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1.
Acta Physiologica Sinica ; (6): 863-873, 2019.
Article in Chinese | WPRIM | ID: wpr-781388

ABSTRACT

The aim of this study was to investigate the inhibitory effect and the underlying mechanism of ethacrynic acid (EA) on the contraction in mice. BL-420S force measuring system was used to measure the tension of mouse tracheal rings. The whole cell patch clamp technique was utilized to record the channel currents of airway smooth muscle (ASM) cells. The calcium imaging system was used to determine the intracellular Ca concentration ([Ca]) in ASM cells. The results showed that EA significantly inhibited the high K (80 mmol/L) and acetylcholine (ACh, 100 µmol/L)-induced contraction of mouse tracheal rings in a dose-dependent manner. The maximal relaxation percentages were (97.02 ± 1.56)% and (85.21 ± 0.03)%, and the median effective concentrations were (40.28 ± 2.20) μmol/L and (56.22 ± 7.62) μmol/L, respectively. EA decreased the K and ACh-induced elevation of [Ca] from 0.40 ± 0.04 to 0.16 ± 0.01 and from 0.50 ± 0.01 to 0.39 ± 0.01, respectively. In addition, EA inhibited L-type voltage-dependent calcium channel (LVDCC) and store-operated calcium channel (SOCC) currents in ASM cells, and Ca influx. Moreover, EA decreased the resistance of the respiratory system (Rrs) in vivo in mice. These results indicated that EA inhibits LVDCC and SOCC, which results in termination of Ca influx and decreases of [Ca], leading to relaxation of ASM. Taken together, EA might be a potential bronchodilator.


Subject(s)
Animals , Calcium , Metabolism , Calcium Channels, L-Type , Enzyme Inhibitors , Pharmacology , Ethacrynic Acid , Pharmacology , Mice , Muscle Contraction , Muscle, Smooth , Respiratory System , Cell Biology
2.
Acta Physiologica Sinica ; (6): 717-724, 2019.
Article in Chinese | WPRIM | ID: wpr-777139

ABSTRACT

The aim of this study was to investigate the effect of interleukin 6 (IL-6) on the contraction of colon longitudinal muscle strips in rats with acute pancreatitis (AP) and its underlying mechanism. Rat AP model was established by combined injection (i. p.) of ceruletide and lipopolysaccharide. The effect of IL-6 on spontaneous contraction of longitudinal smooth muscle strips of rat colon was observed by biological function experiment system. The level of serum IL-6 was detected by ELISA, the expression and distribution of IL-6 in colon were observed by histochemical staining, and the effect of IL-6 on L-type calcium channel in colon smooth muscle cells was observed by whole cell patch clamp technique. The results showed that, compared with the control group, AP group exhibited reduced contractile amplitude and longer contraction cycle of colon smooth muscle strips. IL-6 prolonged the contraction cycle of colon smooth muscle strips, but did not affect their spontaneous contraction amplitude. Serum IL-6 concentration in AP group was significantly higher than that in control group (P > 0.05). IL-6 was diffusely distributed in the colon of the control group, but the expression of IL-6 was significantly up-regulated in the colon gland, mucosa and submucosa of the AP group. IL-6 significantly decreased the peak current density of L-type calcium channel in rat colon smooth muscle cells. These results suggest that the colon motility of AP rats is weakened, and the mechanism may be that up-regulated IL-6 inactivates L-type voltage-dependent calcium channels, and then inhibits the contraction of colon longitudinal smooth muscle.


Subject(s)
Animals , Calcium Channels, L-Type , Metabolism , Colon , Interleukin-6 , Metabolism , Muscle Contraction , Muscle, Smooth , Pancreatitis , Rats
3.
Experimental Neurobiology ; : 578-592, 2019.
Article in English | WPRIM | ID: wpr-763788

ABSTRACT

Depending on the intracellular buffering of calcium by chelation, zinc has the following two apparent effects on neuronal excitability: enhancement or reduction. Zinc increased tonic activity in the depolarized state when neurons were intracellularly dialyzed with EGTA but attenuated the neuronal activity when BAPTA was used as an intracellular calcium buffer. This suggests that neuronal excitability can be modulated by zinc, depending on the internal calcium buffering capacity. In this study, we elucidated the mechanisms of zinc-mediated alterations in neuronal excitability and determined the effect of calcium-related channels on zinc-mediated alterations in excitability. The zinc-induced augmentation of firing activity was mediated via the inhibition of small-conductance calcium-activated potassium (SK) channels with not only the contribution of voltage-gated L-type calcium channels (VGCCs) and ryanodine receptors (RyRs), but also through the activation of VGCCs via melastatin-like transient receptor potential channels. We suggest that zinc modulates the dopaminergic neuronal activity by regulating not only SK channels as calcium sensors, but also VGCCs or RyRs as calcium sources. Our results suggest that the cytosolic calcium-buffering capacity can tightly regulate zinc-induced neuronal firing patterns and that local calcium-signaling domains can determine the physiological and pathological state of synaptic activity in the dopaminergic system.


