. We further observed that δ-tocopherol stimulation increased the expression of voltage-dependent Ca(2+) channels. Moreover, a L-type specific Ca(2+) channel blocker verapamil reduced the percentage of differentiated neurons after δ-tocopherol treatment, and blocked the effects of δ-tocopherol on NSC differentiation into neurons. Together, our study demonstrates that δ-tocopherol may act through elevation of L-type calcium channel activity to increase neuronal differentiation.

  18. Enhanced Neural Processing of Goal-directed Actions After Active Training in 4-Month-Old Infants.

    PubMed

    Bakker, Marta; Sommerville, Jessica A; Gredebäck, Gustaf

    2016-03-01

    The current study explores the neural correlates of action perception and its relation to infants' active experience performing goal-directed actions. Study 1 provided active training with sticky mittens that enables grasping and object manipulation in prereaching 4-month-olds. After training, EEG was recorded while infants observed images of hands grasping toward (congruent) or away from (incongruent) objects. We demonstrate that brief active training facilitates social perception as indexed by larger amplitude of the P400 ERP component to congruent compared with incongruent trials. Study 2 presented 4-month-old infants with passive training in which they observed an experimenter perform goal-directed reaching actions, followed by an identical ERP session to that used in Study 1. The second study did not demonstrate any differentiation between congruent and incongruent trials. These results suggest that (1) active experience alters the brains' response to goal-directed actions performed by others and (2) visual exposure alone is not sufficient in developing the neural networks subserving goal processing during action observation in infancy.

  19. Acetylcholine sensitivity of cerebellar neurones in the cat

    PubMed Central

    Crawford, J. M.; Curtis, D. R.; Voorhoeve, P. E.; Wilson, V. J.

    1966-01-01

    1. Cholinomimetics, acetylcholine antagonists and some other compounds of pharmacological interest were administered electrophoretically near neurones within the vermal cerebellar cortex of anaesthetized (pentobarbitone) and unanaesthetized (cerveau isolé) cats. 2. The neurones were identified by position within the cortex, spontaneous activity, and the responses to afferent and antidromic stimulation. 3. Purkinje cells, but neither granule nor basket cells, were excited by cholinomimetics, and the acetylcholine receptors had muscarinic properties. Excitation was often preceded by depression of the spontaneous firing. 4. Intravenously administered atropine and dihydro-β-erythroidine did not depress the synaptic excitation of cerebellar neurones evoked by impulses in mossy, climbing or parallel fibres. 5. Acetylcholine is thus unlikely to be an excitatory transmitter within the feline cerebellum, particularly at mossy fibre-granule cell synapses, despite the presence of relatively high levels of acetylcholinesterase within mossy fibre terminals. PMID:5914249

  20. Cardiac acetylcholine inhibits ventricular remodeling and dysfunction under pathologic conditions.

    PubMed

    Roy, Ashbeel; Dakroub, Mouhamed; Tezini, Geisa C S V; Liu, Yin; Guatimosim, Silvia; Feng, Qingping; Salgado, Helio C; Prado, Vania F; Prado, Marco A M; Gros, Robert

    2016-02-01

    Autonomic dysfunction is a characteristic of cardiac disease and decreased vagal activity is observed in heart failure. Rodent cardiomyocytes produce de novo ACh, which is critical in maintaining cardiac homeostasis. We report that this nonneuronal cholinergic system is also found in human cardiomyocytes, which expressed choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (VAChT). Furthermore, VAChT expression was increased 3- and 1.5-fold at the mRNA and protein level, respectively, in ventricular tissue from patients with heart failure, suggesting increased ACh secretion in disease. We used mice with genetic deletion of cardiomyocyte-specific VAChT or ChAT and mice overexpressing VAChT to test the functional significance of cholinergic signaling. Mice deficient for VAChT displayed an 8% decrease in fractional shortening and 13% decrease in ejection fraction compared with angiotensin II (Ang II)-treated control animals, suggesting enhanced ventricular dysfunction and pathologic remodeling in response to Ang II. Similar results were observed in ChAT-deficient mice. Conversely, no decline in ventricular function was observed in Ang II-treated VAChT overexpressors. Furthermore, the fibrotic area was significantly greater (P < 0.05) in Ang II-treated VAChT-deficient mice (3.61 ± 0.64%) compared with wild-type animals (2.24 ± 0.11%). In contrast, VAChT overexpressing mice did not display an increase in collagen deposition. Our results provide new insight into cholinergic regulation of cardiac function, suggesting that a compensatory increase in cardiomyocyte VAChT levels may help offset cardiac remodeling in heart failure.

  1. Specific Intensity Direct Current (DC) Electric Field Improves Neural Stem Cell Migration and Enhances Differentiation towards βIII-Tubulin+ Neurons

    PubMed Central

    Zhao, Huiping; Steiger, Amanda; Nohner, Mitch; Ye, Hui

    2015-01-01

    Control of stem cell migration and differentiation is vital for efficient stem cell therapy. Literature reporting electric field–guided migration and differentiation is emerging. However, it is unknown if a field that causes cell migration is also capable of guiding cell differentiation—and the mechanisms for these processes remain unclear. Here, we report that a 115 V/m direct current (DC) electric field can induce directional migration of neural precursor cells (NPCs). Whole cell patching revealed that the cell membrane depolarized in the electric field, and buffering of extracellular calcium via EGTA prevented cell migration under these conditions. Immunocytochemical staining indicated that the same electric intensity could also be used to enhance differentiation and increase the percentage of cell differentiation into neurons, but not astrocytes and oligodendrocytes. The results indicate that DC electric field of this specific intensity is capable of promoting cell directional migration and orchestrating functional differentiation, suggestively mediated by calcium influx during DC field exposure. PMID:26068466

  2. Neural structures involved in visual search guidance by reward-enhanced contextual cueing of the target location.

    PubMed

    Pollmann, Stefan; Eštočinová, Jana; Sommer, Susanne; Chelazzi, Leonardo; Zinke, Wolf

    2016-01-01

    Spatial contextual cueing reflects an incidental form of learning that occurs when spatial distractor configurations are repeated in visual search displays. Recently, it was reported that the efficiency of contextual cueing can be modulated by reward. We replicated this behavioral finding and investigated its neural basis with fMRI. Reward value was associated with repeated displays in a learning session. The effect of reward value on context-guided visual search was assessed in a subsequent fMRI session without reward. Structures known to support explicit reward valuation, such as ventral frontomedial cortex and posterior cingulate cortex, were modulated by incidental reward learning. Contextual cueing, leading to more efficient search, went along with decreased activation in the visual search network. Retrosplenial cortex played a special role in that it showed both a main effect of reward and a reward×configuration interaction and may thereby be a central structure for the reward modulation of context-guided visual search.

  3. Enhanced selective gene delivery to neural stem cells in vivo by an adeno-associated viral variant.

    PubMed

    Kotterman, Melissa A; Vazin, Tandis; Schaffer, David V

    2015-05-15

    Neural stem cells (NSCs) are defined by their ability to self-renew and to differentiate into mature neuronal and glial cell types. NSCs are the subject of intense investigation, owing to their crucial roles in neural development and adult brain function and because they present potential targets for gene and cell replacement therapies following injury or disease. Approaches to specifically genetically perturb or modulate NSC function would be valuable for either motivation. Unfortunately, most gene delivery vectors are incapable of efficient or specific gene delivery to NSCs in vivo. Vectors based on adeno-associated virus (AAV) present a number of advantages and have proven increasingly successful in clinical trials. However, natural AAV variants are inefficient in transducing NSCs. We previously engineered a novel AAV variant (AAV r3.45) capable of efficient transduction of adult NSCs in vitro. Here, to build upon the initial promise of this variant, we investigated its in vitro and in vivo infectivity. AAV r3.45 was more selective for NSCs than mature neurons in a human embryonic stem cell-derived culture containing a mixture of cell types, including NSCs and neurons. It was capable of more efficient and selective transduction of rat and mouse NSCs in vivo than natural AAV serotypes following intracranial vector administration. Delivery of constitutively active β-catenin yielded insights into mechanisms by which this key regulator modulates NSC function, indicating that this engineered AAV variant can be harnessed for preferential modulation of adult NSCs in the hippocampus. The capacity to rapidly genetically modify these cells might greatly accelerate in vivo investigations of adult neurogenesis. PMID:25968319

  4. Enhanced selective gene delivery to neural stem cells in vivo by an adeno-associated viral variant

    PubMed Central

    Kotterman, Melissa A.; Vazin, Tandis; Schaffer, David V.

    2015-01-01

    Neural stem cells (NSCs) are defined by their ability to self-renew and to differentiate into mature neuronal and glial cell types. NSCs are the subject of intense investigation, owing to their crucial roles in neural development and adult brain function and because they present potential targets for gene and cell replacement therapies following injury or disease. Approaches to specifically genetically perturb or modulate NSC function would be valuable for either motivation. Unfortunately, most gene delivery vectors are incapable of efficient or specific gene delivery to NSCs in vivo. Vectors based on adeno-associated virus (AAV) present a number of advantages and have proven increasingly successful in clinical trials. However, natural AAV variants are inefficient in transducing NSCs. We previously engineered a novel AAV variant (AAV r3.45) capable of efficient transduction of adult NSCs in vitro. Here, to build upon the initial promise of this variant, we investigated its in vitro and in vivo infectivity. AAV r3.45 was more selective for NSCs than mature neurons in a human embryonic stem cell-derived culture containing a mixture of cell types, including NSCs and neurons. It was capable of more efficient and selective transduction of rat and mouse NSCs in vivo than natural AAV serotypes following intracranial vector administration. Delivery of constitutively active β-catenin yielded insights into mechanisms by which this key regulator modulates NSC function, indicating that this engineered AAV variant can be harnessed for preferential modulation of adult NSCs in the hippocampus. The capacity to rapidly genetically modify these cells might greatly accelerate in vivo investigations of adult neurogenesis. PMID:25968319

  5. Involvement of β3-adrenoceptors in the inhibitory control of cholinergic activity in human bladder: Direct evidence by [(3)H]-acetylcholine release experiments in the isolated detrusor.

    PubMed

    D' Agostino, Gianluigi; Maria Condino, Anna; Calvi, Paolo

    2015-07-01

    Bladder overactivity (OAB) is a multifactorial bladder disorder that requires therapeutics superior to the current pharmacological treatment with muscarinic antagonists. β3-adrenoceptor (β3-ADR) agonists represent a novel promising approach that differently addresses the parasympathetic pathway, but the clinical efficacy of these drugs has not been fully elucidated to date. Therefore, we aimed to study the pharmacological mechanisms activated by β3-ADR agonists at muscular and neural sites in the isolated human bladder. Detrusor smooth muscle strips obtained from male patients undergoing total cystectomy were labelled with tritiated choline and stimulated with electrical field stimulation (EFS). EFS produced smooth muscle contraction and simultaneous acetylcholine ([(3)H]-ACh) release, which mostly reflects the neural origin of acetylcholine. Isoprenaline (INA), BRL37344 and mirabegron inhibited the EFS-evoked contraction and [(3)H]-ACh release in a concentration-dependent manner, yielding concentration-response curves (CRCs) that were shifted to the right by the selective β3-ADR antagonists L-748,337 and SR59230A. Based on the agonist potency estimates (pEC50) and apparent affinities (pKb) of antagonists evaluated from the CRCs of agonists, our data confirm the occurrence of β3-ADRs at muscle sites. Moreover, our data are consistent with the presence of inhibitory β3-ADRs that are functionally expressed at the neural site. Taken together, these findings elucidate the mechanisms activated by β3-ADR agonists because neural β3-ADRs participate in the inhibition of detrusor motor drive by reducing the amount of acetylcholine involved in the cholinergic pathway. PMID:25861936

  6. A hydrosoluble triphenylene that preferentially binds acetylcholine, epibatidine, and nicotine.

    PubMed

    Givelet, Cécile; Buffeteau, Thierry; Arnaud-Neu, Françoise; Hubscher-Bruder, Véronique; Bibal, Brigitte

    2009-07-17

    Synthesis and binding properties of a new hydrosoluble triphenylene 1b are reported. Selective recognition of acetylcholine (ACh) against other aliphatic ammoniums is achieved by this flat receptor, which also forms complexes with epibatidine and nicotine. Ionic pairing and hydrophobic effects between host 1b and ACh are studied by infrared spectroscopy.

  7. Changes in Acetylcholine Extracellular Levels during Cognitive Processes

    ERIC Educational Resources Information Center

    Pepeu, Giancarlo; Giovannini, Maria Grazia

    2004-01-01

    Measuring the changes in neurotransmitter extracellular levels in discrete brain areas is considered a tool for identifying the neuronal systems involved in specific behavioral responses or cognitive processes. Acetylcholine (ACh) is the first neurotransmitter whose diffusion from the central nervous system was investigated and whose extracellular…

  8. The inhibitory action of noradrenaline and adrenaline on acetylcholine output by guinea-pig ileum longitudinal muscle strip.

    PubMed

    Paton, W D; Vizi, E S

    1969-01-01

    stimulation.8. In strips obtained from animals treated with reserpine and guanethidine, a rise in resting acetylcholine output and in stimulation output at low frequencies was found. In these conditions, noradrenaline was still effective.9. Reducing the hydroxytryptamine content of the strips by treatment with p-chloro-(+/-)-phenylalanine did not significantly affect acetylcholine output.10. It is concluded that acetylcholine output by the nervous networks of the longitudinal strip is under the normal control of the sympathetic by a species of presynaptic inhibition mediated by alpha receptors. This implies that for a tissue under dual autonomic control, withdrawal of sympathetic control will lead to a parasympathetic response which is not only unopposed but also itself enhanced.

  9. PI3K/Akt-independent NOS/HO activation accounts for the facilitatory effect of nicotine on acetylcholine renal vasodilations: modulation by ovarian hormones.

    PubMed

    Gohar, Eman Y; El-gowilly, Sahar M; El-Gowelli, Hanan M; El-Demellawy, Maha A; El-Mas, Mahmoud M

    2014-01-01

    We investigated the effect of chronic nicotine on cholinergically-mediated renal vasodilations in female rats and its modulation by the nitric oxide synthase (NOS)/heme oxygenase (HO) pathways. Dose-vasodilatory response curves of acetylcholine (0.01-2.43 nmol) were established in isolated phenylephrine-preconstricted perfused kidneys obtained from rats treated with or without nicotine (0.5-4.0 mg/kg/day, 2 weeks). Acetylcholine vasodilations were potentiated by low nicotine doses (0.5 and 1 mg/kg/day) in contrast to no effect for higher doses (2 and 4 mg/kg/day). The facilitatory effect of nicotine was acetylcholine specific because it was not observed with other vasodilators such as 5'-N-ethylcarboxamidoadenosine (NECA, adenosine receptor agonist) or papaverine. Increases in NOS and HO-1 activities appear to mediate the nicotine-evoked enhancement of acetylcholine vasodilation because the latter was compromised after pharmacologic inhibition of NOS (L-NAME) or HO-1 (zinc protoporphyrin, ZnPP). The renal protein expression of phosphorylated Akt was not affected by nicotine. We also show that the presence of the two ovarian hormones is necessary for the nicotine augmentation of acetylcholine vasodilations to manifest because nicotine facilitation was lost in kidneys of ovariectomized (OVX) and restored after combined, but not individual, supplementation with medroxyprogesterone acetate (MPA) and estrogen (E2). Together, the data suggests that chronic nicotine potentiates acetylcholine renal vasodilation in female rats via, at least partly, Akt-independent HO-1 upregulation. The facilitatory effect of nicotine is dose dependent and requires the presence of the two ovarian hormones.

  10. Beyond neural cubism: promoting a multidimensional view of brain disorders by enhancing the integration of neurology and psychiatry in education.

    PubMed

    Taylor, Joseph J; Williams, Nolan R; George, Mark S

    2015-05-01

    Cubism was an influential early-20th-century art movement characterized by angular, disjointed imagery. The two-dimensional appearance of Cubist figures and objects is created through juxtaposition of angles. The authors posit that the constrained perspectives found in Cubism may also be found in the clinical classification of brain disorders. Neurological disorders are often separated from psychiatric disorders as if they stemmed from different organ systems. Maintaining two isolated clinical disciplines fractionalizes the brain in the same way that Pablo Picasso fractionalized figures and objects in his Cubist art. This Neural Cubism perpetuates a clinical divide that does not reflect the scope and depth of neuroscience. All brain disorders are complex and multidimensional, with aberrant circuitry and resultant psychopharmacology manifesting as altered behavior, affect, mood, or cognition. Trainees should receive a multidimensional education based on modern neuroscience, not a partial education based on clinical precedent. The authors briefly outline the rationale for increasing the integration of neurology and psychiatry and discuss a nested model with which clinical neuroscientists (neurologists and psychiatrists) can approach and treat brain disorders.

  11. Beyond Neural Cubism: Promoting a Multidimensional View of Brain Disorders by Enhancing the Integration of Neurology and Psychiatry in Education

    PubMed Central

    Taylor, Joseph J.; Williams, Nolan R.; George, Mark S.

    2014-01-01

    Cubism was an influential early 20th century art movement characterized by angular, disjointed imagery. The two-dimensional appearance of Cubist figures and objects is created through juxtaposition of angles. The authors posit that the constrained perspectives found in Cubism may also be found in the clinical classification of brain disorders. Neurological disorders are often separated from psychiatric disorders as if they stem from different organ systems. Maintaining two isolated clinical disciplines fractionalizes the brain in the same way that Pablo Picasso fractionalized figures and objects in his Cubist art. This Neural Cubism perpetuates a clinical divide that does not reflect the scope and depth of neuroscience. All brain disorders are complex and multidimensional, with aberrant circuitry and resultant psychopharmacology manifesting as altered behavior, affect, mood or cognition. Trainees should receive a multidimensional education based on modern neuroscience, not a partial education based on clinical precedent. The authors briefly outline the rationale for increasing the integration of neurology and psychiatry and discuss a nested model with which clinical neuroscientists (neurologists and psychiatrists) can approach and treat brain disorders. PMID:25340364

  12. Enhancement of noradrenergic neural transmission: an effective therapy of myasthenia gravis: a report on 52 consecutive patients.

    PubMed

    Lechin, F; van der Dijs, B; Pardey-Maldonado, B; John, E; Jimenez, V; Orozco, B; Baez, S; Lechin, M E

    2000-01-01

    Neurochemical, neuroautonomic and neuropharmacological assessments carried out on all our myasthenia gravis (MG) patients showed that they presented a neural sympathetic deficit plus excessive adrenal-sympathetic activity. These abnormalities were registered during the basal (supine-resting) state, as well as after several stress tests (orthostasis, exercise, oral glucose and buspirone). In addition, MG patients showed increased levels of free-serotonin (f5HT) in the plasma, supposedly associated with the increased platelet aggregability which we found in all MG patients. As the above trio of neurochemical disorders (low noradrenergic-activity + high adrenergic-activity + increased f-5HT plasma levels) is known to favor Th-1 immunosuppression + Th-2 predominance, we outlined a neuropharmacological strategy for reverting the above neurochemical disorder. This treatment provoked sudden (acute), and late sustained improvements. Acute effects have been attributed to the increase of alpha-1 activity at the spinal motoneuron level. Late improvements always paralleled a significant normalization of immunological disorders. Complete normalization was registered only in non-thymectomized MG patients. PMID:11508327

  13. Beyond neural cubism: promoting a multidimensional view of brain disorders by enhancing the integration of neurology and psychiatry in education.

    PubMed

    Taylor, Joseph J; Williams, Nolan R; George, Mark S

    2015-05-01

    Cubism was an influential early-20th-century art movement characterized by angular, disjointed imagery. The two-dimensional appearance of Cubist figures and objects is created through juxtaposition of angles. The authors posit that the constrained perspectives found in Cubism may also be found in the clinical classification of brain disorders. Neurological disorders are often separated from psychiatric disorders as if they stemmed from different organ systems. Maintaining two isolated clinical disciplines fractionalizes the brain in the same way that Pablo Picasso fractionalized figures and objects in his Cubist art. This Neural Cubism perpetuates a clinical divide that does not reflect the scope and depth of neuroscience. All brain disorders are complex and multidimensional, with aberrant circuitry and resultant psychopharmacology manifesting as altered behavior, affect, mood, or cognition. Trainees should receive a multidimensional education based on modern neuroscience, not a partial education based on clinical precedent. The authors briefly outline the rationale for increasing the integration of neurology and psychiatry and discuss a nested model with which clinical neuroscientists (neurologists and psychiatrists) can approach and treat brain disorders. PMID:25340364

  14. Neural structures involved in visual search guidance by reward-enhanced contextual cueing of the target location.

    PubMed

    Pollmann, Stefan; Eštočinová, Jana; Sommer, Susanne; Chelazzi, Leonardo; Zinke, Wolf

    2016-01-01

    Spatial contextual cueing reflects an incidental form of learning that occurs when spatial distractor configurations are repeated in visual search displays. Recently, it was reported that the efficiency of contextual cueing can be modulated by reward. We replicated this behavioral finding and investigated its neural basis with fMRI. Reward value was associated with repeated displays in a learning session. The effect of reward value on context-guided visual search was assessed in a subsequent fMRI session without reward. Structures known to support explicit reward valuation, such as ventral frontomedial cortex and posterior cingulate cortex, were modulated by incidental reward learning. Contextual cueing, leading to more efficient search, went along with decreased activation in the visual search network. Retrosplenial cortex played a special role in that it showed both a main effect of reward and a reward×configuration interaction and may thereby be a central structure for the reward modulation of context-guided visual search. PMID:26427645

  15. β-adrenoceptor pathway enhances mitochondrial function in human neural stem cells via rotary cell culture system.

    PubMed

    Chiang, Ming-Chang; Lin, Heng; Cheng, Yi-Chuan; Yen, Chia-Hui; Huang, Rong-Nan; Lin, Kuan-Hung

    2012-06-15

    The structure and function of the human nervous system are altered in space when compared with their state on earth. To investigate directly the influence of simulated microgravity conditions which may be beneficial for cultivation and proliferation of human neural stem cells (hNSCs), the rotary cell culture system (RCCS) developed at the National Aeronautics and Space Administration (NASA) was used. RCCS allows the creation of a unique microgravity environment of low shear force, high-mass transfer and enables three-dimensional (3D) cell culture of dissimilar cell types. The results show that simulated microgravity using an RCCS would induce β-adrenoceptor, upregulate cAMP formation and activate both PKA and CREB (cAMP response element binding protein) pathways. The expression of intracellular mitochondrial genes, including PGC1α (PPAR coactivator 1α), nuclear respiratory factors 1 and 2 (NRF1 and NRF2) and mitochondrial transcription factor A (Tfam), regulated by CREB, were all significantly increased at 72 h after the onset of microgravity. Accordingly and importantly, the ATP level and amount of mitochondrial mass were also increased. These results suggest that exposure to simulated microgravity using an RCCS would induce cellular proliferation in hNSCs via an increased mitochondrial function. In addition, the RCCS bioreactor would support hNSCs growth, which may have the potential for cell replacement therapy in neurological disorders. PMID:22524992

  16. Responses of coronary arteries of cardiac transplant patients to acetylcholine.

    PubMed Central

    Fish, R D; Nabel, E G; Selwyn, A P; Ludmer, P L; Mudge, G H; Kirshenbaum, J M; Schoen, F J; Alexander, R W; Ganz, P

    1988-01-01

    Accelerated coronary atherosclerosis is a major cause of graft failure after heart transplantation. Graft atherosclerosis is typically diffuse and difficult to detect even with coronary arteriography. Recently, acetylcholine was shown to dilate blood vessels by releasing a vasorelaxant substance from the endothelium (endothelium-derived relaxing factor). We have demonstrated paradoxical vasoconstriction induced by acetylcholine both early and late in the course of coronary atherosclerosis in patients, suggesting an association of endothelial dysfunction and atherosclerosis. In this report, we tested the hypothesis that coronary arteries of heart transplant patients can show endothelial dysfunction before or in the early stages of angiographically evident coronary atherosclerosis. Acetylcholine was infused into the left anterior descending artery of 13 heart transplant patients at 12 (n = 9) and 24 (n = 4) mo after transplantation. Vascular responses were evaluated by quantitative angiography. Among patients with angiographically smooth coronary arteries, relatively few (6/25) arterial segments had preserved vasodilator responses, while the majority failed to dilate (10/25) or paradoxically constricted (9/25). Angiographically irregular coronary arteries were present in three patients, in whom 8/10 segments showed marked paradoxical constriction and the remaining 2/10 failed to dilate. Only 1 of 13 patients retained appropriate dilation to acetylcholine in all segments. Nitroglycerin, which acts directly on vascular smooth muscle, dilated nearly all segments. No clinical features of the patients, including myocardial rejection appeared to correlate with the impaired functional response of vessels. Thus impaired response to acetylcholine is a common early finding in heart transplant patients and emphasizes the potential importance of endothelial dysfunction in the development of atherosclerosis. Images PMID:3121675

  17. A Fab fragment directed against the neural cell adhesion molecule L1 enhances functional recovery after injury of the adult mouse spinal cord.

    PubMed

    Loers, Gabriele; Cui, Yi-Fang; Neumaier, Irmgard; Schachner, Melitta; Skerra, Arne

    2014-06-15

    Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery, which leads to severe disabilities in motor functions or pain. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration. In the present study, we describe the cloning, functional expression in Escherichia coli cells and purification of a recombinant αL1 Fab fragment that binds to L1 with comparable activity as the function-triggering monoclonal antibody 557.B6 and induces neurite outgrowth and neuronal survival in cultured neurons, despite its monovalent function. Infusion of αL1 Fab into the lesioned spinal cord of mice enhanced functional recovery after thoracic spinal cord compression injury. αL1 Fab treatment resulted in reduced scar volume, enhanced number of tyrosine hydroxylase-positive axons and increased linear density of VGLUT1 (vesicular glutamate transporter 1) on motoneurons. Furthermore, the number and soma size of ChAT (choline acetyltransferase)-positive motoneurons and the linear density of ChAT-positive boutons on motoneurons as well as parvalbumin-positive interneurons in the lumbar spinal cord were elevated. Stimulation of endogenous L1 by application of the αL1 Fab opens new avenues for recombinant antibody technology, offering prospects for therapeutic applications after traumatic nervous system lesions.

  18. A Fab fragment directed against the neural cell adhesion molecule L1 enhances functional recovery after injury of the adult mouse spinal cord.

    PubMed

    Loers, Gabriele; Cui, Yi-Fang; Neumaier, Irmgard; Schachner, Melitta; Skerra, Arne

    2014-06-15

    Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery, which leads to severe disabilities in motor functions or pain. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration. In the present study, we describe the cloning, functional expression in Escherichia coli cells and purification of a recombinant αL1 Fab fragment that binds to L1 with comparable activity as the function-triggering monoclonal antibody 557.B6 and induces neurite outgrowth and neuronal survival in cultured neurons, despite its monovalent function. Infusion of αL1 Fab into the lesioned spinal cord of mice enhanced functional recovery after thoracic spinal cord compression injury. αL1 Fab treatment resulted in reduced scar volume, enhanced number of tyrosine hydroxylase-positive axons and increased linear density of VGLUT1 (vesicular glutamate transporter 1) on motoneurons. Furthermore, the number and soma size of ChAT (choline acetyltransferase)-positive motoneurons and the linear density of ChAT-positive boutons on motoneurons as well as parvalbumin-positive interneurons in the lumbar spinal cord were elevated. Stimulation of endogenous L1 by application of the αL1 Fab opens new avenues for recombinant antibody technology, offering prospects for therapeutic applications after traumatic nervous system lesions. PMID:24673421

  19. Regulation of the neuronal nicotinic acetylcholine receptor by SRC family tyrosine kinases.

    PubMed

    Wang, Kan; Hackett, John T; Cox, Michael E; Van Hoek, Monique; Lindstrom, Jon M; Parsons, Sarah J

    2004-03-01

    Src family kinases (SFKs) are abundant in chromaffin cells that reside in the adrenal medulla and respond to cholinergic stimulation by secreting catecholamines. Our previous work indicated that SFKs regulate acetylcholine- or nicotine-induced secretion, but the site of modulatory action was unclear. Using whole cell recordings, we found that inhibition of SFK tyrosine kinase activity by PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine) treatment or expression of a kinase-defective c-Src reduced the peak amplitude of nicotine-induced currents in chromaffin cells or in human embryonic kidney cells ectopically expressing functional neuronal alpha3beta4alpha5 acetylcholine receptors (AChRs). Conversely, the phosphotyrosine phosphatase inhibitor, sodium vanadate, or expression of mutationally activated c-Src resulted in enhanced current amplitudes. These results suggest that SFKs and putative phosphotyrosine phosphatases regulate the activity of AChRs by opposing actions. This proposed model was supported further by the findings that SFKs physically associate with the receptor and that the AChR is tyrosine-phosphorylated.

  20. Potentiation of the actions of acetylcholine, epibatidine, and nicotine by methyllycaconitine at fetal muscle-type nicotinic acetylcholine receptors.

    PubMed

    Green, Benedict T; Welch, Kevin D; Cook, Daniel; Gardner, Dale R

    2011-07-15

    Methyllycaconitine (MLA) is a norditerpenoid alkaloid found in high abundance in toxic Delphinium (larkspur) species. It is a potent and selective antagonist of α(7)-nicotinic acetylcholine receptors, but has not been well investigated for activity aside from receptor antagonism. The aim of this study was to investigate the effects of MLA alone and in combination with acetylcholine, epibatidine, nicotine, and neostigmine for actions other than receptor antagonism in TE-671 cells expressing (α(1))(2)β(1)γδ nicotinic acetylcholine receptors. Ligand activity was assessed through measurements of membrane potential changes in TE-671 cells using a fluorescent membrane potential-sensitive dye and normalized to the maximum response to epibatidine (10μM). MLA was ineffective in changing cell membrane potential in the absence of other receptor agonists. However at nanomolar concentrations, it acted as a co-agonist to potentiate TE-671 cell responses to acetylcholine, epibatidine, nicotine, and neostigmine. These results suggest that the poisoning of cattle by norditerpenoid alkaloids found in larkspur may be more complex than previously determined.

  1. The effects of LSD in the guinea-pig ileum. Inhibition of acetylcholine release and stimulation of smooth muscle.

    PubMed

    Pfeuffer-Friederich, I; Kilbinger, H

    1985-12-01

    The effects of lysergic acid diethylamide (LSD) on acetylcholine release and on smooth muscle tone were studied in the myenteric plexus-longitudinal muscle preparation of the guinea pig. LSD (0.01-10 microM) depressed in a concentration-dependent manner the electrically-evoked [3H]-acetylcholine outflow from strips preincubated with [3H]-choline. The maximal effect was a 45% inhibition by 1 microM LSD. The spontaneous outflow was not affected. Metitepine competitively antagonized (pA2 8.0) the LSD-induced reduction of the evoked outflow. Tolazoline and mepyramine did not affect the inhibitory action of LSD. The contractions in response to electrical stimulation were enhanced by 34% in the presence of 0.1 microM LSD. Other concentrations of LSD did not affect the twitches. LSD caused an increase in muscle tone which was antagonized non-competitively by mepyramine, metitepine and ketanserin. Ketanserin was a competitive antagonist against the histamine-induced contractions of the longitudinal muscle (pA2 8.49). The results suggest that LSD stimulates presynaptically located 5-HT receptors and thereby decreases the evoked acetylcholine release. In addition, LSD increases smooth muscle tone either directly through stimulation of H1 receptors or indirectly via histamine release.

  2. Selective, direct detection of acetylcholine in PBS solution, with self-assembled fluorescent nano-particles: experiment and modelling.

    PubMed

    Erieau-Peyrard, Lisa; Coiffier, Claire; Bordat, Patrice; Bégué, Didier; Chierici, Sabine; Pinet, Sandra; Gosse, Isabelle; Baraille, Isabelle; Brown, Ross

    2015-02-14

    We report synthesis, characterisation and molecular modelling of a new fluorescent cyclotriveratrylene probe for acetylcholine in aqueous media, with emission around 430 nm thanks to extended conjugation. The probe discriminates acetylcholine from choline, with respective binding constants 540 and 240 M(-1) in PBS buffered saline solution, an order of magnitude improvement over the previous best performance. Dynamic light scattering and transmission electron microscopy show the new probe self-assembles in ca. 5 nm diameter particles in PBS medium. Molecular modelling suggests that the high fluorescence quantum yield of the probe, 20% in aqueous media, is due to features of the molecular arrangement in the nano-particles, contributing both to exposure of the complexation site and to shielding of the fluorescent π system from quenching by water. Titration data for other quaternary ammoniums and modelling indicate that recognition of acetylcholine vs. choline depends on specific electrostatic interactions, and to a lesser extent on exclusion of water by hydrophobic-hydrophilic segregation. Probe-substrate interactions enhance the fluorescence of the probe by shielding against water and by flattening the π system.

  3. Neural enhancement and pre-emptive perception: the genesis of attention and the attentional maintenance of the cortical salience map.

    PubMed

    Gee, Angela L; Ipata, Anna E; Gottlieb, Jacqueline; Bisley, James W; Goldberg, Michael E

    2008-01-01

    One of the stable hypotheses in systems neuroscience is the relationship between attention and the enhancement of visual responses when an animal attends to the stimulus in its receptive field (Goldberg and Wurtz, 1972 Journal of Neurophysiology 35 560-574). This was first discovered in the superior colliculus of the monkey: neurons in the superficial layers of the superior colliculus responded more intensely to the onset of a stimulus during blocks of trials in which the monkey had to make a saccade to it than they did during blocks of trials in which the monkey had to continue fixating a central point and not respond to the stimulus. This enhancement has been found in many brain regions, including prefrontal cortex (Boch and Goldberg, 1987 Investigative Ophthalmology 28 Supplement, 124), V4 (Moran and Desimone, 1985 Science 229 782-784), and lateral intraparietal area (Colby et al, 1996 Journal of Neurophysiology 76 2841-2852; Colby and Goldberg, 1999 Annual Review of Neuroscience 22 319-349), and even V1 (Lamme et al, 2000 Vision Research 40 1507-1521). In these studies the assumption has been that the monkey attended to the stimulus because the stimulus evoked an enhanced response. In the experiments described here we show that for abruptly appearing stimuli, attention is not related to the initial response evoked by the stimulus, but by the activity present on the salience map in the parietal cortex when the stimulus appears. Attention to the stimulus may subsequently, by a top down signal, sustain the map, but stimuli can as easily be suppressed by top down features as they can be enhanced. PMID:18491716

  4. Secreted Isoform of Human Lynx1 (SLURP-2): Spatial Structure and Pharmacology of Interactions with Different Types of Acetylcholine Receptors

    PubMed Central

    Lyukmanova, E. N.; Shulepko, M. A.; Shenkarev, Z. O.; Bychkov, M. L.; Paramonov, A. S.; Chugunov, A. O.; Kulbatskii, D. S.; Arvaniti, M.; Dolejsi, Eva; Schaer, T.; Arseniev, A. S.; Efremov, R. G.; Thomsen, M. S.; Dolezal, V.; Bertrand, D.; Dolgikh, D. A.; Kirpichnikov, M. P.

    2016-01-01

    Human-secreted Ly-6/uPAR-related protein-2 (SLURP-2) regulates the growth and differentiation of epithelial cells. Previously, the auto/paracrine activity of SLURP-2 was considered to be mediated via its interaction with the α3β2 subtype of the nicotinic acetylcholine receptors (nAChRs). Here, we describe the structure and pharmacology of a recombinant analogue of SLURP-2. Nuclear magnetic resonance spectroscopy revealed a ‘three-finger’ fold of SLURP-2 with a conserved β-structural core and three protruding loops. Affinity purification using cortical extracts revealed that SLURP-2 could interact with the α3, α4, α5, α7, β2, and β4 nAChR subunits, revealing its broader pharmacological profile. SLURP-2 inhibits acetylcholine-evoked currents at α4β2 and α3β2-nAChRs (IC50 ~0.17 and >3 μM, respectively) expressed in Xenopus oocytes. In contrast, at α7-nAChRs, SLURP-2 significantly enhances acetylcholine-evoked currents at concentrations <1 μM but induces inhibition at higher concentrations. SLURP-2 allosterically interacts with human M1 and M3 muscarinic acetylcholine receptors (mAChRs) that are overexpressed in CHO cells. SLURP-2 was found to promote the proliferation of human oral keratinocytes via interactions with α3β2-nAChRs, while it inhibited cell growth via α7-nAChRs. SLURP-2/mAChRs interactions are also probably involved in the control of keratinocyte growth. Computer modeling revealed possible SLURP-2 binding to the ‘classical’ orthosteric agonist/antagonist binding sites at α7 and α3β2-nAChRs. PMID:27485575

  5. Calcium-dependent effect of the thymic polypeptide thymopoietin on the desensitization of the nicotinic acetylcholine receptor

    SciTech Connect

    Revah, F.; Mulle, C.; Pinset, C.; Audhya, T.; Goldstein, G.; Changeux, J.P.

    1987-05-01

    The effects of the thymic polypeptide thymopoietin (Tpo) on the properties of the nicotinic acetylcholine receptor (AcChoR) were investigated by patch clamp techniques on mouse C/sub 2/ myotubes and by biochemical assays on AcChoR-rich membrane fragments purified from the Torpedo marmorata electric organ. At high concentrations (> 100 nM), Tpo inhibits the binding of cholinergic agonists to the AcChoR in a Ca/sup 2 +/-insensitive manner. At lower concentrations (2 nM), Tpo applied on C/sub 2/ myotubes simultaneously with nondesensitizing concentrations of acetylcholine results in the appearance of long closed times separating groups of openings. This effect depends on the presence of Ca/sup 2 +/ in the external medium. Outside-out recordings, performed with various concentrations of EGTA in the intracellular medium, suggest that Ca/sup 2 +/ acts on the cytoplasmic face of the membrane after entry through acetylcholine-activated channels. Parallel studies with T. marmorata AcChoR-rich membranes show that in the presence of Ca/sup 2 +/ Tpo causes a decrease in the apparent equilibrium dissociation constant of the noncompetitive blocker (/sup 3/H)phencyclidine, enhances, at low concentrations, the binding of (/sup 3/H)acetylcholine, and also alters the binding kinetics of the fluorescent agonist 6-(5-dimethylamino-1-naphthalenesulfonamido)-n-hexanoic acid ..beta..-(N-trimethylammonium bromide) ethyl ester to the AcChoR. It was concluded that, in the presence of Ca/sup 2 +/, Tpo displaces the conformational equilibrium of the AcChoR towards a high-affinity desensitized state and increases the transition rate towards the same state.

  6. Secreted Isoform of Human Lynx1 (SLURP-2): Spatial Structure and Pharmacology of Interactions with Different Types of Acetylcholine Receptors

    NASA Astrophysics Data System (ADS)

    Lyukmanova, E. N.; Shulepko, M. A.; Shenkarev, Z. O.; Bychkov, M. L.; Paramonov, A. S.; Chugunov, A. O.; Kulbatskii, D. S.; Arvaniti, M.; Dolejsi, Eva; Schaer, T.; Arseniev, A. S.; Efremov, R. G.; Thomsen, M. S.; Dolezal, V.; Bertrand, D.; Dolgikh, D. A.; Kirpichnikov, M. P.

    2016-08-01

    Human-secreted Ly-6/uPAR-related protein-2 (SLURP-2) regulates the growth and differentiation of epithelial cells. Previously, the auto/paracrine activity of SLURP-2 was considered to be mediated via its interaction with the α3β2 subtype of the nicotinic acetylcholine receptors (nAChRs). Here, we describe the structure and pharmacology of a recombinant analogue of SLURP-2. Nuclear magnetic resonance spectroscopy revealed a ‘three-finger’ fold of SLURP-2 with a conserved β-structural core and three protruding loops. Affinity purification using cortical extracts revealed that SLURP-2 could interact with the α3, α4, α5, α7, β2, and β4 nAChR subunits, revealing its broader pharmacological profile. SLURP-2 inhibits acetylcholine-evoked currents at α4β2 and α3β2-nAChRs (IC50 ~0.17 and >3 μM, respectively) expressed in Xenopus oocytes. In contrast, at α7-nAChRs, SLURP-2 significantly enhances acetylcholine-evoked currents at concentrations <1 μM but induces inhibition at higher concentrations. SLURP-2 allosterically interacts with human M1 and M3 muscarinic acetylcholine receptors (mAChRs) that are overexpressed in CHO cells. SLURP-2 was found to promote the proliferation of human oral keratinocytes via interactions with α3β2-nAChRs, while it inhibited cell growth via α7-nAChRs. SLURP-2/mAChRs interactions are also probably involved in the control of keratinocyte growth. Computer modeling revealed possible SLURP-2 binding to the ‘classical’ orthosteric agonist/antagonist binding sites at α7 and α3β2-nAChRs.

  7. The distribution of acetylcholine in the Malayan jack-fruit plant, Artocarpus integra.

    PubMed

    LIN, R C

    1957-09-01

    The distribution of acetylcholine in the seeds and leaves of the Malayan Jack-fruit plant, Artocarpus integra, has been studied with the view to obtaining evidence for the site of its formation. The terminal growing leaves on the side branches had a very high concentration of acetylcholine (770 mug./g.), while the acetylcholine content of the other leaves on the same branch progressively decreased with age. The total amount of acetylcholine stored in the terminal growing leaves was only 42 mug., but in the second leaves which had grown nearly to their full size it was 540 mug. From the third leaves, the amount of acetylcholine stored gradually decreased. The midribs and the secondary veins of the leaves when combined had a higher concentration of acetylcholine than had the blades. The acetylcholine concentration of the pith of the stem was 4.2 times higher than that of the cortex-phloem layer while that of the xylem layer was the lowest; in the root the pith had a value only one-seventh of the cortex. The younger part of the pith and the cortex-phloem layers of the stem contained more acetylcholine than the older parts. These findings support the view that the acetylcholine is synthesized in the growing leaves. An unusual lenticel-like structure in the cortex layer of the root contained more acetylcholine than the surrounding tissue.

