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Tetrodotoxin

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https://www.readbyqxmd.com/read/29238306/calcium-imaging-of-nerve-mast-cell-signaling-in-the-human-intestine
#1
Sabine Buhner, Natasja Barki, Wolfgang Greiter, Pieter Giesbertz, Ihsan E Demir, Güralp O Ceyhan, Florian Zeller, Hannelore Daniel, Michael Schemann
Introduction: It is suggested that an altered microenvironment in the gut wall alters communication along a mast cell nerve axis. We aimed to record for the first time signaling between mast cells and neurons in intact human submucous preparations. Methods: We used the Ca2+ sensitive dye Fluo-4 AM to simultaneously image changes in intracellular calcium [Ca+2]i (%ΔF/F) in neurons and mast cells. Data are presented as median with interquartile ranges (25/75%). Results: We recorded nerve responses in 29 samples upon selective activation of 223 mast cells by IgE receptor cross linking with the antibody mAb22E7...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29232206/bupivacaine-indirectly-potentiates-glutamate-induced-intracellular-calcium-signaling-in-rat-hippocampal-neurons-by-impairing-mitochondrial-function-in-cocultured-astrocytes
#2
Yuan Xing, Nan Zhang, Wei Zhang, Lei-Ming Ren
BACKGROUND: Bupivacaine induces central neurotoxicity at lower blood concentrations than cardiovascular toxicity. However, central sensitivity to bupivacaine is poorly understood. The toxicity mechanism might be related to glutamate-induced excitotoxicity in hippocampal cells. METHODS: The intracellular free Ca concentration ([Ca]i), mitochondrial membrane potential, and reactive oxygen species generation were measured by fluorescence and two-photon laser scanning microscopy in fetal rat hippocampal neurons and astrocytes...
December 12, 2017: Anesthesiology
https://www.readbyqxmd.com/read/29227106/hollow-silica-nanoparticles-penetrate-the-peripheral-nerve-and-enhance-the-nerve-blockade-from-tetrodotoxin
#3
Qian Liu, Claudia M Santamaria, Tuo Wei, Chao Zhao, Tianjiao Ji, Tianshe Yang, Andre Shomorony, Bruce Y Wang, Daniel S Kohane
The efficacy of tetrodotoxin (TTX), a very potent local anesthetic, is limited by its poor penetration through barriers to axonal surfaces. To address this issue, we encapsulated TTX in hollow silica nanoparticles (TTX-HSN) and injected them at the sciatic nerve in rats. TTX-HSN achieved an increased frequency of successful blocks, prolonged the duration of the block, and decreased the toxicity compared to free TTX. In animals injected with fluorescently labeled HSN, the imaging of frozen sections of nerve demonstrated that HSN could penetrate into nerve and that the penetrating ability of silica nanoparticles was highly size-dependent...
December 11, 2017: Nano Letters
https://www.readbyqxmd.com/read/29219034/measuring-relative-coupling-strength-in-circadian-systems
#4
Christoph Schmal, Erik D Herzog, Hanspeter Herzel
Modern imaging techniques allow the monitoring of circadian rhythms of single cells. Coupling between these single cellular circadian oscillators can generate coherent periodic signals on the tissue level that subsequently orchestrate physiological outputs. The strength of coupling in such systems of oscillators is often unclear. In particular, effects on coupling strength by varying cell densities, by knockouts, and by inhibitor applications are debated. In this study, we suggest to quantify the relative coupling strength via analyzing period, phase, and amplitude distributions in ensembles of individual circadian oscillators...
December 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/29207052/molecular-expression-of-multiple-nav1-5-splice-variants-in-the-frontal-lobe-of-the-human-brain
#5
Jun Wang, Shao-Wu Ou, Zhi-Yong Zhang, Bo Qiu, Yun-Jie Wang
Voltage-gated sodium channels serve an essential role in the initiation and propagation of action potentials for central neurons. Previous studies have demonstrated that two novel variants of Nav1.5, designated Nav1.5e and Nav1.5f, were expressed in the human brain cortex. To date, nine distinct sodium channel isoforms of Nav1.5 have been identified. In the present study, the expression of Nav1.5 splice variants in the frontal lobe of the human brain cortex was systematically investigated. The results demonstrated that wild Nav1...
