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Whole cell patch clamp

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https://www.readbyqxmd.com/read/28217366/crizotinib-inhibits-hyperpolarization-activated-cyclic-nucleotide-gated-channel-4-activity
#1
Zhushan Zhang, Tai-Qin Huang, Igor Nepliouev, Hengtao Zhang, Adam S Barnett, Paul B Rosenberg, Sai-Hong I Ou, Jonathan A Stiber
BACKGROUND: Sinus bradycardia is frequently observed in patients treated with crizotinib, a receptor tyrosine kinase inhibitor used for the treatment of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC). We investigated whether crizotinib could influence heart rate (HR) through direct cardiac effects. METHODS: The direct effect of crizotinib on HR was studied using ECG analysis of Langendorff-perfused mouse hearts. The whole-cell patch clamp technique was used to measure the effects of crizotinib on the hyperpolarization-activated funny current, If, in mouse sinoatrial node cells (SANCs) and hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) activity in HEK-293 cells stably expressing human HCN4...
2017: Cardiooncology
https://www.readbyqxmd.com/read/28217084/nad-attenuates-bilirubin-induced-hyperexcitation-in-the-ventral-cochlear-nucleus-by-inhibiting-excitatory-neurotransmission-and-neuronal-excitability
#2
Min Liang, Xin-Lu Yin, Lu-Yang Wang, Wei-Hai Yin, Ning-Ying Song, Hai-Bo Shi, Chun-Yan Li, Shan-Kai Yin
Nicotinamide adenine dinucleotide (NAD+) is an important molecule with extensive biological functions in various cellular processes, including protection against cell injuries. However, little is known regarding the roles of NAD+ in neuronal excitation and excitotoxicity associated with many neurodegenerative disorders and diseases. Using patch-clamp recordings, we studied its potential effects on principal neurons in the ventral cochlear nucleus (VCN), which is particularly vulnerable to bilirubin excitotoxicity...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28216898/depolarizing-effects-of-daikenchuto-on-interstitial-cells-of-cajal-from-mouse-small-intestine
#3
Hyungwoo Kim, Hyun Jung Kim, Dongki Yang, Myeong Ho Jung, Byung Joo Kim
BACKGROUND: Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility. OBJECTIVE: The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine. MATERIALS AND METHODS: Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues...
January 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28216048/chloroquine-blocks-the-kir4-1-channels-by-an-open-pore-blocking-mechanism
#4
Leticia G Marmolejo-Murillo, Iván A Aréchiga-Figueroa, Eloy G Moreno-Galindo, Ricardo A Navarro-Polanco, Aldo A Rodríguez-Menchaca, Meng Cui, José A Sánchez-Chapula, Tania Ferrer
Kir4.1 channels have been implicated in various physiological processes, mainly in the K(+) homeostasis of the central nervous system and in the control of glial function and neuronal excitability. Even though, pharmacological research of these channels is very limited. Chloroquine (CQ) is an amino quinolone derivative known to inhibit Kir2.1 and Kir6.2 channels with different action mechanism and binding site. Here, we employed patch-clamp methods, mutagenesis analysis, and molecular modeling to characterize the molecular pharmacology of Kir4...
February 16, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28213290/zd0947-a-sulphonylurea-receptor-modulator-detects-functional-sulphonylurea-receptor-subunits-in-murine-vascular-smooth-muscle-atp-sensitive-k-channels
#5
Tadashi Yamamoto, Kohei Takahara, Keiichiro Uchida, Noriyoshi Teramoto
In order to identify functional sulphonylurea receptor (SUR.x) subunits of native ATP-sensitive K(+) channels (KATP channels) in mouse portal vein, the effects of ZD0947, a SUR.x modulator, were investigated on spontaneous portal vein contractions, macroscopic membrane currents and unitary currents recorded (using patch-clamp techniques) in freshly dispersed mouse portal vein myocytes. Spontaneous contractions in mouse portal vein were reversibly reduced by ZD0947 in a concentration-dependent manner (Ki = 293nM)...