  8. Prognostic value of acetylcholine challenge test: a prospective study.

    PubMed Central

    Pham, Q T; Mur, J M; Chau, N; Gabiano, M; Henquel, J C; Teculescu, D

    1984-01-01

    Eleven hundred and nine iron mine workers aged 35 to 55 with normal chest radiographs were submitted to a pulmonary examination consisting of a questionnaire, a clinical examination, and pulmonary function testing including an acetylcholine challenge test. A positive response (decrease of FEV1 of more than 10%) was observed in 210 subjects (Ace+). The remaining 899 had a negative response (Ace-). Bronchitis, asthma, dyspnoea, and obstructive syndrome were more frequent in the Ace+ group. Five years later, 820 subjects were reexamined: occasional cough and sputum and chronic bronchitis appeared more frequently among subjects without symptoms at the first examination but with a positive acetylcholine challenge test. The obstructive syndrome was more often observed and regressed more rarely in the Ace+ group. The results confirm the use of a test of bronchial hyperreactivity as a means of identifying subjects at risk from chronic obstructive lung disease. PMID:6722054

  9. Optochemical control of genetically engineered neuronal nicotinic acetylcholine receptors

    NASA Astrophysics Data System (ADS)

    Tochitsky, Ivan; Banghart, Matthew R.; Mourot, Alexandre; Yao, Jennifer Z.; Gaub, Benjamin; Kramer, Richard H.; Trauner, Dirk

    2012-02-01

    Advances in synthetic chemistry, structural biology, molecular modelling and molecular cloning have enabled the systematic functional manipulation of transmembrane proteins. By combining genetically manipulated proteins with light-sensitive ligands, innately ‘blind’ neurobiological receptors can be converted into photoreceptors, which allows them to be photoregulated with high spatiotemporal precision. Here, we present the optochemical control of neuronal nicotinic acetylcholine receptors (nAChRs) with photoswitchable tethered agonists and antagonists. Using structure-based design, we produced heteromeric α3β4 and α4β2 nAChRs that can be activated or inhibited with deep-violet light, but respond normally to acetylcholine in the dark. The generation of these engineered receptors should facilitate investigation of the physiological and pathological functions of neuronal nAChRs and open a general pathway to photosensitizing pentameric ligand-gated ion channels.

  10. SLC18: Vesicular neurotransmitter transporters for monoamines and acetylcholine.

    PubMed

    Lawal, Hakeem O; Krantz, David E

    2013-01-01

    The exocytotic release of neurotransmitters requires active transport into synaptic vesicles and other types of secretory vesicles. Members of the SLC18 family perform this function for acetylcholine (SLC18A3, the vesicular acetylcholine transporter or VAChT) and monoamines such as dopamine and serotonin (SLC18A1 and 2, the vesicular monoamine transporters VMAT1 and 2, respectively). To date, no specific diseases have been attributed to a mutation in an SLC18 family member; however, polymorphisms in SLC18A1 and SLC18A2 may confer risk for some neuropsychiatric disorders. Additional members of this family include SLC18A4, expressed in insects, and SLC18B1, the function of which is not known. SLC18 is part of the Drug:H(+) Antiporter-1 Family (DHA1, TCID 2.A.1.2) within the Major Facilitator Superfamily (MFS, TCID 2.A.1).

  11. SLC18: Vesicular neurotransmitter transporters for monoamines and acetylcholine

    PubMed Central

    Lawal, Hakeem O.; Krantz, David E.

    2012-01-01

    The exocytotic release of neurotransmitters requires active transport into synaptic vesicles and other types of secretory vesicles. Members of the SLC18 family perform this function for acetylcholine (SLC18A3, the vesicular acetylcholine transporter or VAChT) and monoamines such as dopamine and serotonin (SLC18A1 and 2, the vesicular monoamine transporters VMAT1 and 2, respectively). To date, no specific diseases have been attributed to a mutation in an SLC18 family member; however, polymorphisms in SLC18A1 and SLC18A2 may confer risk for some neuropsychiatric disorders. Additional members of this family include SLC18A4, expressed in insects, and SLC18B1, the function of which is not known. SLC18 is part of the Drug:H+ Antiporter-1 Family (DHA1, TCID 2.A.1.2) within the Major Facilitator Superfamily (MFS, TCID 2.A.1). PMID:23506877

  12. Altered isotope charge distribution of acetylcholine neurotransmitter and Myasthenia Gravis.

    PubMed

    Bayri, A; Unal, S; Altin, S; Bulut, F; Dayanc, B E

    2016-04-01

    Acetylcholine (ACh) is a central neurotransmitter that is used for signal transmission among neurons. For signal transmission in neurons, a neurotransmitter must bind to its receptor in order to produce an action potential. It is known that in Myasthenia Gravis (MG) cases, autoantibodies could block this binding. In the future, the treatment of MG could be achieved via modulation of molecular interaction between ACh and acetylcholine receptor (AChR). This study suggests that if an atom on a ligand (i.e. a neurotransmitter) is replaced with its isotope, it may cause charge redistribution such as that the binding between ligand and its receptor may be improved. Hence suggesting that with replacement of atoms with their isotopes in any biologically important ligand could alter its affinity towards its corresponding receptor, which would have a wide array of applications in medicine.

  13. α7 nicotinic acetylcholine receptor subunit in angiogenesis and epithelial to mesenchymal transition.

    PubMed

    Pillai, Smitha; Chellappan, Srikumar

    2012-05-01

    Cigarette smoking is strongly correlated with many diseases like cancer, cardiovascular disease and macular degeneration. Nicotine, the main active and addictive component of tobacco smoke has recently been shown to enhance angiogenesis in many experimental systems and animal models. The pro-angiogenic activity of nicotine is mediated by nicotinic acetylcholine receptors, particularly the alpha 7 subunit, that are expressed on a variety of non-neuronal cells including those in the vasculature such as endothelial cells and smooth muscle cells. The present review focuses on the role of α7nAChR in mediating the pro-angiogenic effects of nicotine and describes the molecular mechanisms involved in nicotine-induced angiogenesis as well as epithelial to mesenchymal transition. These observations on nicotine function highlight the therapeutic potential of α7nAChR agonists and antagonists for combating angiogenesis related diseases.

  14. Effect of oxotremorine, physostigmine, and scopolamine on brain acetylcholine synthesis: a study using HPLC

    SciTech Connect

    Bertrand, N.; Beley, A. )

    1990-11-01

    The synthesis rate of brain acetylcholine (ACh) was estimated in mice following i.v. administration of ({sup 3}H)choline (Ch). The measurements were performed 1 min after the tracer injection, using the ({sup 3}H)ACh/({sup 3}H)Ch specific radioactivity ratio as an index of ACh synthesis rate. Endogenous and labeled Ch and ACh were quantified using HPLC methodology. Oxotremorine and physostigmine (0.5 mg/kg, i.p.) increased the steady state concentration of brain ACh by + 130% and 84%, respectively and of Ch by + 60% (oxotremorine); they decreased ACh synthesis by 62 and 55%, respectively. By contrast, scopolamine (0.7 mg/kg, i.p.) decreased the cerebral content of Ch by - 26% and of ACh by - 23% without enhancing the synthesis of ACh. The results show the utility of HPLC methodology in the investigation of ACh turnover.

  15. Branched nanotrees with immobilized acetylcholine esterase for nanobiosensor applications

    NASA Astrophysics Data System (ADS)

    Risveden, Klas; Dick, Kimberly A.; Bhand, Sunil; Rydberg, Patrik; Samuelson, Lars; Danielsson, Bengt

    2010-02-01

    A novel lab-on-a-chip nanotree enzyme reactor is demonstrated for the detection of acetylcholine. The reactors are intended for use in the RISFET (regional ion sensitive field effect transistor) nanosensor, and are constructed from gold-tipped branched nanorod structures grown on SiNx-covered wafers. Two different reactors are shown: one with simple, one-dimensional nanorods and one with branched nanorod structures (nanotrees). Significantly higher enzymatic activity is found for the nanotree reactors than for the nanorod reactors, most likely due to the increased gold surface area and thereby higher enzyme binding capacity. A theoretical calculation is included to show how the enzyme kinetics and hence the sensitivity can be influenced and increased by the control of electrical fields in relation to the active sites of enzymes in an electronic biosensor. The possible effects of electrical fields employed in the RISFET on the function of acetylcholine esterase is investigated using quantum chemical methods, which show that the small electric field strengths used are unlikely to affect enzyme kinetics. Acetylcholine esterase activity is determined using choline oxidase and peroxidase by measuring the amount of choline formed using the chemiluminescent luminol reaction.

  16. Modulation of cerebral microvascular permeability by endothelial nicotinic acetylcholine receptors.

    PubMed

    Hawkins, Brian T; Egleton, Richard D; Davis, Thomas P

    2005-07-01

    Nicotine increases the permeability of the blood-brain barrier in vivo. This implies a possible role for nicotinic acetylcholine receptors in the regulation of cerebral microvascular permeability. Expression of nicotinic acetylcholine receptor subunits in cerebral microvessels was investigated with immunofluorescence microscopy. Positive immunoreactivity was found for receptor subunits alpha3, alpha5, alpha7, and beta2, but not subunits alpha4, beta3, or beta4. Blood-brain barrier permeability was assessed via in situ brain perfusion with [14C]sucrose. Nicotine increased the rate of sucrose entry into the brain from 0.3 +/- 0.1 to 1.1 +/- 0.2 microl.g(-1).min(-1), as previously described. This nicotine-induced increase in blood-brain barrier permeability was significantly attenuated by both the blood-brain barrier-permeant nicotinic antagonist mecamylamine and the blood-brain barrier-impermeant nicotinic antagonist hexamethonium to 0.5 +/- 0.2 and 0.3 +/- 0.2 microl.g(-1).min(-1), respectively. These data suggest that nicotinic acetylcholine receptors expressed on the cerebral microvascular endothelium mediate nicotine-induced changes in blood-brain barrier permeability.

  17. The coumarin scopoletin potentiates acetylcholine release from synaptosomes, amplifies hippocampal long-term potentiation and ameliorates anticholinergic- and age-impaired memory

    PubMed Central

    Hornick, A.; Lieb, A.; Vo, N.P.; Rollinger, J.M.; Stuppner, H.; Prast, H.

    2011-01-01

    In a previous study the simple, naturally derived coumarin scopoletin (SCT) was identified as an inhibitor of acetylcholinesterase (AChE), using a pharmacophore-based virtual screening approach. In this study the potential of SCT as procholinergic and cognition-enhancing therapeutic was investigated in a more detailed way, using different experimental approaches like measuring newly synthesized acetylcholine (ACh) in synaptosomes, long-term potentiation (LTP) experiments in hippocampal slices, and behavior studies. SCT enhanced the K+-stimulated release of ACh from rat frontal cortex synaptosomes, showing a bell-shaped dose effect curve (Emax: 4 μM). This effect was blocked by the nicotinic ACh receptor (nAChR) antagonists mecamylamine (MEC) and dihydro-β-erythroidine (DHE). The nAChR agonist (and AChE inhibitor) galantamine induced a similar increase in ACh release (Emax: 1 μM). SCT potentiated LTP in hippocampal slices of rat brain. The high-frequency stimulation (HFS)-induced, N-methyl-D-aspartate (NMDA) receptor dependent LTP of field excitatory postsynaptic potentials at CA3-CA1 synapses was greatly enhanced by pre-HFS application of SCT (4 μM for 4 min). This effect was mimicked by nicotine (2 μM) and abolished by MEC, suggesting an effect on nAChRs. SCT did not restore the total inhibition of LTP by NMDA receptor antagonist d, l-2-amino-5-phosphonopentanoic acid (AP-5). SCT (2 μg, i.c.v.) increased T-maze alternation and ameliorated novel object recognition of mice with scopolamine-induced cholinergic deficit. It also reduced age-associated deficits in object memory of 15–18-month-old mice (2 mg/kg sc). Our findings suggest that SCT possesses memory-improving properties, which are based on its direct nAChR agonistic activity. Therefore, SCT might be able to rescue impaired cholinergic functions by enhancing nAChR-mediated release of neurotransmitters and promoting neural plasticity in hippocampus. PMID:21945033

  18. Neural correlates of retrieval-based memory enhancement: An fMRI study of the testing effect

    PubMed Central

    Wing, Erik A.; Marsh, Elizabeth J.; Cabeza, Roberto

    2013-01-01

    Restudying material is a common method for learning new information, but not necessarily an effective one. Research on the testing effect shows that practice involving retrieval from memory can facilitate later memory in contrast to passive restudy. Despite extensive behavioral work, the brain processes that make retrieval an effective learning strategy remain unclear. In the present experiment, we explored how initially retrieving items affected memory a day later as compared to a condition involving traditional restudy. In contrast to restudy, initial testing that contributed to future memory success was associated with engagement of several regions including the anterior hippocampus, lateral temporal cortices, and medial prefrontal cortex (PFC). Additionally, testing enhanced hippocampal connectivity with ventrolateral PFC and midline regions. These findings indicate that the testing effect may be contingent on processes that are typically thought to support memory success at encoding (e.g. relational binding, selection and elaboration of semantically-related information) in addition to those more often associated with retrieval (e.g. memory search). PMID:23607935

  19. Neural correlates of retrieval-based memory enhancement: an fMRI study of the testing effect.

    PubMed

    Wing, Erik A; Marsh, Elizabeth J; Cabeza, Roberto

    2013-10-01

    Restudying material is a common method for learning new information, but not necessarily an effective one. Research on the testing effect shows that practice involving retrieval from memory can facilitate later memory in contrast to passive restudy. Despite extensive behavioral work, the brain processes that make retrieval an effective learning strategy remain unclear. In the present experiment, we explored how initially retrieving items affected memory a day later as compared to a condition involving traditional restudy. In contrast to restudy, initial testing that contributed to future memory success was associated with engagement of several regions including the anterior hippocampus, lateral temporal cortices, and medial prefrontal cortex (PFC). Additionally, testing enhanced hippocampal connectivity with ventrolateral PFC and midline regions. These findings indicate that the testing effect may be contingent on processes that are typically thought to support memory success at encoding (e.g. relational binding, selection and elaboration of semantically-related information) in addition to those more often associated with retrieval (e.g. memory search).

  20. Neuronal specificity of the alpha 7 nicotinic acetylcholine receptor promoter develops during morphogenesis of the central nervous system.

    PubMed Central

    Matter-Sadzinski, L; Hernandez, M C; Roztocil, T; Ballivet, M; Matter, J M

    1992-01-01

    A transient transfection assay has been developed to analyse promoter activity in neuronal cells freshly dissociated from the chick central nervous system. The assay enabled us to identify cis-acting regulatory elements within the 5'-flanking region of the alpha 7 nicotinic acetylcholine receptor gene. In differentiated retina, regulatory elements direct reporter gene expression to a small subset of neurons which has been identified as ganglion cells, i.e. to the population of neurons in which alpha 7 transcripts were localized by in situ hybridization. However, these promoter elements exhibit ubiquitous activity in undifferentiated neural cells and in mesodermal stem cells. Our study supports the idea that alpha 7 regulatory elements acquire their neuronal specificity in the course of embryogenesis. Images PMID:1425587

  1. The role of hydrogels with tethered acetylcholine functionality on the adhesion and viability of hippocampal neurons and glial cells

    PubMed Central

    Zhou, Zhaoli; Yu, Panpan; Geller, Herbert M.; Ober, Christopher K.

    2012-01-01

    In neural tissue engineering, designing materials with the right chemical cues is crucial in providing a permissive microenvironment to encourage and guide neuronal cell attachment and differentiation. Modifying synthetic hydrogels with biologically active molecules has become an increasingly important route in this field to provide a successful biomaterial and cell interaction. This study presents a strategy of using the monomer 2-methacryloxyethyl trimethylammonium chloride (MAETAC) to provide tethered neurotransmitter acetylcholine-like functionality with a complete 2-acetoxy-N,N,N-trimethylethanaminium segment, thereby modifying the properties of commonly used, non-adhesive PEG-based hydrogels. The effect of the functional monomer concentration on the physical properties of the hydrogels was systematically studied, and the resulting hydrogels were also evaluated for mice hippocampal neural cell attachment and growth. Results from this study showed that MAETAC in the hydrogels promotes neuronal cell attachment and differentiation in a concentration-dependent manner, different proportions of MAETAC monomer in the reaction mixture produce hydrogels with different porous structures, swollen states, and mechanical strengths. Growth of mice hippocampal cells cultured on the hydrogels showed differences in number, length of processes and exhibited different survival rates. Our results indicate that chemical composition of the biomaterials is a key factor in neural cell attachment and growth, and integration of the appropriate amount of tethered neurotransmitter functionalities can be a simple and effective way to optimize existing biomaterials for neuronal tissue engineering applications. PMID:22196899

  2. Suitability of Nicotinic Acetylcholine Receptor α7 and Muscarinic Acetylcholine Receptor 3 Antibodies for Immune Detection: Evaluation in Murine Skin.

    PubMed

    Rommel, Frank R; Raghavan, Badrinarayanan; Paddenberg, Renate; Kummer, Wolfgang; Tumala, Susanne; Lochnit, Günter; Gieler, Uwe; Peters, Eva M J

    2015-05-01

    Recent evidence reveals a crucial role for acetylcholine and its receptors in the regulation of inflammation, particularly of nicotinic acetylcholine receptor α7 (Chrna7) and muscarinic acetylcholine receptor 3 (Chrm3). Immunohistochemistry is a key tool for their cellular localization in functional tissues. We evaluated nine different commercially available antibodies on back skin tissue from wild-type (Wt) and gene-deficient (KO) mice. In the immunohistochemical analysis, we focused on key AChR-ligand sensitive skin cells (mast cells, nerve fibers and keratinocytes). All five antibodies tested for Chrm3 and the first three Chrna7 antibodies stained positive in both Wt and respective KO skin. With the 4th antibody (ab23832) nerve fibers were unlabeled in the KO mice. By western blot analysis, this antibody detected bands in both Wt and Chrna7 KO skin and brain. qRT-PCR revealed mRNA amplification with a primer set for the undeleted region in both Wt and KO mice, but none with a primer set for the deleted region in KO mice. By 2D electrophoresis, we found β-actin and β-enolase cross reactivity, which was confirmed by double immunolabeling. In view of the present results, the tested antibodies are not suitable for immunolocalization in skin and suggest thorough control of antibody specificity is required if histomorphometry is intended. PMID:25673288

  3. Participation of adrenergic mechanisms in brain acetylcholine release produced by centrophenoxine.

    PubMed

    Georgiev, V P; Petkov, V; Kirilov, B

    1979-01-01

    The effect of phentolamine (alpha-adrenoceptor antagonist) and propranolol (beta-adrenoceptor antagonist) on the increased brain acetylcholine-releasing effect of centrophenoxine were studied in unanaesthetized cats in which perfusion of the anterior horn of a lateral cerebral ventricle was performed. Phentolamine alone decreased the amount of spontaneously released acetylcholine and did not change the effect of centrophenoxine. Propranolol alone did not change the amount of spontaneously released acetylcholine and reversed the centrophenoxine effect. The effects of centrophenoxine on acetylcholine release are attributed to its action on the presynaptic adrenoceptors (alpha and beta) situated in the cholinergic terminals of structures lying the anterior horn of a lateral cerebral ventricle.

  4. Comparison of (/sup 3/H)nicotine and (/sup 3/H)acetylcholine binding in mouse brain: regional distribution

    SciTech Connect

    Sershen, H.; Reith, M.E.; Hashim, A.; Lajtha, A.

    1985-06-01

    In a continuing study of nicotine binding sites, the authors determined the relative amount of nicotine binding and acetylcholine binding in various brain regions of C57/BL and of DBA mice. Although midbrain showed the highest and cerebellum the lowest binding for both (/sup 3/H)nicotine and (/sup 3/H)acetylcholine, the ratio of nicotine to acetylcholine binding showed a three-fold regional variation. Acetylcholine inhibition of (/sup 3/H)nicotine binding indicated that a portion of nicotine binding was not inhibited by acetylcholine. These results indicate important differences between the binding of (+/-)-(/sup 3/H)nicotine and that of (/sup 3/H)acetylcholine.

  5. ACR-12 ionotropic acetylcholine receptor complexes regulate inhibitory motor neuron activity in Caenorhabditis elegans.

    PubMed

    Petrash, Hilary A; Philbrook, Alison; Haburcak, Marian; Barbagallo, Belinda; Francis, Michael M

    2013-03-27

    Heterogeneity in the composition of neurotransmitter receptors is thought to provide functional diversity that may be important in patterning neural activity and shaping behavior (Dani and Bertrand, 2007; Sassoè-Pognetto, 2011). However, this idea has remained difficult to evaluate directly because of the complexity of neuronal connectivity patterns and uncertainty about the molecular composition of specific receptor types in vivo. Here we dissect how molecular diversity across receptor types contributes to the coordinated activity of excitatory and inhibitory motor neurons in the nematode Caenorhabditis elegans. We show that excitatory and inhibitory motor neurons express distinct populations of ionotropic acetylcholine receptors (iAChRs) requiring the ACR-12 subunit. The activity level of excitatory motor neurons is influenced through activation of nonsynaptic iAChRs (Jospin et al., 2009; Barbagallo et al., 2010). In contrast, synaptic coupling of excitatory and inhibitory motor neurons is achieved through a second population of iAChRs specifically localized at postsynaptic sites on inhibitory motor neurons. Loss of ACR-12 iAChRs from inhibitory motor neurons leads to reduced synaptic drive, decreased inhibitory neuromuscular signaling, and variability in the sinusoidal motor pattern. Our results provide new insights into mechanisms that establish appropriately balanced excitation and inhibition in the generation of a rhythmic motor behavior and reveal functionally diverse roles for iAChR-mediated signaling in this process. PMID:23536067

  6. Nicotine evokes kinetic tremor by activating the inferior olive via α7 nicotinic acetylcholine receptors.

    PubMed

    Kunisawa, Naofumi; Iha, Higor A; Shimizu, Saki; Tokudome, Kentaro; Mukai, Takahiro; Kinboshi, Masato; Serikawa, Tadao; Ohno, Yukihiro

    2016-11-01

    Nicotinic acetylcholine (nACh) receptors are implicated in the pathogenesis of movement disorders (e.g., tremor) and epilepsy. Here, we performed behavioral and immunohistochemical studies using mice and rats to elucidate the mechanisms underlying nicotine-induced tremor. Treatments of animals with nicotine (0.5-2mg/kg, i.p.) elicited kinetic tremor, which was completely suppressed by the nACh receptor antagonist mecamylamine (MEC). The specific α7 nACh receptor antagonist methyllycaconitine (MLA) also inhibited nicotine-induced tremor, whereas the α4β2 nACh antagonist dihydro-β-erythroidine (DHβE) or the peripheral α3β4 nACh antagonist hexamethonium showed no effects. Mapping analysis of Fos protein expression, a biological marker of neural excitation, revealed that a tremorgenic dose (1mg/kg) of nicotine region-specifically elevated Fos expression in the piriform cortex (PirC), medial habenula, solitary nucleus and inferior olive (IO) among 44 brain regions examined. In addition, similarly to the tremor responses, nicotine-induced Fos expression in the PirC and IO was selectively antagonized by MLA, but not by DHβE. Furthermore, an electrical lesioning of the IO, but not the PirC, significantly suppressed the induction of nicotine tremor. The present results suggest that nicotine elicits kinetic tremor in rodents by activating the IO neurons via α7 nACh receptors.

  7. Aversive hypothalamic stimulation releases acetylcholine in the nucleus accumbens, and stimulation-escape decreases it.

    PubMed

    Rada, P V; Hoebel, B G

    2001-01-01

    Hypothalamic electrodes can generate positive reinforcement, as shown by self-stimulation, and negative reinforcement shown by stimulation-escape. It was hypothesized that acetylcholine (ACh) is released in the nucleus accumbens during the aversive state that underlies stimulation-escape. If this is correct, escape behavior should lower extracellular ACh. Rats were prepared with microdialysis probes in the accumbens (posterior shell region) and electrodes in the perifornical lateral hypothalamus. Animals learned to press a lever for 0.5 s trains of stimulation (typically 3600 responses/h). Then they were given automatic stimulation to determine which animals would also learn to press a lever to turn stimulation off for 5 s at a time (typically 75 responses/h). Accumbens microdialysis showed that automatic stimulation caused extracellular ACh to double, but only in the rats that were motivated to learn stimulation-escape. When allowed to escape stimulation, these animals lowered extracellular ACh significantly. It is concluded that ACh release in the accumbens is related to the neural state that animals work to escape.

  8. Biomimetic Polymer Brushes Containing Tethered Acetylcholine Analogs for Protein and Hippocampal Neuronal Cell Patterning

    PubMed Central

    Zhou, Zhaoli; Yu, Panpan; Geller, Herbert M.; Ober, Christopher K.

    2013-01-01

    This paper describes a method to control neuronal cell adhesion and differentiation with both chemical and topographic cues by using a spatially defined polymer brush pattern. First, biomimetic methacrylate polymer brushes containing tethered neurotransmitter acetylcholine functionalities in the form of dimethylaminoethyl methacrylate (DMAEMA), or free hydroxyl-terminated poly(ethylene glycol) (PEG) units were prepared using the “grown from” method through surface-initiated atom transfer radical polymerization (SI-ATRP) reactions. The surface properties of the resulting brushes were thoroughly characterized with various techniques and hippocampal neuronal cell culture on the brush surfaces exhibit cell viability and differentiation comparable to, or even better than, those on commonly used poly-L-lysine coated glass coverslips. The polymer brushes were then patterned via UV photolithography techniques to provide specially designed surface features with different sizes (varying from 2 µm to 200 µm) and orientations (horizontal and vertical). Protein absorption experiments and hippocampal neuronal cell culture tests on the brush patterns showed that both protein and neurons can adhere to the patterns and therefore be guided by such patterns. These results also demonstrate that, because of their unique chemical composition and well-defined nature, the developed polymer brushes may find many potential applications in cell-material interactions studies and neural tissue engineering. PMID:23336729

  9. Nicotine evokes kinetic tremor by activating the inferior olive via α7 nicotinic acetylcholine receptors.

    PubMed

    Kunisawa, Naofumi; Iha, Higor A; Shimizu, Saki; Tokudome, Kentaro; Mukai, Takahiro; Kinboshi, Masato; Serikawa, Tadao; Ohno, Yukihiro

    2016-11-01

    Nicotinic acetylcholine (nACh) receptors are implicated in the pathogenesis of movement disorders (e.g., tremor) and epilepsy. Here, we performed behavioral and immunohistochemical studies using mice and rats to elucidate the mechanisms underlying nicotine-induced tremor. Treatments of animals with nicotine (0.5-2mg/kg, i.p.) elicited kinetic tremor, which was completely suppressed by the nACh receptor antagonist mecamylamine (MEC). The specific α7 nACh receptor antagonist methyllycaconitine (MLA) also inhibited nicotine-induced tremor, whereas the α4β2 nACh antagonist dihydro-β-erythroidine (DHβE) or the peripheral α3β4 nACh antagonist hexamethonium showed no effects. Mapping analysis of Fos protein expression, a biological marker of neural excitation, revealed that a tremorgenic dose (1mg/kg) of nicotine region-specifically elevated Fos expression in the piriform cortex (PirC), medial habenula, solitary nucleus and inferior olive (IO) among 44 brain regions examined. In addition, similarly to the tremor responses, nicotine-induced Fos expression in the PirC and IO was selectively antagonized by MLA, but not by DHβE. Furthermore, an electrical lesioning of the IO, but not the PirC, significantly suppressed the induction of nicotine tremor. The present results suggest that nicotine elicits kinetic tremor in rodents by activating the IO neurons via α7 nACh receptors. PMID:27506652

  10. Alpha-galactosidase stimulates acetylcholine receptor aggregation in skeletal muscle cells via PNA-binding carbohydrates.

    PubMed

    Parkhomovskiy, N; Martin, P T

    2000-04-21

    Aggregation of nicotinic acetylcholine receptors (AChRs) in skeletal muscle is an essential step in the formation of the mammalian neuromuscular junction. While proteins that bind to myotube receptors such as agrin and laminin can stimulate AChR aggregation in cultured myotubes, removal of cell surface sialic acids stimulates aggregation in a ligand-independent manner. Here, we show that removal of cell surface alpha-galactosides also stimulates AChR aggregation in the absence of added laminin or agrin. AChR aggregation stimulated by alpha-galactosidase was blocked by peanut agglutinin (PNA), which binds to lactosamine-containing disaccharides, but not by the GalNAc-binding lectin Vicia villosa agglutinin (VVA-B4). AChR aggregation stimulated by alpha-galactosidase potentiated AChR clustering induced by either neural agrin or laminin-1 and could be inhibited by muscle agrin. These data suggest that capping of cell surface lactosamines or N-acetyllactosamines with alpha-galactose affects AChR aggregation much as capping with sialic acids does.

  11. Recycling of Acetylcholine Receptors at Ectopic Postsynaptic Clusters Induced by Exogenous Agrin in Living Rats

    PubMed Central

    Brenner, Hans Rudolf; Akaaboune, Mohammed

    2014-01-01

    During the development of the neuromuscular junction, motor axons induce the clustering of acetylcholine receptors (AChRs) and increase their metabolic stability in the muscle membrane. Here, we asked whether the synaptic organizer agrin might regulate the metabolic stability and density of AChRs by promoting the recycling of internalized AChRs, which would otherwise be destined for degradation, into synaptic sites. We show that at nerve-free AChR clusters induced by agrin in extrasynaptic membrane, internalized AChRs are driven back into the ectopic synaptic clusters where they intermingle with pre-existing and new receptors. The extent of AChR recycling depended on the strength of the agrin stimulus, but not on the development of junctional folds, another hallmark of mature postsynaptic membranes. In chronically denervated muscles, in which both AChR stability and recycling are significantly decreased by muscle inactivity, agrin maintained the amount of recycled AChRs at agrin-induced clusters at a level similar to that at denervated original endplates. In contrast, AChRs did not recycle at agrin-induced clusters in C2C12 or primary myotubes. Thus, in muscles in vivo, but not in cultured myotubes, neural agrin promotes the recycling of AChRs and thereby increases their metabolic stability. PMID:25093969

  12. The effects of postnatal alcohol exposure and galantamine on the context pre-exposure facilitation effect and acetylcholine efflux using in vivo microdialysis.

    PubMed

    Perkins, Amy E; Fadel, Jim R; Kelly, Sandra J

    2015-05-01

    Fetal alcohol spectrum disorders (FASD) are characterized by damage to multiple brain regions, including the hippocampus, which is involved in learning and memory. The acetylcholine neurotransmitter system provides major input to the hippocampus and is a possible target of developmental alcohol exposure. Alcohol (3.0 g/kg/day) was administered via intubation to male rat pups (postnatal day [PD] 2-10; ethanol-treated [ET]). Controls received a sham intubation (IC) or no treatment (NC). Acetylcholine efflux was measured using in vivo microdialysis (PD 32-35). ET animals were not different at baseline, but had decreased K(+)/Ca(2+)-induced acetylcholine efflux compared to NC animals and an enhanced acetylcholine response to galantamine (acetylcholinesterase inhibitor; 2.0 mg/kg) compared to both control groups. A separate cohort of animals was tested in the context pre-exposure facilitation effect task (CPFE; PD 30-32) following postnatal alcohol exposure and administration of galantamine (2.0 mg/kg; PD 11-30). Neither chronic galantamine nor postnatal alcohol exposure influenced performance in the CPFE task. Using immunohistochemistry, we found that neither alcohol exposure nor behavioral testing significantly altered the density of vesicular acetylcholine transporter or alpha7 nicotinic acetylcholine receptor in the ventral hippocampus (CA1). In the medial septum, the average number of choline acetyltransferase (ChAT+) cells was increased in ET animals that displayed the context-shock association; there were no changes in IC and NC animals that learned the context-shock association or in any animals that were in the control task that entailed no learning. Taken together, these results indicate that the hippocampal acetylcholine system is significantly disrupted under conditions of pharmacological manipulations (e.g., galantamine) in alcohol-exposed animals. Furthermore, ChAT was up‑regulated in ET animals that learned the CPFE, which may account for their ability

  13. The effects of postnatal alcohol exposure and galantamine on the context pre-exposure facilitation effect and acetylcholine efflux using in vivo microdialysis.

    PubMed

    Perkins, Amy E; Fadel, Jim R; Kelly, Sandra J

    2015-05-01

    Fetal alcohol spectrum disorders (FASD) are characterized by damage to multiple brain regions, including the hippocampus, which is involved in learning and memory. The acetylcholine neurotransmitter system provides major input to the hippocampus and is a possible target of developmental alcohol exposure. Alcohol (3.0 g/kg/day) was administered via intubation to male rat pups (postnatal day [PD] 2-10; ethanol-treated [ET]). Controls received a sham intubation (IC) or no treatment (NC). Acetylcholine efflux was measured using in vivo microdialysis (PD 32-35). ET animals were not different at baseline, but had decreased K(+)/Ca(2+)-induced acetylcholine efflux compared to NC animals and an enhanced acetylcholine response to galantamine (acetylcholinesterase inhibitor; 2.0 mg/kg) compared to both control groups. A separate cohort of animals was tested in the context pre-exposure facilitation effect task (CPFE; PD 30-32) following postnatal alcohol exposure and administration of galantamine (2.0 mg/kg; PD 11-30). Neither chronic galantamine nor postnatal alcohol exposure influenced performance in the CPFE task. Using immunohistochemistry, we found that neither alcohol exposure nor behavioral testing significantly altered the density of vesicular acetylcholine transporter or alpha7 nicotinic acetylcholine receptor in the ventral hippocampus (CA1). In the medial septum, the average number of choline acetyltransferase (ChAT+) cells was increased in ET animals that displayed the context-shock association; there were no changes in IC and NC animals that learned the context-shock association or in any animals that were in the control task that entailed no learning. Taken together, these results indicate that the hippocampal acetylcholine system is significantly disrupted under conditions of pharmacological manipulations (e.g., galantamine) in alcohol-exposed animals. Furthermore, ChAT was up‑regulated in ET animals that learned the CPFE, which may account for their ability

  14. Workshop on neural networks

    SciTech Connect

    Uhrig, R.E.; Emrich, M.L.

    1990-01-01

    The topics covered in this report are: Learning, Memory, and Artificial Neural Systems; Emerging Neural Network Technology; Neural Networks; Digital Signal Processing and Neural Networks; Application of Neural Networks to In-Core Fuel Management; Neural Networks in Process Control; Neural Network Applications in Image Processing; Neural Networks for Multi-Sensor Information Fusion; Neural Network Research in Instruments Controls Division; Neural Networks Research in the ORNL Engineering Physics and Mathematics Division; Neural Network Applications for Linear Programming; Neural Network Applications to Signal Processing and Diagnostics; Neural Networks in Filtering and Control; Neural Network Research at Tennessee Technological University; and Global Minima within the Hopfield Hypercube.

  15. Acetylcholine receptors from human muscle as pharmacological targets for ALS therapy

    PubMed Central

    Palma, Eleonora; Reyes-Ruiz, Jorge Mauricio; Lopergolo, Diego; Roseti, Cristina; Bertollini, Cristina; Ruffolo, Gabriele; Cifelli, Pierangelo; Onesti, Emanuela; Limatola, Cristina; Miledi, Ricardo; Inghilleri, Maurizio

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons that leads to progressive paralysis of skeletal muscle. Studies of ALS have revealed defects in expression of acetylcholine receptors (AChRs) in skeletal muscle that occur even in the absence of motor neuron anomalies. The endocannabinoid palmitoylethanolamide (PEA) modified the clinical conditions in one ALS patient, improving muscle force and respiratory efficacy. By microtransplanting muscle membranes from selected ALS patients into Xenopus oocytes, we show that PEA reduces the desensitization of acetylcholine-evoked currents after repetitive neurotransmitter application (i.e., rundown). The same effect was observed using muscle samples from denervated (non-ALS) control patients. The expression of human recombinant α1β1γδ (γ-AChRs) and α1β1εδ AChRs (ε-AChRs) in Xenopus oocytes revealed that PEA selectively affected the rundown of ACh currents in ε-AChRs. A clear up-regulation of the α1 subunit in muscle from ALS patients compared with that from non-ALS patients was found by quantitative PCR, but no differential expression was found for other subunits. Clinically, ALS patients treated with PEA showed a lower decrease in their forced vital capacity (FVC) over time as compared with untreated ALS patients, suggesting that PEA can enhance pulmonary function in ALS. In the present work, data were collected from a cohort of 76 ALS patients and 17 denervated patients. Our results strengthen the evidence for the role of skeletal muscle in ALS pathogenesis and pave the way for the development of new drugs to hamper the clinical effects of the disease. PMID:26929355

  16. Critical metabolic roles of β-cell M3 muscarinic acetylcholine receptors

    PubMed Central

    de Azua, Inigo Ruiz; Gautam, Dinesh; Jain, Shalini; Guettier, Jean-Marc; Wess, Jürgen

    2013-01-01

    Muscarinic acetylcholine (ACh) receptors (mAChRs; M1–M5) regulate the activity of an extraordinarily large number of important physiological processes. We and others previously demonstrated that pancreatic β-cells are endowed with M3 mAChRs which are linked to G proteins of the Gq family. The activation of these receptors by ACh or other muscarinic agonists leads to the augmentation of glucose-induced insulin release via multiple mechanisms. Interestingly, in humans, ACh acting on human β-cell mAChRs is released from adjacent α-cells which express both choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (vAChT), indicative of the presence of a non-neuronal cholinergic system in human pancreatic islets. In order to shed light on the physiological roles of β-cell M3 receptors, we recently generated and analyzed various mutant mouse models. Specifically, we carried out studies with mice which overexpressed M3 receptors or mutant M3 receptors in pancreatic β-cells or which selectively lacked M3 receptors or M3-receptor-associated proteins in pancreatic β-cells. Our findings indicate that β-cell M3 receptors play a key role in maintaining proper insulin release and whole body glucose homeostasis and that strategies aimed at enhancing signaling through β-cell M3 receptors may prove useful to improve β-cell function for the treatment of type 2 diabetes (T2D). PMID:22525375

  17. Impact of acetylcholine and nicotine on human osteoclastogenesis in vitro.

    PubMed

    Ternes, Sebastian; Trinkaus, Katja; Bergen, Ivonne; Knaack, Sven; Gelinsky, Michael; Kilian, Olaf; Heiss, Christian; Lips, Katrin Susanne

    2015-11-01

    Recent studies showed that the non-neuronal cholinergic system (NNCS) is taking part in bone metabolism. Most studies investigated its role in osteoblasts, but up to now, the involvement of the NNCS in human osteoclastogenesis remains relatively unclear. Thus, aim of the present study was to determine whether the application of acetylcholine (ACh, 10(−4) M), nicotine (10(−6) M), mineralized collagen membranes or brain derived neurotrophic factor (BDNF, 40 ng/mL) influences the mRNA regulation of molecular components of the NNCS and the neurotrophin family during osteoclastogenesis. Peripheral blood mononuclear cells (PBMCs) were isolated from the blood of young healthy donors (n = 8) and incubated with bone fragments and osteoclast differentiation media for 21 days. All the results are based on the measurement of RNA. Real-time RT-PCR analysis demonstrated a down-regulation of nicotinic acetylcholine receptor (nAChR) subunit α2 and muscarinic acetylcholine receptor (mAChR) M3by osteoclastogenesis while BDNF mRNA expression was not regulated. Application of ACh, nicotine, BDNF or collagen membranes did not affect osteoclastic differentiation.No regulation was detected for nAChR subunit α7, tropomyosin-related kinase receptor B (TrkB), and cholineacetyl transferase (ChAT). Taken together, we assume that the transcriptional level of osteoclastogenesis of healthy young humans is not regulated by BDNF, ACh, and nicotine. Thus, these drugs do not seem to worsen bone degradation and might therefore be suitable as modulators of bone substitution materials if having a positive effect on bone formation.

  18. Role for acetylcholine in mediating effects of light on reproduction.

    PubMed

    Earnest, D J; Turek, F W

    1983-01-01

    The length of day, or photoperiod, regulates the annual cycle of reproductive activity in the golden hamster. The inhibitory effects of a short-day photoperiod on testicular function were prevented by nighttime, but not daytime, intraventricular injections of carbachol, a cholinergic agonist. Short pulses of light during the night also block short-day induced testicular regression. The findings suggest that acetylcholine may play an important role in the mechanism through which information about the light-dark environment is transferred to the hypothalamic-pituitary-gonadal axis.

  19. Polyethylene glycol-based homologated ligands for nicotinic acetylcholine receptors☆

    PubMed Central

    Scates, Bradley A.; Lashbrook, Bethany L.; Chastain, Benjamin C.; Tominaga, Kaoru; Elliott, Brandon T.; Theising, Nicholas J.; Baker, Thomas A.; Fitch, Richard W.

    2010-01-01

    A homologous series of polyethylene glycol (PEG) monomethyl ethers were conjugated with three ligand series for nicotinic acetylcholine receptors. Conjugates of acetylaminocholine, the cyclic analog 1-acetyl-4,4-dimethylpiperazinium, and pyridyl ether A-84543 were prepared. Each series was found to retain significant affinity at nicotinic receptors in rat cerebral cortex with tethers of up to six PEG units. Such compounds are hydrophilic ligands which may serve as models for fluorescent/affinity probes and multivalent ligands for nAChR. PMID:19006672

  20. Neuromuscular block after intra-arterially injected acetylcholine

    PubMed Central

    Pinelli, P.; Tonali, P.; Gambi, D.