November 24, 2017: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/29204119/differential-effects-of-inactivation-of-discrete-regions-of-medial-prefrontal-cortex-on-memory-consolidation-of-moderate-and-intense-inhibitory-avoidance-training
#6
María E Torres-García, Andrea C Medina, Gina L Quirarte, Roberto A Prado-Alcalá
It has been found that the medial prefrontal cortex (mPFC) is involved in memory encoding of aversive events, such as inhibitory avoidance (IA) training. Dissociable roles have been described for different mPFC subregions regarding various memory processes, wherein the anterior cingulate cortex (ACC), prelimbic cortex (PL), and infralimbic cortex (IL) are involved in acquisition, retrieval, and extinction of aversive events, respectively. On the other hand, it has been demonstrated that intense training impedes the effects on memory of treatments that typically interfere with memory consolidation...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29204056/effects-of-hemp-seed-soft-capsule-on-colonic-ion-transport-in-rats
#7
Xiao-Fang Lu, Meng-Di Jia, Sheng-Sheng Zhang, Lu-Qing Zhao
AIM: To investigate the effect of Hemp seed soft capsule (HSCC) on colonic ion transport and its related mechanisms in constipation rats. METHODS: Sprague-Dawley male rats were randomly divided into three groups: normal group, constipation group and HSSC group. Rats in the constipation and HSSC groups were administrated loperamide 3 mg/kg per day orally for 12 d to induce the constipation model. Then, the HSSC group was given HSSC 0.126 g/kg per day by gavage for 7 d...
November 14, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/29177486/glucagon-like-peptide-1-inhibits-prandial-gastrointestinal-motility-through-myenteric-neuronal-mechanisms-in-humans
#8
Md Abdul Halim, Marie Degerblad, Magnus Sundbom, Urban Karlbom, Jens Juul Holst, Dominic-Luc Webb, Per M Hellström
Context: Glucagon-like peptide-1 (GLP-1) secretion from L-cells and postprandial inhibition of gastrointestinal motility. Objective: Investigate whether physiological plasma concentrations of GLP-1 can inhibit human postprandial gastrointestinal motility; determine target mechanism of GLP-1 and analogue ROSE-010 action. Design: Single-blind parallel study. Setting: University research laboratory. Participants: Healthy volunteers investigated with antroduodenojejunal manometry...
November 21, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/29169227/korean-red-ginseng-excitation-of-paraventricular-nucleus-neurons-via-non-nmda-glutamate-receptor-activation-in-mice
#9
Yiming Shen, Janardhan P Bhattarai, Soo Joung Park, Gyu Seung Lee, Pan Dong Ryu, Seong Kyu Han
It has been reported that Korean red ginseng (KRG) as a valuable and important traditional medicine has various effects on central nervous system suggesting its complicated actions. Paraventricular nucleus (PVN) neurons of hypothalamus play a critical role for stress responses and hormone secretions. Although many studies have reported the action mechanisms of KRG on various cell and systems, the direct membrane effects of KRG on the PVN neurons which are involved in stress response are still poorly understood...
November 23, 2017: Journal of Veterinary Science
https://www.readbyqxmd.com/read/29167643/post-inflammatory-ileitis-induces-non-neuronal-purinergic-signaling-adjustments-of-cholinergic-neurotransmission-in-the-myenteric-plexus
#10
Cátia Vieira, Fátima Ferreirinha, Maria T Magalhães-Cardoso, Isabel Silva, Patrícia Marques, Paulo Correia-de-Sá
Uncoupling between ATP overflow and extracellular adenosine formation changes purinergic signaling in post-inflammatory ileitis. Adenosine neuromodulation deficits were ascribed to feed-forward inhibition of ecto-5'-nucleotidase/CD73 by high extracellular adenine nucleotides in the inflamed ileum. Here, we hypothesized that inflammation-induced changes in cellular density may also account to unbalance the release of purines and their influence on [(3)H]acetylcholine release from longitudinal muscle-myenteric plexus preparations of the ileum of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-treated rats...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29159902/histamine-enhanced-contractile-responses-of-gastric-smooth-muscle-via-interstitial-cells-of-cajal-in-the-syrian-hamster
#11
S Naganuma, T Shiina, S Yasuda, Y Suzuki, Y Shimizu
BACKGROUND: Gastric motility is controlled by the autonomic and enteric nervous systems and by interstitial cells of Cajal (ICCs). Although histamine is known to be released from enterochromaffin-like cells in the gastric mucosa, its regulatory roles in gastric motility are still controversial. Therefore, we investigated the functional roles of histamine in gastric motility. METHODS: Stomach preparations from hamsters were used because the stomach of hamsters can be easily separated into the forestomach and the glandular stomach...