February 14, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28205094/knockdown-of-cardiac-kir3-1-gene-with-sirna-can-improve-bradycardia-in-an-experimental-sinus-bradycardia-rat-model
#6
Yang Li, Xiaodan Fu, Zhi Zhang, Bo Yu
The objective of this study was to explore whether the inhibition of potassium inwardly rectifying channel (Kir3.1) with short interfering RNA (siRNA) can improve bradycardia in an experimental sinus bradycardia rat model. 54 Sprague Dawley (SD) rats were randomly divided into three groups: experimental group, control group, and sham group. Sinus bradycardia model was established in SD rats through chemical ablation of sinoatrial (SA) node with 20% formaldehyde. Variations of Kir3.1 expression at mRNA and protein level were examined with qPCR and Western blotting...
February 15, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28203415/changes-in-the-action-potential-and-transient-outward-potassium-current-in-cardiomyocytes-during-acute-cardiac-rejection-in-rats
#7
Wenqi Luo, Yixin Jia, Shuai Zheng, Yan Li, Jie Han, Xu Meng
BACKGROUND: Acute cardiac rejection contributes to the changes in the electrophysiological properties of grafted hearts. However, the electrophysiological changes of cardiomyocytes during acute cardiac rejection are still unknown. An understanding of the electrophysiological mechanisms of cardiomyocytes could improve the diagnosis and treatment of acute cardiac rejection. So it is important to characterize the changes in the action potential (AP) and the transient outward potassium current (Ito ) in cardiomyocytes during acute cardiac rejection...
January 2017: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28202576/differential-effect-of-brief-electrical-stimulation-on-voltage-gated-potassium-channels
#8
Morven Alison Cameron, Amr Al Abed, Yossi Buskila, Socrates Dokos, Nigel H Lovell, John W Morley
Electrical stimulation of neuronal tissue is a promising strategy to treat a variety of neurological disorders. The mechanism of neuronal activation by external electrical stimulation is governed by voltage-gated ion channels. This stimulus, typically brief in nature, leads to membrane potential depolarization, which increases ion flow across the membrane by increasing the open probability of these voltage-gated channels. In spiking neurons, it is activation of voltage-gated sodium channels (NaV-channels) that leads to action potential generation...
February 15, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28197552/altered-channel-conductance-states-and-gating-of-gabaa-receptors-by-a-pore-mutation-linked-to-dravet-syndrome
#9
Ciria C Hernandez, Weijing Kong, Ningning Hu, Yujia Zhang, Wangzhen Shen, Laurel Jackson, Xiaoyan Liu, Yuwu Jiang, Robert L Macdonald
We identified a de novo missense mutation, P302L, in the γ-aminobutyric acid type A (GABAA) receptor γ2 subunit gene GABRG2 in a patient with Dravet syndrome using targeted next-generation sequencing. The mutation was in the cytoplasmic portion of the transmembrane segment M2 of the γ2 subunit that faces the pore lumen. GABAA receptor α1 and β3 subunits were coexpressed with wild-type (wt) γ2L or mutant γ2L(P302L) subunits in HEK 293T cells and cultured mouse cortical neurons. We measured currents using whole-cell and single-channel patch clamp techniques, surface and total expression levels using surface biotinylation and Western blotting, and potential structural perturbations in mutant GABAA receptors using structural modeling...
January 2017: ENeuro
https://www.readbyqxmd.com/read/28196855/inactivation-of-girk-channels-weakens-the-pre-and-postsynaptic-inhibitory-activity-in-dorsal-raphe-neurons
#10
Nerea Llamosas, Luisa Ugedo, Maria Torrecilla
The serotonergic tone of the dorsal raphe (DR) is regulated by 5-HT1A receptors, which negatively control serotonergic activity via the activation of G protein-coupled inwardly rectifying K(+) (GIRK) channels. In addition, DR activity is modulated by local GABAergic transmission, which is believed to play a key role in the development of mood-related disorders. Here, we sought to characterize the role of GIRK2 subunit-containing channels on the basal electrophysiological properties of DR neurons and to investigate whether the presynaptic and postsynaptic activities of 5-HT1A, GABAB, and GABAA receptors are affected by Girk2 gene deletion...