    1973-01-01

    It has been suggested that the effect of ACTH in myasthenia gravis may be ascribed to an action involving neuromuscular transmission which favours repolarization processes, with a tendency towards hyperpolarization of the membranes of muscle fibres and motor nerve endings. A similar mechanism has been postulated for the action of ACTH in epilepsy (Klein, 1970). A direct or indirect action on nerve membrane would interfere with depolarization. There is evidence of raised concentration of intracellular potassium and increased outflow of sodium ions which would cause hyperpolarization of the membrane. This paper studies the effect of ACTH on the late block of neuromuscular transmission caused by acetylcholine (ACTH). Images PMID:4350704

  1. alpha-1 Adrenergic receptors stimulation induces the proliferation of neural progenitor cells in vitro.

    PubMed

    Hiramoto, Takeshi; Ihara, Yoshiaki; Watanabe, Yasuhiro

    2006-11-01

    The proliferation of neural progenitor cells (NPCs) is regulated by classical neurotransmitters such as dopamine, serotonin and acetylcholine, via its own receptors. Previous studies have reported that the depletion of L-norepinephrine decreases the proliferation of NPCs in the adult rat hippocampus and it has been suggested that L-norepinephrine regulates the proliferation of NPCs. However, it remains unknown whether or not adrenergic receptors are involved in the increased proliferation of NPCs. In the present study, an MTT cell proliferation assay was carried out in order to investigate the roles played by adrenergic receptors in the proliferation of NPCs. We demonstrated that L-epinephrine enhanced the proliferation of embryonic NPCs in vitro. In addition, the alpha-1 adrenergic receptor agonist L-phenylephrine was found to enhance the proliferation of NPCs, whereas an alpha-adrenergic antagonist and selective alpha-1 antagonists significantly inhibited cell proliferation increases induced by L-epinephrine and L-phenylephrine. These results suggest that stimulation with alpha-1 adrenergic receptors induces the proliferation of embryonic NPCs.

  2. Neural effects of acute nicotinic treatment on visual spatial attention in non-smokers.

    PubMed

    Shah, Dhrasti; Impey, Danielle; Chique-Alfonzo, Mario; Fisher, Derek; Lorenzo-López, Laura; Knott, Verner

    2011-12-01

    Enhanced cortical cholinergic signaling associated with nicotinic acetylcholine receptor (nAChR) stimulation has been linked with pro-cognitive actions in a variety of performance domains, including attentional tasks. Improvements in stimulus selection with the nAChR agonist nicotine have been reported but its effects on visual spatial selective attention are unclear. Employing a double-blind, placebo-controlled design, this study examined the acute actions of nicotine (6 mg) in 24 non-smokers performing a visual search task of spatial attention that was probed with behavioral performance measures and the N2pc component of the event-related potentials (ERPs), which served as a neural index of spatial attentional selection. Nicotine did not affect behavioral performance indices. In high symptomatic subjects (as indexed by greater increases in heart rate post-administration), nicotine was associated with an N2pc amplitude enhancement while in low symptomatic individuals it was associated with an N2pc difference amplitude decrease. Nicotine modulation of the ERP marker of spatial attentional selection corroborates in general the attentional effects of nAChR agonists and extends these properties to include altered selective mechanisms during visual spatial processing.

  3. Acetylcholine and acetylcarnitine transport in peritoneum: Role of the SLC22A4 (OCTN1) transporter.

    PubMed

    Pochini, Lorena; Scalise, Mariafrancesca; Di Silvestre, Sara; Belviso, Stefania; Pandolfi, Assunta; Arduini, Arduino; Bonomini, Mario; Indiveri, Cesare

    2016-04-01

    A suitable experimental tool based on proteoliposomes for assaying Organic Cation Transporter Novel member 1 (OCTN1) of peritoneum was pointed out. OCTN1, recently acknowledged as acetylcholine transporter, was immunodetected in rat peritoneum. Transport was assayed following flux of radiolabelled TEA, acetylcholine or acetylcarnitine in proteoliposomes reconstituted with peritoneum extract. OCTN1 mediated, besides TEA, also acetylcholine and a slower acetylcarnitine transport. External sodium inhibited acetylcholine uptake but not its release from proteoliposomes. Differently, sodium did not affect acetylcarnitine uptake. These results suggested that physiologically, acetylcholine should be released while acetylcarnitine was taken up by peritoneum cells. Transport was impaired by OCTN1 inhibitors, butyrobetaine, spermine, and choline. Biotin was also found as acetylcholine transport inhibitor. Anti-OCTN1 antibody specifically inhibited acetylcholine transport confirming the involvement of OCTN1. The transporter was also immunodetected in human mesothelial primary cells. Extract from these cells was reconstituted in proteoliposomes. Transport features very similar to those found with rat peritoneum were observed. Validation of the proteoliposome model for peritoneal transport study was then achieved assaying transport in intact mesothelial cells. TEA, butyrobetaine and Na(+) inhibited acetylcholine transport in intact cells while efflux was Na(+) insensitive. Therefore transport features in intact cells overlapped those found in proteoliposomes.

  4. Identification of subunits of acetylcholine receptor that interact with a cholesterol photoaffinity probe

    SciTech Connect

    Middlemas, D.S.; Raftery, M.A.

    1987-03-10

    All four subunits of the acetylcholine receptor in membrane vesicles isolated from Torpedo californica have been labeled with (/sup 3/H)cholesteryl diazoacetate. As this probe incorporates into lipid bilayers analogously to cholesterol, this result indicates that acetylcholine receptor interacts with cholesterol. This investigation also demonstrates that this probe is a useful reagent for studying the interaction of cholesterol with membrane proteins.

  5. Influence of acetylcholine on binding of 4-[125I]iododexetimide to muscarinic brain receptors.

    PubMed

    Weckesser, M; Fixmann, A; Holschbach, M; Müller-Gärtner, H W

    1998-11-01

    The distribution of nicotinic and muscarinic cholinergic receptors in the human brain in vivo has been successfully characterized using radiolabeled tracers and emission tomography. The effect of acetylcholine release into the synaptic cleft on receptor binding of these tracers has not yet been investigated. The present study examined the influence of acetylcholine on binding of 4-[125I]iododexetimide to muscarinic cholinergic receptors of porcine brain synaptosomes in vitro. 4-Iododexetimide is a subtype-unspecific muscarinic receptor antagonist with high affinity. Acetylcholine competed with 4-[125I]iododexetimide in a dose-dependent manner. A concentration of 500 microM acetylcholine inhibited 50% of total specific 4-[125I]iododexetimide binding to synaptosomes when both substances were given simultaneously. An 800 microM acetylcholine solution reduced total specific 4-[125I]iododexetimide binding by about 35%, when acetylcholine was given 60 min after incubation of synaptosomes with 4-[125I]iododexetimide. Variations in the synaptic acetylcholine concentration might influence muscarinic cholinergic receptor imaging in vivo using 4-[123I]iododexetimide. Conversely, 4-[123I]iododexetimide might be an appropriate molecule to investigate alterations of acetylcholine release into the synaptic cleft in vivo using single photon emission computed tomography. PMID:9863566

  6. The biological role of non-neuronal acetylcholine in plants and humans.

    PubMed

    Wessler, I; Kilbinger, H; Bittinger, F; Kirkpatrick, C J

    2001-01-01

    Acetylcholine, one of the most exemplary neurotransmitters, has been detected in bacteria, algae, protozoa, tubellariae and primitive plants, suggesting an extremely early appearance in the evolutionary process and a wide expression in non-neuronal cells. In plants (Urtica dioica), acetylcholine is involved in the regulation of water resorption and photosynthesis. In humans, acetylcholine and/or the synthesizing enzyme, choline acetyltransferase, have been demonstrated in epithelial (airways, alimentary tract, urogenital tract, epidermis), mesothelial (pleura, pericardium), endothelial, muscle and immune cells (granulocytes, lymphocytes, macrophages, mast cells). The widespread expression of non-neuronal acetylcholine is accompanied by the ubiquitous expression of cholinesterase and acetylcholine sensitive receptors (nicotinic, muscarinic). Both receptor populations interact with more or less all cellular signalling pathways. Thus, non-neuronal acetylcholine can be involved in the regulation of basic cell functions like gene expression, proliferation, differentiation, cytoskeletal organization, cell-cell contact (tight and gap junctions, desmosomes), locomotion, migration, ciliary activity, electrical activity, secretion and absorption. Non-neuronal acetylcholine also plays a role in the control of unspecific and specific immune functions. Future experiments should be designed to analyze the cellular effects of acetylcholine in greater detail and to illuminate the involvement of the non-neuronal cholinergic system in the pathogenesis of diseases such as acute and chronic inflammation, local and systemic infection, dementia, atherosclerosis, and finally cancer. PMID:11243568

  7. Acetylcholine receptors and cholinergic ligands: biochemical and genetic aspects in Torpedo californica and Drosophila melanogaster

    SciTech Connect

    Rosenthal, L.S.

    1987-01-01

    This study evaluates the biochemical and genetic aspects of the acetylcholine receptor proteins and cholinergic ligands in Drosophila melanogaster and Torpedo californica. Included are (1) a comparative study of nicotinic ligand-induced cation release from acetylcholine receptors isolated from Torpedo californica and from Drosophila melanogaster, (2) solution studies of the cholinergic ligands, nikethamide and ethamivan, aimed at measuring internal molecular rotational barriers in solvents of different polarity; and (3) the isolation and characterization of the gene(s) for the acetylcholine receptor in Drosophila melasogaster. Acetylcholine receptor proteins isolated from Drosphila melanogaster heads were found to behave kinetically similar (with regards to cholinergic ligand-induced /sup 155/Eu:/sup 3 +/ displacement from prelabeled proteins) to receptor proteins isolated from Torpedo californica electric tissue, providing additional biochemical evidence for the existence of a Drosophila acetylcholine receptor.

  8. Effects of intracoronary infusions of acetylcholine and nicotine on the dog heart in vivo.

    PubMed

    Ross, G

    1973-08-01

    1. In anaesthetized dogs intracoronary infusions of high doses of nicotine and acetylcholine increased myocardial contractile force and this could be prevented by pre-treatment with desmethylimipramine or phenoxybenzamine.2. The inotropic effect of nicotine was brief and subsided during the continuing infusion of the drug. The infusion of nicotine did not reduce the inotropic effects of cardiac sympathetic nerve stimulation.3. The motropic effect of intracoronary acetylcholine often fluctuated during prolonged infusions and was not altered by pretreatment with atropine. Acetylcholine infusions reduced the inotropic responses produced by cardiac sympathetic nerve stimulation and led to a substantial transient reduction in the associated pressor responses. Intracoronary acetylcholine also reduced the pressor and inotropic effect of intravenous noradrenaline. The attenuation of these adrenergic cardiovascular responses by acetylcholine was prevented by atropine.

  9. Organophosphate acetylcholine esterase inhibitor poisoning from a home-made shampoo.

    PubMed

    Sadaka, Yair; Broides, Arnon; Tzion, Raffi Lev; Lifshitz, Matitiahu

    2011-07-01

    Organophosphate acetylcholine esterase inhibitor poisoning is a major health problem in children. We report an unusual cause of organophosphate acetylcholine esterase inhibitor poisoning. Two children were admitted to the pediatric intensive care unit due to organophosphate acetylcholine esterase inhibitor poisoning after exposure from a home-made shampoo that was used for the treatment of head lice. Owing to no obvious source of poisoning, the diagnosis of organophosphate acetylcholine esterase inhibitor poisoning in one of these patients was delayed. Both patients had an uneventful recovery. Organophosphate acetylcholine esterase inhibitor poisoning from home-made shampoo is possible. In cases where the mode of poisoning is unclear, direct questioning about the use of home-made shampoo is warranted, in these cases the skin and particularly the scalp should be rinsed thoroughly as soon as possible.

  10. Organophosphate acetylcholine esterase inhibitor poisoning from a home-made shampoo

    PubMed Central

    Sadaka, Yair; Broides, Arnon; Tzion, Raffi Lev; Lifshitz, Matitiahu

    2011-01-01

    Organophosphate acetylcholine esterase inhibitor poisoning is a major health problem in children. We report an unusual cause of organophosphate acetylcholine esterase inhibitor poisoning. Two children were admitted to the pediatric intensive care unit due to organophosphate acetylcholine esterase inhibitor poisoning after exposure from a home-made shampoo that was used for the treatment of head lice. Owing to no obvious source of poisoning, the diagnosis of organophosphate acetylcholine esterase inhibitor poisoning in one of these patients was delayed. Both patients had an uneventful recovery. Organophosphate acetylcholine esterase inhibitor poisoning from home-made shampoo is possible. In cases where the mode of poisoning is unclear, direct questioning about the use of home-made shampoo is warranted, in these cases the skin and particularly the scalp should be rinsed thoroughly as soon as possible. PMID:21887044

  11. Autocrine control of angiogenesis by endogenous acetylcholine in an in vitro model using human endothelial cells: evidence for an autocrine cholinergic system in endothelial cells.

    PubMed

    Dhein, Stefan; Wermke, Alice; von Salisch, Sandy; Schlegel, Franziska; Stepan, Holger; Dohmen, Pascal Maria; Kostelka, Martin; Mohr, Friedrich-Wilhelm

    2015-05-01

    We wanted to elucidate whether acetylcholine as the endogenous ligand at cholinoceptors (ChRs) may have effects on angiogenesis and whether they are transduced through muscarinic or nicotinic ChRs. Human umbilical vein endothelial cells were cultured until confluence and thereafter seeded in Matrigel in vitro angiogenesis assays for 18 hours. During the entire cell culture and angiogenesis period, cells were treated with vehicle, eserine (1 μM), in the absence or presence of additional atropine (1 μM) or mecamylamine (1 μM). Finally, the resulting angiogenetic network was investigated histologically. Eserine significantly enhanced acetylcholine formation. When acetylcholine acted through muscarinic ChRs (eserine + mecamylamine), we observed enhanced complexity of the angiogenic network pattern with increased tube length and cell number. In contrast, when acting through nicotinic ChRs (eserine + atropine), we found reduced complexity of pattern with less branches, shorter tubes, and reduced cell number. If acting on both types of ChRs (eserine alone), there were only very small effects. Using α-bungarotoxin, lobeline, and dihydro-β-erythroidine, we also could show that these effects to various degrees involve α7, α3/β2, and α4/β2 n-ChRs. In conclusion, our results support the hypothesis that human umbilical vein endothelial cells possess an autocrine nonneuronal cholinergic system regulating angiogenesic branch formation through the partially opposing effects of n-ChRs and m-ChRs.

  12. Expression of cloned α6* nicotinic acetylcholine receptors.

    PubMed

    Wang, Jingyi; Kuryatov, Alexander; Lindstrom, Jon

    2015-09-01

    Nicotinic acetylcholine receptors (AChRs) are ACh-gated ion channels formed from five homologous subunits in subtypes defined by their subunit composition and stoichiometry. Some subtypes readily produce functional AChRs in Xenopus oocytes and transfected cell lines. α6β2β3* AChRs (subtypes formed from these subunits and perhaps others) are not easily expressed. This may be because the types of neurons in which they are expressed (typically dopaminergic neurons) have unique chaperones for assembling α6β2β3* AChRs, especially in the presence of the other AChR subtypes. Because these relatively minor brain AChR subtypes are of major importance in addiction to nicotine, it is important for drug development as well as investigation of their functional properties to be able to efficiently express human α6β2β3* AChRs. We review the issues and progress in expressing α6* AChRs. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.

  13. Corelease of acetylcholine and GABA from cholinergic forebrain neurons

    PubMed Central

    Saunders, Arpiar; Granger, Adam J; Sabatini, Bernardo L

    2015-01-01

    Neurotransmitter corelease is emerging as a common theme of central neuromodulatory systems. Though corelease of glutamate or GABA with acetylcholine has been reported within the cholinergic system, the full extent is unknown. To explore synaptic signaling of cholinergic forebrain neurons, we activated choline acetyltransferase expressing neurons using channelrhodopsin while recording post-synaptic currents (PSCs) in layer 1 interneurons. Surprisingly, we observed PSCs mediated by GABAA receptors in addition to nicotinic acetylcholine receptors. Based on PSC latency and pharmacological sensitivity, our results suggest monosynaptic release of both GABA and ACh. Anatomical analysis showed that forebrain cholinergic neurons express the GABA synthetic enzyme Gad2 and the vesicular GABA transporter (Slc32a1). We confirmed the direct release of GABA by knocking out Slc32a1 from cholinergic neurons. Our results identify GABA as an overlooked fast neurotransmitter utilized throughout the forebrain cholinergic system. GABA/ACh corelease may have major implications for modulation of cortical function by cholinergic neurons. DOI: http://dx.doi.org/10.7554/eLife.06412.001 PMID:25723967

  14. Caenorhabditis elegans nicotinic acetylcholine receptors are required for nociception

    PubMed Central

    Cohen, Emiliano; Chatzigeorgiou, Marios; Husson, Steven J.; Steuer-Costa, Wagner; Gottschalk, Alexander; Schafer, William R.; Treinin, Millet

    2014-01-01

    Polymodal nociceptors sense and integrate information on injurious mechanical, thermal, and chemical stimuli. Chemical signals either activate nociceptors or modulate their responses to other stimuli. One chemical known to activate or modulate responses of nociceptors is acetylcholine (ACh). Across evolution nociceptors express subunits of the nicotinic acetylcholine receptor (nAChR) family, a family of ACh-gated ion channels. The roles of ACh and nAChRs in nociceptor function are, however, poorly understood. Caenorhabditis elegans polymodal nociceptors, PVD, express nAChR subunits on their sensory arbor. Here we show that mutations reducing ACh synthesis and mutations in nAChR subunits lead to defects in PVD function and morphology. A likely cause for these defects is a reduction in cytosolic calcium measured in ACh and nAChR mutants. Indeed, overexpression of a calcium pump in PVD mimics defects in PVD function and morphology found in nAChR mutants. Our results demonstrate, for the first time, a central role for nAChRs and ACh in nociceptor function and suggest that calcium permeating via nAChRs facilitates activity of several signaling pathways within this neuron. PMID:24518198

  15. Fluorescent staining of acetylcholine receptors in vertebrate skeletal muscle

    PubMed Central

    Anderson, M. J.; Cohen, M. W.

    1974-01-01

    1. α-Bungarotoxin was labelled with fluorescent dyes and used as a stain for visualizing the distribution of acetylcholine receptors in vertebrate skeletal muscle fibres. 2. Dye-toxin conjugates had the same pharmacological properties as native toxin, but their potencies were lower. 3. Fluorescent staining was examined in teased muscle fibres. The stain was found to be confined to the neuromuscular junction and associated with the subsynaptic membrane. 4. Staining intensity was reduced by curare and even more so by carbachol, but not by atropine or neostigmine. Pre-treatment of muscles with unlabelled α-bungarotoxin entirely prevented staining. 5. The staining at amphibian neuromuscular junctions was characterized by a pattern of intense transverse bands occurring at intervals of approximately 0·5-1 μm, with fluorescence of lower intensity between them. Fluorescent staining was not detected on adjacent, extrasynaptic, muscle membrane. In side views the staining appeared as a fine line with small protuberances occurring at the same intervals as the intense bands seen face-on. These results indicate that acetylcholine receptors are associated with the entire subsynaptic membrane, including the membrane of the junctional folds and that their density changes abruptly at the border between synaptic and extrasynaptic muscle membrane. ImagesPlate 3Plate 4Plate 1Plate 2 PMID:4133039

  16. END-PLATE ACETYLCHOLINE RECEPTOR: STRUCTURE, MECHANISM, PHARMACOLOGY, AND DISEASE

    PubMed Central

    Sine, Steven M.

    2012-01-01

    The synapse is a localized neurohumoral contact between a neuron and an effector cell and may be considered the quantum of fast intercellular communication. Analogously, the postsynaptic neurotransmitter receptor may be considered the quantum of fast chemical to electrical transduction. Our understanding of postsynaptic receptors began to develop about a hundred years ago with the demonstration that electrical stimulation of the vagus nerve released acetylcholine and slowed the heart beat. During the past 50 years, advances in understanding postsynaptic receptors increased at a rapid pace, owing largely to studies of the acetylcholine receptor (AChR) at the motor endplate. The endplate AChR belongs to a large superfamily of neurotransmitter receptors, called Cys-loop receptors, and has served as an exemplar receptor for probing fundamental structures and mechanisms that underlie fast synaptic transmission in the central and peripheral nervous systems. Recent studies provide an increasingly detailed picture of the structure of the AChR and the symphony of molecular motions that underpin its remarkably fast and efficient chemoelectrical transduction. PMID:22811427

  17. Purification of muscarinic acetylcholine receptors by affinity chromatography.

    PubMed Central

    André, C; De Backer, J P; Guillet, J C; Vanderheyden, P; Vauquelin, G; Strosberg, A D

    1983-01-01

    Calf forebrain homogenates contain 2.8 pM muscarinic acetylcholine receptors per mg of protein. [3H]Antagonist saturation binding experiments under equilibrium conditions revealed a single class of sites with equilibrium dissociation constants of 0.82 nM for [3H]dexetimide and 0.095 nM for [3H]quinuclidinyl benzilate. Displacement binding studies with agonists revealed the presence of low and high affinity sites. Here we describe the solubilization of muscarinic acetylcholine receptors with digitonin and their purification by affinity chromatography using an affinity gel which consisted of dexetimide coupled to Affi-Gel 10 (i.e., carboxy N-hydroxysuccinimide esters linked via a 1 nm spacer arm to agarose beads). Purified proteins were obtained by specific elution with muscarinic drugs, i.e., the antagonist atropine and the irreversible ligand propylbenzilylcholine mustard. SDS-polyacrylamide gel electrophoresis of the radioiodinated purified preparations revealed a major 70-K protein. Images Fig. 3. PMID:6605245

  18. Molecular modeling of human pentameric alpha(7) neuronal nicotinic acetylcholine receptor and its interaction with its agonist and competitive antagonist.

    PubMed

    Parthiban, Marimuthu; Rajasekaran, Mohan Babu; Ramakumar, Suryanarayanarao; Shanmughavel, Piramanayagam

    2009-04-01

    The nicotinic Acetylcholine Receptor (nAChR) is the major class of neurotransmitter receptors that is involved in many neurodegenerative conditions such as schizophrenia, Alzheimer's and Parkinson's diseases. The N-terminal region or Ligand Binding Domain (LBD) of nAChR is located at pre- and post-synaptic nervous system, which mediates synaptic transmission. nAChR acts as the drug target for agonist and competitive antagonist molecules that modulate signal transmission at the nerve terminals. Based on Acetylcholine Binding Protein (AChBP) from Lymnea stagnalis as the structural template, the homology modeling approach was carried out to build three dimensional model of the N-terminal region of human alpha(7)nAChR. This theoretical model is an assembly of five alpha(7) subunits with 5 fold axis symmetry, constituting a channel, with the binding pocket present at the interface region of the subunits. alpha-neurotoxin is a potent nAChR competitive antagonist that readily blocks the channel resulting in paralysis. The molecular interaction of alpha-Bungarotoxin, a long chain alpha-neurotoxin from (Bungarus multicinctus) and human alpha(7)nAChR was studied. Agonists such as acetylcholine, nicotine, which are used in a diverse array of biological activities, such as enhancements of cognitive performances, were also docked with the theoretical model of human alpha(7)nAChR. These docked complexes were analyzed further for identifying the crucial residues involved in interaction. These results provide the details of interaction of agonists and competitive antagonists with three dimensional model of the N-terminal region of human alpha(7)nAChR and thereby point to the design of novel lead compounds.

  19. Evolvable synthetic neural system

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  20. Neural Networks

    SciTech Connect

    Smith, Patrick I.

    2003-09-23

    Physicists use large detectors to measure particles created in high-energy collisions at particle accelerators. These detectors typically produce signals indicating either where ionization occurs along the path of the particle, or where energy is deposited by the particle. The data produced by these signals is fed into pattern recognition programs to try to identify what particles were produced, and to measure the energy and direction of these particles. Ideally, there are many techniques used in this pattern recognition software. One technique, neural networks, is particularly suitable for identifying what type of particle caused by a set of energy deposits. Neural networks can derive meaning from complicated or imprecise data, extract patterns, and detect trends that are too complex to be noticed by either humans or other computer related processes. To assist in the advancement of this technology, Physicists use a tool kit to experiment with several neural network techniques. The goal of this research is interface a neural network tool kit into Java Analysis Studio (JAS3), an application that allows data to be analyzed from any experiment. As the final result, a physicist will have the ability to train, test, and implement a neural network with the desired output while using JAS3 to analyze the results or output. Before an implementation of a neural network can take place, a firm understanding of what a neural network is and how it works is beneficial. A neural network is an artificial representation of the human brain that tries to simulate the learning process [5]. It is also important to think of the word artificial in that definition as computer programs that use calculations during the learning process. In short, a neural network learns by representative examples. Perhaps the easiest way to describe the way neural networks learn is to explain how the human brain functions. The human brain contains billions of neural cells that are responsible for processing

  1. Sharpened cortical tuning and enhanced cortico-cortical communication contribute to the long-term neural mechanisms of visual motion perceptual learning.

    PubMed

    Chen, Nihong; Bi, Taiyong; Zhou, Tiangang; Li, Sheng; Liu, Zili; Fang, Fang

    2015-07-15

    Much has been debated about whether the neural plasticity mediating perceptual learning takes place at the sensory or decision-making stage in the brain. To investigate this, we trained human subjects in a visual motion direction discrimination task. Behavioral performance and BOLD signals were measured before, immediately after, and two weeks after training. Parallel to subjects' long-lasting behavioral improvement, the neural selectivity in V3A and the effective connectivity from V3A to IPS (intraparietal sulcus, a motion decision-making area) exhibited a persistent increase for the trained direction. Moreover, the improvement was well explained by a linear combination of the selectivity and connectivity increases. These findings suggest that the long-term neural mechanisms of motion perceptual learning are implemented by sharpening cortical tuning to trained stimuli at the sensory processing stage, as well as by optimizing the connections between sensory and decision-making areas in the brain.

  2. Transcription of a zebrafish gene of the hairy-Enhancer of split family delineates the midbrain anlage in the neural plate.

    PubMed

    Müller, M; von Weizsäcker, E; Campos-Ortega, J A

    1996-09-01

    her5 encodes a basic helix-loop-helix (bHLH) protein with all features characteristic of the Drosophila hairy-E(spl) family. her5 is expressed in a band of cells within the neural anlage from about 90% epiboly on to at least 36 h postfertilization (hpf). After completion of brain morphogenesis, her5-expressing cells are located in the caudal region of the midbrain, at the boundary with the rhombencephalon. Labelling of cells within the her5 expression domain in the neural plate by injection of fluorescein-dextran allows their labelled progeny to be localized in the 36-hpf-old embryo using an anti-fluorescein antibody. This shows that the her5 expression domain corresponds to the midbrain primordium, including both the tectum and the tegmentum, in the neural plate. A possible function for her5 in regionalization of the brain and/or control of the midbrain-hindbrain boundary is discussed.

  3. Morphogenic role for acetylcholinesterase in axonal outgrowth during neural development.

    PubMed Central

    Bigbee, J W; Sharma, K V; Gupta, J J; Dupree, J L

    1999-01-01

    Acetylcholinesterase (AChE) is the enzyme that hydrolyzes the neurotransmitter acetylcholine at cholinergic synapses and neuromuscular junctions. However, results from our laboratory and others indicate that AChE has an extrasynaptic, noncholinergic role during neural development. This article is a review of our findings demonstrating the morphogenic role of AChE, using a neuronal cell culture model. We also discuss how these data suggest that AChE has a cell adhesive function during neural development. These results could have additional significance as AChE is the target enzyme of agricultural organophosphate and carbamate pesticides as well as the commonly used household organophosphate chlorpyrifos (Dursban). Prenatal exposure to these agents could have adverse effects on neural development by interfering with the morphogenic function of AChE. Images Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 PMID:10229710

  4. Impairment of bidirectional synaptic plasticity in the striatum of a mouse model of DYT1 dystonia: role of endogenous acetylcholine

    PubMed Central

    Martella, Giuseppina; Tassone, Annalisa; Sciamanna, Giuseppe; Platania, Paola; Cuomo, Dario; Viscomi, Maria Teresa; Bonsi, Paola; Cacci, Emanuele; Biagioni, Stefano; Usiello, Alessandro; Bernardi, Giorgio; Sharma, Nutan

    2009-01-01

    DYT1 dystonia is a severe form of inherited dystonia, characterized by involuntary twisting movements and abnormal postures. It is linked to a deletion in the dyt1 gene, resulting in a mutated form of the protein torsinA. The penetrance for dystonia is incomplete, but both clinically affected and non-manifesting carriers of the DYT1 mutation exhibit impaired motor learning and evidence of altered motor plasticity. Here, we characterized striatal glutamatergic synaptic plasticity in transgenic mice expressing either the normal human torsinA or its mutant form, in comparison to non-transgenic (NT) control mice. Medium spiny neurons recorded from both NT and normal human torsinA mice exhibited normal long-term depression (LTD), whereas in mutant human torsinA littermates LTD could not be elicited. In addition, although long-term potentiation (LTP) could be induced in all the mice, it was greater in magnitude in mutant human torsinA mice. Low-frequency stimulation (LFS) can revert potentiated synapses to resting levels, a phenomenon termed synaptic depotentiation. LFS induced synaptic depotentiation (SD) both in NT and normal human torsinA mice, but not in mutant human torsinA mice. Since anti-cholinergic drugs are an effective medical therapeutic option for the treatment of human dystonia, we reasoned that an excess in endogenous acetylcholine could underlie the synaptic plasticity impairment. Indeed, both LTD and SD were rescued in mutant human torsinA mice either by lowering endogenous acetylcholine levels or by antagonizing muscarinic M1 receptors. The presence of an enhanced acetylcholine tone was confirmed by the observation that acetylcholinesterase activity was significantly increased in the striatum of mutant human torsinA mice, as compared with both normal human torsinA and NT littermates. Moreover, we found similar alterations of synaptic plasticity in muscarinic M2/M4 receptor knockout mice, in which an increased striatal acetylcholine level has been

  5. Impairment of bidirectional synaptic plasticity in the striatum of a mouse model of DYT1 dystonia: role of endogenous acetylcholine.

    PubMed

    Martella, Giuseppina; Tassone, Annalisa; Sciamanna, Giuseppe; Platania, Paola; Cuomo, Dario; Viscomi, Maria Teresa; Bonsi, Paola; Cacci, Emanuele; Biagioni, Stefano; Usiello, Alessandro; Bernardi, Giorgio; Sharma, Nutan; Standaert, David G; Pisani, Antonio

    2009-09-01

    DYT1 dystonia is a severe form of inherited dystonia, characterized by involuntary twisting movements and abnormal postures. It is linked to a deletion in the dyt1 gene, resulting in a mutated form of the protein torsinA. The penetrance for dystonia is incomplete, but both clinically affected and non-manifesting carriers of the DYT1 mutation exhibit impaired motor learning and evidence of altered motor plasticity. Here, we characterized striatal glutamatergic synaptic plasticity in transgenic mice expressing either the normal human torsinA or its mutant form, in comparison to non-transgenic (NT) control mice. Medium spiny neurons recorded from both NT and normal human torsinA mice exhibited normal long-term depression (LTD), whereas in mutant human torsinA littermates LTD could not be elicited. In addition, although long-term potentiation (LTP) could be induced in all the mice, it was greater in magnitude in mutant human torsinA mice. Low-frequency stimulation (LFS) can revert potentiated synapses to resting levels, a phenomenon termed synaptic depotentiation. LFS induced synaptic depotentiation (SD) both in NT and normal human torsinA mice, but not in mutant human torsinA mice. Since anti-cholinergic drugs are an effective medical therapeutic option for the treatment of human dystonia, we reasoned that an excess in endogenous acetylcholine could underlie the synaptic plasticity impairment. Indeed, both LTD and SD were rescued in mutant human torsinA mice either by lowering endogenous acetylcholine levels or by antagonizing muscarinic M1 receptors. The presence of an enhanced acetylcholine tone was confirmed by the observation that acetylcholinesterase activity was significantly increased in the striatum of mutant human torsinA mice, as compared with both normal human torsinA and NT littermates. Moreover, we found similar alterations of synaptic plasticity in muscarinic M2/M4 receptor knockout mice, in which an increased striatal acetylcholine level has been

  6. Acetylcholine promotes the emergence and elongation of lateral roots of Raphanus sativus.

    PubMed

    Sugiyama, Kou-ichi; Tezuka, Takafumi

    2011-10-01

    Radish (Raphanus sativus L.) was grown on four layers of paper towel moistened with distilled water with and without acetylcholine (ACh) for five days in the dark after sowing. ACh at 1 nM promoted the growth (emergence and elongation) of lateral roots of radish plants, but had no effect on the stems and main roots. Moreover, ACh enhanced the dry weight of roots [main (primary) + lateral roots]. Neostigmine, an inhibitor of acetylcholinesterase (AChE) also promoted the emergence and elongation of lateral roots, and atropine, a competitive inhibitor of ACh receptor, suppressed the emergence and elongation. ACh suppressed the activity of AChE and increased the amount of proteins and pyridine nucleotides (NAD and NADH) in the roots of the seedlings. It also increased the activities of NAD-forming enzymes [NAD synthetase and ATP-nicotinamide mononucleotide (ATP-NMN) adenyltransferase], and enhanced the amount of DNA in the roots of the seedlings. The relationship between ACh and the emergence and growth of lateral roots was discussed from a biochemical viewpoint.

  7. Acetylcholine promotes the emergence and elongation of lateral roots of Raphanus sativus.

    PubMed

    Sugiyama, Kou-ichi; Tezuka, Takafumi

    2011-10-01

    Radish (Raphanus sativus L.) was grown on four layers of paper towel moistened with distilled water with and without acetylcholine (ACh) for five days in the dark after sowing. ACh at 1 nM promoted the growth (emergence and elongation) of lateral roots of radish plants, but had no effect on the stems and main roots. Moreover, ACh enhanced the dry weight of roots [main (primary) + lateral roots]. Neostigmine, an inhibitor of acetylcholinesterase (AChE) also promoted the emergence and elongation of lateral roots, and atropine, a competitive inhibitor of ACh receptor, suppressed the emergence and elongation. ACh suppressed the activity of AChE and increased the amount of proteins and pyridine nucleotides (NAD and NADH) in the roots of the seedlings. It also increased the activities of NAD-forming enzymes [NAD synthetase and ATP-nicotinamide mononucleotide (ATP-NMN) adenyltransferase], and enhanced the amount of DNA in the roots of the seedlings. The relationship between ACh and the emergence and growth of lateral roots was discussed from a biochemical viewpoint. PMID:21900743

  8. Modulation of acetylcholine release from rat striatal slices by the GABA/benzodiazepine receptor complex

    SciTech Connect

    Supavilai, P.; Karobath, M.

    1985-02-04

    GABA, THIP and muscimol enhance spontaneous and inhibit electrically induced release of tritium labelled compounds from rat striatal slices which have been pre-labelled with /sup 3/H-choline. Baclofen is inactive in this model. Muscimol can inhibit electrically induced release of tritiated material by approximately 75% with half maximal effects at 2 ..mu..M. The response to muscimol can be blocked by the GABA antagonists bicuculline methobromide, picrotoxin, anisatin, R 5135 and CPTBO (cyclopentylbicyclophosphate). Drugs which act on the benzodiazepine receptor (BR) require the presence of muscimol to be effective and they modulate the effects of muscimol in a bidirectional manner. Thus BR agonists enhance and inverse BR agonists attenuate the inhibitory effects of muscimol on electrically induced release. Ro15-1788, a BR antagonist, does not modulate the inhibitory effects of muscimol but antagonizes the actions of clonazepam, a BR agonist, and of DMCM, an inverse BR agonist. These results demonstrate that a GABA/benzodiazepine receptor complex can modulate acetylcholine release from rat striatal slices in vitro. 24 references, 3 figures, 5 table.

  9. Sex differences in acetylcholine-induced sweating responses due to physical training

    PubMed Central

    2014-01-01

    Purpose The present study examined sex differences in the sweat gland response to acetylcholine (ACh) in physically trained and untrained male and female subjects. Methods Sweating responses were induced on the forearm and thigh in resting subjects by ACh iontophoresis using a 10% solution at 2 mA for 5 min at 26°C and 50% relative humidity. Results The ACh-induced sweating rate (SR) on the forearm and thigh was greater in physically trained male (P < 0.001 for the forearm and thigh, respectively) and female (P = 0.08 for the forearm, P < 0.001 for the thigh) subjects than in untrained subjects of both sexes. The SR was also significantly greater in physically trained males compared to females at both sites (P < 0.001) and in untrained males compared to females on the thigh (P < 0.02) only, although the degree of difference was greater in trained subjects than in untrained subjects. These sex differences can be attributed to the difference in sweat output per gland rather than the number of activated sweat glands. Conclusion We conclude that physical training enhances the ACh-induced SR in both sexes but that the degree of enhancement is greater in male than in female subjects. The effects of physical training and sex on the SR may be due to changes in peripheral sensitivity to ACh and/or sweat gland size. PMID:24887294

  10. Leukemia inhibitory factor (LIF) enhances MAP2 + and HUC/D + neurons and influences neurite extension during differentiation of neural progenitors derived from human embryonic stem cells.

    EPA Science Inventory

    Leukemia Inhibitory Factor (L1F), a member of the Interleukin 6 cytokine family, has a role in differentiation of Human Neural Progenitor (hNP) cells in vitro. hNP cells, derived from Human Embryonic Stem (hES) cells, have an unlimited capacity for self-renewal in monolayer cultu...

  11. Nanoengineered Polystyrene Surfaces with Nanopore Array Pattern Alters Cytoskeleton Organization and Enhances Induction of Neural Differentiation of Human Adipose-Derived Stem Cells.

    PubMed

    Jung, Ae Ryang; Kim, Richard Y; Kim, Hyung Woo; Shrestha, Kshitiz Raj; Jeon, Seung Hwan; Cha, Kyoung Je; Park, Yong Hyun; Kim, Dong Sung; Lee, Ji Youl

    2015-07-01

    Human adipose-derived stem cells (hADSCs) can differentiate into various cell types depending on chemical and topographical cues. One topographical cue recently noted to be successful in inducing differentiation is the nanoengineered polystyrene surface containing nanopore array-patterned substrate (NP substrate), which is designed to mimic the nanoscale topographical features of the extracellular matrix. In this study, efficacies of NP and flat substrates in inducing neural differentiation of hADSCs were examined by comparing their substrate-cell adhesion rates, filopodia growth, nuclei elongation, and expression of neural-specific markers. The polystyrene nano Petri dishes containing NP substrates were fabricated by a nano injection molding process using a nickel electroformed nano-mold insert (Diameter: 200 nm. Depth of pore: 500 nm. Center-to-center distance: 500 nm). Cytoskeleton and filopodia structures were observed by scanning electron microscopy and F-actin staining, while cell adhesion was tested by vinculin staining after 24 and 48 h of seeding. Expression of neural specific markers was examined by real-time quantitative polymerase chain reaction and immunocytochemistry. Results showed that NP substrates lead to greater substrate-cell adhesion, filopodia growth, nuclei elongation, and expression of neural specific markers compared to flat substrates. These results not only show the advantages of NP substrates, but they also suggest that further study into cell-substrate interactions may yield great benefits for biomaterial engineering. PMID:25919423

  12. Prostate stem cell antigen interacts with nicotinic acetylcholine receptors and is affected in Alzheimer's disease.

    PubMed

    Jensen, Majbrit M; Arvaniti, Maria; Mikkelsen, Jens D; Michalski, Dominik; Pinborg, Lars H; Härtig, Wolfgang; Thomsen, Morten S

    2015-04-01

    Alzheimer's disease (AD) is a neurodegenerative disorder involving impaired cholinergic neurotransmission and dysregulation of nicotinic acetylcholine receptors (nAChRs). Ly-6/neurotoxin (Lynx) proteins have been shown to modulate cognition and neural plasticity by binding to nAChR subtypes and modulating their function. Hence, changes in nAChR regulatory proteins such as Lynx proteins could underlie the dysregulation of nAChRs in AD. Using Western blotting, we detected bands corresponding to the Lynx proteins prostate stem cell antigen (PSCA) and Lypd6 in human cortex indicating that both proteins are present in the human brain. We further showed that PSCA forms stable complexes with the α4 nAChR subunit and decreases nicotine-induced extracellular-signal regulated kinase phosphorylation in PC12 cells. In addition, we analyzed protein levels of PSCA and Lypd6 in postmortem tissue of medial frontal gyrus from AD patients and found significantly increased PSCA levels (approximately 70%). In contrast, no changes in Lypd6 levels were detected. In concordance with our findings in AD patients, PSCA levels were increased in the frontal cortex of triple transgenic mice with an AD-like pathology harboring human transgenes that cause both age-dependent β-amyloidosis and tauopathy, whereas Tg2576 mice, which display β-amyloidosis only, had unchanged PSCA levels compared to wild-type animals. These findings identify PSCA as a nAChR-binding protein in the human brain that is affected in AD, suggesting that PSCA-nAChR interactions may be involved in the cognitive dysfunction observed in AD. PMID:25680266

  13. [Mechanisms of contractile action of acetylcholine on hepatic veins].