November 21, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/29152410/ultrasound-triggered-local-anaesthesia
#12
Alina Y Rwei, Juan L Paris, Bruce Wang, Weiping Wang, Christopher D Axon, María Vallet-Regí, Robert Langer, Daniel S Kohane
On-demand relief of local pain would allow patients to control the timing, intensity and duration of nerve block in a safe and non-invasive manner. Ultrasound would be a suitable trigger for such a system, as it is in common clinical use and can penetrate deeply into the body. Here, we demonstrate that ultrasound-triggered delivery of an anaesthetic from liposomes allows the timing, intensity and duration of nerve block to be controlled by ultrasound parameters. On insonation, the encapsulated sonosensitizer protoporphyrin IX produces reactive oxygen species that react with the liposomal membrane, leading to the release of the potent local anaesthetic tetrodotoxin...
2017: Nature Biomedical Engineering
https://www.readbyqxmd.com/read/29142468/glucagon-like-peptide-2-modulates-the-nitrergic-neurotransmission-in-strips-from-the-mouse-gastric-fundus
#13
Rachele Garella, Eglantina Idrizaj, Chiara Traini, Roberta Squecco, Maria Giuliana Vannucchi, Maria Caterina Baccari
AIM: To investigate whether glucagon-like peptide-2 (GLP-2) influences the neurally-induced responses in gastric strips from mice, since no data are available. METHODS: For functional experiments, gastric fundal strips were mounted in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation (EFS) was applied via two platinum wire rings through which the preparation was threaded...
October 28, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/29138759/identification-of-persistent-and-resurgent-sodium-currents-in-spiral-ganglion-neurons-cultured-from-the-mouse-cochlea
#14
Lorcan Browne, Katie E Smith, Daniel J Jagger
In spiral ganglion neurons (SGNs), the afferent single units of the auditory nerve, high spontaneous and evoked firing rates ensure preservation of the temporal code describing the key features of incoming sound. During postnatal development, the spatiotemporal distribution of ion channel subtypes contributes to the maturation of action potential generation in SGNs, and to their ability to generate spike patterns that follow rapidly changing inputs. Here we describe tetrodotoxin (TTX)-sensitive Na+ currents in SGNs cultured from mice, whose properties may support this fast spiking behavior...
November 2017: ENeuro
https://www.readbyqxmd.com/read/29114923/histamine-modulates-spinal-motoneurons-and-locomotor-circuits
#15
Tamara Coslovich, Michele R Brumley, Giuseppe D'Angelo, Alberto Della Mora, Hillary E Swann, Fulvia Ortolani, Giuliano Taccola
Spinal motoneurons and locomotor networks are regulated by monoamines, among which, the contribution of histamine has yet to be fully addressed. The present study investigates histaminergic regulation of spinal activity, combining intra- and extracellular electrophysiological recordings from neonatal rat spinal cord in vitro preparations. Histamine dose-dependently and reversibly generated motoneuron depolarization and action potential firing. Histamine (20 µM) halved the area of dorsal root reflexes and always depolarized motoneurons...
November 8, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/29109054/assessing-the-presence-of-marine-toxins-in-bivalve-molluscs-from-southwest-india
#16
Andrew D Turner, Monika Dhanji-Rapkova, Stephanie Rowland-Pilgrim, Lucy M Turner, Ashwin Rai, Moleyur N Venugopal, Indrani Karunasagar, Anna Godhe
The south west coast of India has been showing a steady increase in shellfish cultivation both for local consumption and fishery export, over recent years. Perna viridis and Crassostrea madrasensis are two species of bivalve molluscs which grow in some selected regions of southern Karnataka, close to the city of Mangalore. In the early 1980s, shellfish consumers in the region were affected by intoxication from Paralytic Shellfish Poison present in local bivalves (clams and oysters) resulting in hospitalisation of many, including one fatality...