Subject(s)
Animals , Calcium , Calcium Channels, L-Type , Cytosol , Dopaminergic Neurons , Egtazic Acid , Electrophysiology , Fires , Neurons , Potassium , Rats , Ryanodine Receptor Calcium Release Channel , Transient Receptor Potential Channels , Zinc
4.
Article in English | WPRIM | ID: wpr-761809

ABSTRACT

Anoctamin 5 (ANO5)/TMEM16E belongs to a member of the ANO/TMEM16 family member of anion channels. However, it is a matter of debate whether ANO5 functions as a genuine plasma membrane chloride channel. It has been recognized that mutations in the ANO5 gene cause many skeletal muscle diseases such as limb girdle muscular dystrophy type 2L (LGMD2L) and Miyoshi muscular dystrophy type 3 (MMD3) in human. However, the molecular mechanisms of the skeletal myopathies caused by ANO5 defects are poorly understood. To understand the role of ANO5 in skeletal muscle development and function, we silenced the ANO5 gene in C2C12 myoblasts and evaluated whether it impairs myogenesis and myotube function. ANO5 knockdown (ANO5-KD) by shRNA resulted in clustered or aggregated nuclei at the body of myotubes without affecting differentiation or myotube formation. Nuclear positioning defect of ANO5-KD myotubes was accompanied with reduced expression of Kif5b protein, a kinesin-related motor protein that controls nuclear transport during myogenesis. ANO5-KD impaired depolarization-induced [Ca²⁺]i transient and reduced sarcoplasmic reticulum (SR) Ca²⁺ storage. ANO5-KD resulted in reduced protein expression of the dihydropyridine receptor (DHPR) and SR Ca²⁺-ATPase subtype 1. In addition, ANO5-KD compromised co-localization between DHPR and ryanodine receptor subtype 1. It is concluded that ANO5-KD causes nuclear positioning defect by reduction of Kif5b expression, and compromises Ca²⁺ signaling by downregulating the expression of DHPR and SERCA proteins.


Subject(s)
Active Transport, Cell Nucleus , Calcium Channels, L-Type , Cell Membrane , Chloride Channels , Humans , Muscle Development , Muscle Fibers, Skeletal , Muscle, Skeletal , Muscular Diseases , Muscular Dystrophies , Muscular Dystrophies, Limb-Girdle , Myoblasts , RNA, Small Interfering , Ryanodine Receptor Calcium Release Channel , Sarcoplasmic Reticulum
5.
Article in Chinese | WPRIM | ID: wpr-813171

ABSTRACT

To investigate the relationship between single nucleotide polymorphisms (SNPs) of CACNA1C (SNPs rs58619945, rs7316246 and rs216008) and susceptibility of chronic spontaneous urticaria (CSU) as well as the curative effect of non-sedating antihistamine drugs.
 Methods: Peripheral blood were extracted from 191 CSU patients to collect DNA. Urticaria Activity Score 7 (UAS7) and Dermatology Life Quality Index (DLQI) changes were collected from these patients with different non-sedating antihistamine drugs. PubMed retrieval system was used to select the 3 SNPs (rs58619945, rs7316246 and rs216008) of CACNA1C. Susceptibility of CSU and curative effect of non-sedating antihistamine drugs (desloratadine, mizolastine, fisofenadine) in 189 CSU patients and 105 controls with different SNPs were compared with Chi-squared test. Data of 105 southern Chinese controls were extracted from the 1 000 genome database.
 Results: Frequency of rs58619945 G allele in the CSU patients was significantly higher than that in the controls [OR(95%CI)=0.660(0.470-0.925), P=0.016]. However, there was no significant differences in rs7316246 and rs216008 between the CSU patients and the controls. Meanwhile there was no significant difference in general curative effect of the 3 drugs in the 3 SNPs (rs58619945: OR=0.843, P=0.454; rs7316246: OR=2.103, P=0.102; rs216008: OR=0.237, P=0.363). There was significant difference in different alleles of rs216008 in the patients administered by desloratadine [OR(95%CI)=0.480(0.247-0.933), P=0.029]. No difference was shown in the 3 SNPs in patients administered by mizolastine.
 Conclusion: The rs58619945 A/G might be related to susceptibility of CSU, and the rs216008 mutation might affect drug response of desloratadine.