    PubMed

    Ianchuk, P I; Prykhod'ko, T P; Pasichnichenko, O M; Tieriekhov, A A; Tsybenko, V O

    2011-01-01

    In acute experiments on anesthetized rats, acetylcholine (Ach) constricts hepatic venous vessels, causing blood mobilization from the liver, and dilates the sphincters of hepatic veins at the exit from this organ, contributing to the intensification of the outflow of blood deposited in the liver. Vasoconstrictor reactions of capacitive vessels of the liver to Ach are realized through M-cholinoreceptors on endotheliocytes with further involvement of messenger, possibly noradrenaline, which activates alpha-adrenoreceptors on smooth muscle cells (SMC) of capasitive vessels. Dilation of Hv sphincters is carried out due to Ach-induced release of messenger in the vessel wall, probably adrenaline, which in turn activates beta-adrenoreceptors on SMC of the Hv. It is possible, that in such reaction partially involved NO.

  14. Nicotinic acetylcholine receptor ligands; a patent review (2006-2011)

    PubMed Central

    Gündisch, Daniela; Eibl, Christoph

    2012-01-01

    Introduction Nicotinic acetylcholine receptors (nAChRs), pentameric ligand-gated cation channels, are potential targets for the development of therapeutics for a variety of disease states. Areas covered This article is reviewing recent advances in the development of small molecule ligands for diverse nAChR subtypes and is a continuation of an earlier review in this journal. Expert opinion The development of nAChR ligands with preference for α4β2 or α7 subtypes for the treatment of CNS disorders are in the most advanced developmental stage. In addition, there is a fast growing interest to generate so-called PAMs, positive allosteric modulators, to influence the channels’ functionalities. PMID:22098319

  15. Cholinergic modulation of dopamine pathways through nicotinic acetylcholine receptors.

    PubMed

    de Kloet, Sybren F; Mansvelder, Huibert D; De Vries, Taco J

    2015-10-15

    Nicotine addiction is highly prevalent in current society and is often comorbid with other diseases. In the central nervous system, nicotine acts as an agonist for nicotinic acetylcholine receptors (nAChRs) and its effects depend on location and receptor composition. Although nicotinic receptors are found in most brain regions, many studies on addiction have focused on the mesolimbic system and its reported behavioral correlates such as reward processing and reinforcement learning. Profound modulatory cholinergic input from the pedunculopontine and laterodorsal tegmentum to dopaminergic midbrain nuclei as well as local cholinergic interneuron projections to dopamine neuron axons in the striatum may play a major role in the effects of nicotine. Moreover, an indirect mesocorticolimbic feedback loop involving the medial prefrontal cortex may be involved in behavioral characteristics of nicotine addiction. Therefore, this review will highlight current understanding of the effects of nicotine on the function of mesolimbic and mesocortical dopamine projections in the mesocorticolimbic circuit. PMID:26208783

  16. A novel mechanism for acetylcholine to generate diacylglycerol in brain

    SciTech Connect

    Qian, Z.; Drewes, L.R. )

    1990-03-05

    The classical scheme involving inositol phospholipid breakdown by phospholipase C as the sole source of diacylglycerol (DAG) has recently been challenged by evidence that phosphatidylcholine (PC) is an alternative source. In synaptic membranes of canine cerebral cortex, cholinergic agonists caused rapid accumulation of ({sup 3}H)phosphatidic acid (PA) from ({sup 3}H)PC within 15 s, whereas (3H)DAG formation showed a transient lag period before becoming elevated and then exceeding the amount of ({sup 3}H)PA. Additional evidence shows that DAG is produced from PC by the action of phospholipase D to yield PA, which is further dephosphorylated to DAG by PA phosphatase. Our results indicate that this muscarinic acetylcholine receptor-regulated PC phospholipase D-PA phosphatase pathway may be a novel mechanism in cell signal transduction processes for activation of protein kinase C in brain.

  17. Septic encephalopathy: when cytokines interact with acetylcholine in the brain.

    PubMed

    Zhang, Qing-Hong; Sheng, Zhi-Yong; Yao, Yong-Ming

    2014-01-01

    Sepsis-associated encephalopathy (SAE) is a brain dysfunction that occurs secondary to infection in the body, characterized by alteration of consciousness, ranging from delirium to coma, seizure or focal neurological signs. SAE involves a number of mechanisms, including neuroinflammation, in which the interaction between cytokines and acetylcholine results in neuronal loss and alterations in cholinergic signaling. Moreover, the interaction also occurs in the periphery, accelerating a type of immunosuppressive state. Although its diagnosis is not specific in biochemistry and imaging tests, it could potentiate severe outcomes, including increased mortality, cognitive decline, progressive immunosuppression, cholinergic anti-inflammatory deficiency, and even metabolic and hydroelectrolyte imbalance. Therefore, the bilateral communication between SAE and the multiple peripheral organs and especially the immune system should be emphasized in sepsis management.

  18. Frizzled-9 impairs acetylcholine receptor clustering in skeletal muscle cells

    PubMed Central

    Avilés, Evelyn C.; Pinto, Cristina; Hanna, Patricia; Ojeda, Jorge; Pérez, Viviana; De Ferrari, Giancarlo V.; Zamorano, Pedro; Albistur, Miguel; Sandoval, Daniel; Henríquez, Juan P.

    2014-01-01

    Cumulative evidence indicates that Wnt pathways play crucial and diverse roles to assemble the neuromuscular junction (NMJ), a peripheral synapse characterized by the clustering of acetylcholine receptors (AChR) on postsynaptic densities. The molecular determinants of Wnt effects at the NMJ are still to be fully elucidated. We report here that the Wnt receptor Frizzled-9 (Fzd9) is expressed in developing skeletal muscles during NMJ synaptogenesis. In cultured myotubes, gain- and loss-of-function experiments revealed that Fzd9-mediated signaling impairs the AChR-clustering activity of agrin, an organizer of postsynaptic differentiation. Overexpression of Fzd9 induced the cytosolic accumulation of β-catenin, a key regulator of Wnt signaling. Consistently, Fzd9 and β-catenin localize in the postsynaptic domain of embryonic NMJs in vivo. Our findings represent the first evidence pointing to a crucial role of a Fzd-mediated, β-catenin-dependent signaling on the assembly of the vertebrate NMJ. PMID:24860427

  19. Effect of hypnotic and anxiolytic agents on regional concentration of acetylcholine in rat brain.

    PubMed

    Sethy, V H

    1978-01-01

    Pentobarbital (30 and 60 mg/kg) and chloral hydrate (300 and 600 mg/kg) administered in anesthetic/hypnotic doses produced significant increases in acetylcholine concentration in the cerebral cortex, striatum, hippocampus and brainstem. Hypnotic/anxiolytic agents like diazepam, flurazepam (100 mg/kg each) and triazolam (30 mg/kg) significantly increased the acetylcholine concentration only in the cerebral cortex and striatum. Alprazolam and ketazolam had no significant effect on regional distribution of acetylcholine in the brain. The results have been discussed with respect to the role of central cholinergic system in anesthetic and hypnotic actions of these drugs.

  20. Avian Imc-tectal projection is mediated by acetylcholine and glutamate.

    PubMed

    Wang, S R; Wu, G Y; Felix, D

    1995-03-27

    In the bird, biochemical and histochemical data suggest that the neurotransmitter between nucleus isthmi pars magnocellularis (Imc) and tectum is either acetylcholine or glutamate. There are, however, discrepancies regarding the functional role of acetylcholine. In the present study we investigated the action of acetylcholine and glutamate and their specific antagonists on excitatory isthmo-tectal synaptic transmission using electrophysiological and microiontophoretic techniques. The results show two different population of cells: (1) excitatory cholinergic input, blocked by atropine sulphate but not by glutamate antagonist; (2) excitatory glutamatergic input of NMDA or non-NMDA receptor type, which is blocked or reduced by CPP or CNQX but not by atropine sulphate.

  1. Structure and dynamics of the M3 muscarinic acetylcholine receptor

    SciTech Connect

    Kruse, Andrew C.; Hu, Jianxin; Pan, Albert C.; Arlow, Daniel H.; Rosenbaum, Daniel M.; Rosemond, Erica; Green, Hillary F.; Liu, Tong; Chae, Pil Seok; Dror, Ron O.; Shaw, David E.; Weis, William I.; Wess, Jürgen; Kobilka, Brian K.

    2012-03-01

    Acetylcholine, the first neurotransmitter to be identified, exerts many of its physiological actions via activation of a family of G-protein-coupled receptors (GPCRs) known as muscarinic acetylcholine receptors (mAChRs). Although the five mAChR subtypes (M1-M5) share a high degree of sequence homology, they show pronounced differences in G-protein coupling preference and the physiological responses they mediate. Unfortunately, despite decades of effort, no therapeutic agents endowed with clear mAChR subtype selectivity have been developed to exploit these differences. We describe here the structure of the G{sub q/11}-coupled M3 mAChR ('M3 receptor', from rat) bound to the bronchodilator drug tiotropium and identify the binding mode for this clinically important drug. This structure, together with that of the G{sub i/o}-coupled M2 receptor, offers possibilities for the design of mAChR subtype-selective ligands. Importantly, the M3 receptor structure allows a structural comparison between two members of a mammalian GPCR subfamily displaying different G-protein coupling selectivities. Furthermore, molecular dynamics simulations suggest that tiotropium binds transiently to an allosteric site en route to the binding pocket of both receptors. These simulations offer a structural view of an allosteric binding mode for an orthosteric GPCR ligand and provide additional opportunities for the design of ligands with different affinities or binding kinetics for different mAChR subtypes. Our findings not only offer insights into the structure and function of one of the most important GPCR families, but may also facilitate the design of improved therapeutics targeting these critical receptors.

  2. Morphine Increases Acetylcholine Release in the Trigeminal Nuclear Complex

    PubMed Central

    Zhu, Zhenghong; Bowman, Heather R.; Baghdoyan, Helen A.; Lydic, Ralph

    2008-01-01

    Study Objectives: The trigeminal nuclear complex (V) contains cholinergic neurons and includes the principal sensory trigeminal nucleus (PSTN) which receives sensory input from the face and jaw, and the trigeminal motor nucleus (MoV) which innervates the muscles of mastication. Pain associated with pathologies of V is often managed with opioids but no studies have characterized the effect of opioids on acetylcholine (ACh) release in PSTN and MoV. Opioids can increase or decrease ACh release in brainstem nuclei. Therefore, the present experiments tested the 2-tailed hypothesis that microdialysis delivery of opioids to the PSTN and MoV significantly alters ACh release. Design: Using a within-subjects design and isoflurane-anesthetized Wistar rats (n = 53), ACh release in PSTN during microdialysis with Ringer's solution (control) was compared to ACh release during dialysis delivery of the sodium channel blocker tetrodotoxin, muscarinic agonist bethanechol, opioid agonist morphine, mu opioid agonist DAMGO, antagonists for mu (naloxone) and kappa (nor-binaltorphimine; nor-BNI) opioid receptors, and GABAA antagonist bicuculline. Measurements and Results: Tetrodotoxin decreased ACh, confirming action potential-dependent ACh release. Bethanechol and morphine caused a concentration-dependent increase in PSTN ACh release. The morphine-induced increase in ACh release was blocked by nor-BNI but not by naloxone. Bicuculline delivered to the PSTN also increased ACh release. ACh release in the MoV was increased by morphine, and this increase was not blocked by naloxone or nor-BNI. Conclusions: These data comprise the first direct measures of ACh release in PSTN and MoV and suggest synaptic disinhibition as one possible mechanism by which morphine increases ACh release in the trigeminal nuclei. Citation: Zhu Z; Bowman HR; Baghdoyan HA; Lydic R. Morphine increases acetylcholine release in the trigeminal nuclear complex. SLEEP 2008;31(12):1629–1637. PMID:19090318

  3. The activation of the nicotinic acetylcholine receptor by the transmitter.

    PubMed

    Taylor, D B; Spivak, C E

    1985-02-01

    Experimental evidence has been published from isolated guinea pig muscle in vitro, and from direct ligand binding to receptors from T. californica, indicating that two agonist ions react with the nicotinic receptor by exchanging for one magnesium ion. It is the basis of the ion exchange receptor pair model, in which two acetylcholine ions exchange for one magnesium ion in contact with and between a pair of negatively charged receptor groups about 4 A apart. In the resting state the electrostatic attraction between the negatively charged receptor groups and the Mg2+ ion exerts a binding force. This binding force is opposed by the quantum mechanical repulsions of the electron clouds of the charged groups and ions in contact, together with the mutual repulsion of the pair of receptor oxyanions. When the Mg2+ ion is replaced by two acetylcholine ions the quaternary heads of the latter are positioned so that they form two mutually repelling ACh+ receptor group dipoles. As the Mg2+ ion leaves, its rehydration energy contributes to the sum of the electron cloud repulsions and the ACh+ receptor group dipole repulsions, causing the receptor groups to be forced apart activating the receptor macromolecule. The subsequent decrease in ACh+ concentration results in the reestablishment of the resting state. The coulombic electrostatic energy, the Born repulsion energy, the London attraction energy and the oxyanion ACh+ dipole repulsion energies have been calculated and shown to be consistent with the model. The displacement of the Mg2+ by two ACh+ ions makes several hundred kcals of energy available for receptor group separation and receptor activation.

  4. Serotoninergic dorsal raphe neurons possess functional postsynaptic nicotinic acetylcholine receptors.

    PubMed

    Galindo-Charles, Luis; Hernandez-Lopez, Salvador; Galarraga, Elvira; Tapia, Dagoberto; Bargas, José; Garduño, Julieta; Frías-Dominguez, Carmen; Drucker-Colin, René; Mihailescu, Stefan

    2008-08-01

    Very few neurons in the telencephalon have been shown to express functional postsynaptic nicotinic acetylcholine receptors (nAChRs), among them, the noradrenergic and dopaminergic neurons. However, there is no evidence for postsynaptic nAChRs on serotonergic neurons. In this study, we asked if functional nAChRs are present in serotonergic (5-HT) and nonserotonergic (non-5-HT) neurons of the dorsal raphe nucleus (DRN). In rat midbrain slices, field stimulation at the tegmental pedunculopontine (PPT) nucleus evoked postsynaptic currents (eEPSCs) with different components in DRN neurons. After blocking the glutamatergic and GABAergic components, the remaining eEPSCs were blocked by mecamylamine and reduced by either the selective alpha7 nAChR antagonist methyllycaconitine (MLA) or the selective alpha4beta2 nAChR antagonist dihydro-beta-eritroidine (DHbetaE). Simultaneous addition of MLA and DHbetaE blocked all eEPSCs. Integrity of the PPT-DRN pathway was assessed by both anterograde biocytin tracing and antidromic stimulation from the DRN. Inward currents evoked by the direct application of acetylcholine (ACh), in the presence of atropine and tetrodotoxin, consisted of two kinetically different currents: one was blocked by MLA and the other by DHbetaE; in both 5-HT and non-5-HT DR neurons. Analysis of spontaneous (sEPSCs) and evoked (eEPSCs) synaptic events led to the conclusion that nAChRs were located at the postsynaptic membrane. The possible implications of these newly described nAChRs in various physiological processes and behavioral events, such as the wake-sleep cycle, are discussed. PMID:18512214

  5. The Drosophila Acetylcholine Receptor Subunit Dα5 Is Part of an α-Bungarotoxin Binding Acetylcholine Receptor*

    PubMed Central

    Wu, Peipei; Ma, Dongdong; Pierzchala, Marek; Wu, Jun; Yang, Lee-Chuan; Mai, Xiaoping; Chang, Xiaoying; Schmidt-Glenewinkel, Thomas

    2011-01-01

    The central nervous system of Drosophila melanogaster contains an α-bungarotoxin-binding protein with the properties expected of a nicotinic acetylcholine receptor. This protein was purified 5800-fold from membranes prepared from Drosophila heads. The protein was solubilized with 1% Triton X-100 and 0.5 m sodium chloride and then purified using an α-cobratoxin column followed by a lentil lectin affinity column. The purified protein had a specific activity of 3.9 μmol of 125I-α-bungarotoxin binding sites/g of protein. The subunit composition of the purified receptor was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. This subunit profile was identical with that revealed by in situ labeling of the membrane-bound protein using the photolyzable methyl-4-azidobenzoimidate derivative of 125I-α-bungarotoxin. The purified receptor reveals two different protein bands with molecular masses of 42 and 57 kDa. From sedimentation analysis of the purified protein complex in H2O and D2O and gel filtration, a mass of 270 kDa was calculated. The receptor has a s20,w of 9.4 and a Stoke's radius of 7.4 nm. The frictional coefficient was calculated to be 1.7 indicating a highly asymmetric protein complex compatible with a transmembrane protein forming an ion channel. The sequence of a peptide obtained after tryptic digestion of the 42-kDa protein allowed the specific identification of the Drosophila Dα5 subunit by sequence comparison. A peptide-specific antibody raised against the Dα5 subunit provides further evidence that this subunit is a component of an α-bungarotoxin binding nicotinic acetylcholine receptor from the central nervous system of Drosophila. PMID:15781463

  6. Differential Effects of Quercetin and Quercetin Glycosides on Human α7 Nicotinic Acetylcholine Receptor-Mediated Ion Currents

    PubMed Central

    Lee, Byung-Hwan; Choi, Sun-Hye; Kim, Hyeon-Joong; Jung, Seok-Won; Hwang, Sung-Hee; Pyo, Mi-Kyung; Rhim, Hyewhon; Kim, Hyoung-Chun; Kim, Ho-Kyoung; Lee, Sang-Mok; Nah, Seung-Yeol

    2016-01-01

    Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin-3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we showed that quercetin can enhance α7 nicotinic acetylcholine receptor (α7 nAChR)-mediated ion currents. However, the role of the carbohydrates attached to quercetin in the regulation of α7 nAChR channel activity has not been determined. In the present study, we investigated the effects of quercetin glycosides on the acetylcholine induced peak inward current (IACh) in Xenopus oocytes expressing the α7 nAChR. IACh was measured with a two-electrode voltage clamp technique. In oocytes injected with α7 nAChR copy RNA, quercetin enhanced IACh, whereas quercetin glycosides inhibited IACh. Quercetin glycosides mediated an inhibition of IACh, which increased when they were pre-applied and the inhibitory effects were concentration dependent. The order of IACh inhibition by quercetin glycosides was Rutin≥Rham1>Rham2. Quercetin glycosides-mediated IACh enhancement was not affected by ACh concentration and appeared voltage-independent. Furthermore, quercetin-mediated IACh inhibition can be attenuated when quercetin is co-applied with Rham1 and Rutin, indicating that quercetin glycosides could interfere with quercetin-mediated α7 nAChR regulation and that the number of carbohydrates in the quercetin glycoside plays a key role in the interruption of quercetin action. These results show that quercetin and quercetin glycosides regulate the α7 nAChR in a differential manner. PMID:27098860

  7. Adaptive handoff algorithms based on self-organizing neural networks to enhance the quality of service of nonstationary traffic in heirarchical cellular networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2000-03-01

    Third-generation (3G) wireless networks, based on a hierarchical cellular structure, support tiered levels of multimedia services. These services can be categorized as real-time and delay-sensitive, or non-real-time and delay- insensitive. Each call carries demand for one or more services in parallel; each with a guaranteed quality of service (QoS). Roaming is handled by handoff procedures between base stations (BSs) and the mobile subscribers (MSs) within the network. Metrics such as the probabilities of handoff failure, dropped calls and blocked calls; handoff transition time; and handoff rate are used to evaluate the handoff schemes, which also directly affects QoS. Previous researchers have proposed a fuzzy logic system (FLS) with neural encoding of the rule base and probabilistic neural network to solve the handoff decision as a pattern recognition problem in the set of MS signal measurements and mobility amid fading path uncertainties. Both neural approaches evalute only voice traffic in a closed, single- layer network of uniform cells. This paper proposed a new topology-preserving, self-organizing neural network (SONN) for both handoff and admission control as part of an overall resource allocation (RA) problem to support QoS in a three- layer, wideband CDMA HCS with dynamic loading of multimedia services. MS profiles include simultaneous service requirements, which are mapped to a new set of variables, defined in terms of the network radio resources (RRs). Simulations of the new SONN-based algorithms under various operating scenarios of MS mobility, dynamic loading, active set size, and RR bounds, using published traffic models of 3G services, compare their performance with earlier approaches.

  8. Insulin-like Growth Factor-II (IGF-II) and IGF-II Analogs with Enhanced Insulin Receptor-a Binding Affinity Promote Neural Stem Cell Expansion*

    PubMed Central

    Ziegler, Amber N.; Chidambaram, Shravanthi; Forbes, Briony E.; Wood, Teresa L.; Levison, Steven W.

    2014-01-01

    The objective of this study was to employ genetically engineered IGF-II analogs to establish which receptor(s) mediate the stemness promoting actions of IGF-II on mouse subventricular zone neural precursors. Neural precursors from the subventricular zone were propagated in vitro in culture medium supplemented with IGF-II analogs. Cell growth and identity were analyzed using sphere generation and further analyzed by flow cytometry. F19A, an analog of IGF-II that does not bind the IGF-2R, stimulated an increase in the proportion of neural stem cells (NSCs) while decreasing the proportion of the later stage progenitors at a lower concentration than IGF-II. V43M, which binds to the IGF-2R with high affinity but which has low binding affinity to the IGF-1R and to the A isoform of the insulin receptor (IR-A) failed to promote NSC growth. The positive effects of F19A on NSC growth were unaltered by the addition of a functional blocking antibody to the IGF-1R. Altogether, these data lead to the conclusion that IGF-II promotes stemness of NSCs via the IR-A and not through activation of either the IGF-1R or the IGF-2R. PMID:24398690

  9. Cyclic nucleotides of canine antral smooth muscle. Effects of acetylcholine, catecholamines and gastrin.

    PubMed

    Baur, S; Grant, B; Wooton, J

    1981-01-01

    1. The effects of acetylcholine, catecholamines and gastrin on the intracellular content of cyclic AMP and cyclic GMP in antral circular muscle have been determined. 2. Acetylcholine results in a significant but transient increase in intracellular cyclic GMP. 3. Isoproterenol and norepinephrine increase intracellular cyclic AMP. Based on half-maximal effective doses, isoproterenol is 2.7-times more effective than norepinephrine. The increase in intracellular cyclic AMP by both agents is inhibited by propranolol but not phentolamine, indicating that both agents act on the muscle cell by a beta-receptor-coupled mechanism. 4. Gastrin has no demonstrable effect on either cyclic AMP or cyclic GMP. This suggests that while gastrin and acetylcholine can produce a like myoelectric response in the muscle cell, the action of gastrin is mediated by a separate receptor, presumably on the muscle cell, and not by a release of acetylcholine.

  10. Effect of centrophenoxine on acetylcholine release in perfused cerebral ventricles of cats under dynamic electrophysiological control.

    PubMed

    Georgiev, V; Chavdarov, D; Petkov, V; Kirilov, B

    1979-01-01

    The effects of centrophenoxine on the release of acetylcholine and on the changes in the bioelectrical activity are determined in experiments on non-anaesthesized cats subjected to perfusion of the anterior horn of the lateral cerebral ventricle and simultaneous recording of the bioelectrical activity of cortical and subcortical structures. Centrophenoxine is tested in doses of 25, 50 and 100 mg/kg intravenously. Most characteristic changes are found to occur after the dose of 50 mg/kg, when centrophenoxine markedly increases the amount of the released acetylcholine and changes the bioelectrical activity (synchronous changes in the cortex and hypothalamus). The parallelism between the increase release of acetylcholine and the bioelectrical changes continued until the time of the peak effect of centrophenoxine (45 min), followed by dissociation between them (the level of the released acetylcholine gradually approached the initial level, while the changed bioelectrical activity persisted for a longer time.

  11. Selective potentiation of (α4)3(β2)2 nicotinic acetylcholine receptors augments amplitudes of prefrontal acetylcholine- and nicotine-evoked glutamatergic transients in rats.

    PubMed

    Grupe, Morten; Paolone, Giovanna; Jensen, Anders A; Sandager-Nielsen, Karin; Sarter, Martin; Grunnet, Morten

    2013-11-15

    Prefrontal glutamate release evoked through activation of α4β2* nicotinic acetylcholine receptors (nAChRs) situated on thalamic glutamatergic afferents mediates cue detection processes and thus contributes to attentional performance. However, little is known about the respective contributions of the high sensitivity and low sensitivity (LS) stoichiometries of the α4β2 nAChR, (α4)2(β2)3 and (α4)3(β2)2, to these processes. In the present study we employed glutamate-sensitive microelectrodes and the (α4)3(β2)2-selective positive allosteric modulator (PAM) NS9283 to investigate the importance of the LS α4β2 nAChR for glutamate release in the rat medial prefrontal cortex (mPFC). Firstly, the signaling evoked by physiologically relevant ACh concentrations through the (α4)3(β2)2 nAChR in HEK293 cells was potentiated by NS9283, consistent with the classification of NS9283 as a PAM. In urethane-anesthetized rats, intra-prefrontal pressure ejections of NS9283 evoked glutamatergic transients. Importantly, this glutamate release was attenuated by removal of cholinergic projections to the recording area. This finding indicates that the effects of NS9283 depend on endogenous ACh, again consistent with effects of a PAM. We then conducted microdialysis to demonstrate the presence of extracellular ACh in urethane-anesthetized control rats. While detectable, those levels were significantly lower than in awake rats. Finally, the amplitudes of glutamatergic transients evoked by local pressure ejections of a low concentration of nicotine were significantly augmented following systemic administration of NS9283 (3.0mg/kg). In conclusion, our results indicate that a LS α4β2 nAChR PAM such as NS9283 may enhance the cholinergic modulation of glutamatergic neurotransmission in the cortex, thereby perhaps alleviating the attentional impairments common to a range of brain disorders.

  12. Selective potentiation of (α4)3(β2)2 nicotinic acetylcholine receptors augments amplitudes of prefrontal acetylcholine- and nicotine-evoked glutamatergic transients in rats

    PubMed Central

    Grupe, Morten; Paolone, Giovanna; Jensen, Anders A.; Sandager-Nielsen, Karin; Sarter, Martin; Grunnet, Morten

    2013-01-01

    Prefrontal glutamate release evoked through activation of α4β2* nicotinic acetylcholine receptors (nAChRs) situated on thalamic glutamatergic afferents mediates cue detection processes and thus contributes to attentional performance. However, little is known about the respective contributions of the high sensitivity and low sensitivity (LS) stoichiometries of the α4β2 nAChR, (α4)2(β2)3 and (α4)3(β2)2, to these processes. In the present study we employed glutamate-sensitive microelectrodes and the (α4)3(β2)2-selective positive allosteric modulator (PAM) NS9283 to investigate the importance of the LS α4β2 nAChR for glutamate release in the rat medial prefrontal cortex (mPFC). Firstly, the signaling evoked by physiologically relevant ACh concentrations through the (α4)3(β2)2 nAChR in HEK293 cells was potentiated by NS9283, consistent with the classification of NS9238 as a PAM. In urethane-anesthetized rats, intra-prefrontal pressure ejections of NS9283 evoked glutamatergic transients. Importantly, this glutamate release was attenuated by removal of cholinergic projections to the recording area. This finding indicates that the effects of NS9283 depend on endogenous ACh, again consistent with effects of a PAM. We then conducted microdialysis to demonstrate the presence of extracellular ACh in urethane-anesthetized control rats. While detectable, those levels were significantly lower than in awake rats. Finally, the amplitudes of glutamatergic transients evoked by local pressure ejections of a low concentration of nicotine were significantly augmented following systemic administration of NS9283 (3.0 mg/kg). In conclusion, our results indicate that a LS α4β2 nAChR PAMs such as NS9283 may enhance the cholinergic modulation of glutamatergic neurotransmission in the cortex, thereby perhaps alleviating the attentional impairments common to a range of brain disorders. PMID:24051136

  13. Neural network technologies

    NASA Technical Reports Server (NTRS)

    Villarreal, James A.

    1991-01-01

    A whole new arena of computer technologies is now beginning to form. Still in its infancy, neural network technology is a biologically inspired methodology which draws on nature's own cognitive processes. The Software Technology Branch has provided a software tool, Neural Execution and Training System (NETS), to industry, government, and academia to facilitate and expedite the use of this technology. NETS is written in the C programming language and can be executed on a variety of machines. Once a network has been debugged, NETS can produce a C source code which implements the network. This code can then be incorporated into other software systems. Described here are various software projects currently under development with NETS and the anticipated future enhancements to NETS and the technology.

  14. Role of dopamine receptor and muscarinic acetylcholine receptor blockade in the antiapomorphine action of neuroleptics

    SciTech Connect

    Zharkovskii, A.M.; Langel, Yu.L.; Chereshka, K.S.; Zharkovskaya, T.A.

    1987-08-01

    The authors analyze the role of dopamine and muscarinic acetylcholine receptor blocking components in the antistereotypic action of neuroleptics with different chemical structure. To determine dopamine-blocking activity in vitro, binding of /sup 3/H-spiperone with membranes of the rat striatum was measured. To study the blocking action of the substances on muscarinic acetylcholine receptors, binding of /sup 3/H-quinuclidinyl benzylate with brain membranes was chosen.

  15. Acetylcholine test in patients with angina pectoris and normal coronary angiography

    NASA Astrophysics Data System (ADS)

    Barbieri, Enrico; Destro, Gianni; Oliva, Massimo; Zardini, Piero

    1994-02-01

    Angina pectoris with normal coronary artery on the coronary angiography is an intriguing issue. Intracoronary infusion of acetylcholine has recently been used to test the integrity of endothelial cells. We studied 16 patients with this syndrome. A relationship has been found between the acetylcholine test and the exercise stress test in normotensive patients. The presence of hypertension makes the evaluation of the test more unpredictable, probably because of the damage on the endothelial cells related to systemic hypertension.

  16. A D-peptide ligand of nicotine acetylcholine receptors for brain-targeted drug delivery.

    PubMed

    Wei, Xiaoli; Zhan, Changyou; Shen, Qing; Fu, Wei; Xie, Cao; Gao, Jie; Peng, Chunmei; Zheng, Ping; Lu, Weiyue

    2015-03-01

    Lysosomes of brain capillary endothelial cells are implicated in nicotine acetylcholine receptor (nAChR)-mediated transcytosis and act as an enzymatic barrier for the transport of peptide ligands to the brain. A D-peptide ligand of nAChRs (termed (D)CDX), which binds to nAChRs with an IC50 value of 84.5 nM, was developed by retro-inverso isomerization. (D)CDX displayed exceptional stability in lysosomal homogenate and serum, and demonstrated significantly higher transcytosis efficiency in an in vitro blood-brain barrier monolayer compared with the parent L-peptide. When modified on liposomal surface, (D)CDX facilitated significant brain-targeted delivery of liposomes. As a result, brain-targeted delivery of (D)CDX modified liposomes enhanced therapeutic efficiency of encapsulated doxorubicin for glioblastoma. This study illustrates the importance of ligand stability in nAChRs-mediated transcytosis, and paves the way for developing stable brain-targeted entities.

  17. Chemosensitivity of single smooth muscle cells to acetylcholine, noradrenaline, and histamine in vitro.

    PubMed

    Sinback, C N; Shain, W

    1980-02-01

    Electrical responses to acetylcholine, noradrenaline, and histamine were recorded from solitary smooth muscle cells. Iontophoresis of each transmitter elicited three fast responses: a hyperpolarization, a depolarization, or a biphasic hyperpolarization-depolarization. Each transmitter activated a specific receptor since responses were specifically blocked by antagonists, two transmitters elicited different responses in solitary cells, and desensitization of response to one transmitter did not cause desensitization of responses to other transmitters. Responses were due to increased ion conductances since input resistance decreased during responses and reversal potentials were measured for depolarizing responses (-5 mV) and hyperpolarizing responses (-60 mV). Regional differences in transmitter sensitivity were mapped on solitary cells. Biphasic responses were due to simultaneous activation of receptors mediating hyperpolarizing responses and receptors mediating depolarizing responses which were segregated in the cell membrane. Noradrenaline enhanced action potential amplitude by regulation of voltage-dependent ion conductances. Finally, noradrenaline and histamine elicited periodic hyperpolarizing potentials, which may be due to increased intracellular Ca++.

  18. Muscarinic and Nicotinic Acetylcholine Receptor Agonists and Allosteric Modulators for the Treatment of Schizophrenia

    PubMed Central

    Jones, Carrie K; Byun, Nellie; Bubser, Michael

    2012-01-01

    Muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs) are emerging as important targets for the development of novel treatments for the symptoms associated with schizophrenia. Preclinical and early proof-of-concept clinical studies have provided strong evidence that activators of specific mAChR (M1 and M4) and nAChR (α7 and α2β4) subtypes are effective in animal models of antipsychotic-like activity and/or cognitive enhancement, and in the treatment of positive and cognitive symptoms in patients with schizophrenia. While early attempts to develop selective mAChR and nAChR agonists provided important preliminary findings, these compounds have ultimately failed in clinical development due to a lack of true subtype selectivity and subsequent dose-limiting adverse effects. In recent years, there have been major advances in the discovery of highly selective activators for the different mAChR and nAChR subtypes with suitable properties for optimization as potential candidates for clinical trials. One novel strategy has been to identify ligands that activate a specific receptor subtype through actions at sites that are distinct from the highly conserved ACh-binding site, termed allosteric sites. These allosteric activators, both allosteric agonists and positive allosteric modulators, of mAChR and nAChR subtypes demonstrate unique mechanisms of action and high selectivity in vivo, and may provide innovative treatment strategies for schizophrenia. PMID:21956443

  19. The nicotinic acetylcholine receptor gene family of the malaria mosquito, Anopheles gambiae.

    PubMed

    Jones, Andrew K; Grauso, Marta; Sattelle, David B

    2005-02-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission in the insect nervous system and are targets of widely selling insecticides. We have identified the nAChR gene family from the genome of the malaria mosquito vector, Anopheles gambiae, to be the second complete insect nAChR gene family described following that of Drosophila melanogaster. Like Drosophila, Anopheles possesses 10 nAChR subunits with orthologous relationships evident between the two insects. Interestingly, the Anopheles orthologues of Dbeta2 and Dbeta3 possess the vicinal cysteines that define alpha subunits. As with Dalpha4 and Dalpha6, the Anopheles orthologues are alternatively spliced at equivalent exons. Reverse transcription-polymerase chain reaction analysis shows that RNA A-to-I editing sites conserved between Dalpha6 of Drosophila and alpha7-2 of the tobacco budworm, Heliothis virescens, are not shared with the equivalent nAChR subunit of Anopheles. Indeed, RNA-editing sites identified in functionally significant regions of Dbeta1, Dalpha5, and Dalpha6 are not conserved in the mosquito orthologues, indicating considerable divergence of RNA molecules targeted for editing within the insect order Diptera. These findings shed further light on the diversity of nAChR subunits and may present a useful basis for the development of improved malaria control agents by enhancing our understanding of a validated mosquito insecticide target.

  20. α7-Nicotinic Acetylcholine Receptor: Role in Early Odor Learning Preference in Mice

    PubMed Central

    Hellier, Jennifer L.; Arevalo, Nicole L.; Smith, Lynelle; Xiong, Ka-Na; Restrepo, Diego

    2012-01-01

    Recently, we have shown that mice with decreased expression of α7-nicotinic acetylcholine receptors (α7) in the olfactory bulb were associated with a deficit in odor discrimination compared to wild-type mice. However, it is unknown if mice with decreased α7-receptor expression also show a deficit in early odor learning preference (ELP), an enhanced behavioral response to odors with attractive value observed in rats. In this study, we modified ELP methods performed in rats and implemented similar conditions in mice. From post-natal days 5–18, wild-type mice were stroked simultaneously with an odor presentation (conditioned odor) for 90 s daily. Control mice were only stroked, exposed to odor, or neither. On the day of testing (P21), mice that were stroked in concert with a conditioned odor significantly investigated the conditioned odor compared to a novel odor, as observed similarly in rats. However, mice with a decrease in α7-receptor expression that were stroked during a conditioned odor did not show a behavioral response to that odorant. These results suggest that decreased α7-receptor expression has a role in associative learning, olfactory preference, and/or sensory processing deficits. PMID:22514723

  1. Antigenic role of single residues within the main immunogenic region of the nicotinic acetylcholine receptor.

    PubMed Central

    Papadouli, I; Potamianos, S; Hadjidakis, I; Bairaktari, E; Tsikaris, V; Sakarellos, C; Cung, M T; Marraud, M; Tzartos, S J

    1990-01-01

    The target of most of the autoantibodies against the acetylcholine receptor (AChR) in myasthenic sera is the main immunogenic region (MIR) on the extracellular side of the AChR alpha-subunit. Binding of anti-MIR monoclonal antibodies (mAbs) has been recently localized between residues alpha 67 and alpha 76 of Torpedo californica electric organ (WNPADYGGIK) and human muscle (WNPDDYGGVK) AChR. In order to evaluate the contribution of each residue to the antigenicity of the MIR, we synthesized peptides corresponding to residues alpha 67-76 from Torpedo and human AChRs, together with 13 peptide analogues. Nine of these analogues had one residue of the Torpedo decapeptide replaced by L-alanine, three had a structure which was intermediate between those of the Torpedo and human alpha 67-76 decapeptides, and one had D-alanine in position 73. Binding studies employing six anti-MIR mAbs and all 15 peptides revealed that some residues (Asn68 and Asp71) are indispensable for binding by all mAbs tested, whereas others are important only for binding by some mAbs. Antibody binding was mainly restricted to residues alpha 68-74, the most critical sequence being alpha 68-71. Fish electric organ and human MIR form two distinct groups of strongly overlapping epitopes. Some peptide analogues enhanced mAb binding compared with Torpedo and human peptides, suggesting that the construction of a very antigenic MIR is feasible. PMID:1695844

  2. Agonist mediated conformational changes of solubilized calf forebrain muscarinic acetylcholine receptors.

    PubMed

    Vanderheyden, P; Andre, C; de Backer, J P; Vauquelin, G

    1984-10-01

    Muscarinic receptors in calf forebrain membranes can be identified by the specific binding of the radiolabelled antagonist [3H]dexetimide. These receptors (2.8 pM/mg protein) comprise two non-interconvertible subpopulations with respectively high and low agonist affinity but with the same antagonist affinity. For all the agonists tested the low affinity sites represent 85 +/- 5% of the total receptor population. 0.5% Digitonin solubilized extracts contain 0.8 pM muscarinic receptor/mg protein. In contrast with the membranes, these extracts contain only sites with low agonist affinity. The alkylating reagent N-ethylmaleimide causes an increase of the acetylcholine affinity for the low affinity sites in membranes as well as for the solubilized sites. This effect is time dependent until a maximal 3-fold increase in affinity is attained. The rate of N-ethylmaleimide action is enhanced by the concomitant presence of agonists. In contrast, N-ethylmaleimide does not affect antagonist binding. This suggests that agonists mediate a conformational change of both the membrane bound low affinity muscarinic sites and of the solubilized sites, resulting in their increased susceptibility towards NEM alkylation. PMID:6487351

  3. Effects of selected muscarinic cholinergic antagonists on [3H]acetylcholine release from rat hippocampal slices.

    PubMed

    Pohorecki, R; Head, R; Domino, E F

    1988-01-01

    A number of cholinergic muscarinic (M) agonists and antagonists were studied for their ability to enhance tritiated acetylcholine ([3H]ACh) release from electrically field-stimulated rat hippocampal slices. A Ca++-free medium and carbachol, but not nicotine, inhibited [3H]ACh release. Atropine, methylatropine and dexetimide produced concentration-dependent increases in [3H]ACh release to a maximum of about 50% above control. Aprophen and benactyzine produced a maximal response 25 to 35% above control. The selective M1 antagonist pirenzepine had the least effect on [3H]ACh release. Of the nonspecific M1-M2 antagonists studied, benactyzine produced the least amount of [3H]ACh release. The order of potency of the M antagonists in promoting a 15% increase in [3H]ACh release was aprophen greater than benactyzine greater than methylatropine greater than dexetimide greater than pirenzepine greater than atropine. However, the order of promoting maximal release of [3H]ACh was atropine greater than dexetimide greater than methylatropine greater than aprophen greater than benactyzine greater than pirenzepine. PMID:3335998

  4. Electronic neural networks for global optimization

    NASA Technical Reports Server (NTRS)

    Thakoor, A. P.; Moopenn, A. W.; Eberhardt, S.

    1990-01-01

    An electronic neural network with feedback architecture, implemented in analog custom VLSI is described. Its application to problems of global optimization for dynamic assignment is discussed. The convergence properties of the neural network hardware are compared with computer simulation results. The neural network's ability to provide optimal or near optimal solutions within only a few neuron time constants, a speed enhancement of several orders of magnitude over conventional search methods, is demonstrated. The effect of noise on the circuit dynamics and the convergence behavior of the neural network hardware is also examined.

  5. Electrolyte and protein secretion by the perfused rabbit mandibular gland stimulated with acetylcholine or catecholamines

    PubMed Central

    Case, R. M.; Conigrave, A. D.; Novak, I.; Young, J. A.