November 3, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/29100418/contribution-of-gabaa-gabac-and-glycine-receptors-to-rat-dark-adapted-oscillatory-potentials-in-the-time-and-frequency-domain
#17
Jiaman Dai, Juncai He, Gang Wang, Min Wang, Shiying Li, Zheng Qin Yin
Retinal oscillatory potentials (OPs) consist of a series of relatively high-frequency rhythmic wavelets, superimposed onto the ascending phase of the b-wave of the electroretinogram (ERG). However, the origin of OPs is uncertain and methods of measurement of OPs are diverse. In this study, we first isolated OPs from the rat ERG and fitted them with Gabor functions and found that the envelope of the OP contained information about maximum amplitude and time-to-peak to enable satisfactory quantification of the later OPs...
September 29, 2017: Oncotarget
https://www.readbyqxmd.com/read/29099662/local-oxygen-homeostasis-during-various-neuronal-network-activity-states-in-the-mouse-hippocampus
#18
Justus Schneider, Nikolaus Berndt, Ismini E Papageorgiou, Jana Maurer, Sascha Bulik, Martin Both, Andreas Draguhn, Hermann-Georg Holzhütter, Oliver Kann
Cortical information processing comprises various activity states emerging from timed synaptic excitation and inhibition. However, the underlying energy metabolism is widely unknown. We determined the cerebral metabolic rate of oxygen (CMRO2) along a tissue depth of <0.3 mm in the hippocampal CA3 region during various network activities, including gamma oscillations and sharp wave-ripples that occur during wakefulness and sleep. These physiological states associate with sensory perception and memory formation, and critically depend on perisomatic GABA inhibition...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/29099519/a-new-lateral-flow-immunochromatographic-strip-combined-with-quantum-dot-nanobeads-and-gold-nanoflowers-for-rapid-detection-of-tetrodotoxin
#19
Haicong Shen, Fei Xu, Meng Xiao, Qiangqiang Fu, Zhenzhu Cheng, Shiwei Zhang, Caihong Huang, Yong Tang
Tetrodotoxin (TTX) is a potent, low molecular weight analyte that can lead to fatal poisoning and requires a sensitive, rapid detection method. Here, we have developed a competitive, lateral-flow immunochromatographic strip combined with quantum dot nanobeads (QDNBs) and gold nanoflowers (AuNFs). This approach is called turn-on C-LFICS and it meets all testing requirements. Subsequent analysis revealed that this turn-on C-LFICS was rapid (8 min), sensitive (LOD = 0.2 ng mL(-1)), and quantitative (DLR = 1.56-100 ng mL(-1)), and had a positive signal readout (based on fluorescence quenching effects) for TTX detection...
November 3, 2017: Analyst
https://www.readbyqxmd.com/read/29097069/dose-related-ethanol-intake-cx43-and-nav1-5-remodeling-exploring-insights-of-altered-ventricular-conduction-and-qrs-fragmentation-in-excessive-alcohol-users
#20
Chung-Lieh Hung, Yu-Jun Lai, Po-Ching Chi, Liang-Chia Chen, Ya-Ming Tseng, Jen-Yuan Kuo, Cheng-I Lin, Yao-Chang Chen, Shing-Jong Lin, Hung-I Yeh
BACKGROUND: Chronic, excessive ethanol intake has been linked with various electrical instabilities, conduction disturbances, and even sudden cardiac death, but the underlying cause for the latter is insufficiently delineated. METHODS: We studied surface electrocardiography (ECG) in a community-dwelling cohort with moderate-to-heavy daily alcohol intake (grouped as >90g/day, ≤90g/day, and nonintake). RESULTS: Compared with nonintake, heavier alcohol users showed markedly widened QRS duration and higher prevalence of QRS fragmentation (64...
October 30, 2017: Journal of Molecular and Cellular Cardiology
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