February 2017: Physiological Reports
https://www.readbyqxmd.com/read/28193694/different-cav1-3-channel-isoforms-control-distinct-components-of-the-synaptic-vesicle-cycle-in-auditory-inner-hair-cells
#11
Philippe Fy Vincent, Yohan Bouleau, Gilles Charpentier, Alice Emptoz, Saaid Safieddine, Christine Petit, Didier Dulon
The mechanisms orchestrating transient and sustained exocytosis in auditory inner hair cells (IHCs) remain largely unknown. These exocytotic responses are believed to mobilize sequentially a readily releasable pool of vesicles (RRP) underneath the synaptic ribbons and a slowly releasable pool of vesicles (SRP) at farther distance from them. They are both governed by Cav1.3 channels and require otoferlin as Ca(2+) sensor but whether they use the same Cav1.3 isoforms is still unknown. Using whole cell patch clamp recordings in post-hearing mice, we show that only a proportion (∼25 %) of the total Ca(2+) current in IHCs, displaying fast inactivation and resistance to 20 μM nifedipine, a L-type Ca(2+) channel blocker, is sufficient to trigger RRP but not SRP exocytosis...
February 13, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28192542/functional-diversity-of-secreted-cestode-kunitz-proteins-inhibition-of-serine-peptidases-and-blockade-of-cation-channels
#12
Martín Fló, Mariana Margenat, Leonardo Pellizza, Martín Graña, Rosario Durán, Adriana Báez, Emilio Salceda, Enrique Soto, Beatriz Alvarez, Cecilia Fernández
We previously reported a multigene family of monodomain Kunitz proteins from Echinococcus granulosus (EgKU-1-EgKU-8), and provided evidence that some EgKUs are secreted by larval worms to the host interface. In addition, functional studies and homology modeling suggested that, similar to monodomain Kunitz families present in animal venoms, the E. granulosus family could include peptidase inhibitors as well as channel blockers. Using enzyme kinetics and whole-cell patch-clamp, we now demonstrate that the EgKUs are indeed functionally diverse...
February 13, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28190519/matrix-metalloproteinase-9-and-synaptic-plasticity-in-the-central-amygdala-in-control-of-alcohol-seeking-behavior
#13
Marzena Stefaniuk, Anna Beroun, Tomasz Lebitko, Olga Markina, Szymon Leski, Ksenia Meyza, Anna Grzywacz, Jerzy Samochowiec, Agnieszka Samochowiec, Kasia Radwanska, Leszek Kaczmarek
BACKGROUND: Dysfunction of the glutamatergic system has been implicated in alcohol addiction; however, the molecular underpinnings of this phenomenon are still poorly understood. In the current study we have investigated the possible function of matrix metalloproteinase-9 (MMP-9) in alcohol addiction because this protein has recently emerged as an important regulator of excitatory synaptic plasticity. METHODS: For long-term studies of alcohol drinking in mice we used IntelliCages...
January 5, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/28188777/enhanced-ability-of-trpv1-channels-in-regulating-glutamatergic-transmission-after-repeated-morphine-exposure-in-the-nucleus-accumbens-of-rat
#14
Haitao Zhang, Dong Jia, Yuan Wang, Liang Qu, Xuelian Wang, Jian Song, Lijun Heng, Guodong Gao
Glutamatergic projections to nucleus accumbens (NAc) drive drug-seeking behaviors during opioids withdrawal. Modulating glutamatergic neurotransmission provides a novel pharmacotherapeutic avenue for treatment of opioids dependence. Great deals of researches have verified that transient receptor potential vanilloid 1 (TRPV1) channels alters synaptic transmitter release and regulate neural plasticity. In the present study, whole-cell patch clamp recordings were adopted to examine the activity of TRPV1 Channels in regulating glutamate-mediated excitatory postsynaptic currents (EPSCs) in NAc of rat during morphine withdrawal for 3 days and 3 weeks...
February 7, 2017: Brain Research
https://www.readbyqxmd.com/read/28185983/prenatal-melamine-exposure-impairs-spatial-cognition-and-hippocampal-synaptic-plasticity-by-presynaptic-and-postsynaptic-inhibition-of-glutamatergic-transmission-in-adolescent-offspring
#15
Lei An, Wei Sun
Our previous studies showed that prenatal melamine exposure (PME) could impair spatial cognition and hippocampal long-term potentiation (LTP). More importantly, the synaptic dysfunction induced by PME was associated with the probability of presynaptic glutamate release. Considering the crucial role of the other form of synaptic plasticity, long-term depression (LTD), in some types of learning and memory process, the aim of present study was to investigate if the hippocampal LTD and cognitive flexibility were affected...