    1980-01-01

    1. A method is described for the isolation and vascular perfusion in vitro of the mandibular gland of the rabbit. The perfusate is a physiological salt solution containing glucose as the only metabolic substrate. 2. During perfusion with solutions containing acetylcholine, the gland secretes vigorously at a rate and in a manner similar to that seen in vivo. Although the gland becomes oedematous during perfusion, the extent of this oedema appears to have no influence on secretory ability: the perfused glands were capable of functioning for at least 4 h, and often for more than 6 h. 3. Acetylcholine evoked a small secretory response at a concentration of 8 × 10-9 mol l-1 and a maximum response at 8 × 10-7 mol l-1. Eserine (2 × 10-5 mol l-1) evoked secretory responses comparable to those evoked by acetylcholine in a concentration of 8 × 10-9 mol l-1. Secretion, whether unstimulated or evoked by acetylcholine or eserine, could be blocked completely by atropine. 4. During prolonged stimulation with acetylcholine, the fluid secretory response declined rapidly over a period of about 15 min from an initial high value to a much lower plateau value. After 3 or more hours of stimulation, the secretory response began once more to decline, this time towards zero. If, before the second period of decline begins, stimulation is interrupted for about 30 min, the gland recovers its initial responsiveness to further stimulation with acetylcholine. 5. The Na, K, Cl and HCO3 concentrations and the osmolality of acetylcholine evoked saliva exhibited flow-dependency similar to that seen in vivo. The concentrations of Na and Cl, but not K and HCO3, increased by about 25 mmol l-1 during periods of prolonged stimulation with acetylcholine even though the salivary secretory rate was constant. The concentrations of K and HCO3, but not Na and Cl, increased progressively as the concentration of infused acetylcholine was increased. 6. Salivary protein secretion increased with increasing

  6. Activation of endplate nicotinic acetylcholine receptors by agonists.

    PubMed

    Auerbach, Anthony

    2015-10-15

    The interaction of a small molecule made in one cell with a large receptor made in another is the signature event of cell signaling. Understanding the structure and energy changes associated with agonist activation is important for engineering drugs, receptors and synapses. The nicotinic acetylcholine receptor (AChR) is a ∼300kD ion channel that binds the neurotransmitter acetylcholine (ACh) and other cholinergic agonists to elicit electrical responses in the central and peripheral nervous systems. This mini-review is in two sections. First, general concepts of skeletal muscle AChR operation are discussed in terms of energy landscapes for conformational change. Second, adult vs. fetal AChRs are compared with regard to interaction energies between ACh and agonist-site side chains, measured by single-channel electrophysiology and molecular dynamics simulations. The five aromatic residues that form the core of each agonist binding site can be divided into two working groups, a triad (led by αY190) that behaves similarly at all sites and a coupled pair (led by γW55) that has a large influence on affinity only in fetal AChRs. Each endplate AChR has 5 homologous subunits, two of α(1) and one each of β, δ, and either γ (fetal) or ϵ (adult). These nicotinic AChRs have only 2 functional agonist binding sites located in the extracellular domain, at αδ and either αγ or αϵ subunit interfaces. The receptor undergoes a reversible, global isomerization between structures called C and O. The C shape does not conduct ions and has a relatively low affinity for ACh, whereas O conducts cations and has a higher affinity. When both agonist sites are empty (filled only with water) the probability of taking on the O conformation (PO) is low, <10(-6). When ACh molecules occupy the agonist sites the C→O opening rate constant and C↔O gating equilibrium constant increase dramatically. Following a pulse of ACh at the nerve-muscle synapse, the endplate current rises rapidly

  7. Neural Engineering

    NASA Astrophysics Data System (ADS)

    He, Bin

    About the Series: Bioelectric Engineering presents state-of-the-art discussions on modern biomedical engineering with respect to applications of electrical engineering and information technology in biomedicine. This focus affirms Springer's commitment to publishing important reviews of the broadest interest to biomedical engineers, bioengineers, and their colleagues in affiliated disciplines. Recent volumes have covered modeling and imaging of bioelectric activity, neural engineering, biosignal processing, bionanotechnology, among other topics.

  8. Neuronal Nicotinic Acetylcholine Receptor Modulators Reduce Sugar Intake.

    PubMed

    Shariff, Masroor; Quik, Maryka; Holgate, Joan; Morgan, Michael; Patkar, Omkar L; Tam, Vincent; Belmer, Arnauld; Bartlett, Selena E

    2016-01-01

    Excess sugar consumption has been shown to contribute directly to weight gain, thus contributing to the growing worldwide obesity epidemic. Interestingly, increased sugar consumption has been shown to repeatedly elevate dopamine levels in the nucleus accumbens (NAc), in the mesolimbic reward pathway of the brain similar to many drugs of abuse. We report that varenicline, an FDA-approved nicotinic acetylcholine receptor (nAChR) partial agonist that modulates dopamine in the mesolimbic reward pathway of the brain, significantly reduces sucrose consumption, especially in a long-term consumption paradigm. Similar results were observed with other nAChR drugs, namely mecamylamine and cytisine. Furthermore, we show that long-term sucrose consumption increases α4β2 * and decreases α6β2* nAChRs in the nucleus accumbens, a key brain region associated with reward. Taken together, our results suggest that nAChR drugs such as varenicline may represent a novel treatment strategy for reducing sugar consumption. PMID:27028298

  9. Mechanisms of acetylcholine receptor loss in myasthenia gravis.

    PubMed Central

    Drachman, D B; Adams, R N; Stanley, E F; Pestronk, A

    1980-01-01

    The fundamental abnormality affecting the neuromuscular junctions of myasthenic patients is a reduction of available AChRs, due to an autoimmune attack directed against the receptors. Antibodies to AChR are present in most patients, and there is evidence that they have a predominant pathogenic role in the disease, aided by complement. The mechanism of antibody action involves acceleration of the rate of degradation of AChRs, attributable to cross-linking of the receptors. In addition, antibodies may block AChRs, and may participate in producing destructive changes, perhaps in conjunction with complement. The possibility that cell-mediated mechanisms may play a role in the autoimmune responses of some myasthenic patients remains to be explored. Although the target of the autoimmune attack in myasthenic patients is probably always the acetylcholine receptors, it is not yet clear which of these immune mechanisms are most important. It is likely that the relative role of each mechanism varies from patient to patient. One of the goals of future research will be to identify the relative importance of each of these mechanisms in the individual patient, and to tailor specific immunotherapeutic measures to the abnormalities found. PMID:6249894

  10. Nicotinic acetylcholine receptor agonist attenuates ILC2-dependent airway hyperreactivity

    PubMed Central

    Galle-Treger, Lauriane; Suzuki, Yuzo; Patel, Nisheel; Sankaranarayanan, Ishwarya; Aron, Jennifer L.; Maazi, Hadi; Chen, Lin; Akbari, Omid

    2016-01-01

    Allergic asthma is a complex and chronic inflammatory disorder that is associated with airway hyperreactivity (AHR) and driven by Th2 cytokine secretion. Type 2 innate lymphoid cells (ILC2s) produce large amounts of Th2 cytokines and contribute to the development of AHR. Here, we show that ILC2s express the α7-nicotinic acetylcholine receptor (α7nAChR), which is thought to have an anti-inflammatory role in several inflammatory diseases. We show that engagement of a specific agonist with α7nAChR on ILC2s reduces ILC2 effector function and represses ILC2-dependent AHR, while decreasing expression of ILC2 key transcription factor GATA-3 and critical inflammatory modulator NF-κB, and reducing phosphorylation of upstream kinase IKKα/β. Additionally, the specific α7nAChR agonist reduces cytokine production and AHR in a humanized ILC2 mouse model. Collectively, our data suggest that α7nAChR expressed by ILC2s is a potential therapeutic target for the treatment of ILC2-mediated asthma. PMID:27752043

  11. Neuronal Nicotinic Acetylcholine Receptor Modulators Reduce Sugar Intake

    PubMed Central

    Shariff, Masroor; Quik, Maryka; Holgate, Joan; Morgan, Michael; Patkar, Omkar L.; Tam, Vincent; Belmer, Arnauld; Bartlett, Selena E.

    2016-01-01

    Excess sugar consumption has been shown to contribute directly to weight gain, thus contributing to the growing worldwide obesity epidemic. Interestingly, increased sugar consumption has been shown to repeatedly elevate dopamine levels in the nucleus accumbens (NAc), in the mesolimbic reward pathway of the brain similar to many drugs of abuse. We report that varenicline, an FDA-approved nicotinic acetylcholine receptor (nAChR) partial agonist that modulates dopamine in the mesolimbic reward pathway of the brain, significantly reduces sucrose consumption, especially in a long-term consumption paradigm. Similar results were observed with other nAChR drugs, namely mecamylamine and cytisine. Furthermore, we show that long-term sucrose consumption increases α4β2 * and decreases α6β2* nAChRs in the nucleus accumbens, a key brain region associated with reward. Taken together, our results suggest that nAChR drugs such as varenicline may represent a novel treatment strategy for reducing sugar consumption. PMID:27028298

  12. Crosslinking-induced endocytosis of acetylcholine receptors by quantum dots.

    PubMed

    Lee, Chi Wai; Zhang, Hailong; Geng, Lin; Peng, H Benjamin

    2014-01-01

    In a majority of patients with myasthenia gravis (MG), anti-acetylcholine receptor (AChR) antibodies target postsynaptic AChR clusters and thus compromise the membrane integrity of neuromuscular junctions (NMJs) and lead to muscle weakness. Antibody-induced endocytosis of AChRs in the postsynaptic membrane represents the initial step in the pathogenesis of MG; however, the molecular mechanisms underlying AChR endocytosis remain largely unknown. Here, we developed an approach to mimic the pathogenic antibodies for inducing the crosslinking and internalization of AChRs from the postsynaptic membrane. Using biotin-α-bungarotoxin and quantum dot (QD)-streptavidin, cell-surface and internalized AChRs could be readily distinguished by comparing the size, fluorescence intensity, trajectory, and subcellular localization of the QD signals. QD-induced AChR endocytosis was mediated by clathrin-dependent and caveolin-independent mechanisms, and the trafficking of internalized AChRs in the early endosomes required the integrity of microtubule structures. Furthermore, activation of the agrin/MuSK (muscle-specific kinase) signaling pathway strongly suppressed QD-induced internalization of AChRs. Lastly, QD-induced AChR crosslinking potentiated the dispersal of aneural AChR clusters upon synaptic induction. Taken together, our results identify a novel approach to study the mechanisms of AChR trafficking upon receptor crosslinking and endocytosis, and demonstrate that agrin-MuSK signaling pathways protect against crosslinking-induced endocytosis of AChRs. PMID:24587270

  13. Gating Movement of Acetylcholine Receptor Caught by Plunge-Freezing

    PubMed Central

    Unwin, Nigel; Fujiyoshi, Yoshinori

    2012-01-01

    The nicotinic acetylcholine (ACh) receptor converts transiently to an open-channel form when activated by ACh released into the synaptic cleft. We describe here the conformational change underlying this event, determined by electron microscopy of ACh-sprayed and freeze-trapped postsynaptic membranes. ACh binding to the α subunits triggers a concerted rearrangement in the ligand-binding domain, involving an ~ 1‐Å outward displacement of the extracellular portion of the β subunit where it interacts with the juxtaposed ends of α-helices shaping the narrow membrane-spanning pore. The β-subunit helices tilt outward to accommodate this displacement, destabilising the arrangement of pore-lining helices, which in the closed channel bend inward symmetrically to form a central hydrophobic gate. Straightening and tangential motion of the pore-lining helices effect channel opening by widening the pore asymmetrically and increasing its polarity in the region of the gate. The pore-lining helices of the αγ and δ subunits, by flexing between alternative bent and straight conformations, undergo the greatest movements. This coupled allosteric transition shifts the structure from a tense (closed) state toward a more relaxed (open) state. PMID:22841691

  14. Looking below the surface of nicotinic acetylcholine receptors.

    PubMed

    Stokes, Clare; Treinin, Millet; Papke, Roger L

    2015-08-01

    The amino acid sequences of nicotinic acetylcholine receptors (nAChRs) from diverse species can be compared across extracellular, transmembrane, and intracellular domains. The intracellular domains are most divergent among subtypes, yet relatively consistent among species. The diversity indicates that each nAChR subtype has a unique language for communication with its host cell. The conservation across species also suggests that the intracellular domains have defining functional roles for each subtype. Secondary structure prediction indicates two relatively conserved alpha helices within the intracellular domains of all nAChRs. Among all subtypes, the intracellular domain of α7 nAChR is one of the most well conserved, and α7 nAChRs have effects in non-neuronal cells independent of generating ion currents, making it likely that the α7 intracellular domain directly mediates signal transduction. There are potential phosphorylation and protein-binding sites in the α7 intracellular domain, which are conserved and may be the basis for α7-mediated signal transduction.

  15. Effects of two oxadiazolidinones on cholinesterases and acetylcholine receptors

    SciTech Connect

    Bakry, N.; Lockyer, S.; Sherby, S.; Eldefrawi, A.; Eldefrawi, M.

    1986-03-05

    Inhibition of acetylcholinesterase (AChE) and butyryl cholinesterase (BuChE) by 3-(2,3-dihydro-2,2-dimethyl-benzofuran-'7-yl)-5-methoxy-1,3,4-oxadiazol-2(/sup 3/H)-one (DBOX) and 3-(2-methoxyphenyl)-5-methoxy-1,3,4-oxadiazol-2(/sup 3/H)-one (MPOX) was measured by the Ellmann spectrophotometric method. Inhibition was quasi first order and irreversible. DBOX was 2-3 orders of magnitude more potent than MPOX. Housefly brain AChE and horse serum BuChE were more sensitive than AChEs of red blood cells or eel and Torpedo electric organs. It is suggested that the nonesteratic oxadiazolidinones are activated to carbanillates on the surface of the enzyme and produce a carbanillated enzyme which ages rapidly. Carbamate anticholinesterases protected AChE against carbanillation as they did against phosphorylation. At higher concentrations, the two oxadiazolidinones also affected binding of (/sup 125/I) ..cap alpha.. bungarotoxin and (/sup 3/H)perhydrohistrionicotoxin to Torpedo nicotinic acetylcholine receptors, but did not affect binding of (/sup 3/H)quinuclidinyl benzilate to rat brain muscarinic receptors.

  16. Activation of muscarinic acetylcholine receptors via their allosteric binding sites.

    PubMed Central

    Jakubík, J; Bacáková, L; Lisá, V; el-Fakahany, E E; Tucek, S

    1996-01-01

    Ligands that bind to the allosteric-binding sites on muscarinic acetylcholine receptors alter the conformation of the classical-binding sites of these receptors and either diminish or increase their affinity for muscarinic agonists and classical antagonists. It is not known whether the resulting conformational change also affects the interaction between the receptors and the G proteins. We have now found that the muscarinic receptor allosteric modulators alcuronium, gallamine, and strychnine (acting in the absence of an agonist) alter the synthesis of cAMP in Chinese hamster ovary (CHO) cells expressing the M2 or the M4 subtype of muscarinic receptors in the same direction as the agonist carbachol. In addition, most of their effects on the production of inositol phosphates in CHO cells expressing the M1 or the M3 muscarinic receptor subtypes are also similar to (although much weaker than) those of carbachol. The agonist-like effects of the allosteric modulators are not observed in CHO cells that have not been transfected with the gene for any of the subtypes of muscarinic receptors. The effects of alcuronium on the formation of cAMP and inositol phosphates are not prevented by the classical muscarinic antagonist quinuclidinyl benzilate. These observations demonstrate for the first time that the G protein-mediated functional responses of muscarinic receptors can be evoked not only from their classical, but also from their allosteric, binding sites. This represents a new mechanism of receptor activation. PMID:8710935

  17. An unusual beta-spectrin associated with clustered acetylcholine receptors

    PubMed Central

    1989-01-01

    The clustering of acetylcholine receptors (AChR) in the postsynaptic membrane is an early event in the formation of the neuromuscular junction. The mechanism of clustering is still unknown, but is generally believed to be mediated by the postsynaptic cytoskeleton. We have identified an unusual isoform of beta-spectrin which colocalizes with AChR in AChR clusters isolated from rat myotubes in vitro. A related antigen is present postsynaptically at the neuromuscular junction of the rat. Immunoprecipitation, peptide mapping and immunofluorescence show that the beta-spectrin in AChR clusters resembles but is distinct from the beta-spectrin of human erythrocytes. alpha-Spectrin appears to be absent from AChR clusters. Semiquantitative immunofluorescence techniques indicate that there are from two to seven beta-spectrin molecules present for every clustered AChR, the higher values being obtained from rapidly prepared clusters, the lower values from clusters that require several minutes or more for isolation. Upon incubation of isolated AChR clusters for 1 h at room temperature, beta-spectrin is slowly depleted and the AChR redistribute into microaggregates. The beta-spectrin that remains associated with the myotube membrane is concentrated at these microaggregates. beta- Spectrin is quantitatively lost from clusters upon digestion with chymotrypsin, which causes AChR to redistribute in the plane of the membrane. These results suggest that AChR in clusters is closely linked to an unusual isoform of beta-spectrin. PMID:2645300

  18. Acetylcholine-induced current in perfused rat myoballs

    PubMed Central

    1980-01-01

    Spherical "myoballs" were grown under tissue culture conditions from striated muscle of neonatal rat thighs. The myoballs were examined electrophysiologically with a suction pipette which was used to pass current and perfuse internally. A microelectrode was used to record membrane potential. Experiments were performed with approximately symmetrical (intracellular and extracellular) sodium aspartate solutions. The resting potential, acetylcholine (ACh) reversal potential, and sodium channel reversal potential were all approximately 0 mV. ACh-induced currents were examined by use of both voltage jumps and voltage ramps in the presence of iontophoretically applied agonist. The voltage-jump relaxations had a single exponential time-course. The time constant, tau, was exponentially related to membrane potential, increasing e-fold for 81 mV hyperpolarization. The equilibrium current- voltage relationship was also approximately exponential, from -120 to +81 mV, increasing e-fold for 104 mV hyperpolarization. The data are consistent with a first-order gating process in which the channel opening rate constant is slightly voltage dependent. The instantaneous current-voltage relationship was sublinear in the hyperpolarizing direction. Several models are discussed which can account for the nonlinearity. Evidence is presented that the "selectivity filter" for the ACh channel is located near the intracellular membrane surface. PMID:7381423

  19. Genetics of nicotinic acetylcholine receptors: relevance to nicotine addiction

    PubMed Central

    Mineur, Yann S.; Picciotto, Marina R.

    2008-01-01

    Human twin studies have suggested that there is a substantial genetic component underlying nicotine dependence, ongoing smoking and ability to quit. Similarly, animal studies have identified a number of genes and gene products that are critical for behaviors related to nicotine addiction. Classical genetic approaches, gene association studies and genetic engineering techniques have been used to identify the gene products involved in nicotine dependence. One class of genes involved in nicotine-related behavior is the family of nicotinic acetylcholine receptors (nAChRs). These receptors are the primary targets for nicotine in the brain. Genetic engineering studies in mice have identified a number of subunits that are critical for the ability of nicotine to activate the reward system in the brain, consisting of the dopaminergic cell bodies in the ventral tegmental area and their terminals in the nucleus accumbens and other portions of the mesolimbic system. In this review we will discuss the various lines of evidence suggesting that nAChRs may be involved in smoking behavior, and will review the human and animal studies that have been performed to date examining the genetic basis for nicotine dependence and smoking. PMID:17632086

  20. Identification of petrogenic produced water components as acetylcholine esterase inhibitors.

    PubMed

    Froment, Jean; Langford, Katherine; Tollefsen, Knut Erik; Bråte, Inger Lise N; Brooks, Steven J; Thomas, Kevin V

    2016-08-01

    Effect-directed analysis (EDA) was applied to identify acetylcholine esterase (AChE) inhibitors in produced water. Common produced water components from oil production activities, such as polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and naphthenic acids were tested for AChE inhibition using a simple mixture of PAHs and naphthenic acids. Produced water samples collected from two offshore platforms in the Norwegian sector of the North Sea were extracted by solid phase extraction and fractionated by open-column liquid solid chromatography and high-performance liquid chromatography (HPLC) before being tested using a high-throughput and automated AChE assay. The HPLC fractions causing the strongest AChE inhibition were analysed by gas chromatography coupled to a high-resolution time-of-flight mass spectrometry (GC-HR-ToF-MS). Butylated hydroxytoluene and 4-phenyl-1,2-dihydronaphthalene were identified as two produced water components capable of inhibiting AChE at low concentrations. In order to assess the potential presence of such compounds discharged into aquatic ecosystems, AChE activity in fish tissues was measured. Saithe (Pollachius virens) caught near two offshore platforms showed lower enzymatic activity than those collected from a reference location. Target analysis of saithe did not detected the presence of these two putative AChE inhibitors and suggest that additional compounds such as PAHs, naphthenic acids and yet un-identified compounds may also contribute to the purported AChE inhibition observed in saithe. PMID:27176761

  1. Crosslinking-Induced Endocytosis of Acetylcholine Receptors by Quantum Dots

    PubMed Central

    Geng, Lin; Peng, H. Benjamin

    2014-01-01

    In a majority of patients with myasthenia gravis (MG), anti-acetylcholine receptor (AChR) antibodies target postsynaptic AChR clusters and thus compromise the membrane integrity of neuromuscular junctions (NMJs) and lead to muscle weakness. Antibody-induced endocytosis of AChRs in the postsynaptic membrane represents the initial step in the pathogenesis of MG; however, the molecular mechanisms underlying AChR endocytosis remain largely unknown. Here, we developed an approach to mimic the pathogenic antibodies for inducing the crosslinking and internalization of AChRs from the postsynaptic membrane. Using biotin-α-bungarotoxin and quantum dot (QD)-streptavidin, cell-surface and internalized AChRs could be readily distinguished by comparing the size, fluorescence intensity, trajectory, and subcellular localization of the QD signals. QD-induced AChR endocytosis was mediated by clathrin-dependent and caveolin-independent mechanisms, and the trafficking of internalized AChRs in the early endosomes required the integrity of microtubule structures. Furthermore, activation of the agrin/MuSK (muscle-specific kinase) signaling pathway strongly suppressed QD-induced internalization of AChRs. Lastly, QD-induced AChR crosslinking potentiated the dispersal of aneural AChR clusters upon synaptic induction. Taken together, our results identify a novel approach to study the mechanisms of AChR trafficking upon receptor crosslinking and endocytosis, and demonstrate that agrin-MuSK signaling pathways protect against crosslinking-induced endocytosis of AChRs. PMID:24587270

  2. Acetylcholine receptor and behavioral deficits in mice lacking apolipoprotein E

    PubMed Central

    Siegel, Jessica A; Benice, Theodore S; Van Meer, Peter; Park, Byung S; Raber, Jacob

    2011-01-01

    Apolipoprotein E (apoE) is involved in the risk to develop sporadic Alzheimer’s disease (AD). Since impaired central acetylcholine (ACh) function is a hallmark of AD, apoE may influence ACh function by modulating muscarinic ACh receptors (mAChRs). To test this hypothesis, mAChR binding was measured in mice lacking apoE and wild type C57BL/6J mice. Mice were also tested on the pre-pulse inhibition, delay eyeblink classical conditioning, and 5-choice serial reaction time tasks, which are all modulated by ACh transmission. Mice were also given scopolamine to challenge central mAChR function. Compared to wild type mice, mice lacking apoE had reduced number of cortical and hippocampal mAChRs. Scopolamine had a small effect on delay eyeblink classical conditioning in wild type mice but a large effect in mice lacking apoE. Mice lacking apoE were also unable to acquire performance on the 5-choice serial reaction time task. These results support a role for apoE in ACh function and suggest that modulation of cortical and hippocampal mAChRs might contribute to genotype differences in scopolamine sensitivity and task acquisition. Impaired apoE functioning may result in cholinergic deficits that contribute to the cognitive impairments seen in AD. PMID:19178986

  3. Vesicular acetylcholine transporter knock down-mice are more susceptible to inflammation, c-Fos expression and sickness behavior induced by lipopolysaccharide.

    PubMed

    Leite, Hércules Ribeiro; Oliveira-Lima, Onésia Cristina de; Pereira, Luciana de Melo; Oliveira, Vinícius Elias de Moura; Prado, Vania Ferreira; Prado, Marco Antônio Máximo; Pereira, Grace Schenatto; Massensini, André Ricardo

    2016-10-01

    In addition to the well-known functions as a neurotransmitter, acetylcholine (ACh) can modulate of the immune system. Nonetheless, how endogenous ACh release inflammatory responses is still not clear. To address this question, we took advantage of an animal model with a decreased ACh release due a reduction (knockdown) in vesicular acetylcholine transporter (VAChT) expression (VAChT-KD(HOM)). These animals were challenged with lipopolysaccharide (LPS). Afterwards, we evaluated sickness behavior and quantified systemic and cerebral inflammation as well as neuronal activation in the dorsal vagal complex (DVC). VAChT-KD(HOM) mice that were injected with LPS (10mg/kg) showed increased mortality rate as compared to control mice. In line with this result, a low dose of LPS (0.1mg/kg) increased the levels of pro-inflammatory (TNF-α, IL-1β, and IL-6) and anti-inflammatory (IL-10) cytokines in the spleen and brain of VAChT-KD(HOM) mice in comparison with controls. Similarly, serum levels of TNF-α and IL-6 were increased in VAChT-KD(HOM) mice. This excessive cytokine production was completely prevented by administration of a nicotinic receptor agonist (0.4mg/kg) prior to the LPS injection. Three hours after the LPS injection, c-Fos expression increased in the DVC region of VAChT-KD(HOM) mice compared to controls. In addition, VAChT-KD(HOM) mice showed behavioral changes such as lowered locomotor and exploratory activity and reduced social interaction after the LPS challenge, when compared to control mice. Taken together, our results show that the decreased ability to release ACh exacerbates systemic and cerebral inflammation and promotes neural activation and behavioral changes induced by LPS. In conclusion, our findings support the notion that activity of cholinergic pathways, which can be modulated by VAChT expression, controls inflammatory and neural responses to LPS challenge.

  4. Nicotine activates and up-regulates nicotinic acetylcholine receptors in bronchial epithelial cells.

    PubMed

    Fu, Xiao Wen; Lindstrom, Jon; Spindel, Eliot R

    2009-07-01

    Prenatal nicotine exposure impairs normal lung development and leads to diminished pulmonary function after birth. Previous work from our laboratory has demonstrated that nicotine alters lung development by affecting a nonneuronal cholinergic autocrine loop that is expressed in lung. Bronchial epithelial cells (BECs) express choline acetyltransferase, the choline high-affinity transporter and nicotinic acetylcholine (ACh) receptor (nAChR) subunits. We now demonstrate through a combination of morphological and electrophysiological techniques that nicotine affects this autocrine loop by up-regulating and activating cholinergic signaling. RT-PCR showed the expression of alpha 3, alpha 4, alpha 7, alpha 9, alpha 10, beta2, and beta 4 nAChR mRNAs in rhesus monkey lung and cultured BECs. The expression of alpha 7, alpha 4, and beta2 nAChR was confirmed by immunofluorescence in the cultured BECs and lung. The electrophysiological characteristics of nAChR in BECs were determined using whole-cell patch-clamp on cultured BECs. Both ACh and nicotine evoked an inward current, with a rapid desensitizing current. Nicotine induced inward currents in a concentration-dependent manner, with an EC(50) of 26.7 microM. Nicotine-induced currents were reversibly blocked by the nicotinic antagonists, mecamylamine, dihydro-beta-erythroidine, and methyllcaconitine. Incubation of BECs with 1 microM nicotine for 48 hours enhanced nicotine-induced currents by roughly 26%. The protein tyrosine phosphorylation inhibitor, genistein, increased nicotine-induced currents by 58% and enhanced methyllcaconitine-sensitive currents (alpha 7 nAChR activities) 2.3-fold, whereas the protein tyrosine phosphatase inhibitor, pervanadate, decreased the effects of nicotine. These results demonstrate that chronic nicotine exposure up-regulates nAChR activity in developing lung, and that nAChR activity can be further modified by tyrosine phosphorylation.

  5. Improvement of Acetylcholine-Induced Vasodilation by Acute Exercise in Ovariectomized Hypertensive Rats.

    PubMed

    Cheng, Tsung-Lin; Lin, Yi-Yuan; Su, Chia-Ting; Hu, Chun-Che; Yang, Ai-Lun

    2016-06-30

    Postmenopause is associated with the development of cardiovascular disease, such as hypertension. However, limited information is available regarding effects of exercise on cardiovascular responses and its underlying mechanisms in the simultaneous postmenopausal and hypertensive status. We aimed to investigate whether acute exercise could enhance vasodilation mediated by acetylcholine (ACh) and sodium nitroprusside (SNP) in ovariectomized hypertensive rats. The fifteen-week-old female spontaneously hypertensive rats (SHR) were bilaterally ovariectomized, at the age of twenty-four weeks, and randomly divided into sedentary (SHR-O) and acute exercise (SHR-OE) groups. Age-matched WKY rats were used as the normotensive control group. The SHR-OE group ran on a motor-driven treadmill at a speed of 24 m/min for one hour in a moderate-intensity program. Following a single bout of exercise, rat aortas were isolated for the evaluation of the endothelium-dependent (ACh-induced) and endothelium-independent (SNP-induced) vasodilation by the organ bath system. Also, the serum levels of oxidative stress and antioxidant activities, including malondialdehyde (MDA), superoxide dismutase (SOD), and catalase, were measured after acute exercise among the three groups. We found that acute exercise significantly enhanced the ACh-induced vasodilation, but not the SNP-induced vasodilation, in ovariectomized hypertensive rats. This increased vasodilation was eliminated after the inhibition of nitric oxide synthase (NOS). Also, the activities of SOD and catalase were significantly increased after acute exercise, whereas the level of MDA was comparable among the three groups. These results indicated that acute exercise improved the endothelium-dependent vasodilating response to ACh through the NOS-related pathway in ovariectomized hypertensive rats, which might be associated with increased serum antioxidant activities.

  6. Inhibition of Nicotinic Acetylcholine Receptors, a Novel Facet in the Pleiotropic Activities of Snake Venom Phospholipases A2

    PubMed Central

    Vulfius, Catherine A.; Kasheverov, Igor E.; Starkov, Vladislav G.; Osipov, Alexey V.; Andreeva, Tatyana V.; Filkin, Sergey Yu.; Gorbacheva, Elena V.; Astashev, Maxim E.; Tsetlin, Victor I.; Utkin, Yuri N.

    2014-01-01

    Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes. PMID:25522251

  7. Highly Selective and Sensitive Detection of Acetylcholine Using Receptor-Modified Single-Walled Carbon Nanotube Sensors

    NASA Astrophysics Data System (ADS)

    Xu, Shihong; Kim, Byeongju; Song, Hyun Seok; Jin, Hye Jun; Park, Eun Jin; Lee, Sang Hun; Lee, Byung Yang; Park, Tai Hyun; Hong, Seunghun

    2015-03-01

    Acetylcholine (ACh) is a neurotransmitter in a human central nervous system and is related to various neural functions such as memory, learning and muscle contractions. Dysfunctional ACh regulations in a brain can induce several neuropsychiatric diseases such as Alzheimer's disease, Parkinson's disease and myasthenia gravis. In researching such diseases, it is important to measure the concentration of ACh in the extracellular fluid of the brain. Herein, we developed a highly sensitive and selective ACh sensor based on single-walled carbon nanotube-field effect transistors (swCNT-FETs). In our work, M1 mAChR protein, an ACh receptor, was expressed in E.coli and coated on swCNT-FETs with lipid membranes. Here, the binding of ACh onto the receptors could be detected by monitoring the change of electrical currents in the underlying swCNT-FETs, allowing the real-time detection of ACh at a 100 pM concentration. Furthermore, our sensor could selectively detect ACh from other neurotransmitters. This is the first report of the real-time sensing of ACh utilizing specific binding between the ACh and M1 mAChR, and it may lead to breakthroughs in various biomedical applications such as drug screening and disease diagnosis.

  8. Enhanced Efficacy of Human Brain-Derived Neural Stem Cells by Transplantation of Cell Aggregates in a Rat Model of Parkinson's Disease

    PubMed Central

    Shin, Eun Sil; Hwang, Onyou; Hwang, Yu-Shik; Suh, Jun-Kyo Francis; Chun, Young Il

    2014-01-01

    Objective Neural tissue transplantation has been a promising strategy for the treatment of Parkinson's disease (PD). However, transplantation has the disadvantages of low-cell survival and/or development of dyskinesia. Transplantation of cell aggregates has the potential to overcome these problems, because the cells can extend their axons into the host brain and establish synaptic connections with host neurons. In this present study, aggregates of human brain-derived neural stem cells (HB-NSC) were transplanted into a PD animal model and compared to previous report on transplantation of single-cell suspensions. Methods Rats received an injection of 6-OHDA into the right medial forebrain bundle to generate the PD model and followed by injections of PBS only, or HB-NSC aggregates in PBS into the ipsilateral striatum. Behavioral tests, multitracer (2-deoxy-2-[18F]-fluoro-D-glucose ([18F]-FDG) and [18F]-N-(3-fluoropropyl)-2-carbomethoxy-3-(4-iodophenyl)nortropane ([18F]-FP-CIT) microPET scans, as well as immunohistochemical (IHC) and immunofluorescent (IF) staining were conducted to evaluate the results. Results The stepping test showed significant improvement of contralateral forelimb control in the HB-NSC group from 6-10 weeks compared to the control group (p<0.05). [18F]-FP-CIT microPET at 10 weeks posttransplantation demonstrated a significant increase in uptake in the HB-NSC group compared to pretransplantation (p<0.05). In IHC and IF staining, tyrosine hydroxylase and human β2 microglobulin (a human cell marker) positive cells were visualized at the transplant site. Conclusion These results suggest that the HB-NSC aggregates can survive in the striatum and exert therapeutic effects in a PD model by secreting dopamine. PMID:25535514

  9. Loss of Acetylcholine Signaling Reduces Cell Clearance Deficiencies in Caenorhabditis elegans.

    PubMed

    Pinto, Sérgio M; Almendinger, Johann; Cabello, Juan; Hengartner, Michael O

    2016-01-01

    The ability to eliminate undesired cells by apoptosis is a key mechanism to maintain organismal health and homeostasis. Failure to clear apoptotic cells efficiently can cause autoimmune diseases in mammals. Genetic studies in Caenorhabditis elegans have greatly helped to decipher the regulation of apoptotic cell clearance. In this study, we show that the loss of levamisole-sensitive acetylcholine receptor, but not of a typical neuronal acetylcholine receptor causes a reduction in the number of persistent cell corpses in worms suffering from an engulfment deficiency. This reduction is not caused by impaired or delayed cell death but rather by a partial restoration of the cell clearance capacity. Mutants in acetylcholine turn-over elicit a similar phenotype, implying that acetylcholine signaling is the process responsible for these observations. Surprisingly, tissue specific RNAi suggests that UNC-38, a major component of the levamisole-sensitive receptor, functions in the dying germ cell to influence engulfment efficiency. Animals with loss of acetylcholine receptor exhibit a higher fraction of cell corpses positive for the "eat-me" signal phosphatidylserine. Our results suggest that modulation by ion channels of ion flow across plasma membrane in dying cells can influence the dynamics of phosphatidylserine exposure and thus clearance efficiency. PMID:26872385

  10. Acetylcholine content in the brain of rats treated with paraoxon and obidoxime

    PubMed Central

    Milošević, M. P.

    1970-01-01

    1. The effect of obidoxime on the rise in brain acetylcholine caused by the anticholinesterase paraoxon was studied in the rat. 2. In animals poisoned with a sublethal dose of paraoxon and thereafter treated with obidoxime the levels of both “free” and total brain acetylcholine were practically the same as those in rats injected with paraoxon only. 3. After poisoning with doses of paraoxon which are lethal unless an oxime is also given, the total acetylcholine in the brain of obidoxime-protected rats continued to accumulate, reaching a peak 2 h after injection of paraoxon. At this time no signs of central effects such as convulsions or tremor were seen. 4. Atropine, given 30 min before paraoxon, markedly reduced the rise in total brain acetylcholine seen when the anticholinesterase is given alone. 5. In rats pretreated with atropine and obidoxime excessive doses of paraoxon which are lethal in the absence of the antidotes produced a rise in total brain acetylcholine which was directly proportional to the dose of paraoxon administered. PMID:5485148

  11. Loss of Acetylcholine Signaling Reduces Cell Clearance Deficiencies in Caenorhabditis elegans.

    PubMed

    Pinto, Sérgio M; Almendinger, Johann; Cabello, Juan; Hengartner, Michael O

    2016-01-01

    The ability to eliminate undesired cells by apoptosis is a key mechanism to maintain organismal health and homeostasis. Failure to clear apoptotic cells efficiently can cause autoimmune diseases in mammals. Genetic studies in Caenorhabditis elegans have greatly helped to decipher the regulation of apoptotic cell clearance. In this study, we show that the loss of levamisole-sensitive acetylcholine receptor, but not of a typical neuronal acetylcholine receptor causes a reduction in the number of persistent cell corpses in worms suffering from an engulfment deficiency. This reduction is not caused by impaired or delayed cell death but rather by a partial restoration of the cell clearance capacity. Mutants in acetylcholine turn-over elicit a similar phenotype, implying that acetylcholine signaling is the process responsible for these observations. Surprisingly, tissue specific RNAi suggests that UNC-38, a major component of the levamisole-sensitive receptor, functions in the dying germ cell to influence engulfment efficiency. Animals with loss of acetylcholine receptor exhibit a higher fraction of cell corpses positive for the "eat-me" signal phosphatidylserine. Our results suggest that modulation by ion channels of ion flow across plasma membrane in dying cells can influence the dynamics of phosphatidylserine exposure and thus clearance efficiency.

  12. Acetylcholine and calcium on membrane permeability and contraction of intestinal smooth muscle.

    PubMed

    Hurwitz, L; Von Hagen, S; Joiner, P D

    1967-05-01

    Acetylcholine elicited a sustained contraction and an increase in potassium efflux in longitudinal muscle isolated from the guinea pig ileum. Stepwise increases in the calcium concentration of the bathing medium, from 0.06 to 36 mM generally reduced the increase in potassium efflux, but had a complex effect on the mechanical response. Contractions produced by high levels of acetylcholine became progressively larger or remained at a high magnitude as the calcium concentration was increased. Contractions produced by low levels of acetylcholine also improved initially, but were depressed again by the highest concentration of calcium introduced. Ethanol, in the appropriate concentration, inhibited completely the acetylcholine-induced contraction without reducing the increase in potassium efflux. Calcium reversed this effect. Both extracellular calcium and ethanol depressed the large, transient increase in muscle tone developed by fibers that were preincubated in a high calcium medium and then exposed to a calcium-free medium. These findings suggested that extracellular calcium ions react with two different sites in the membrane, a stabilizing site and a storage site. A muscle contraction is activated by calcium ions which diffuse from the storage site to the myoplasm. Calcium ions reacting with the stabilizing site impede this diffusion process. Part of the stimulatory effect of acetylcholine is derived from its capacity to counteract the action of calcium at the stabilizing site.

  13. Purinergic component in the coronary vasodilatation to acetylcholine after ischemia-reperfusion in perfused rat hearts.

    PubMed

    García-Villalón, Ángel Luis; Granado, Miriam; Monge, Luis; Fernández, Nuria; Carreño-Tarragona, Gonzalo; Amor, Sara

    2014-01-01

    To determine the involvement of purinergic receptors in coronary endothelium-dependent relaxation, the response to acetylcholine (1 × 10(-8) to 3 × 10(-7)M) was recorded in isolated rat hearts perfused according to the Langendorff procedure before and after 30 min of ischemia and 15 min of reperfusion and after the inhibition of nitric oxide synthesis with L-NAME (10(-4)M), in the absence and presence of the antagonist of purinergic P2X receptors, PPADS (3 × 10(-6)M), and of the antagonist of purinergic P2Y receptors, Reactive Blue 2 (3 × 10(-7)M). In control conditions, the relaxation to acetylcholine was not altered by PPADS or Reactive Blue 2. The relaxation to acetylcholine was reduced after ischemia-reperfusion, and, in this condition, it was further reduced by treatment with PPADS or Reactive Blue 2. Likewise, the relaxation to acetylcholine was reduced by L-NAME, and reduced further by Reactive Blue 2 but not by PPADS. These results suggest that the relaxation to acetylcholine may be partly mediated by purinergic receptors after ischemia-reperfusion, due to the reduction of nitric oxide release in this condition.

  14. Evaluation of benzyltetrahydroisoquinolines as ligands for neuronal nicotinic acetylcholine receptors

    PubMed Central

    Exley, Richard; Iturriaga-Vásquez, Patricio; Lukas, Ronald J; Sher, Emanuele; Cassels, Bruce K; Bermudez, Isabel

    2005-01-01

    Effects of derivatives of coclaurine (C), which mimic the ‘eastern' or the nonquaternary halves of the alkaloids tetrandrine or d-tubocurarine, respectively, both of which are inhibitors of nicotinic acetylcholine receptors (nACh), were examined on recombinant, human α7, α4β2 and α4β4 nACh receptors expressed in Xenopus oocytes and clonal cell lines using two-electrode voltage clamping and radioligand binding techniques. In this limited series, Cs have higher affinity and are most potent at α4 subunit-containing-nACh receptors and least potent at homomeric α7 receptors, and this trend is very marked for the N-unsubstituted C and its O,O′-bisbenzyl derivative. 7-O-Benzyl-N-methylcoclaurine (BBCM) and its 12-O-methyl derivative showed the highest affinities and potencies at all three receptor subtypes, and this suggests that lipophilicity at C7 and/or C12 increases potency. Laudanosine and armepavine (A) were noncompetitive and voltage-dependent inhibitors of α7, α4β2 or α4β4 receptors, but the bulkier C7-benzylated 7BNMC (7-O-benzyl-N-methylcoclaurine) and 7B12MNMC (7-O-benzyl-N,12-O-dimethyl coclaurine) were voltage-independent, noncompetitive inhibitors of nACh receptors. Voltage-dependence was also lost on going from A to its N-ethyl analogue. These studies suggest that C derivatives may be useful tools for studies characterising the antagonist and ion channel sites on human α7, α4β2 or α4β4 nACh receptors and for revealing structure–function relationships for nACh receptor antagonists. PMID:15980871

  15. Rapid synthesis of acetylcholine receptors at neuromuscular junctions.

    PubMed

    Ramsay, D A; Drachman, D B; Pestronk, A

    1988-10-11

    The rate of acetylcholine receptor (AChR) degradation in mature, innervated mammalian neuromuscular junctions has recently been shown to be biphasic; up to 20% are rapidly turned over (RTOs; half life less than 1 day) whereas the remainder are lost more slowly ('stable' AChRs; half life 10-12 days). In order to maintain normal junctional receptor density, synthesis and insertion of AChRs should presumably be sufficiently rapid to replace both the RTOs and the stable receptors. We have tested this prediction by blocking pre-existing AChRs in the mouse sternomastoid muscle with alpha-bungarotoxin (alpha-BuTx), and monitoring the subsequent appearance of 'new' junctional AChRs at intervals of 3 h to 20 days by labeling them with 125I-alpha-BuTx. The results show that new receptors were initially inserted rapidly (16% at 24 h and 28% at 48 h). The rate of increase of 'new' 125I-alpha-BuTx binding sites gradually slowed down during the remainder of the time period studied. Control observations excluded possible artifacts of the experimental procedure including incomplete blockade of AChRs, dissociation of toxin-receptor complexes, or experimentally induced alteration of receptor synthesis. The present demonstration of rapid synthesis and incorporation of AChRs at innervated neuromuscular junctions provides support for the concept of a subpopulation of rapidly turned over AChRs. The RTOs may serve as precursors for the larger population of stable receptors and have an important role in the metabolism of the neuromuscular synapse.