February 6, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28185917/increment-of-late-sodium-currents-in-the-left-atrial-myocytes-and-its-potential-contribution-to-the-increased-susceptibility-of-atrial-fibrillation-in-castrated-male-mice
#16
Yang Zhang, Hui-Min Wang, Ying-Zhe Wang, Yi-Yuan Zhang, Xue-Xin Jin, Yue Zhao, Jin Wang, Yi-Lin Sun, Gen-Long Xue, Peng-Hui Li, Qi-He Huang, Bao-Feng Yang, Zhen-Wei Pan
BACKGROUND: The incidence of atrial fibrillation (AF) is correlated with the declined levels of testosterone in elder men. Late sodium current may exert a role in AF pathogenesis. OBJECTIVE: In this study we explored the effect of testosterone deficiency on AF susceptibility and the therapeutic effect of late sodium current inhibitors in mice. METHODS: Male ICR mice (5-week old) were castrated to establish testosterone deficiency model. One month after castration, dihydrotestosterone (5mg/kg) was administered subcutaneously for 2 months...
February 6, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28182698/prevention-of-remifentanil-induced-postoperative-hyperalgesia-by-dexmedetomidine-via-regulating-the-trafficking-and-function-of-spinal-nmda-receptors-as-well-as-pkc-and-camkii-level-in-vivo-and-in-vitro
#17
Yuan Yuan, Zhe Sun, Yi Chen, Yuxin Zheng, Ke-Liang Xie, Ying He, Zhifen Wang, Guo-Lin Wang, Yong-Hao Yu
Remifentanil-induced secondary hyperalgesia has been demonstrated in both animal experiments and clinical trials. Enhancement of N-methyl-D-aspartate (NMDA) receptor trafficking as well as protein kinase C (PKC) and calmodulin-dependent protein kinase II (CaMKII) have been reported to be involved in the induction and maintenance of central sensitization. In the current study, it was demonstrated that dexmedetomidine could prevent remifentanil-induced hyperalgesia (RIH) via regulating spinal NMDAR-PKC-Ca2+/ CaMKII pathway in vivo and in vitro...
2017: PloS One
https://www.readbyqxmd.com/read/28179480/transient-voltage-activated-k-currents-in-central-antennal-lobe-neurons-cell-type-specific-functional-properties
#18
Lars Paeger, Viktor Bardos, Peter Kloppenburg
Here we analyzed transient voltage-activated K(+) currents (IA) of projection neurons and local interneurons in the antennal lobe (AL) of the cockroach Periplaneta americana. The AL is the first synaptic processing station for olfactory information in insects. Local interneurons are crucial for computing olfactory information and form local synaptic connections exclusively in the AL, while a primary task of the projection neurons is the transfer of preprocessed olfactory information from the AL to the protocerebrum...
February 8, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28174298/the-startle-disease-mutation-e103k-impairs-activation-of-human-homomeric-%C3%AE-1-glycine-receptors-by-disrupting-an-intersubunit-salt-bridge-across-the-agonist-binding-site
#19
Fatemah Safar, Elliot Hurdiss, Marios Erotocritou, Timo Greiner, Remigijus Lape, Mark W Irvine, Guangyu Fang, David Jane, Rilei Yu, Marc A Dämgen, Philip C Biggin, Lucia G Sivilotti
Glycine receptors (GlyR) belong to the pentameric ligand gated ion channel (pLGIC) superfamily and mediate fast inhibitory transmission in the vertebrate CNS. Disruption of glycinergic transmission by inherited mutations produces startle disease in man. Many startle mutations are in GlyRs and provide useful clues to the function of the channel domains. E103K is one of few startle mutations found in the extracellular agonist binding site of the channel, in loop A of the principal side of the subunit interface...
February 7, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28167075/inhibition-of-the-nmda-and-ampa-receptor-channels-by-antidepressants-and-antipsychotics
#20
Oleg I Barygin, Elina I Nagaeva, Denis B Tikhonov, Darya A Belinskaya, Nina P Vanchakova, Natalia N Shestakova
It is known that some antidepressants and antipsychotics directly inhibit NMDA-type ionotropic glutamate receptors. In this study we systematically studied action of seven drugs (Fluoxetine, Citalopram, Desipramine, Amitriptyline, Atomoxetine, Chlorpromazine, and Clozapine) on NMDA receptors and Ca(2+)-permeable and -impermeable AMPA receptors in rat brain neurons by whole-cell patch-clamp technique. Except for weak effect of fluoxetine, all drugs were virtually inactive against Ca(2+)-impermeable AMPA receptors...
February 3, 2017: Brain Research
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