  16. Vascular effects of acetylcholine in the perfused rabbit lung

    SciTech Connect

    Cherry, P.D.; Gillis, C.N.

    1986-03-05

    Acetylcholine (ACh) relaxes large, isolated arteries by releasing an endothelium-derived relaxing factor (EDRF). The authors decided to determine if ACh releases EDRF in rabbit lungs (RL) perfused in situ and if chemical injury with tetradecanoyl phorbol myristate acetate (TPA) could modify EDRF release in RL and in rabbit pulmonary arteries (RPA) in vitro. RL were perfused at 15 ml/min with Krebs-dextran solution. 1 ..mu..M ACh infusion raised perfusion pressure (P) in RL that was blocked by 30 ..mu..M indomethacin (IND) in the perfusate. However, when IND-treated RL were perfused with the stable endoperoxide analog, U46619 (2-6nM) to increase P, ACh infusion (0.01-1.0 ..mu..M) consistently decreased elevated P. The vasodilator response to infusion of 1 ..mu..M ACh was acutely antagonized by infusion of either 20 ..mu..M quinacrine (Q) or 10 ..mu..M Fe/sup + +/-hemoglobin (Hb). ACh did not decrease P in IND-treated RL pre-equilibrated with Q or Hb. TPA (10 nM) antagonized ACh-reduction of P and the ACh-induced relaxation of isolated RPA. The TPA antagonism of ACh-relaxation of RPA was prevented by catalase (300 U/ml). From these results they conclude that: 1) ACh-induced vasoconstriction in RL depends on cyclooxygenase product(s). 2) IND unmasks ACh-induced vasodilatation in RL that is inhibited by Q and by Hb suggesting that the effect is mediated by EDRF. 3) TPA inhibits ACh-induced vasodilatation and relaxation of RPA via the release of H/sub 2/O/sub 2/ or a related oxidant that injures the endothelium.

  17. Functional interaction between Lypd6 and nicotinic acetylcholine receptors.

    PubMed

    Arvaniti, Maria; Jensen, Majbrit M; Soni, Neeraj; Wang, Hong; Klein, Anders B; Thiriet, Nathalie; Pinborg, Lars H; Muldoon, Pretal P; Wienecke, Jacob; Imad Damaj, M; Kohlmeier, Kristi A; Gondré-Lewis, Marjorie C; Mikkelsen, Jens D; Thomsen, Morten S

    2016-09-01

    Nicotinic acetylcholine receptors (nAChRs) affect multiple physiological functions in the brain and their functions are modulated by regulatory proteins of the Lynx family. Here, we report for the first time a direct interaction of the Lynx protein LY6/PLAUR domain-containing 6 (Lypd6) with nAChRs in human brain extracts, identifying Lypd6 as a novel regulator of nAChR function. Using protein cross-linking and affinity purification from human temporal cortical extracts, we demonstrate that Lypd6 is a synaptically enriched membrane-bound protein that binds to multiple nAChR subtypes in the human brain. Additionally, soluble recombinant Lypd6 protein attenuates nicotine-induced hippocampal inward currents in rat brain slices and decreases nicotine-induced extracellular signal-regulated kinase phosphorylation in PC12 cells, suggesting that binding of Lypd6 is sufficient to inhibit nAChR-mediated intracellular signaling. We further show that perinatal nicotine exposure in rats (4 mg/kg/day through minipumps to dams from embryonic day 7 to post-natal day 21) significantly increases Lypd6 protein levels in the hippocampus in adulthood, which did not occur after exposure to nicotine in adulthood only. Our findings suggest that Lypd6 is a versatile inhibitor of cholinergic signaling in the brain, and that Lypd6 is dysregulated by nicotine exposure during early development. Regulatory proteins of the Lynx family modulate the function of nicotinic receptors (nAChRs). We report for the first time that the Lynx protein Lypd6 binds to nAChRs in human brain extracts, and that recombinant Lypd6 decreases nicotine-induced ERK phosphorylation and attenuates nicotine-induced hippocampal inward currents. Our findings suggest that Lypd6 is a versatile inhibitor of cholinergic signaling in the brain. PMID:27344019

  18. Circulating antibodies against nicotinic acetylcholine receptors in chagasic patients

    PubMed Central

    GOIN, J C; VENERA, G; BONINO, M BISCOGLIO DE JIMÉNEZ; STERIN-BORDA, L

    1997-01-01

    Human and experimental Chagas' disease causes peripheral nervous system damage involving neuromuscular transmission alterations at the neuromuscular junction. Additionally, autoantibodies directed to peripheral nerves and sarcolemmal proteins of skeletal muscle have been described. In this work, we analyse the ability of serum immunoglobulin factors associated with human chagasic infection to bind the affinity-purified nicotinic acetylcholine receptor (nAChR) from electric organs of Discopyge tschudii and to identify the receptor subunits involved in the interaction. The frequency of serum anti-nAChR reactivity assayed by dot-blot was higher in seropositive chagasic patients than in uninfected subjects. Purified IgG obtained from chagasic patients immunoprecipitated a significantly higher fraction of the solubilized nAChR than normal IgG. Furthermore, immunoblotting assays indicated that α and β are the main subunits involved in the interaction. Chagasic IgG was able to inhibit the binding of α-bungarotoxin to the receptor in a concentration-dependent manner, confirming the contribution of the α-subunit in the autoantibody-receptor interaction. The presence of anti-nAChR antibodies was detected in 73% of chagasic patients with impairment of neuromuscular transmission in conventional electromyographical studies, indicating a strong association between seropositive reactivity against nAChR and electromyographical abnormalities in chagasic patients. The chronic binding of these autoantibodies to the nAChR could induce a decrease in the population of functional nAChRs at the neuromuscular junction and consequently contribute to the electrophysiological neuromuscular alterations described in the course of chronic Chagas' disease. PMID:9367405

  19. Functional differences between neurotransmitter binding sites of muscle acetylcholine receptors.

    PubMed

    Nayak, Tapan K; Bruhova, Iva; Chakraborty, Srirupa; Gupta, Shaweta; Zheng, Wenjun; Auerbach, Anthony

    2014-12-01

    A muscle acetylcholine receptor (AChR) has two neurotransmitter binding sites located in the extracellular domain, at αδ and either αε (adult) or αγ (fetal) subunit interfaces. We used single-channel electrophysiology to measure the effects of mutations of five conserved aromatic residues at each site with regard to their contribution to the difference in free energy of agonist binding to active versus resting receptors (ΔGB1). The two binding sites behave independently in both adult and fetal AChRs. For four different agonists, including ACh and choline, ΔGB1 is ∼-2 kcal/mol more favorable at αγ compared with at αε and αδ. Only three of the aromatics contribute significantly to ΔGB1 at the adult sites (αY190, αY198, and αW149), but all five do so at αγ (as well as αY93 and γW55). γW55 makes a particularly large contribution only at αγ that is coupled energetically to those contributions of some of the α-subunit aromatics. The hydroxyl and benzene groups of loop C residues αY190 and αY198 behave similarly with regard to ΔGB1 at all three kinds of site. ACh binding energies estimated from molecular dynamics simulations are consistent with experimental values from electrophysiology and suggest that the αγ site is more compact, better organized, and less dynamic than αε and αδ. We speculate that the different sensitivities of the fetal αγ site versus the adult αε and αδ sites to choline and ACh are important for the proper maturation and function of the neuromuscular synapse. PMID:25422413

  20. Cholinergic synaptic vesicle heterogeneity: evidence for regulation of acetylcholine transport

    SciTech Connect

    Gracz, L.M.; Wang, W.; Parsons, S.M.

    1988-07-12

    Crude cholinergic synaptic vesicles from a homogenate of the electric organ of Torpedo californica were centrifuged to equilibrium in an isosmotic sucrose density gradient. The classical VP/sub 1/ synaptic vesicles banding at 1.055 g/mL actively transported (/sup 3/H)acetylcholine (AcCh). An organelle banding at about 1.071 g/mL transported even more (/sup 3/H)AcCh. Transport by both organelles was inhibited by the known AcCh storage blockers trans-2-(4-phenylpiperidino)cyclohexanol (vesamicol, formerly AH5183) and nigericin. Relative to VP/sub 1/ vesicles the denser organelle was slightly smaller as shown by size-exclusion chromatography. It is concluded that the denser organelle corresponds to the recycling VP/sub 2/ synaptic vesicle originally described in intact Torpedo marmorata electric organ. The properties of the receptor for vesamicol were studied by measuring binding of (/sup 3/H)vesamicol, and the amount of SV2 antigen characteristic of secretory vesicles was assayed with a monoclonal antibody directed against it. Relative to VP/sub 1/ vesicles the VP/sub 2/ vesicles had a ratio of (/sup 3/H)AcCh transport activity to vesamicol receptor concentration that typically was 4-7-fold higher, whereas the ratio of SV2 antigen concentration to vesamicol receptor concentration was about 2-fold higher. The Hill coefficients ..cap alpha../sub H/ and equilibrium dissociation constants K for vesamicol binding to VP/sub 1/ and VP/sub 2/ vesicles were essentially the same. The positive Hill coefficient suggests that the vesamicol receptor exists as a homotropic oligomeric complex. The results demonstrate that VP/sub 1/ and VP/sub 2/ synaptic vesicles exhibit functional differences in the AcCh transport system, presumably as a result of regulatory phenomena.

  1. Strain differences in guinea pigs' bronchial sensitivity to acetylcholine.

    PubMed

    Mikami, H; Nishibata, R; Kawamoto, Y; Ino, T

    1990-01-01

    The bronchial sensitivity to acetylcholine (ACh) of guinea pigs of various strains was investigated to clarify strain differences. Inbred Strain 2, Strain 13 and JY-1 and non-inbred Hartley strain (two colonies) were used in this experiment. (1) Guinea pigs were exposed to 0.08% ACh aerosol and the time needed to produce falling down (TNPFD) was determined. Mean +/- standard error of TNPFD (n = 14 per group) of animals was 182 +/- 28 sec, 148 +/- 22 sec, 210 +/- 30 sec, 342 +/- 24 sec and 406 +/- 36 sec in Strain 2, Strain 13, JY-1, Hartley (Japan SLC) and Hartley (Hitachi), respectively. There was a significant difference in TNPFD between inbred strains and non-inbred strains (P less than 0.05 or P less than 0.01), indicating that inbred strains had higher sensitivity. (2) Guinea pigs were exposed to 20-5000 micrograms/ml ACh for 2 min. The mean dose threshold as determined by transcutaneous oxygen pressure was 524 micrograms/ml, 424 micrograms/ml, 614 micrograms/ml, 1317 micrograms/ml and 1651 micrograms/ml (n = 14 per group) in Strain 2, Strain 13, JY-1, Hartley (Japan SLC) and Hartley (Hitachi), respectively. Inbred strains showed lower dose thresholds than non-inbred strains. (3) Isolated trachea-lungs of 5 guinea pigs were perfused with 10(-9)-10(-5) g/ml ACh to determine strain differences. Dose response curves of animals of inbred strains shifted to the left (lower concentrations), unlike those of non-inbred strains, suggesting that inbred strains had higher sensitivity to ACh than non-inbred strains.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Purification of the muscarinic acetylcholine receptor from porcine atria.

    PubMed Central

    Peterson, G L; Herron, G S; Yamaki, M; Fullerton, D S; Schimerlik, M I

    1984-01-01

    The muscarinic acetylcholine receptor from porcine atria has been purified 100,000-fold to homogeneity by solubilization in digitonin/cholate and sequential chromatography on wheat germ agglutinin-agarose, diethylaminoethylagarose, hydroxylapatite, and 3-(2'-aminobenzhydryloxy)tropane-agarose. The yield of purified receptor was 4.3% of that found in the membrane fraction, and the purified receptor bound 11.1-12.8 nmol of L-[3H]quinuclidinyl benzilate per mg of protein, corresponding to a binding component Mr of 78,400-90,000. The purified receptor preparation consisted of two polypeptides in approximately equimolar amounts when examined on silver-stained sodium dodecyl sulfate/polyacrylamide gels. The larger polypeptide (Mr 78,000 on 8% polyacrylamide gels) was specifically alkylated with [3H]propylbenzilylcholine mustard, whereas the smaller polypeptide (Mr 14,800) was not labeled. The possibility that the small polypeptide is a contaminant fortuitously appearing in equimolar amounts with the large polypeptide cannot be ruled out at this time. The purified preparation was highly stable, with no measurable change in the number of ligand binding sites or the gel pattern after 1 month's storage on ice. Scatchard analysis showed a single class of binding sites for the antagonist L-[3H]quinuclidinyl benzilate with a dissociation constant of 61 +/- 4 pM. Equilibrium titration experiments demonstrated that the antagonist L-hyoscyamine displaced L-[3H]quinuclidinyl benzilate from a single class of sites (Kd = 475 +/- 30 pM), whereas the agonist carbamoylcholine interacted at two populations of sites (53% +/- 3% high affinity, Kd = 1.1 +/- 0.3 microM; 47% +/- 3% low affinity, Kd = 67 +/- 14 microM). The ligand binding data were very similar to that for the membrane-bound receptor, suggesting that the receptor has not been altered radically during purification. Images PMID:6589642

  3. Potassium channel-mediated relaxation to acetylcholine in rabbit arteries.

    PubMed

    Cowan, C L; Palacino, J J; Najibi, S; Cohen, R A

    1993-09-01

    Endothelium-dependent relaxation is associated with smooth muscle hyperpolarization in many arteries which may account for relaxation that persists in the presence of nitric oxide inhibitors such as NG-nitro-L-arginine methyl ester (L-NAME). Acetylcholine (ACh)-induced relaxations of the rabbit thoracic and abdominal aorta and iliac and carotid arteries were studied for the relative contribution of nitric oxide-dependent and -independent mechanisms in rings suspended for measurement of isometric tension. Although relaxation of the thoracic aorta to ACh (10(-6) M) was almost blocked completely by L-NAME (3 x 10(-5) M), the maximal relaxation in the abdominal aorta, carotid and iliac arteries was only reduced by 28, 26 and 62%, respectively. In rings of abdominal aorta, L-NAME blocked the ACh-stimulated (10(-6) M) rise in cyclic GMP verifying that relaxation which persists in L-NAME-treated rings is not mediated by nitric oxide. The L-NAME resistant response was nearly abolished by elevated external K+ in rings of abdominal aorta and carotid artery, suggesting this relaxation may be mediated by a membrane potential sensitive mechanism. Furthermore, tetraethylammonium (10(-3) M) partially and charybdotoxin (5 x 10(-8) M) completely inhibited the remaining L-NAME-resistant relaxation in both abdominal aorta and carotid artery, suggesting a role for Ca(++)-activated K(+)-channels. Blockers of ATP-sensitive K+ channels also inhibited the L-NAME resistant relaxation in the abdominal aorta only.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8396636

  4. Functional analysis of Torpedo californica nicotinic acetylcholine receptors in multiple activation states by SSM-based electrophysiology.

    PubMed

    Niessen, K V; Muschik, S; Langguth, F; Rappenglück, S; Seeger, T; Thiermann, H; Worek, F

    2016-04-15

    Organophosphorus compounds (OPC), i.e. nerve agents or pesticides, are highly toxic due to their strong inhibition potency against acetylcholinesterase (AChE). Inhibited AChE results in accumulation of acetylcholine in the synaptic cleft and thus the desensitisation of the nicotinic acetylcholine receptor (nAChR) in the postsynaptic membrane is provoked. Direct targeting of nAChR to reduce receptor desensitisation might be an alternative therapeutic approach. For drug discovery, functional properties of potent therapeutic candidates need to be investigated in addition to affinity properties. Solid supported membrane (SSM)-based electrophysiology is useful for functional characterisation of ligand-gated ion channels like nAChRs, as charge translocations via capacitive coupling of the supporting membrane can be measured. By varying the agonist (carbamoylcholine) concentration, different functional states of the nAChR were initiated. Using plasma membrane preparations obtained from Torpedo californica electric organ, functional properties of selected nAChR ligands and non-oxime bispyridinium compounds were investigated. Depending on overall-size, the bispyridinium compounds enhanced or inhibited cholinergic signals induced by 100 μM carbamoylcholine. Applying excessive concentrations of the agonist carbamoylcholine provoked desensitisation of the nAChRs, whereas addition of bispyridinium compounds bearing short alkyl linkers exhibited functional recovery of previously desensitised nAChRs. The results suggest that these non-oxime bispyridinium compounds possibly interacted with nAChR subtypes in a manner of a positive allosteric modulator (PAM). The described newly developed functional assay is a valuable tool for the assessment of functional properties of potential compounds such as nAChR modulating ligands, which might be a promising approach in the therapeutically treatment of OPC-poisonings. PMID:26851639

  5. Prejunctional inhibition of norepinephrine release caused by acetylcholine in the human saphenous vein

    SciTech Connect

    Rorie, D.K.; Rusch, N.J.; Shepherd, J.T.; Vanhoutte, P.M.; Tyce, G.M.

    1981-08-01

    We performed experiments to determine whether or not acetylcholine exerts a prejunctional inhibitory effect on adrenergic neurotransmission in the human blood vessel wall. Rings of human greater saphenous veins were prepared 2 to 15 hours after death and mounted for isometric tension recording in organ chambers filled with Krebs-Ringer solution. Acetylcholine depressed contractile responses to electric activation of the sympathetic nerve endings significantly more than those to exogenous norepinephrine; the relaxations caused by the cholinergic transmitter were antagonized by atropine. Helical strips were incubated with (/sub 3/H)norepinephrine and mounted for superfusion. Electric stimulation augmented the fractional release of labeled norepinephrine. Acetylcholine caused a depression of the evoked /sub 3/H release which was antagonized by atropine but not by hexamethonium. These experiments demonstrate that, as in animal cutaneous veins, there are prejunctional inhibitory muscarinic receptors on the adrenergic nerve endings in the human saphenous vein. By contrast, the human vein also contains postjunctional inhibitory muscarinic receptors.

  6. Chemical modification and reactivity of sulfhydryls and disulfides of rat brain nicotinic-like acetylcholine receptors

    SciTech Connect

    Lukas, R.J.; Bennett, E.L.

    1980-06-25

    Rat central nervous system binding sites for ..cap alpha..-bungarotoxin display considerable biochemical homology with characterized nicotinic acetylcholine receptors from the periphery. They possess a critical disulfide residue(s), which is susceptible to chemical modification and consequent specific alteration in the affinity of the binding site for cholinergic agonists. After reaction with Na/sub 2/S/sub 2/O/sub 5/, as with reaction with dithiothreitol and 5,5'-dithiobis(2-nitrobenzoic acid), the binding site is frozen in a high affinity state toward acetylcholine. After reduction with dithiothreitol and alkylation with a variety of compounds of different molecular configuration or electrical charge, or both, the binding site is frozen in a low affinity state toward acetylcholine. Thus, effects of disulfide/sulfhydryl modification on agonist binding affinity appear to be attributable to the nature of the covalent modification rather than charge or steric alteration at the receptor active site brought about by chemical modification.

  7. Comparison of the cardiostimulatory effects of acetylcholine and nicotine on the working guinea-pig heart.

    PubMed

    Rodgers, R L; Moore, J I; Hornbrook, K R

    1979-12-01

    The isolated working guinea-pig heart was used to compare the cardiostimulatory effects of acetylcholine and nicotine observed in the presence of atropine. Both agonists increased aortic pressure, left ventricular pressure, left ventricular dP/dt, cardiac output, and ventricular cyclic AMP levels. These responses were qualitatively and quantitatively similar to the effects of exogenous norepinephrine. Hexamethonium treatment abolished the responses to acetylcholine and to nicotine. However, several differences in the responses of the two agonists were also observed with respect to: 1) the effect of propranolol pretreatment, 2) selective effects on coronary and aortic flow rates, 3) coefficients of correlation between ventricular cyclic AMP and changes in dP/dt, and 4) the "autoinhibition" effect. The results support the view that the cardiostimulatory effects of acetylcholine are due entirely to endogenous catecholamine release, but that the effects of nicotine may involve an additional action.

  8. Acetylcholine activates an inward current in single mammalian smooth muscle cells.

    PubMed

    Benham, C D; Bolton, T B; Lang, R J

    Acetylcholine, the major excitatory neurotransmitter to the smooth muscle of mammalian intestine, is known to depolarize smooth muscle cells with an apparent increase in membrane conductance. However, the ionic mechanisms that are triggered by muscarinic receptor activation and underlie this response are poorly understood, due in part to the technical problems associated with the electrophysiological study of smooth muscle. The muscarinic action of acetylcholine in certain neurones has been shown to involve the switching off of a resting K+ current (M-current) and a similar mechanism has recently also been identified in smooth muscle of amphibian stomach. We have now applied the patch-clamp technique to single smooth muscle cells of rabbit jejunum and find that muscarinic receptor activation switches on a nonselective, voltage-sensitive inward current. In addition, acetylcholine activates and then suppresses spontaneous K+ current transients, which are probably triggered by rises in intracellular Ca2+ in these cells.

  9. Identification of a molecular weight 43,000 protein kinase in acetylcholine receptor-enriched membranes.

    PubMed Central

    Gordon, A S; Milfay, D; Diamond, I

    1983-01-01

    A photoaffinity ATP ligand is used to identify the protein kinase present in acetylcholine receptor-enriched membranes from Torpedo californica. Incubation of these membranes with 8-azido-[alpha-32P]ATP and subsequent irradiation with UV light resulted in covalent labeling of a major band of Mr 43,000. Alkali-stripped membranes that show a selective reduction in the Mr 43,000 polypeptide also show a corresponding reduction in incorporation of photoaffinity label. In addition, the neutralized alkaline extract also showed one band at Mr 43,000 when labeled with the photoaffinity ligand. After alkali extraction, endogenous protein kinase activity decreased in the membranes in proportion to the loss of Mr 43,000 peptide. Moreover, the alkaline extract was able to phosphorylate casein in an exogenous assay system. These results suggest that a Mr 43,000 polypeptide in acetylcholine receptor-enriched membranes is the acetylcholine receptor kinase. Images PMID:6577458

  10. Some properties of human neuronal alpha 7 nicotinic acetylcholine receptors fused to the green fluorescent protein.

    PubMed

    Palma, Eleonora; Mileo, Anna M; Martinez-Torres, Ataulfo; Eusebi, Fabrizio; Miledi, Ricardo

    2002-03-19

    The functional properties and cellular localization of the human neuronal alpha7 nicotinic acetylcholine (AcCho) receptor (alpha7 AcChoR) and its L248T mutated (mut) form were investigated by expressing them alone or as gene fusions with the enhanced version of the green fluorescent protein (GFP). Xenopus oocytes injected with wild-type (wt), mutalpha7, or the chimeric subunit cDNAs expressed receptors that gated membrane currents when exposed to AcCho. As already known, AcCho currents generated by wtalpha7 receptors decay much faster than those elicited by the mutalpha7 receptors. Unexpectedly, the fusion of GFP to the wt and mutated alpha7 receptors led to opposite results: the AcCho-current decay of the wt receptors became slower, whereas that of the mutated receptors was accelerated. Furthermore, repetitive applications of AcCho led to a considerable "run-down" of the AcCho currents generated by mutalpha7-GFP receptors, whereas those of the wtalpha7-GFP receptors remained stable or increased in amplitude. The AcCho-current run-down of mutalpha7-GFP oocytes was accompanied by a marked decrease of alpha-bungarotoxin binding activity. Fluorescence, caused by the chimeric receptors expressed, was seen over the whole oocyte surface but was more intense and abundant in the animal hemisphere, whereas it was much weaker in the vegetal hemisphere. We conclude that fusion of GFP to wtalpha7 and mutalpha7 receptors provides powerful tools to study the distribution and function of alpha7 receptors. We also conclude that fused genes do not necessarily recapitulate all of the properties of the original receptors. This fact must be borne close in mind whenever reporter genes are attached to proteins.

  11. Alpha7 nicotinic acetylcholine receptor agonists and PAMs as adjunctive treatment in schizophrenia. An experimental study.

    PubMed

    Marcus, Monica M; Björkholm, Carl; Malmerfelt, Anna; Möller, Annie; Påhlsson, Ninni; Konradsson-Geuken, Åsa; Feltmann, Kristin; Jardemark, Kent; Schilström, Björn; Svensson, Torgny H

    2016-09-01

    Nicotine has been found to improve cognition and reduce negative symptoms in schizophrenia and a genetic and pathophysiological link between the α7 nicotinic acetylcholine receptors (nAChRs) and schizophrenia has been demonstrated. Therefore, there has been a large interest in developing drugs affecting the α7 nAChRs for schizophrenia. In the present study we investigated, in rats, the effects of a selective α7 agonist (PNU282987) and a α7 positive allosteric modulator (PAM; NS1738) alone and in combination with the atypical antipsychotic drug risperidone for their utility as adjunct treatment in schizophrenia. Moreover we also investigated their utility as adjunct treatment in depression in combination with the SSRI citalopram. We found that NS1738 and to some extent also PNU282987, potentiated a subeffective dose of risperidone in the conditioned avoidance response test. Both drugs also potentiated the effect of a sub-effective concentration of risperidone on NMDA-induced currents in pyramidal cells of the medial prefrontal cortex. Moreover, NS1738 and PNU282987 enhanced recognition memory in the novel object recognition test, when given separately. Both drugs also potentiated accumbal but not prefrontal risperidone-induced dopamine release. Finally, PNU282987 reduced immobility in the forced swim test, indicating an antidepressant-like effect. Taken together, our data support the utility of drugs targeting the α7 nAChRs, perhaps especially α7 PAMs, to potentiate the effect of atypical antipsychotic drugs. Moreover, our data suggest that α7 agonists and PAMs can be used to ameliorate cognitive symptoms in schizophrenia and depression. PMID:27474687

  12. In vivo protection against soman toxicity by known inhibitors of acetylcholine synthesis in vitro.

    PubMed

    Sterling, G H; Doukas, P H; Sheldon, R J; O'Neill, J J

    1988-02-01

    Soman inhibits the enzyme acetylcholinesterase, essentially irreversibly, producing an accumulation of acetylcholine (ACh) which is responsible for many of its toxic effects. Current approaches to treatment include: (1) atropine, a muscarinic receptor blocker; (2) pyridine-2-aldoxime methylchloride (2-PAM), an enzyme reactivator; and (3) carbamate protection of the enzyme. However, no fully satisfactory regimen has been found, primarily because of the rapid aging process. In this study, compounds known to inhibit ACh synthesis in vitro were evaluated in combination with atropine and 2-PAM so as to assess their potential utility in protection against soman toxicity in rats. Acetylsecohemicholinium (100 micrograms/kg, i.c.v.t., 30 min prior to soman), an inhibitor of high affinity choline uptake (HAChU) and cholineacetyltransferase (ChAT) activity in vitro, enhanced the protective effects of atropine and 2-PAM, reducing the mortality within the first 2 hr following soman. N-Hydroxyethylnaphthylvinylpyridine (NHENVP), a quaternary ChAT inhibitor (1.7 mumol/kg, i.m.), significantly reduced the overall percent mortality due to soman from 80% to 20%. The compound was most effective when administered 2-3 min prior to soman and was effective only by the intramuscular route. N-Allyl-3-quinuclidinol, a potent HAChU inhibitor (1 mumol/kg, i.m.) was the most effective quinuclidine analog evaluated, also reducing the percent mortality for a 24-hr period. Unlike NHENVP, it was most effective when given 30-60 min prior to soman. It is suggested from the data that compounds that disrupt presynaptic ACh synthesis in vitro may prove effective in treating organophosphate poisoning. The results demonstrate interesting differences among the compounds studied and provide insight for the design of protectants against soman toxicity. These findings further underscore the need to examine the structure activity and pharmacokinetic properties of these compounds, i.e. comparison of routes of

  13. In vivo protection against soman toxicity by known inhibitors of acetylcholine synthesis in vitro.

    PubMed

    Sterling, G H; Doukas, P H; Sheldon, R J; O'Neill, J J

    1988-02-01

    Soman inhibits the enzyme acetylcholinesterase, essentially irreversibly, producing an accumulation of acetylcholine (ACh) which is responsible for many of its toxic effects. Current approaches to treatment include: (1) atropine, a muscarinic receptor blocker; (2) pyridine-2-aldoxime methylchloride (2-PAM), an enzyme reactivator; and (3) carbamate protection of the enzyme. However, no fully satisfactory regimen has been found, primarily because of the rapid aging process. In this study, compounds known to inhibit ACh synthesis in vitro were evaluated in combination with atropine and 2-PAM so as to assess their potential utility in protection against soman toxicity in rats. Acetylsecohemicholinium (100 micrograms/kg, i.c.v.t., 30 min prior to soman), an inhibitor of high affinity choline uptake (HAChU) and cholineacetyltransferase (ChAT) activity in vitro, enhanced the protective effects of atropine and 2-PAM, reducing the mortality within the first 2 hr following soman. N-Hydroxyethylnaphthylvinylpyridine (NHENVP), a quaternary ChAT inhibitor (1.7 mumol/kg, i.m.), significantly reduced the overall percent mortality due to soman from 80% to 20%. The compound was most effective when administered 2-3 min prior to soman and was effective only by the intramuscular route. N-Allyl-3-quinuclidinol, a potent HAChU inhibitor (1 mumol/kg, i.m.) was the most effective quinuclidine analog evaluated, also reducing the percent mortality for a 24-hr period. Unlike NHENVP, it was most effective when given 30-60 min prior to soman. It is suggested from the data that compounds that disrupt presynaptic ACh synthesis in vitro may prove effective in treating organophosphate poisoning. The results demonstrate interesting differences among the compounds studied and provide insight for the design of protectants against soman toxicity. These findings further underscore the need to examine the structure activity and pharmacokinetic properties of these compounds, i.e. comparison of routes of

  14. Electrocatalytic Microelectrode Detectors for Choline and Acetylcholine following Separation by Capillary Electrophoresis

    PubMed Central

    Mukherjee, Jhindan; Kirchhoff, Jon R.

    2009-01-01

    Two electrocatalytic enzyme modified microelectrode systems were employed as end-column amperometric detectors of choline (Ch) and acetylcholine (ACh) following separation by capillary electrophoresis (CE). Horseradish peroxidase crosslinked in an Os based redox polymer hydrogel (HRP-Os) was physically adsorbed on Au microelectrodes followed by chemical crosslinking of the enzymes acetylcholinesterase (AChE) and choline oxidase (ChO). An alternative approach utilized the deposition of the transition metal catalyst, Prussian Blue (PB), on Pt microelectrodes as the electrocatalyst. Utilizing butyrylcholine (BuCh) as an internal standard, the HRP-Os/AChE-ChO and PB/AChE-ChO electrodes exhibited excellent linear responses from 2–2000 μM and 10–2000 μM, respectively, for both Ch and ACh. Detection limits of 0.1 μM or 38 amol were determined for the HRP-Os/AChE-ChO electrode. The limit of detection for ACh and Ch at the PB/AChE-ChO electrode was 5 μM or 9.5 fmol. The electrodes were operated at potentials of +0.10 and −0.10 V vs. Ag/AgCl (3M NaCl), respectively, and thus minimized the potential response from oxidizable interferences. In addition, both electrocatalytic electrodes showed good operational stability for more than 70 hours. The enhanced detection capability of the HRP-Os/AChE-ChO and PB/AChE-ChO electrodes in combination with efficient CE separation of Ch and ACh provides a new sensitive and selective strategy for monitoring and quantifying these cholinergic biomarkers in biological fluids. PMID:20337384

  15. High Throughput Random Mutagenesis and Single Molecule Real Time Sequencing of the Muscle Nicotinic Acetylcholine Receptor

    PubMed Central

    Groot-Kormelink, Paul J.; Ferrand, Sandrine; Kelley, Nicholas; Bill, Anke; Freuler, Felix; Imbert, Pierre-Eloi; Marelli, Anthony; Gerwin, Nicole; Sivilotti, Lucia G.; Miraglia, Loren; Orth, Anthony P.; Oakeley, Edward J.; Schopfer, Ulrich; Siehler, Sandra

    2016-01-01

    High throughput random mutagenesis is a powerful tool to identify which residues are important for the function of a protein, and gain insight into its structure-function relation. The human muscle nicotinic acetylcholine receptor was used to test whether this technique previously used for monomeric receptors can be applied to a pentameric ligand-gated ion channel. A mutant library for the α1 subunit of the channel was generated by error-prone PCR, and full length sequences of all 2816 mutants were retrieved using single molecule real time sequencing. Each α1 mutant was co-transfected with wildtype β1, δ, and ε subunits, and the channel function characterized by an ion flux assay. To test whether the strategy could map the structure-function relation of this receptor, we attempted to identify mutations that conferred resistance to competitive antagonists. Mutant hits were defined as receptors that responded to the nicotinic agonist epibatidine, but were not inhibited by either α-bungarotoxin or tubocurarine. Eight α1 subunit mutant hits were identified, six of which contained mutations at position Y233 or V275 in the transmembrane domain. Three single point mutations (Y233N, Y233H, and V275M) were studied further, and found to enhance the potencies of five channel agonists tested. This suggests that the mutations made the channel resistant to the antagonists, not by impairing antagonist binding, but rather by producing a gain-of-function phenotype, e.g. increased agonist sensitivity. Our data show that random high throughput mutagenesis is applicable to multimeric proteins to discover novel functional mutants, and outlines the benefits of using single molecule real time sequencing with regards to quality control of the mutant library as well as downstream mutant data interpretation. PMID:27649498

  16. High Throughput Random Mutagenesis and Single Molecule Real Time Sequencing of the Muscle Nicotinic Acetylcholine Receptor.

    PubMed

    Groot-Kormelink, Paul J; Ferrand, Sandrine; Kelley, Nicholas; Bill, Anke; Freuler, Felix; Imbert, Pierre-Eloi; Marelli, Anthony; Gerwin, Nicole; Sivilotti, Lucia G; Miraglia, Loren; Orth, Anthony P; Oakeley, Edward J; Schopfer, Ulrich; Siehler, Sandra

    2016-01-01

    High throughput random mutagenesis is a powerful tool to identify which residues are important for the function of a protein, and gain insight into its structure-function relation. The human muscle nicotinic acetylcholine receptor was used to test whether this technique previously used for monomeric receptors can be applied to a pentameric ligand-gated ion channel. A mutant library for the α1 subunit of the channel was generated by error-prone PCR, and full length sequences of all 2816 mutants were retrieved using single molecule real time sequencing. Each α1 mutant was co-transfected with wildtype β1, δ, and ε subunits, and the channel function characterized by an ion flux assay. To test whether the strategy could map the structure-function relation of this receptor, we attempted to identify mutations that conferred resistance to competitive antagonists. Mutant hits were defined as receptors that responded to the nicotinic agonist epibatidine, but were not inhibited by either α-bungarotoxin or tubocurarine. Eight α1 subunit mutant hits were identified, six of which contained mutations at position Y233 or V275 in the transmembrane domain. Three single point mutations (Y233N, Y233H, and V275M) were studied further, and found to enhance the potencies of five channel agonists tested. This suggests that the mutations made the channel resistant to the antagonists, not by impairing antagonist binding, but rather by producing a gain-of-function phenotype, e.g. increased agonist sensitivity. Our data show that random high throughput mutagenesis is applicable to multimeric proteins to discover novel functional mutants, and outlines the benefits of using single molecule real time sequencing with regards to quality control of the mutant library as well as downstream mutant data interpretation. PMID:27649498

  17. The nicotinic acetylcholine receptor gene family of the honey bee, Apis mellifera.

    PubMed

    Jones, Andrew K; Raymond-Delpech, Valerie; Thany, Steeve H; Gauthier, Monique; Sattelle, David B

    2006-11-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission and play roles in many cognitive processes. They are under intense research as potential targets of drugs used to treat neurodegenerative diseases and neurological disorders such as Alzheimer's disease and schizophrenia. Invertebrate nAChRs are targets of anthelmintics as well as a major group of insecticides, the neonicotinoids. The honey bee, Apis mellifera, is one of the most beneficial insects worldwide, playing an important role in crop pollination, and is also a valuable model system for studies on social interaction, sensory processing, learning, and memory. We have used the A. mellifera genome information to characterize the complete honey bee nAChR gene family. Comparison with the fruit fly Drosophila melanogaster and the malaria mosquito Anopheles gambiae shows that the honey bee possesses the largest family of insect nAChR subunits to date (11 members). As with Drosophila and Anopheles, alternative splicing of conserved exons increases receptor diversity. Also, we show that in one honey bee nAChR subunit, six adenosine residues are targeted for RNA A-to-I editing, two of which are evolutionarily conserved in Drosophila melanogaster and Heliothis virescens orthologs, and that the extent of editing increases as the honey bee lifecycle progresses, serving to maximize receptor diversity at the adult stage. These findings on Apis mellifera enhance our understanding of nAChR functional genomics and provide a useful basis for the development of improved insecticides that spare a major beneficial insect species.

  18. Functional Expression of Two Neuronal Nicotinic Acetylcholine Receptors from cDNA Clones Identifies a Gene Family

    NASA Astrophysics Data System (ADS)

    Boulter, Jim; Connolly, John; Deneris, Evan; Goldman, Dan; Heinemann, Steven; Patrick, Jim

    1987-11-01

    A family of genes coding for proteins homologous to the α subunit of the muscle nicotinic acetylcholine receptor has been identified in the rat genome. These genes are transcribed in the central and peripheral nervous systems in areas known to contain functional nicotinic receptors. In this paper, we demonstrate that three of these genes, which we call alpha3, alpha4, and beta2, encode proteins that form functional nicotinic acetylcholine receptors when expressed in Xenopus oocytes. Oocytes expressing either alpha3 or alpha4 protein in combination with the beta2 protein produced a strong response to acetylcholine. Oocytes expressing only the alpha4 protein gave a weak response to acetylcholine. These receptors are activated by acetylcholine and nicotine and are blocked by Bungarus toxin 3.1. They are not blocked by α -bungarotoxin, which blocks the muscle nicotinic acetylcholine receptor. Thus, the receptors formed by the alpha3, alpha4, and beta2 subunits are pharmacologically similar to the ganglionic-type neuronal nicotinic acetylcholine receptor. These results indicate that the alpha3, alpha4, and beta2 genes encode functional nicotinic acetylcholine receptor subunits that are expressed in the brain and peripheral nervous system.

  19. Agonist self-inhibition at the nicotinic acetylcholine receptor a nonspecific action

    SciTech Connect

    Forman, S.A.; Firestone, L.L.; Miller, K.W.

    1987-05-19

    Agonist concentration-response relationships at nicotinic postsynaptic receptors were established by measuring /sup 86/Rb/sup +/ efflux from acetylcholine receptor rich native Torpedo membrane vesicles under three different conditions: (1) integrated net ion efflux (in 10 s) from untreated vesicles, (2) integrated net efflux from vesicles in which most acetylcholine sites were irreversibly blocked with ..cap alpha..-bungarotoxin, and (3) initial rates of efflux (5-100 ms) from vesicles that were partially blocked with ..cap alpha..-bungarotoxin. Exposure to acetylcholine, carbamylcholine, suberyldicholine, phenyltrimethylammonium, or (-)-nicotine over 10/sup 8/-fold concentration ranges results in bell-shaped ion flux response curves due to stimulation of acetylcholine receptor channel opening at low concentrations and inhibition of channel function at 60-2000 times higher concentrations. Concentrations of agonists that inhibit their own maximum /sup 86/Rb/sup +/ efflux by 50% (K/sub B/ values) are 110, 211, 3.0, 39, and 8.9 mM, respectively, for the agonists listed above. For acetylcholine and carbamylcholine, K/sub B/ values determined from both 10-s and 15-ms efflux measurements are the same, indicating that the rate of agonist-induced desensitization increases to maximum at concentrations lower than those causing self-inhibition. For all partial and full agonists studied, Hill coefficients for self-inhibition are close to 1.0. Concentrations of agonists up to 8 times K/sub B/ did not change the order parameter reported by a spin-labeled fatty acid incorporated in Torpedo membranes. The authors conclude that agonist self-inhibition cannot be attributed to a general nonspecific membrane perturbation. Instead, these results are consistent with a saturable site of action either at the lipid-protein interface or on the acetylcholine receptor protein itself.

  20. Tranilast Increases Vasodilator Response to Acetylcholine in Rat Mesenteric Resistance Arteries through Increased EDHF Participation

    PubMed Central

    Sastre, Esther; Caracuel, Laura; Callejo, María; Balfagón, Gloria

    2014-01-01

    Background and Purpose Tranilast, in addition to its capacity to inhibit mast cell degranulation, has other biological effects, including inhibition of reactive oxygen species, cytokines, leukotrienes and prostaglandin release. In the current study, we analyzed whether tranilast could alter endothelial function in rat mesenteric resistance arteries (MRA). Experimental Approach Acetylcholine-induced relaxation was analyzed in MRA (untreated and 1-hour tranilast treatment) from 6 month-old Wistar rats. To assess the possible participation of endothelial nitric oxide or prostanoids, acetylcholine-induced relaxation was analyzed in the presence of L-NAME or indomethacin. The participation of endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced response was analyzed by preincubation with TRAM-34 plus apamin or by precontraction with a high K+ solution. Nitric oxide (NO) and superoxide anion levels were measured, as well as vasomotor responses to NO donor DEA-NO and to large conductance calcium-activated potassium channel opener NS1619. Key Results Acetylcholine-induced relaxation was greater in tranilast-incubated MRA. Acetylcholine-induced vasodilation was decreased by L-NAME in a similar manner in both experimental groups. Indomethacin did not modify vasodilation. Preincubation with a high K+ solution or TRAM-34 plus apamin reduced the vasodilation to ACh more markedly in tranilast-incubated segments. NO and superoxide anion production, and vasodilator responses to DEA-NO or NS1619 remained unmodified in the presence of tranilast. Conclusions and Implications Tranilast increased the endothelium-dependent relaxation to acetylcholine in rat MRA. This effect is independent of the nitric oxide and cyclooxygenase pathways but involves EDHF, and is mediated by an increased role of small conductance calcium-activated K+ channels. PMID:24992476

  1. Enhancing dissolved oxygen control using an on-line hybrid fuzzy-neural soft-sensing model-based control system in an anaerobic/anoxic/oxic process.

    PubMed

    Huang, Mingzhi; Wan, Jinquan; Hu, Kang; Ma, Yongwen; Wang, Yan

    2013-12-01

    An on-line hybrid fuzzy-neural soft-sensing model-based control system was developed to optimize dissolved oxygen concentration in a bench-scale anaerobic/anoxic/oxic (A(2)/O) process. In order to improve the performance of the control system, a self-adapted fuzzy c-means clustering algorithm and adaptive network-based fuzzy inference system (ANFIS) models were employed. The proposed control system permits the on-line implementation of every operating strategy of the experimental system. A set of experiments involving variable hydraulic retention time (HRT), influent pH (pH), dissolved oxygen in the aerobic reactor (DO), and mixed-liquid return ratio (r) was carried out. Using the proposed system, the amount of COD in the effluent stabilized at the set-point and below. The improvement was achieved with optimum dissolved oxygen concentration because the performance of the treatment process was optimized using operating rules implemented in real time. The system allows various expert operational approaches to be deployed with the goal of minimizing organic substances in the outlet while using the minimum amount of energy. PMID:24052227

  2. Neural Networks for Flight Control

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C.

    1996-01-01

    Neural networks are being developed at NASA Ames Research Center to permit real-time adaptive control of time varying nonlinear systems, enhance the fault-tolerance of mission hardware, and permit online system reconfiguration. In general, the problem of controlling time varying nonlinear systems with unknown structures has not been solved. Adaptive neural control techniques show considerable promise and are being applied to technical challenges including automated docking of spacecraft, dynamic balancing of the space station centrifuge, online reconfiguration of damaged aircraft, and reducing cost of new air and spacecraft designs. Our experiences have shown that neural network algorithms solved certain problems that conventional control methods have been unable to effectively address. These include damage mitigation in nonlinear reconfiguration flight control, early performance estimation of new aircraft designs, compensation for damaged planetary mission hardware by using redundant manipulator capability, and space sensor platform stabilization. This presentation explored these developments in the context of neural network control theory. The discussion began with an overview of why neural control has proven attractive for NASA application domains. The more important issues in control system development were then discussed with references to significant technical advances in the literature. Examples of how these methods have been applied were given, followed by projections of emerging application needs and directions.

  3. Comparative study of muscarinic acetylcholine receptors of human and rat cortical glial cells

    SciTech Connect

    Demushkin, V.P.; Burbaeva, G.S.; Dzhaliashvili, T.A.; Plyashkevich, Y.G.

    1985-04-01

    The aim of the present investigation was a comparative studyof muscarinic acetylcholine receptors in human and rat glial cells. (/sup 3/H)Quinuclidinyl-benzylate ((/sup 3/H)-QB), atropine, platiphylline, decamethonium, carbamylcholine, tubocurarine, and nicotine were used. The glial cell fraction was obtained from the cerebral cortex of rats weighing 130-140 g and from the frontal pole of the postmortem brain from men aged 60-70 years. The use of the method of radioimmune binding of (/sup 3/H)-QB with human and rat glial cell membranes demonstrated the presence of a muscarinic acetylcholine receptor in the glial cells.

  4. [Ionic mechanisms of endothelium-dependent relaxation of vascular smooth muscle under the action of acetylcholine].

    PubMed

    Taranenko, V M; Talaeva, T V; Bratus', V V

    1988-04-01

    Acetylcholine and nitroglycerin were shown to induce relaxation in muscles of the ring vascular segments of canine coronary arteries and rabbit aortic archs, the magnitude of the reaction depending on the level of initial tonic tension. Methylene blue abolished the relaxation. Mechanical removal of endothelium abolished the reaction to acetylcholine but not to nitroglycerin. Verapamil decreased the relaxation by 70%. The endothelium-dependent relaxation seems to be connected mainly with a decrease in the calcium entering vascular smooth muscle cells through voltage-dependent channels.

  5. (/sup 14/C)chloroacetylcholine as an advantageous affinity label of the acetylcholine receptor

    SciTech Connect

    Bodmer, D.M.; Sin-Ren, A.C.; Waser, P.G.

    1987-01-01

    The alkylating agent (/sup 14/C)chloroacetylcholine perchlorate ((/sup 14/C) ClACh) was synthesized and used for affinity labelling of the nicotinic acetylcholine receptor from Torpedo marmorata. Solubilized and affinity-purified receptor proteins were reduced and alkylated according to the bromoacetylcholine-method. Covalent binding of (/sup 14/C) ClACh to the cholinergic receptor proved to be specific and saturable, and occurred exclusively to the alpha-subunit. Halogen substitution of acetylcholine by chlorine and insertion of a /sup 14/C-isotope instead of the widely used /sup 3/H resulted in favorable properties of the affinity label.

  6. Computer modeling of the neurotoxin binding site of acetylcholine receptor spanning residues 185 through 196

    NASA Technical Reports Server (NTRS)

    Garduno-Juarez, R.; Shibata, M.; Zielinski, T. J.; Rein, R.

    1987-01-01

    A model of the complex between the acetylcholine receptor and the snake neurotoxin, cobratoxin, was built by molecular model building and energy optimization techniques. The experimentally identified functionally important residues of cobratoxin and the dodecapeptide corresponding to the residues 185-196 of acetylcholine receptor alpha subunit were used to build the model. Both cis and trans conformers of cyclic L-cystine portion of the dodecapeptide were examined. Binding residues independently identified on cobratoxin are shown to interact with the dodecapeptide AChR model.

  7. Purinergic P2X3 heteroreceptors enhance parasympathetic motor drive in isolated porcine detrusor, a reliable model for development of P2X selective blockers for detrusor hyperactivity.

    PubMed

    D'Agostino, Gianluigi; Condino, Anna Maria; Calvi, Valentina; Boschi, Federica; Gioglio, Luciana; Barbieri, Annalisa

    2012-01-01

    Various forms of low urinary tract symptoms (LUTS) seem dependant upon dysregulation of the purinergic pathway which produces sensory- or motor-activated incontinence. A body of evidence in human urinary bladders supports a link between up-regulation of purinergic activity and the pathogenesis of detrusor instability. This study investigated the potential role of adenosine 5'-triphosphate (ATP) in the control of detrusor motor drive in a model of porcine urinary bladder. The involvement of ATP on excitatory activity was assessed by measuring neurally-evoked [(3)H]-acetylcholine (ACh) release and smooth muscle contraction in detrusor strips. Epithelium-deprived preparations were used to minimize the influence of non-neural sources of ACh and ATP on parasympathetic neurotransmission. ACh release and smooth muscle contractility were not significantly affected by neural ATP in normal detrusor, but markedly enhanced when ATP hydrolysis was reduced by ectoATPase inhibitors, as well as by α,β-methylene-ATP (ABMA), agonist resistant to ecto-enzymes degradation. Prejunctional P2X receptors located on cholinergic nerves are involved in such potentiating effect. These purinergic heteroreceptors were characterized as P2X(3) subunits by means of the putative antagonists: NF449 (P2X(1,3) selective), NF023 (P2X(1,3) selective), PPNDS (P2X(1) selective) and A-317491 (P2X(3) selective). In porcine detrusor, P2X(3) receptors are functionally expressed at neural site facilitating neurogenic ACh release. When purine breakdown is experimentally down-regulated to mimicking the impaired purinergic pathway observed in pathological human bladders, endogenous ATP can markedly enhance detrusor contractility through activation of these receptors. Since P2X(3) blockade represents a potential therapeutic approach for diseases of the urinary tract, isolated porcine detrusor represents a reliable model for development of novel selective P2X(3) antagonists beneficial in the treatment of detrusor

  8. Central nervous system promotes thermotolerance via FoxO/DAF-16 activation through octopamine and acetylcholine signaling in Caenorhabditis elegans.

    PubMed

    Furuhashi, Tsubasa; Sakamoto, Kazuichi

    2016-03-25

    The autonomic nervous system (ANS) responds to many kinds of stressors to maintain homeostasis. Although the ANS is believed to regulate stress tolerance, the exact mechanism underlying this is not well understood. To understand this, we focused on longevity genes, which have functions such as lifespan extension and promotion of stress tolerance. To understand the relationship between ANS and longevity genes, we analyzed stress tolerance of Caenorhabditis elegans treated with octopamine, which has an affinity to noradrenaline in insects, and acetylcholine. Octopamine and acetylcholine did not show resistance against H2O2, but the neurotransmitters promoted thermotolerance via DAF-16. However, chronic treatment with octopamine and acetylcholine did not extend the lifespan, although DAF-16 plays an important role in longevity. In conclusion, our results show that octopamine and acetylcholine activate DAF-16 in response to stress, but chronic induction of octopamine and acetylcholine is not beneficial for increasing longevity.

  9. Benzodiazepine Site Agonists Differentially Alter Acetylcholine Release in Rat Amygdala

    PubMed Central

    Hambrecht-Wiedbusch, Viviane S.; Mitchell, Melinda F.; Firn, Kelsie A.; Baghdoyan, Helen A.; Lydic, Ralph

    2014-01-01

    Background Agonist binding at the benzodiazepine site of γ-aminobutric acid type A receptors diminishes anxiety and insomnia by actions in the amygdala. The neurochemical effects of benzodiazepine-site agonists remain incompletely understood. Cholinergic neurotransmission modulates amygdala function, and in this study we tested the hypothesis that benzodiazepine-site agonists alter acetylcholine (ACh) release in the amygdala. Methods Microdialysis and high performance liquid chromatography quantified ACh release in the amygdala of Sprague-Dawley rats (n=33). ACh was measured before and after IV administration (3 mg/kg) of midazolam or eszopiclone, with and without anesthesia. ACh in isoflurane-anesthetized rats during dialysis with Ringer’s solution(control) was compared to ACh release during dialysis with Ringer’s solution containing (100 μM) midazolam, diazepam, eszopiclone, or zolpidem. Results In unanesthetized rats, ACh in the amygdala was decreased by IV midazolam (−51.1%; P=0.0029; 95% CI= −73.0% to −29.2%) and eszopiclone (−39.6%; P=0.0222; 95% CI= −69.8% to −9.3%). In anesthetized rats, ACh in the amygdala was decreased by IV administration of midazolam (−46.2%; P=0.0041; 95% CI= −67.9% to −24.5%) and eszopiclone (−34.0%; P=0.0009; 95% CI= −44.7% to −23.3%), and increased by amygdala delivery of diazepam (43.2%; P=0.0434; 95% CI= 2.1% to 84.3%), and eszopiclone (222.2%; P=0.0159; 95% CI= 68.5% to 375.8%). Conclusions ACh release in the amygdala was decreased by IV delivery of midazolam and eszopiclone. Dialysis delivery directly into the amygdala caused either increased (eszopiclone and diazepam) or likely no significant change (midazolam and zolpidem) in ACh release. These contrasting effects of delivery route on ACh release support the interpretation that systemically administered midazolam and eszopiclone decrease ACh release in the amygdala by acting on neuronal systems outside of the amygdala. PMID:24842176

  10. Temporal coherency between receptor expression, neural activity and AP-1-dependent transcription regulates Drosophila motoneuron dendrite development

    PubMed Central

    Vonhoff, Fernando; Kuehn, Claudia; Blumenstock, Sonja; Sanyal, Subhabrata; Duch, Carsten

    2013-01-01

    Neural activity has profound effects on the development of dendritic structure. Mechanisms that link neural activity to nuclear gene expression include activity-regulated factors, such as CREB, Crest or Mef2, as well as activity-regulated immediate-early genes, such as fos and jun. This study investigates the role of the transcriptional regulator AP-1, a Fos-Jun heterodimer, in activity-dependent dendritic structure development. We combine genetic manipulation, imaging and quantitative dendritic architecture analysis in a Drosophila single neuron model, the individually identified motoneuron MN5. First, Dα7 nicotinic acetylcholine receptors (nAChRs) and AP-1 are required for normal MN5 dendritic growth. Second, AP-1 functions downstream of activity during MN5 dendritic growth. Third, using a newly engineered AP-1 reporter we demonstrate that AP-1 transcriptional activity is downstream of Dα7 nAChRs and Calcium/calmodulin-dependent protein kinase II (CaMKII) signaling. Fourth, AP-1 can have opposite effects on dendritic development, depending on the timing of activation. Enhancing excitability or AP-1 activity after MN5 cholinergic synapses and primary dendrites have formed causes dendritic branching, whereas premature AP-1 expression or induced activity prior to excitatory synapse formation disrupts dendritic growth. Finally, AP-1 transcriptional activity and dendritic growth are affected by MN5 firing only during development but not in the adult. Our results highlight the importance of timing in the growth and plasticity of neuronal dendrites by defining a developmental period of activity-dependent AP-1 induction that is temporally locked to cholinergic synapse formation and dendritic refinement, thus significantly refining prior models derived from chronic expression studies. PMID:23293292

  11. 86Rb+ Efflux Mediated by α4β2*-Nicotinic Acetylcholine Receptors with High and Low Sensitivity to Stimulation by Acetylcholine Display Similar Agonist-Induced Desensitization

    PubMed Central

    Marks, Michael J.; Meinerz, Natalie M.; Brown, Robert W. B.; Collins, Allan C.

    2010-01-01

    The nicotinic acetylcholine receptors (nAChR) assembled from α4 and β2 subunits are the most densely expressed subtype in the brain. Concentration-effect curves for agonist activation of α4β2*-nAChR are biphasic. This biphasic agonist sensitivity is ascribed to differences in subunit stoichiometry. The studies described here evaluated desensitization elicited by low concentrations of epibatidine, nicotine, cytisine or methylcarbachol of brain α4β2-nAChR function measured with acetylcholine stimulated 86Rb+ efflux from mouse thalamic synaptosomes. Each agonist elicited concentration-dependent desensitization. The agonists differed in potency. However, IC50 values for each agonist for desensitization of 86Rb+ efflux both with high (EC50≈3 μM) and low (EC50≈ 150 μM) acetylcholine sensitivity were not significantly different. Concentrations required to elicit desensitization were higher that their respective KD values for receptor binding. Even though the two components of α4β2*-nAChR mediated 86Rb+ efflux from mouse brain differ markedly in EC50 values for agonist activation, they are equally sensitive to desensitization by exposure to low agonist concentrations. Mice were also chronically treated with nicotine by continuous infusion of 0, 0.5 or 4.0 mg/kg/hr and desensitization induced by nicotine was evaluated. Consistent with previous results, chronic nicotine treatment increased the density of epibatidine binding sites. Acute exposure to nicotine also elicited concentration-dependent desensitization of both high sensitivity and low sensitivity acetylcholine-stimulated 86Rb+ efflux from cortical and thalamic synaptosomes. Although chronic nicotine treatment reduced maximal 86Rb+ efflux from thalamus, IC50 values in both brain regions were unaffected by chronic nicotine treatment. PMID:20599770

  12. Electronic Neural Networks

    NASA Technical Reports Server (NTRS)

    Thakoor, Anil

    1990-01-01

    Viewgraphs on electronic neural networks for space station are presented. Topics covered include: electronic neural networks; electronic implementations; VLSI/thin film hybrid hardware for neurocomputing; computations with analog parallel processing; features of neuroprocessors; applications of neuroprocessors; neural network hardware for terrain trafficability determination; a dedicated processor for path planning; neural network system interface; neural network for robotic control; error backpropagation algorithm for learning; resource allocation matrix; global optimization neuroprocessor; and electrically programmable read only thin-film synaptic array.

  13. Higher-Order Neural Networks Recognize Patterns

    NASA Technical Reports Server (NTRS)

    Reid, Max B.; Spirkovska, Lilly; Ochoa, Ellen

    1996-01-01

    Networks of higher order have enhanced capabilities to distinguish between different two-dimensional patterns and to recognize those patterns. Also enhanced capabilities to "learn" patterns to be recognized: "trained" with far fewer examples and, therefore, in less time than necessary to train comparable first-order neural networks.

  14. Amino acids of the Torpedo marmorata acetylcholine receptor. cap alpha. subunit labeled by a photoaffinity ligand for the acetylcholine binding site

    SciTech Connect

    Dennis, M.; Giraudat, J.; Kotzyba-Hibert, F.; Goeldner, M.; Hirth, C.; Chang, J.Y.; Lazure, C.; Chretien, M.; Changeux, J.P.

    1988-04-05

    The acetylcholine-binding sites on the native, membrane-bound acetylcholine receptor from Torpedo marmorata were covalently labeled with the photoaffinity reagent (/sup 3/H)-p-(dimethylamino)-benzenediazonium fluoroborate (DDF) in the presence of phencyclidine by employing an energy-transfer photolysis procedure. The ..cap alpha..-chains isolated from receptor-rich membranes photolabeled in the absence or presence of carbamoylcholine were cleaved with CNBr and the radiolabeled fragments purified by high-performance liquid chromatography. Amino acid and/or sequence analysis demonstrated that the ..cap alpha..-chain residues Trp-149, Tyr-190, Cys-192, and Cys-193 and an unidentified residue(s) in the segment ..cap alpha.. 31-105 were all labeled by the photoaffinity reagent in an agonist-protectable manner. The labeled amino acids are located within three distinct regions of the large amino-terminal hydrophilic domain of the ..cap alpha..-subunit primary structure and plausibly lie in proximity to one another at the level of the acetylcholine-binding sites in the native receptor. These findings are in accord with models proposed for the transmembrane topology of the ..cap alpha..-chain that assign the amino-terminal segment ..cap alpha.. 1-210 to the synaptic cleft. Furthermore, the results suggest that the four identified (/sup 3/H)DDF-labeled resides, which are conserved in muscle and neuronal ..cap alpha..-chains but not in the other subunits, may be directly involved in agonist binding.

  15. Neural correlates of HIV risk feelings

    PubMed Central

    Schmälzle, Ralf; Renner, Britta; Schupp, Harald T.

    2015-01-01

    Field studies on HIV risk perception suggest that people rely on impressions they have about the safety of their partner. The present fMRI study investigated the neural correlates of the intuitive perception of risk. First, during an implicit condition, participants viewed a series of unacquainted persons and performed a task unrelated to HIV risk. In the following explicit condition, participants evaluated the HIV risk for each presented person. Contrasting responses for high and low HIV risk revealed that risky stimuli evoked enhanced activity in the anterior insula and medial prefrontal regions, which are involved in salience processing and frequently activated by threatening and negative affect-related stimuli. Importantly, neural regions responding to explicit HIV risk judgments were also enhanced in the implicit condition, suggesting a neural mechanism for intuitive impressions of riskiness. Overall, these findings suggest the saliency network as neural correlate for the intuitive sensing of risk. PMID:24982263

  16. Neural correlates of HIV risk feelings.

    PubMed

    Häcker, Frank E K; Schmälzle, Ralf; Renner, Britta; Schupp, Harald T

    2015-04-01

    Field studies on HIV risk perception suggest that people rely on impressions they have about the safety of their partner. The present fMRI study investigated the neural correlates of the intuitive perception of risk. First, during an implicit condition, participants viewed a series of unacquainted persons and performed a task unrelated to HIV risk. In the following explicit condition, participants evaluated the HIV risk for each presented person. Contrasting responses for high and low HIV risk revealed that risky stimuli evoked enhanced activity in the anterior insula and medial prefrontal regions, which are involved in salience processing and frequently activated by threatening and negative affect-related stimuli. Importantly, neural regions responding to explicit HIV risk judgments were also enhanced in the implicit condition, suggesting a neural mechanism for intuitive impressions of riskiness. Overall, these findings suggest the saliency network as neural correlate for the intuitive sensing of risk.

  17. Nicotine enhances both excitatory and inhibitory synaptic inputs to inspiratory-activated airway vagal preganglionic neurons.

    PubMed

    Zhou, Xujiao; Chen, Yonghua; Ge, Dengyun; Yuan, Wenjun; Wang, Jijiang

    2013-01-01

    The airway vagal preganglionic neurons (AVPNs) supply the essential excitatory drive to the postganglionic neurons and dominate the neural control of the airway both physiologically and pathophysiologically. The AVPNs express multiple subunits of nicotinic acetylcholine receptors (nAChRs), but the influences of exogenous nicotine and endogenous acetylcholine are unknown. This study examined the effects of nicotine and endogenous acetylcholine on retrogradely labelled, functionally identified inspiratory-activated AVPNs (IA-AVPNs) using the patch-clamp technique. Nicotine (10 μmol l(-1)) significantly increased the frequency and amplitude of the spontaneous EPSCs of IA-AVPNs, and these effects were insensitive to methyllycaconitine (MLA, 100 nmol l(-1)), an antagonist of the α7 type of nAChR, but was prevented by dihydro-β-erythroidine (DHβE, 3 μmol l(-1)), an antagonist of the α4β2 type of nAChR. Nicotine caused a tonic inward current in IA-AVPNs, which was reduced by MLA or DHβE alone, but was not abolished by co-application of MLA and DHβE. Nicotine caused a significant increase in the frequency of GABAergic and glycinergic spontaneous IPSCs and significantly increased the amplitude of glycinergic spontaneous IPSCs, all of which were prevented by DHβE. Nicotine had no effects on the miniature EPSCs or miniature IPSCs following pretreatment with TTX. Under current clamp, nicotine caused depolarization and increased the firing rate of IA-AVPNs during inspiratory intervals. Neostigmine (10 μmol l(-1)), an acetylcholinesterase inhibitor, mimicked the effects of nicotine. These results demonstrate that nicotine and endogenous ACh enhance the excitatory and inhibitory synaptic inputs of IA-AVPNs and cause a postsynaptic excitatory current and that the nicotinic effects are mediated presynaptically by activation of the α4β2 type of nAChR and postsynaptically by activation of multiple nAChRs, including α7 and α4β2 types.

  18. Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes.

    PubMed

    Courtot, Elise; Charvet, Claude L; Beech, Robin N; Harmache, Abdallah; Wolstenholme, Adrian J; Holden-Dye, Lindy; O'Connor, Vincent; Peineau, Nicolas; Woods, Debra J; Neveu, Cedric

    2015-12-01

    Acetylcholine receptors are pentameric ligand-gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR.

  19. Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes

    PubMed Central

    Courtot, Elise; Charvet, Claude L.; Beech, Robin N.; Harmache, Abdallah; Wolstenholme, Adrian J.; Holden-Dye, Lindy; O’Connor, Vincent; Peineau, Nicolas; Woods, Debra J.; Neveu, Cedric

    2015-01-01

    Acetylcholine receptors are pentameric ligand–gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR. PMID:26625142

  20. Nicotine alters lung branching morphogenesis through the alpha7 nicotinic acetylcholine receptor.

    PubMed

    Wongtrakool, Cherry; Roser-Page, Susanne; Rivera, Hilda N; Roman, Jesse

    2007-09-01

    There is abundant epidemiological data linking prenatal environmental tobacco smoke with childhood asthma and wheezing, but the underlying molecular and physiological mechanisms that occur in utero to explain this link remain unelucidated. Several studies suggest that nicotine, which traverses the placenta, is a causative agent. Therefore, we studied the effects of nicotine on lung branching morphogenesis using embryonic murine lung explants. We found that the expression of alpha(7) nicotinic acetylcholine receptors, which mediate many of the biological effects of nicotine, is highest in pseudoglandular stage lungs compared with lungs at later stages. We then studied the effects of nicotine in the explant model and found that nicotine stimulated lung branching in a dose-dependent fashion. alpha-Bungarotoxin, an antagonist of alpha(7) nicotinic acetylcholine receptors, blocked the stimulatory effect of nicotine, whereas GTS-21, a specific agonist, stimulated branching, thereby mimicking the effects of nicotine. Explants deficient in alpha(7) nicotinic acetylcholine receptors did not respond to nicotine. Nicotine also stimulated the growth of the explant. Altogether, these studies suggest that nicotine stimulates lung branching morphogenesis through alpha(7) nicotinic acetylcholine receptors and may contribute to dysanaptic lung growth, which in turn may predispose the host to airway disease in the postnatal period.

  1. Structure of the human M2 muscarinic acetylcholine receptor bound to an antagonist

    SciTech Connect

    Haga, Kazuko; Kruse, Andrew C.; Asada, Hidetsugu; Yurugi-Kobayashi, Takami; Shiroishi, Mitsunori; Zhang, Cheng; Weis, William I.; Okada, Tetsuji; Kobilka, Brian K.; Haga, Tatsuya; Kobayashi, Takuya

    2012-03-15

    The parasympathetic branch of the autonomic nervous system regulates the activity of multiple organ systems. Muscarinic receptors are G-protein-coupled receptors that mediate the response to acetylcholine released from parasympathetic nerves. Their role in the unconscious regulation of organ and central nervous system function makes them potential therapeutic targets for a broad spectrum of diseases. The M2 muscarinic acetylcholine receptor (M2 receptor) is essential for the physiological control of cardiovascular function through activation of G-protein-coupled inwardly rectifying potassium channels, and is of particular interest because of its extensive pharmacological characterization with both orthosteric and allosteric ligands. Here we report the structure of the antagonist-bound human M2 receptor, the first human acetylcholine receptor to be characterized structurally, to our knowledge. The antagonist 3-quinuclidinyl-benzilate binds in the middle of a long aqueous channel extending approximately two-thirds through the membrane. The orthosteric binding pocket is formed by amino acids that are identical in all five muscarinic receptor subtypes, and shares structural homology with other functionally unrelated acetylcholine binding proteins from different species. A layer of tyrosine residues forms an aromatic cap restricting dissociation of the bound ligand. A binding site for allosteric ligands has been mapped to residues at the entrance to the binding pocket near this aromatic cap. The structure of the M2 receptor provides insights into the challenges of developing subtype-selective ligands for muscarinic receptors and their propensity for allosteric regulation.

  2. Corticotropin-releasing factor administered centrally, but not peripherally, stimulates hippocampal acetylcholine release.

    PubMed

    Day, J C; Koehl, M; Le Moal, M; Maccari, S

    1998-08-01

    In addition to corticotropin-releasing factor's well-known role in mediating hormonal and behavioral responses to stress, this peptide also reportedly affects arousal and cognition, processes that classically have been associated with forebrain cholinergic systems. Corticotropin-releasing factor stimulation of cholinergic neurons might thus provide a mechanism for this peptide's cognitive effects. To examine this possibility, the present experiments characterize the effect of corticotropin-releasing factor on cholinergic neurotransmission, using in vivo microdialysis to measure hippocampal acetylcholine release. Corticotropin-releasing factor (0.5-5.0 microg/rat intracerebroventricularly) was found to increase dialysate concentrations of acetylcholine in a dose-dependent manner in comparison with a control injection, the ovine peptide having a greater effect than the same dose of the human/rat peptide. This effect was found to be centrally mediated, independent of the peripheral effects of an exogenous corticotropin-releasing factor injection; subcutaneous injections of the peptide increased plasma concentrations of corticosterone, the adrenal hormone ultimately secreted in the rat's stress response, to the same level as did the central injections, without affecting hippocampal acetylcholine release. These results demonstrate that corticotropin-releasing factor, acting centrally, regulates hippocampal cholinergic activity, and suggest that corticotropin-releasing factor/acetylcholine interactions may underlie some of the previously identified roles of these neurotransmitters in arousal, cognition, and stress.

  3. Interactions between acetylcholine, 5-hydroxytryptamine, nicotine and morphine on isolated rabbit atria

    PubMed Central

    Chittal, S. M.; Dadkar, N. K.; Gaitondé, B. B.

    1968-01-01

    1. The effects of 5-hydroxytryptamine (5-HT) and morphine on the responses to acetylcholine and nicotine of isolated rabbit atria were studied. 2. 5-Hydroxytryptamine (10 μg/ml.) and morphine (20 μg/ml.) blocked the negative chronotropic and inotropic actions of acetylcholine. 3. Nicotine (20 μg/ml.) produced stimulation of the atria, which was blocked by dichlorisoprenaline, morphine, 5-HT, bretylium and hemicholinium. Hemicholinium block was reversed by choline. 4. In reserpinized preparations, nicotine produced inhibition of atria and this action was also blocked by atropine, 5-HT and morphine. Inhibition induced by nicotine was potentiated by physostigmine. 5. 5-Hydroxytryptamine (20 μg/ml.) produced stimulation of atria. This was blocked by bretylium and reduced by hemicholinium. Hemicholinium block was reversed by choline. 6. It is concluded that 5-HT in low concentrations acts as a weak agonist at the cholinoceptive receptors and therefore blocks the action of acetylcholine. Furthermore, nicotine and larger doses of 5-HT have actions on ganglionic structures and liberate acetylcholine, which in turn releases catecholamines. PMID:4386371

  4. Regional circadian variation of acetylcholine muscarinic receptors in the rat brain

    SciTech Connect

    Por, S.B.; Bondy, S.C.

    1981-01-01

    The level of binding of a labeled acetylcholine muscarinic antagonist (quinuclidinyl benzilate) to different cerebral membranes has been measured. Of the regions examined, circadian rhythmicity of binding could only be detected significantly in the hippocampus and the hypothalamus and not in the cerebral cortex, striatum, or cerebellum.

  5. Interactions between acetylcholine, 5-hydroxytryptamine, nicotine and morphine on isolated rabbit atria.

    PubMed

    Chittal, S M; Dadkar, N K; Gaitondé, B B

    1968-09-01

    1. The effects of 5-hydroxytryptamine (5-HT) and morphine on the responses to acetylcholine and nicotine of isolated rabbit atria were studied.2. 5-Hydroxytryptamine (10 mug/ml.) and morphine (20 mug/ml.) blocked the negative chronotropic and inotropic actions of acetylcholine.3. Nicotine (20 mug/ml.) produced stimulation of the atria, which was blocked by dichlorisoprenaline, morphine, 5-HT, bretylium and hemicholinium. Hemicholinium block was reversed by choline.4. In reserpinized preparations, nicotine produced inhibition of atria and this action was also blocked by atropine, 5-HT and morphine. Inhibition induced by nicotine was potentiated by physostigmine.5. 5-Hydroxytryptamine (20 mug/ml.) produced stimulation of atria. This was blocked by bretylium and reduced by hemicholinium. Hemicholinium block was reversed by choline.6. It is concluded that 5-HT in low concentrations acts as a weak agonist at the cholinoceptive receptors and therefore blocks the action of acetylcholine. Furthermore, nicotine and larger doses of 5-HT have actions on ganglionic structures and liberate acetylcholine, which in turn releases catecholamines.

  6. Structure, oligosaccharide structures, and posttranslationally modified sites of the nicotinic acetylcholine receptor.

    PubMed Central

    Poulter, L; Earnest, J P; Stroud, R M; Burlingame, A L

    1989-01-01

    Using mass spectrometry, we have examined the transmembrane topography of the nicotinic acetylcholine receptor, a five-subunit glycosylated protein complex that forms a gated ion channel in the neuromuscular junction. The primary sequences of the four polypeptide chains making up the acetylcholine receptor from Torpedo californica contain many possible sites for glycosylation or phosphorylation. We have used liquid secondary ion mass spectrometry to identify posttranslationally modified residues and to determine the intact oligosaccharide structures of the carbohydrate present on the acetylcholine receptor. Asparagine-143 of the alpha subunit (in consensus numbering) is shown to be glycosylated with high-mannose oligosaccharide. Asparagine-453 of the gamma subunit is not glycosylated, a fact that bears on the question of the orientations of putative transmembranous helices M3, MA, and M4. The structures of the six major acetylcholine receptor oligosaccharides are determined: the major components (70%) are of the high-mannose type, with bi-, tri-, and tetraantennary complex oligosaccharides making up approximately equal to 22 mol% of the total carbohydrate. This application of a multichannel array detector mass spectrometer provided a breakthrough in sensitivity that allowed us to identify the site of attachment of, and the sequence of, oligosaccharides on a 300-kDa membrane protein from only 5 pmol of the isolated oligosaccharide. Images PMID:2771948

  7. Spiroindolines Identify the Vesicular Acetylcholine Transporter as a Novel Target for Insecticide Action

    PubMed Central

    Sluder, Ann; Shah, Sheetal; Cassayre, Jérôme; Clover, Ralph; Maienfisch, Peter; Molleyres, Louis-Pierre; Hirst, Elizabeth A.; Flemming, Anthony J.; Shi, Min; Cutler, Penny; Stanger, Carole; Roberts, Richard S.; Hughes, David J.; Flury, Thomas; Robinson, Michael P.; Hillesheim, Elke; Pitterna, Thomas; Cederbaum, Fredrik; Worthington, Paul A.; Crossthwaite, Andrew J.; Windass, John D.; Currie, Richard A.; Earley, Fergus G. P.

    2012-01-01

    The efficacy of all major insecticide classes continues to be eroded by the development of resistance mediated, in part, by selection of alleles encoding insecticide insensitive target proteins. The discovery of new insecticide classes acting at novel protein binding sites is therefore important for the continued protection of the food supply from insect predators, and of human and animal health from insect borne disease. Here we describe a novel class of insecticides (Spiroindolines) encompassing molecules that combine excellent activity against major agricultural pest species with low mammalian toxicity. We confidently assign the vesicular acetylcholine transporter as the molecular target of Spiroindolines through the combination of molecular genetics in model organisms with a pharmacological approach in insect tissues. The vesicular acetylcholine transporter can now be added to the list of validated insecticide targets in the acetylcholine signalling pathway and we anticipate that this will lead to the discovery of novel molecules useful in sustaining agriculture. In addition to their potential as insecticides and nematocides, Spiroindolines represent the only other class of chemical ligands for the vesicular acetylcholine transporter since those based on the discovery of vesamicol over 40 years ago, and as such, have potential to provide more selective tools for PET imaging in the diagnosis of neurodegenerative disease. They also provide novel biochemical tools for studies of the function of this protein family. PMID:22563457

  8. Theoretical investigation of interaction between the set of ligands and α7 nicotinic acetylcholine receptor

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Prytkova, T. R.; Shmygin, D. S.

    2016-03-01

    Nicotinic acetylcholine receptors (nAChRs) are neuron receptor proteins that provide a transmission of nerve impulse through the synapses. They are composed of a pentametric assembly of five homologous subunits (5 α7 subunits for α7nAChR, for example), oriented around the central pore. These receptors might be found in the chemical synapses of central and peripheral nervous system, and also in the neuromuscular synapses. Transmembrane domain of the one of such receptors constitutes ion channel. The conductive properties of ion channel strongly depend on the receptor conformation changes in the response of binding with some molecule, f.e. acetylcholine. Investigation of interaction between ligands and acetylcholine receptor is important for drug design. In this work we investigate theoretically the interaction between the set of different ligands (such as vanillin, thymoquinone, etc.) and the nicotinic acetylcholine receptor (primarily with subunit of the α7nAChR) by different methods and packages (AutodockVina, GROMACS, KVAZAR, HARLEM, VMD). We calculate interaction energy between different ligands in the subunit using molecular dynamics. On the base of obtained calculation results and using molecular docking we found an optimal location of different ligands in the subunit.

  9. INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS.

    EPA Science Inventory

    INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS.
    A.S. Bale*; P.J. Bushnell; C.A. Meacham; T.J. Shafer
    Neurotoxicology Division, NHEERL, ORD, US Environmental Protection Agency, Research Triangle Park, NC, USA
    Toluene (TOL...

  10. AGE-RELATED EFFECTS OF CHLORPYRIFOS ON ACETYLCHOLINE RELEASE IN RAT BRAIN. (R825811)

    EPA Science Inventory

    Chlorpyrifos (CPF) is an organophosphorus insecticide that elicits toxicity through inhibition of acetylcholinesterase (AChE). Young animals are markedly more sensitive than adults to the acute toxicity of CPF. We evaluated acetylcholine (ACh) release and its muscarinic recept...

  11. Anterior Thalamic Lesions Alter Both Hippocampal-Dependent Behavior and Hippocampal Acetylcholine Release in the Rat

    ERIC Educational Resources Information Center

    Savage, Lisa M.; Hall, Joseph M.; Vetreno, Ryan P.

    2011-01-01

    The anterior thalamic nuclei (ATN) are important for learning and memory as damage to this region produces a persistent amnestic syndrome. Dense connections between the ATN and the hippocampus exist, and importantly, damage to the ATN can impair hippocampal functioning. Acetylcholine (ACh) is a key neurotransmitter in the hippocampus, and in vivo…

  12. Septohippocampal Acetylcholine: Involved in but Not Necessary for Learning and Memory?

    ERIC Educational Resources Information Center

    Parent, Marise B.; Baxter, Mark G.

    2004-01-01

    The neurotransmitter acetylcholine (ACh) has been accorded an important role in supporting learning and memory processes in the hippocampus. Cholinergic activity in the hippocampus is correlated with memory, and restoration of ACh in the hippocampus after disruption of the septohippocampal pathway is sufficient to rescue memory. However, selective…

  13. Acetylcholine Release in the Hippocampus and Striatum during Place and Response Training

    ERIC Educational Resources Information Center

    Pych, Jason C.; Chang, Qing; Colon-Rivera, Cynthia; Haag, Renee; Gold, Paul E.

    2005-01-01

    These experiments examined the release of acetylcholine in the hippocampus and striatum when rats were trained, within single sessions, on place or response versions of food-rewarded mazes. Microdialysis samples of extra-cellular fluid were collected from the hippocampus and striatum at 5-min increments before, during, and after training. These…

  14. Effect of a nicotinic acetylcholine receptor agonists and antagonists on motor function in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nicotinic acetylcholine receptors (nAChR) are ligand-gated cation channels found throughout the body, and serve to mediate diverse physiological functions. Muscle-type nAChR located in the motor endplate region of muscle fibers play an integral role in muscle contraction and thus motor function. The...

  15. A constitutively active G protein-coupled acetylcholine receptor regulates motility of larval Schistosoma mansoni.

    PubMed

    MacDonald, Kevin; Kimber, Michael J; Day, Tim A; Ribeiro, Paula

    2015-07-01

    The neuromuscular system of helminths controls a variety of essential biological processes and therefore represents a good source of novel drug targets. The neuroactive substance, acetylcholine controls movement of Schistosoma mansoni but the mode of action is poorly understood. Here, we present first evidence of a functional G protein-coupled acetylcholine receptor in S. mansoni, which we have named SmGAR. A bioinformatics analysis indicated that SmGAR belongs to a clade of invertebrate GAR-like receptors and is related to vertebrate muscarinic acetylcholine receptors. Functional expression studies in yeast showed that SmGAR is constitutively active but can be further activated by acetylcholine and, to a lesser extent, the cholinergic agonist, carbachol. Anti-cholinergic drugs, atropine and promethazine, were found to have inverse agonist activity towards SmGAR, causing a significant decrease in the receptor's basal activity. An RNAi phenotypic assay revealed that suppression of SmGAR activity in early-stage larval schistosomulae leads to a drastic reduction in larval motility. In sum, our results provide the first molecular evidence that cholinergic GAR-like receptors are present in schistosomes and are required for proper motor control in the larvae. The results further identify SmGAR as a possible candidate for antiparasitic drug targeting.

  16. Corticotropin-releasing factor administered centrally, but not peripherally, stimulates hippocampal acetylcholine release.

    PubMed

    Day, J C; Koehl, M; Le Moal, M; Maccari, S

    1998-08-01

    In addition to corticotropin-releasing factor's well-known role in mediating hormonal and behavioral responses to stress, this peptide also reportedly affects arousal and cognition, processes that classically have been associated with forebrain cholinergic systems. Corticotropin-releasing factor stimulation of cholinergic neurons might thus provide a mechanism for this peptide's cognitive effects. To examine this possibility, the present experiments characterize the effect of corticotropin-releasing factor on cholinergic neurotransmission, using in vivo microdialysis to measure hippocampal acetylcholine release. Corticotropin-releasing factor (0.5-5.0 microg/rat intracerebroventricularly) was found to increase dialysate concentrations of acetylcholine in a dose-dependent manner in comparison with a control injection, the ovine peptide having a greater effect than the same dose of the human/rat peptide. This effect was found to be centrally mediated, independent of the peripheral effects of an exogenous corticotropin-releasing factor injection; subcutaneous injections of the peptide increased plasma concentrations of corticosterone, the adrenal hormone ultimately secreted in the rat's stress response, to the same level as did the central injections, without affecting hippocampal acetylcholine release. These results demonstrate that corticotropin-releasing factor, acting centrally, regulates hippocampal cholinergic activity, and suggest that corticotropin-releasing factor/acetylcholine interactions may underlie some of the previously identified roles of these neurotransmitters in arousal, cognition, and stress. PMID:9681452

  17. Nonenzymatic all-solid-state coated wire electrode for acetylcholine determination in vitro.

    PubMed

    He, Cheng; Wang, Zhan; Wang, You; Hu, Ruifen; Li, Guang

    2016-11-15

    A nonenzymatic all-solid-state coated wire acetylcholine electrode was investigated. Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT/PSS) as conducting polymer was coated on one end of a gold wire (0.5mm in diameter). The acetylcholine selective membrane containing heptakis(2,3,6-tri-Ο-methyl)-β-cyclodextrin as an ionophore covered the conducting polymer layer. The electrode could work stably in a pH range of 6.5-8.5 and a temperature range of 15-40°C. It covered an acetylcholine concentration range of 10(-5)-10(-1)M with a slope of 54.04±1.70mV/decade, while detection limit was 5.69±1.06µM. The selectivity, dynamic response, reproducibility and stability were evaluated. The electrode could work properly in the rat brain homogenate to detect different concentrations of acetylcholine. PMID:27254787

  18. Transient Receptor Potential Channel Opening Releases Endogenous Acetylcholine, which Contributes to Endothelium-Dependent Relaxation Induced by Mild Hypothermia in Spontaneously Hypertensive Rat but Not Wistar-Kyoto Rat Arteries.

    PubMed

    Zou, Q; Leung, S W S; Vanhoutte, P M

    2015-08-01

    Mild hypothermia causes endothelium-dependent relaxations, which are reduced by the muscarinic receptor antagonist atropine. The present study investigated whether endothelial endogenous acetylcholine contributes to these relaxations. Aortic rings of spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats were contracted with prostaglandin F2 α and exposed to progressive mild hypothermia (from 37 to 31°C). Hypothermia induced endothelium-dependent, Nω-nitro-l-arginine methyl ester-sensitive relaxations, which were reduced by atropine, but not by mecamylamine, in SHR but not in WKY rat aortae. The responses in SHR aortae were also reduced by acetylcholinesterase (the enzyme responsible for acetylcholine degradation), bromoacetylcholine (inhibitor of acetylcholine synthesis), hemicholinium-3 (inhibitor of choline uptake), and vesamicol (inhibitor of acetylcholine release). The mild hypothermia-induced relaxations in both SHR and WKY rat aortae were inhibited by AMTB [N-(3-aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)-benzamide; the transient receptor potential (TRP) M8 inhibitor]; only those in SHR aortae were inhibited by HC-067047 [2-methyl-1-[3-(4-morpholinyl)propyl]-5-phenyl-N-[3-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide; TRPV4 antagonist] while those in WKY rat aortae were reduced by HC-030031 [2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7H-purin-7-yl)-N-(4-isopropylphenyl)acetamide; TRPA1 antagonist]. The endothelial uptake of extracellular choline and release of cyclic guanosine monophosphate was enhanced by mild hypothermia and inhibited by HC-067047 in SHR but not in WKY rat aortae. Compared with WKY rats, the SHR preparations expressed similar levels of acetylcholinesterase and choline acetyltransferase, but a lesser amount of vesicular acetylcholine transporter, located mainly in the endothelium. Thus, mild hypothermia causes nitric oxide-dependent relaxations by opening TRPA1 channels in WKY rat aortae

  19. Postsynaptic activity reverses the sign of the acetylcholine-induced long-term plasticity of GABAA inhibition

    PubMed Central

    Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

    2014-01-01

    Acetylcholine (ACh) regulates forms of plasticity that control cognitive functions but the underlying mechanisms remain largely unknown. ACh controls the intrinsic excitability, as well as the synaptic excitation and inhibition of CA1 hippocampal pyramidal cells (PCs), cells known to participate in circuits involved in cognition and spatial navigation. However, how ACh regulates inhibition in function of postsynaptic activity has not been well studied. Here we show that in rat PCs, a brief pulse of ACh or a brief stimulation of cholinergic septal fibers combined with repeated depolarization induces strong long-term enhancement of GABAA inhibition (GABAA-LTP). Indeed, this enhanced inhibition is due to the increased activation of α5βγ2 subunit-containing GABAA receptors by the GABA released. GABAA-LTP requires the activation of M1-muscarinic receptors and an increase in cytosolic Ca2+. In the absence of PC depolarization ACh triggered a presynaptic depolarization-induced suppression of inhibition (DSI), revealing that postsynaptic activity gates the effects of ACh from presynaptic DSI to postsynaptic LTP. These results provide key insights into mechanisms potentially linked with cognitive functions, spatial navigation, and the homeostatic control of abnormal hyperexcitable states. PMID:24938789

  20. Acetylcholinesterase liquid crystal biosensor based on modulated growth of gold nanoparticles for amplified detection of acetylcholine and inhibitor.

    PubMed

    Liao, Shuzhen; Qiao, Yanan; Han, Wenting; Xie, Zhaoxia; Wu, Zhaoyang; Shen, Guoli; Yu, Ruqin

    2012-01-01

    A novel acetylcholinesterase (AChE) liquid crystal (LC) biosensor based on enzymatic growth of gold nanoparticles (Au NPs) has been developed for amplified detection of acetylcholine (ACh) and AChE inhibitor. In this method, AChE mediates the hydrolysis of acetylthiocholine (ATCl) to form thiocholine, and the latter further reduces AuCl(4)(-) to Au NPs without Au nanoseeds. This process, termed biometallization, leads to a great enhancement in the optical signal of the LC biosensor due to the large size of Au NPs, which can greatly disrupt the orientational arrangement of LCs. On the other hand, the hydrolysis of ATCl is inhibited in the presence of ACh or organophosphate pesticides (OPs, a AChE inhibitor), which will decrease the catalytic growth of Au NPs and, as a result, reduce the orientational response of LCs. On the basis of such an inhibition mechanism, the AChE LC biosensor can be used as an effective way to realize the detection of ACh and AChE inhibitors. The results showed that the AChE LC biosensor was highly sensitive to ACh with a detection limit of 15 μmol/L and OPs with a detection limit of 0.3 nmol/L. This study provides a simple and sensitive AChE LC biosensing approach and offers effective signal enhanced strategies for the development of enzyme LC biosensors. PMID:22148672

  1. Effects of acute chlorpyrifos exposure on in vivo acetylcholine accumulation in rat striatum

    SciTech Connect

    Karanth, Subramanya; Liu, Jing; Mirajkar, Nikita; Pope, Carey . E-mail: carey.pope@okstate.edu

    2006-10-01

    This study examined the acute effects of chlorpyrifos (CPF) on cholinesterase inhibition and acetylcholine levels in the striatum of freely moving rats using in vivo microdialysis. Adult, male Sprague-Dawley rats were treated with vehicle (peanut oil, 2 ml/kg) or CPF (84, 156 or 279 mg/kg, sc) and functional signs of toxicity, body weight and motor activity recorded. Microdialysis was conducted at 1, 4 and 7 days after CPF exposure for measurement of acetylcholine levels in striatum. Rats were then sacrificed and the contralateral striatum and diaphragm were collected for biochemical measurements. Few overt signs of cholinergic toxicity were noted in any rats. Body weight gain was significantly affected in the high-dose (279 mg/kg) group only, while motor activity (nocturnal rearing) was significantly reduced in all CPF-treated groups at one day (84 mg/kg) or from 1-4 days (156 and 279 mg/kg) after dosing. Cholinesterase activities in both diaphragm and striatum were markedly inhibited (50-92%) in a time-dependent manner, but there were relatively minimal dose-related changes. In contrast, time- and dose-dependent changes in striatal acetylcholine levels were noted, with significantly higher levels noted in the high-dose group compared to other groups. Maximal increases in striatal acetylcholine levels were observed at 4-7 days after dosing (84 mg/kg, 7-9-fold; 156 mg/kg, 10-13-fold; 279 mg/kg, 35-57-fold). Substantially higher acetylcholine levels were noted when an exogenous cholinesterase inhibitor was included in the perfusion buffer, but CPF treatment-related differences were substantially lower in magnitude under those conditions. The results suggest that marked differences in acetylcholine accumulation can occur with dosages of CPF eliciting relatively similar degrees of cholinesterase inhibition. Furthermore, the minimal expression of classic signs of cholinergic toxicity in the presence of extensive brain acetylcholine accumulation suggests that some

  2. Recent Duplication and Functional Divergence in Parasitic Nematode Levamisole-Sensitive Acetylcholine Receptors

    PubMed Central

    Duguet, Thomas B.; Charvet, Claude L.; Forrester, Sean G.; Wever, Claudia M.; Dent, Joseph A.; Neveu, Cedric; Beech, Robin N.

    2016-01-01

    Helminth parasites rely on fast-synaptic transmission in their neuromusculature to experience the outside world and respond to it. Acetylcholine plays a pivotal role in this and its receptors are targeted by a wide variety of both natural and synthetic compounds used in human health and for the control of parasitic disease. The model, Caenorhabditis elegans is characterized by a large number of acetylcholine receptor subunit genes, a feature shared across the nematodes. This dynamic family is characterized by both gene duplication and loss between species. The pentameric levamisole-sensitive acetylcholine receptor has been characterized from C. elegans, comprised of five different subunits. More recently, cognate receptors have been reconstituted from multiple parasitic nematodes that are found to vary in subunit composition. In order to understand the implications of receptor composition change and the origins of potentially novel drug targets, we investigated a specific example of subunit duplication based on analysis of genome data for 25 species from the 50 helminth genome initiative. We found multiple independent duplications of the unc-29, acetylcholine receptor subunit, where codon substitution rate analysis identified positive, directional selection acting on amino acid positions associated with subunit assembly. Characterization of four gene copies from a model parasitic nematode, Haemonchus contortus, demonstrated that each copy has acquired unique functional characteristics based on phenotype rescue of transgenic C. elegans and electrophysiology of receptors reconstituted in Xenopus oocytes. We found evidence that a specific incompatibility has evolved for two subunits co-expressed in muscle. We demonstrated that functional divergence of acetylcholine receptors, driven by directional selection, can occur more rapidly than previously thought and may be mediated by alteration of receptor assembly. This phenomenon is common among the clade V parasitic

  3. A patch-clamp study of bovine chromaffin cells and of their sensitivity to acetylcholine.

    PubMed Central

    Fenwick, E M; Marty, A; Neher, E

    1982-01-01

    1. Bovine chromaffin cells were enzymatically isolated and kept in short term tissue culture. Their electrical properties were studied using recent advances of the patch-clamp technique (Hamill, Marty, Neher, Sakmann & Sigworth, 1981). 2. When a patch pipette was sealed tightly to a chromaffin cell ('cell-attached configuration') current wave forms due to intracellular action potentials could be observed. The frequency of the wave forms was altered by changing the pipette potential. When acetylcholine was present in the pipette solution, acetylcholine-induced single channel currents were evident in the patch recording. Action potential wave forms were then often seen to follow acetycholine-induced single channel currents. 3. In the cell-attached configuration, large single channel current events did not resemble square pulses but showed exponential relaxations with time constants of the order of 50 ms. 4. After rupture of the patch of membrane, the pipette--cell seal remained stable ('whole-cell recording', Hamill et al. 1981). Chromaffin cells were found to have a resting potential of -50 to -80 mV, and an input resistance around 5 G omega. The high cell resistance accounts for the relaxing currents evident in the cell-attached configuration. 5. In the best cases, the effective time constant of the voltage clamp in the whole-cell recording mode was 15 microseconds. Exchange of small ions such as Na+ ions between pipette and cell interior solutions was then complete within 15 s. 6. Acetylcholine-induced currents were obtained at various acetylcholine concentrations. Single acetylcholine-induced channels had a slope conductance of 44 pS between -100 and -55 mV, and a mean duration of 27 ms at -80 mV (at room temperature). Images Fig. 1 PMID:6296371

  4. Recent Duplication and Functional Divergence in Parasitic Nematode Levamisole-Sensitive Acetylcholine Receptors.

    PubMed

    Duguet, Thomas B; Charvet, Claude L; Forrester, Sean G; Wever, Claudia M; Dent, Joseph A; Neveu, Cedric; Beech, Robin N

    2016-07-01

    Helminth parasites rely on fast-synaptic transmission in their neuromusculature to experience the outside world and respond to it. Acetylcholine plays a pivotal role in this and its receptors are targeted by a wide variety of both natural and synthetic compounds used in human health and for the control of parasitic disease. The model, Caenorhabditis elegans is characterized by a large number of acetylcholine receptor subunit genes, a feature shared across the nematodes. This dynamic family is characterized by both gene duplication and loss between species. The pentameric levamisole-sensitive acetylcholine receptor has been characterized from C. elegans, comprised of five different subunits. More recently, cognate receptors have been reconstituted from multiple parasitic nematodes that are found to vary in subunit composition. In order to understand the implications of receptor composition change and the origins of potentially novel drug targets, we investigated a specific example of subunit duplication based on analysis of genome data for 25 species from the 50 helminth genome initiative. We found multiple independent duplications of the unc-29, acetylcholine receptor subunit, where codon substitution rate analysis identified positive, directional selection acting on amino acid positions associated with subunit assembly. Characterization of four gene copies from a model parasitic nematode, Haemonchus contortus, demonstrated that each copy has acquired unique functional characteristics based on phenotype rescue of transgenic C. elegans and electrophysiology of receptors reconstituted in Xenopus oocytes. We found evidence that a specific incompatibility has evolved for two subunits co-expressed in muscle. We demonstrated that functional divergence of acetylcholine receptors, driven by directional selection, can occur more rapidly than previously thought and may be mediated by alteration of receptor assembly. This phenomenon is common among the clade V parasitic

  5. Species differences in the negative inotropic effect of acetylcholine and soman in rat, guinea pig, and rabbit hearts. (Reannouncement with new availability information)

    SciTech Connect

    Maxwell, D.M.; Thomsen, R.H.; Baskin, S.I.

    1991-12-31

    Acetylcholine reduced atrial contractions by 82.5% in guinea pig, 50.8% in rat, and 41.5% in rabbit. 2. The EC50, values for the negative inotropic effect of acetylcholine were 3.3 x 10(-7) M in rat and guinea pig atria and 4.1 x 10(-6) M in rabbit atria. 3. There was no correlation between the species differences in the negative inotropic effect of acetylcholine in atria and the density or affinity of acetylcholinesterase or muscarinic receptors. 4. Inhibition of atrial acetylcholinesterase with soman reduced the EC50 of acetylcholine three-fold in all species, but did not change the maximal inotropic effect of acetylcholine. 5. Species differences in the negative inotropic effect of acetylcholine may be caused by differences in the coupling between myocardial muscarinic receptors and the ion channels that mediate negative inotropy. Acetylcholine, cardiovascular response, species variation negative inotropic response.

  6. Choline acetyltransferase and organic cation transporters are responsible for synthesis and propionate-induced release of acetylcholine in colon epithelium.

    PubMed

    Bader, Sandra; Klein, Jochen; Diener, Martin

    2014-06-15

    Acetylcholine is not only a neurotransmitter, but is found in a variety of non-neuronal cells. For example, the enzyme choline acetyltransferase (ChAT), catalyzing acetylcholine synthesis, is expressed by the colonic epithelium of different species. These cells release acetylcholine across the basolateral membrane after luminal exposure to propionate, a short-chain fatty acid. The functional consequence is the induction of chloride secretion, measurable as increase in short-circuit current (Isc) in Ussing chamber experiments. It is unclear how acetylcholine is produced and released by colonic epithelium. Therefore, the aim of the present study was the identification (on mRNA and protein level) and functional characterization (in Ussing chamber experiments combined with HPLC detection of acetylcholine) of transporters/enzymes in the cholinergic system of rat colonic epithelium. Immunohistochemical staining as well as RT-PCR revealed the expression of high-affinity choline transporter, ChAT, carnitine acetyltransferase (CarAT), vesicular acetylcholine transporter (VAChT), and organic cation transporters (OCT 1, 2, 3) in colonic epithelium. In contrast to blockade of ChAT with bromoacetylcholine, inhibition of CarAT with mildronate did not inhibit the propionate-induced increase in Isc, suggesting a predominant synthesis of epithelial acetylcholine by ChAT. Although being expressed, blockade of VAChT with vesamicol was ineffective, whereas inhibition of OCTs with omeprazole and corticosterone inhibited propionate-induced Isc and the release of acetylcholine into the basolateral compartment. In summary, OCTs seem to be involved in regulated acetylcholine release by colonic epithelium, which is assumed to be involved in chemosensing of luminal short-chain fatty acids by the intestinal epithelium.

  7. Activation of α2A-Containing Nicotinic Acetylcholine Receptors Mediates Nicotine-Induced Motor Output in Embryonic Zebrafish

    PubMed Central

    Menelaou, Evdokia; Udvadia, Ava J.; Tanguay, Robert L.; Svoboda, Kurt R.

    2014-01-01

    It is well established that cholinergic signaling has critical roles during central nervous system development. In physiological and behavioral studies, activation of nicotinic acetylcholine receptors has been implicated in mediating cholinergic signaling. In developing spinal cord, cholinergic transmission is associated with neural circuits responsible for producing locomotor behaviors. In this study, we investigated the expression pattern of the α2A nAChR subunit as evidence from others suggested it could be expressed by spinal neurons. In situ hybridization and immunohistochemistry revealed that the α2A nAChR subunits are expressed in spinal Rohon-Beard (RB) neurons and olfactory sensory neurons in young embryos. In order to examine the functional role of the α2A nAChR subunit during embryogenesis, we blocked its expression using antisense modified oligonucleotides. Blocking the expression of α2A nAChR subunits had no effect on spontaneous motor activity. However, it did alter the embryonic nicotine-induced motor output. This reduction in motor activity was not accompanied by defects in neuronal and muscle elements associated with the motor output. Moreover, the anatomy and functionality of RB neurons was normal even in the absence of the α2A nAChR subunit. Thus, we propose that α2A-containing nAChR are dispensable for normal RB development. However, in the context of nicotine-induced motor output, α2A-containing nAChRs on RB neurons provide the substrate that nicotine acts upon to induce the motor output. These findings also indicate that functional neuronal nAChRs are present within spinal cord at the time when locomotor output in zebrafish first begins to manifest itself. PMID:24738729

  8. alpha 7-type acetylcholine receptor localization and its modulation by nicotine and cholesterol in vascular endothelial cells.

    PubMed

    Peña, Victoria B Ayala; Bonini, Ida C; Antollini, Silvia S; Kobayashi, Toshihide; Barrantes, Francisco J

    2011-11-01

    The neuronal-type α7 nicotinic acetylcholine receptor (α7AChR) is also found in various non-neural tissues, including vascular endothelium, where its peculiar ionotropic properties (high Ca(2+) permeability) and its supervening Ca(2+) -mediated intracellular cascades may play important roles in physiology (angiogenesis) and pathology (inflammation and atherogenesis). Changes in molecular (up-regulation, affinity, and conformational states) and cellular (distribution, association with membranes) properties of the α7AChR related to angiogenesis (wound-repair cell migration) and atherogenesis (alterations in cholesterol content) were studied in living endothelial cells, with the aim of determining whether such changes constitute early markers of inflammatory response. The combination of pharmacological, biochemical, and fluorescence microscopy tools showed that α7AChRs in rat arterial endothelial (RAEC) and human venous endothelial (HUVEC) cells occur at extremely low expression levels (∼50 fmol/mg protein) but undergo agonist-induced up-regulation at relatively high nicotine concentrations (∼300-fold with 50 µM ligand), increasing their cell-surface exposure. When analyzed in terms of cold Triton X-100 solubility and subcellular distribution, α7AChRs occur in the "non-raft" subcellular membrane fractions. Acute cholesterol depletion reduced not only cholesterol levels but also the number of cell-surface α7AChRs. Nicotine exposure markedly stimulated cell migration and accelerated wound repair, which drastically diminished in cells deprived of the sterol. The angiogenic effect of nicotine appears to be synergistic with cholesterol content. Finally, the apparent K(D) of α7AChRs for the open-channel blocker crystal violet was found to be ∼600-fold lower in receptor-enriched membranes obtained from up-regulated HUVEC.

  9. Activation of α2A-containing nicotinic acetylcholine receptors mediates nicotine-induced motor output in embryonic zebrafish.

    PubMed

    Menelaou, Evdokia; Udvadia, Ava J; Tanguay, Robert L; Svoboda, Kurt R

    2014-07-01

    It is well established that cholinergic signaling has critical roles during central nervous system development. In physiological and behavioral studies, activation of nicotinic acetylcholine receptors (nAChRs) has been implicated in mediating cholinergic signaling. In developing spinal cord, cholinergic transmission is associated with neural circuits responsible for producing locomotor behaviors. In this study, we investigated the expression pattern of the α2A nAChR subunit as previous evidence suggested it could be expressed by spinal neurons. In situ hybridization and immunohistochemistry revealed that the α2A nAChR subunits are expressed in spinal Rohon-Beard (RB) neurons and olfactory sensory neurons in young embryos. To examine the functional role of the α2A nAChR subunit during embryogenesis, we blocked its expression using antisense modified oligonucleotides. Blocking the expression of α2A nAChR subunits had no effect on spontaneous motor activity. However, it did alter the embryonic nicotine-induced motor output. This reduction in motor activity was not accompanied by defects in neuronal and muscle elements associated with the motor output. Moreover, the anatomy and functionality of RB neurons was normal even in the absence of the α2A nAChR subunit. Thus, we propose that α2A-containing nAChRs are dispensable for normal RB development. However, in the context of nicotine-induced motor output, α2A-containing nAChRs on RB neurons provide the substrate that nicotine acts upon to induce the motor output. These findings also indicate that functional neuronal nAChRs are present within spinal cord at the time when locomotor output in zebrafish first begins to manifest itself.

  10. Sex difference in the 24-h acetylcholine release profile in the premotor/supplementary motor area of behaving rats.

    PubMed

    Takase, Kenkichi; Mitsushima, Dai; Funabashi, Toshiya; Kimura, Fukuko

    2007-06-18

    The sex differences in various motor functions suggest a sex-specific neural basis in the nonprimary or primary motor area. To examine the sex difference in the 24-h profile of acetylcholine (ACh) release in the rostral frontal cortex area 2 (rFr2), which is equivalent to the premotor/supplementary motor area in primates, we performed an in vivo microdialysis study in both sexes of rats fed pelleted or powdered diet. The dialysate was automatically collected from the rFr2 for 24 h under freely moving conditions. Moreover, the number of cholinergic neurons in the nucleus basalis magnocellularis (NBM) was examined. Further, to confirm the relation between ACh release in the rFr2 and motor function, the spontaneous locomotor activity was monitored for 24 h. Both sexes showed a distinct 24-h rhythm of ACh release, which was high during the dark phase and low during the light phase. Female rats, however, showed a greater ACh release and more cholinergic neurons in the NBM than male rats. Similarly, spontaneous locomotor activity also showed a 24-h rhythm, which paralleled the changes in ACh release in both sexes, and these changes were again greater in female rats than in male rats. In addition, feeding with powdered diet significantly increased the ACh release and spontaneous locomotor activity. The present study is the first to report the sex difference in the 24-h profile of ACh release in the rFr2 in rats. The sex specific ACh release in the rFr2 may partly contribute to the sex difference in motor function in rats.

  11. Endogenous acetylcholine and nicotine activation enhances GABAergic and glycinergic inputs to cardiac vagal neurons.

    PubMed

    Wang, Jijiang; Wang, Xin; Irnaten, Mustapha; Venkatesan, Priya; Evans, Cory; Baxi, Sunit; Mendelowitz, David

    2003-05-01

    The heart slows during expiration and heart rate increases during inspiration. This cardiorespiratory interaction is thought to occur by increased inhibitory synaptic events to cardiac vagal neurons during inspiration. Since cholinergic receptors have been suggested to be involved in this cardiorespiratory interaction, we tested whether endogenous cholinergic activity modulates GABAergic and glycinergic neurotransmission to cardiac vagal neurons in the nucleus ambiguus, whether nicotine can mimic this facilitation, and we examined the nicotinic receptors involved. Cardiac vagal neurons in the rat were labeled with a retrograde fluorescent tracer and studied in an in vitro slice using patch-clamp techniques. Application of neostigmine (10 microM), an acetylcholinerase inhibitor, significantly increased the frequency of both GABAergic and glycinergic inhibitory postsynaptic currents (IPSCs) in cardiac vagal neurons. Exogenous application of nicotine increased the frequency and amplitude of both GABAergic and glycinergic IPSCs. The nicotinic facilitation of both GABAergic and glycinergic IPSCs were insensitive to 100 nM alpha-bungarotoxin but were abolished by dihydro-beta-erythrodine (DHbetaE) at a concentration (3 microM) specific for alpha4beta2 nicotinic receptors. In the presence of TTX, nicotine increased the frequency of GABAergic and glycinergic miniature synaptic events, which were also abolished by DHbetaE (3 microM). This work demonstrates that there is endogenous cholinergic facilitation of GABAergic and glycinergic synaptic inputs to cardiac vagal neurons, and activation of alpha4beta2 nicotinic receptors at presynaptic terminals facilitates GABAergic and glycinergic neurotransmission to cardiac vagal neurons. Nicotinic facilitation of inhibitory neurotransmission to premotor cardiac parasympathetic neurons may be involved in generating respiratory sinus arrhythmia.

  12. Parallel architectures and neural networks

    SciTech Connect

    Calianiello, E.R. )

    1989-01-01

    This book covers parallel computer architectures and neural networks. Topics include: neural modeling, use of ADA to simulate neural networks, VLSI technology, implementation of Boltzmann machines, and analysis of neural nets.

  13. FGF signaling transforms non-neural ectoderm into neural crest.

    PubMed

    Yardley, Nathan; García-Castro, Martín I

    2012-12-15

    The neural crest arises at the border between the neural plate and the adjacent non-neural ectoderm. It has been suggested that both neural and non-neural ectoderm can contribute to the neural crest. Several studies have examined the molecular mechanisms that regulate neural crest induction in neuralized tissues or the neural plate border. Here, using the chick as a model system, we address the molecular mechanisms by which non-neural ectoderm generates neural crest. We report that in response to FGF the non-neural ectoderm can ectopically express several early neural crest markers (Pax7, Msx1, Dlx5, Sox9, FoxD3, Snail2, and Sox10). Importantly this response to FGF signaling can occur without inducing ectopic mesodermal tissues. Furthermore, the non-neural ectoderm responds to FGF by expressing the prospective neural marker Sox3, but it does not express definitive markers of neural or anterior neural (Sox2 and Otx2) tissues. These results suggest that the non-neural ectoderm can launch the neural crest program in the absence of mesoderm, without acquiring definitive neural character. Finally, we report that prior to the upregulation of these neural crest markers, the non-neural ectoderm upregulates both BMP and Wnt molecules in response to FGF. Our results provide the first effort to understand the molecular events leading to neural crest development via the non-neural ectoderm in amniotes and present a distinct response to FGF signaling. PMID:23000357

  14. Parallel Consensual Neural Networks

    NASA Technical Reports Server (NTRS)

    Benediktsson, J. A.; Sveinsson, J. R.; Ersoy, O. K.; Swain, P. H.

    1993-01-01

    A new neural network architecture is proposed and applied in classification of remote sensing/geographic data from multiple sources. The new architecture is called the parallel consensual neural network and its relation to hierarchical and ensemble neural networks is discussed. The parallel consensual neural network architecture is based on statistical consensus theory. The input data are transformed several times and the different transformed data are applied as if they were independent inputs and are classified using stage neural networks. Finally, the outputs from the stage networks are then weighted and combined to make a decision. Experimental results based on remote sensing data and geographic data are given. The performance of the consensual neural network architecture is compared to that of a two-layer (one hidden layer) conjugate-gradient backpropagation neural network. The results with the proposed neural network architecture compare favorably in terms of classification accuracy to the backpropagation method.

  15. Neural Tube Defects

    MedlinePlus

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the first month ... she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In spina ...

  16. Neuropeptide Treatment with Cerebrolysin Enhances the Survival of Grafted Neural Stem Cell in an α-Synuclein Transgenic Model of Parkinson’s Disease

    PubMed Central

    Rockenstein, Edward; Desplats, Paula; Ubhi, Kiren; Mante, Michael; Florio, Jazmin; Adame, Anthony; Winter, Stefan; Brandstaetter, Hemma; Meier, Dieter; Moessler, Herbert; Masliah, Eliezer

    2015-01-01

    Neuronal stem cell (NSC) grafts have been investigated as a potential neuro-restorative therapy in Parkinson’s disease (PD) but their use is compromised by the death of grafted cells. We investigated the use of Cerebrolysin (CBL), a neurotrophic peptide mixture, as an adjunct to NSC therapy in the α-synuclein (α-syn) transgenic (tg) model of PD. In vehicle-treated α-syn tg mice, there was decreased survival of NSCs. In contrast, CBL treatment enhanced the survival of NSCs in α-syn tg groups and ameliorated behavioral deficits. The grafted NSCs showed lower levels of terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells in the CBL-treated mice when compared with vehicle-treated α-syn tg mice. No evidence of tumor growth was detected. Levels of α-syn were similar in the vehicle in CBL-treated tg mice. In conclusion, CBL treatment might be a potential adjuvant for therapeutic NSC grafting in PD. PMID:27429559

  17. Neuropeptide Treatment with Cerebrolysin Enhances the Survival of Grafted Neural Stem Cell in an α-Synuclein Transgenic Model of Parkinson's Disease.

    PubMed

    Rockenstein, Edward; Desplats, Paula; Ubhi, Kiren; Mante, Michael; Florio, Jazmin; Adame, Anthony; Winter, Stefan; Brandstaetter, Hemma; Meier, Dieter; Moessler, Herbert; Masliah, Eliezer

    2015-01-01

    Neuronal stem cell (NSC) grafts have been investigated as a potential neuro-restorative therapy in Parkinson's disease (PD) but their use is compromised by the death of grafted cells. We investigated the use of Cerebrolysin (CBL), a neurotrophic peptide mixture, as an adjunct to NSC therapy in the α-synuclein (α-syn) transgenic (tg) model of PD. In vehicle-treated α-syn tg mice, there was decreased survival of NSCs. In contrast, CBL treatment enhanced the survival of NSCs in α-syn tg groups and ameliorated behavioral deficits. The grafted NSCs showed lower levels of terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells in the CBL-treated mice when compared with vehicle-treated α-syn tg mice. No evidence of tumor growth was detected. Levels of α-syn were similar in the vehicle in CBL-treated tg mice. In conclusion, CBL treatment might be a potential adjuvant for therapeutic NSC grafting in PD.

  18. The Enhancer of Split Complex and Adjacent Genes in the 96f Region of Drosophila Melanogaster Are Required for Segregation of Neural and Epidermal Progenitor Cells

    PubMed Central

    Schrons, H.; Knust, E.; Campos-Ortega, J. A.

    1992-01-01

    The Enhancer of split complex [E(spl)-C] of Drosophila melanogaster is located in the 96F region of the third chromosome and comprises at least seven structurally related genes, HLH-mδ, HLH-mγ, HLH-mβ, HLH-m3, HLH-m5, HLH-m7 and E(spl). The functions of these genes are required during early neurogenesis to give neuroectodermal cells access to the epidermal pathway of development. Another gene in the 96F region, namely groucho, is also required for this process. However, groucho is not structurally related to, and appears to act independently of, the genes of the E(spl)-C; the possibility is discussed that groucho acts upstream to the E(spl)-C genes. Indirect evidence suggests that a neighboring transcription unit (m4) may also take part in the process. Of all these genes, only gro is essential; m4 is a dispensable gene, the deletion of which does not produce detectable morphogenetic abnormalities, and the genes of the E(spl)-C are to some extent redundant and can partially substitute for each other. This redundancy is probably due to the fact that the seven genes of the E(spl)-C encode highly conserved putative DNA-binding proteins of the bHLH family. The genes of the complex are interspersed among other genes which appear to be unrelated to the neuroepidermal lineage dichotomy. PMID:1427039

  19. Role and mechanisms of action of acetylcholine in the regulation of rat cholangiocyte secretory functions.

    PubMed Central

    Alvaro, D; Alpini, G; Jezequel, A M; Bassotti, C; Francia, C; Fraioli, F; Romeo, R; Marucci, L; Le Sage, G; Glaser, S S; Benedetti, A

    1997-01-01

    We investigated, in isolated bile duct units (IBDU) and cholangiocytes isolated from normal rat liver, the occurrence of acetylcholine (ACh) receptors, and the role and mechanisms of ACh in the regulation of the Cl-/HCO3- exchanger activity. The Cl-/HCO3- exchanger activity was evaluated measuring changes in intracellular pH induced by acute Cl- removal/readmission. M3 subtype ACh receptors were detected in IBDU and isolated cholangiocytes by immunofluorescence, immunoelectron microscopy, and reverse transcriptase PCR. M1 subtype ACh receptor mRNA was not detected by reverse transcriptase PCR and M2 subtype was negative by immunofluorescence. ACh (10 microM) showed no effect on the basal activity of the Cl-/HCO3- exchanger. When IBDU were exposed to ACh plus secretin, ACh significantly (P < 0.03) increased the maximal rate of alkalinization after Cl- removal and the maximal rate of recovery after Cl- readmission compared with secretin alone (50 nM), indicating that ACh potentiates the stimulatory effect of secretin on the Cl-/HCO3- exchanger activity. This effect of ACh was blocked by the M3 ACh receptor antagonist, 4-diphenyl-acetoxy-N-(2-chloroethyl)-piperidine (40 nM), by the intracellular Ca2+ chelator, 1,2-bis (2-Aminophenoxy)- ethane-N,N,N', N'-tetraacetic acid acetoxymethylester (50 microM), but not by the protein kinase C antagonist, staurosporine (0.1 microM). Intracellular cAMP levels, in isolated rat cholangiocytes, were unaffected by ACh alone, but were markedly higher after exposure to secretin plus ACh compared with secretin alone (P < 0.01). The ACh-induced potentiation of the secretin effect on both intracellular cAMP levels and the Cl-/HCO3- exchanger activity was individually abolished by two calcineurin inhibitors, FK-506 and cyclosporin A (100 nM). Conclusions: M3 ACh receptors are markedly and diffusively represented in rat cholangiocytes. ACh did not influence the basal activity of the Cl-/HCO3- exchanger, but enhanced the stimulation by

  20. Neuronal nicotinic acetylcholine receptor agonists: pharmacophores, evolutionary QSAR and 3D-QSAR models.

    PubMed

    Nicolotti, Orazio; Altomare, Cosimo; Pellegrini-Calace, Marialuisa; Carotti, Angelo

    2004-01-01

    Neuronal nicotinic acetylcholine ion channel receptors (nAChRs) exist as several subtypes and are involved in a variety of functions and disorders of the central nervous system (CNS), such as Alzheimer's and Parkinson's diseases. The lack of reliable information on the 3D structure of nAChRs prompted us to focus efforts on pharmacophore and structure-affinity relationships (SAFIRs). The use of DISCO (DIStance COmparison) and Catalyst/HipHop led to the formulation of a pharmacophore that is made of three geometrically unrelated features: (i) an ammonium head involved in coulombic and/or H-bond interactions, (ii) a lone pair of a pyridine nitrogen or a carbonyl oxygen, as H-bond acceptor site, and (iii) a hydrophobic molecular region generally constituted by aliphatic cycles. The quantitative SAFIR (QSAFIR) study was carried out on about three hundred nicotinoid agonists, and coherent results were obtained from classical Hansch-type approach, 3D QSAFIRs, based on Comparative Molecular Field Analysis (CoMFA), and trade-off models generated by Multi-objective Genetic QSAR (MoQSAR), a novel evolutionary software that makes use of Genetic Programming (GP) and multi-objective optimization (MO). Within each congeneric series, Hansch-type equations revealed detrimental steric effects as the major factors modulating the receptor affinity, whereas CoMFA allowed us to merge progressively single-class models in a more global one, whose robustness was supported by crossvalidation, high prediction statistics and satisfactory predictions of the affinity data of a true external ligand set (r(2)(pred) = 0.796). Next, MoQSAR was used to analyze a data set of 58 highly active nicotinoids characterized by 56 descriptors, that are log P, MR and 54 low inter-correlated WHIM (Weighted Holistic Invariant Molecular) indices. Equivalent QSAFIR models, that represent different compromises between structural model complexity, fitting and internal model complexity, were found. Our attention was

  1. Neuronal nicotinic acetylcholine receptor agonists: pharmacophores, evolutionary QSAR and 3D-QSAR models.

    PubMed

    Nicolotti, Orazio; Altomare, Cosimo; Pellegrini-Calace, Marialuisa; Carotti, Angelo

    2004-01-01

    Neuronal nicotinic acetylcholine ion channel receptors (nAChRs) exist as several subtypes and are involved in a variety of functions and disorders of the central nervous system (CNS), such as Alzheimer's and Parkinson's diseases. The lack of reliable information on the 3D structure of nAChRs prompted us to focus efforts on pharmacophore and structure-affinity relationships (SAFIRs). The use of DISCO (DIStance COmparison) and Catalyst/HipHop led to the formulation of a pharmacophore that is made of three geometrically unrelated features: (i) an ammonium head involved in coulombic and/or H-bond interactions, (ii) a lone pair of a pyridine nitrogen or a carbonyl oxygen, as H-bond acceptor site, and (iii) a hydrophobic molecular region generally constituted by aliphatic cycles. The quantitative SAFIR (QSAFIR) study was carried out on about three hundred nicotinoid agonists, and coherent results were obtained from classical Hansch-type approach, 3D QSAFIRs, based on Comparative Molecular Field Analysis (CoMFA), and trade-off models generated by Multi-objective Genetic QSAR (MoQSAR), a novel evolutionary software that makes use of Genetic Programming (GP) and multi-objective optimization (MO). Within each congeneric series, Hansch-type equations revealed detrimental steric effects as the major factors modulating the receptor affinity, whereas CoMFA allowed us to merge progressively single-class models in a more global one, whose robustness was supported by crossvalidation, high prediction statistics and satisfactory predictions of the affinity data of a true external ligand set (r(2)(pred) = 0.796). Next, MoQSAR was used to analyze a data set of 58 highly active nicotinoids characterized by 56 descriptors, that are log P, MR and 54 low inter-correlated WHIM (Weighted Holistic Invariant Molecular) indices. Equivalent QSAFIR models, that represent different compromises between structural model complexity, fitting and internal model complexity, were found. Our attention was

  2. Nested Neural Networks

    NASA Technical Reports Server (NTRS)

    Baram, Yoram

    1992-01-01

    Report presents analysis of nested neural networks, consisting of interconnected subnetworks. Analysis based on simplified mathematical models more appropriate for artificial electronic neural networks, partly applicable to biological neural networks. Nested structure allows for retrieval of individual subpatterns. Requires fewer wires and connection devices than fully connected networks, and allows for local reconstruction of damaged subnetworks without rewiring entire network.

  3. Electronic neural networks

    SciTech Connect

    Howard, R.E.; Jackel, L.D.; Graf, H.P.

    1988-02-01

    The use of electronic neural networks to handle some complex computing problems is discussed. A simple neural model is shown and discussed in terms of its computational aspects. The use of electronic neural networks in machine pattern recognition and classification and in machine learning is examined. CMOS programmable networks are discussed. 15 references.

  4. Spatial and intracellular relationships between the α7 nicotinic acetylcholine receptor and the vesicular acetylcholine transporter in the prefrontal cortex of rat and mouse

    PubMed Central

    Duffy, Aine M.; Zhou, Ping; Milner, Teresa A.; Pickel, Virginia M.

    2009-01-01

    The alpha-7 subunit of the nicotinic acetylcholine receptor (α7nAChR) is expressed in the prefrontal cortex (PFC), a brain region where these receptors are implicated in cognitive function and in the pathophysiology of schizophrenia. Activation of this receptor is dependent on release of acetylcholine (ACh) from axon terminals that contain the vesicular acetylcholine transporter (VAChT). Since rat and mouse models are widely used for studies of specific abnormalities in schizophrenia, we sought to determine the subcellular location of the α7nAChR with respect to VAChT storage vesicles in axon terminals in the PFC in both species. For this, we used dual electron microscopic immunogold and immunoperoxidase labeling of antisera raised against the α7nAChR and VAChT. In both species, the α7nAChR-immunoreactivity (-ir) was principally identified within dendrites and dendritic spines, receptive to axon terminals forming asymmetric excitatory-type synapses, but lacking detectable α7nAChR or VAChT-ir. Quantitative analysis of the rat PFC revealed that of α7nAChR labeled neuronal profiles, 65% (299/463) were postsynaptic structures (dendrites and dendritic spine) and only 22% (104/463) were axon terminals or small unmyelinated axons. In contrast, VAChT was principally localized to varicose vesicle-filled axonal profiles, without recognized synaptic specializations (n = 240). Of the α7nAChR-labeled axons, 47% (37/79) also contained VAChT, suggesting that ACh release is autoregulated through the presynaptic α7nAChR. The VAChT-labeled terminals rarely formed synapses, but frequently apposed α7nAChR-containing neuronal profiles. These results suggest that in rodent PFC, the α7nAChR plays a major role in modulation of the postsynaptic excitation in spiny dendrites in contact with VAChT containing axons. PMID:19374941

  5. Pharmacological and biochemical characterization of the D-1 dopamine receptor mediating acetylcholine release in rabbit retina

    SciTech Connect

    Hensler, J.G.; Cotterell, D.J.; Dubocovich, M.L.

    1987-12-01

    Superfusion w