Subject(s)
Calcium Channels, L-Type , Genetics , Chronic Disease , Genetic Predisposition to Disease , Histamine H1 Antagonists, Non-Sedating , Therapeutic Uses , Humans , Loratadine , Therapeutic Uses , Polymorphism, Single Nucleotide , Prognosis , Retrospective Studies , Urticaria , Drug Therapy , Genetics
6.
Braz. j. med. biol. res ; 50(6): e6141, 2017. graf
Article in English | LILACS | ID: biblio-839302

ABSTRACT

Cannabinoid type 1 receptor (CB1R) inhibition tends to be one of the promising strategies for the treatment of obesity and other related metabolic disorders. Although CB1R inhibition may cause adverse psychiatric effects including depression and anxiety, the investigation of the role of peripheral CB1R on weight loss and related metabolic parameters are urgently needed. We first explored the effect of rimonabant, a selective CB1R antagonist/inverse agonist, on some metabolic parameters in high fat-diet (HFD)-induced obesity in mice. Then, real-time PCR and electrophysiology were used to explore the contribution of high voltage-activated Ca2+ channels (HVACCs), especially Cav1.1, on rimonabant's effect in skeletal muscle (SM) in HFD-induced obesity. Five-week HFD feeding caused body weight gain, and decreased glucose/insulin tolerance in mice compared to those in the regular diet group (P<0.05), which was restored by rimonabant treatment compared to the HFD group (P<0.05). Interestingly, HVACCs and Cav1.1 were decreased in soleus muscle cells in the HFD group compared to the control group. Daily treatment with rimonabant for 5 weeks was shown to counter such decrease (P<0.05). Collectively, our findings provided a novel understanding for peripheral CB1R's role in the modulation of body weight and glucose homeostasis and highlight peripheral CB1R as well as Cav1.1 in the SM as potential targets for obesity treatment.


Subject(s)
Animals , Male , Blood Glucose/drug effects , Calcium Channels/drug effects , Cannabinoid Receptor Antagonists/pharmacology , Muscle, Skeletal/drug effects , Piperidines/pharmacology , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Body Weight/drug effects , Calcium Channels, L-Type/drug effects , Calcium Channels, L-Type/metabolism , Calcium Channels/metabolism , Diet, High-Fat/adverse effects , Glucose Intolerance/etiology , Insulin Resistance , Mice, Inbred C57BL , Models, Animal , Muscle, Skeletal/metabolism , Obesity/etiology , Receptor, Cannabinoid, CB1/physiology
7.
Protein & Cell ; (12): 401-438, 2017.
Article in English | WPRIM | ID: wpr-757322

ABSTRACT

Voltage-gated sodium (Na) channels are essential for the rapid upstroke of action potentials and the propagation of electrical signals in nerves and muscles. Defects of Na channels are associated with a variety of channelopathies. More than 1000 disease-related mutations have been identified in Na channels, with Na1.1 and Na1.5 each harboring more than 400 mutations. Na channels represent major targets for a wide array of neurotoxins and drugs. Atomic structures of Na channels are required to understand their function and disease mechanisms. The recently determined atomic structure of the rabbit voltage-gated calcium (Ca) channel Ca1.1 provides a template for homology-based structural modeling of the evolutionarily related Na channels. In this Resource article, we summarized all the reported disease-related mutations in human Na channels, generated a homologous model of human Na1.7, and structurally mapped disease-associated mutations. Before the determination of structures of human Na channels, the analysis presented here serves as the base framework for mechanistic investigation of Na channelopathies and for potential structure-based drug discovery.


Subject(s)
Animals , Calcium Channels, L-Type , Chemistry , Genetics , Metabolism , Channelopathies , Genetics , Metabolism , Humans , Mutation , Chemistry , Genetics , Metabolism , Chemistry , Genetics , Metabolism , Chemistry , Genetics , Metabolism , Protein Domains , Rabbits , Structure-Activity Relationship
8.
Radiol. bras ; 48(2): 86-92, Mar-Apr/2015. tab
Article in English | LILACS | ID: lil-746624

ABSTRACT

Objective: To evaluate the evolution of mammographic image quality in the state of Rio de Janeiro on the basis of parameters measured and analyzed during health surveillance inspections in the period from 2006 to 2011. Materials and Methods: Descriptive study analyzing parameters connected with imaging quality of 52 mammography apparatuses inspected at least twice with a one-year interval. Results: Amongst the 16 analyzed parameters, 7 presented more than 70% of conformity, namely: compression paddle pressure intensity (85.1%), films development (72.7%), film response (72.7%), low contrast fine detail (92.2%), tumor mass visualization (76.5%), absence of image artifacts (94.1%), mammography-specific developers availability (88.2%). On the other hand, relevant parameters were below 50% conformity, namely: monthly image quality control testing (28.8%) and high contrast details with respect to microcalcifications visualization (47.1%). Conclusion: The analysis revealed critical situations in terms of compliance with the health surveillance standards. Priority should be given to those mammography apparatuses that remained non-compliant at the second inspection performed within the one-year interval. .


Objetivo: Avaliar a evolução da qualidade da imagem de mamógrafos localizados no Estado do Rio de Janeiro, de 2006 a 2011, com base em parâmetros medidos e observados durante inspeções sanitárias. Materiais e Métodos: Estudo descritivo sobre a evolução de parâmetros que condicionam a qualidade da imagem focalizou 52 mamógrafos, inspecionados no mínimo duas vezes, com intervalo de um ano. Resultados: Dos 16 parâmetros avaliados, 7 apresentaram mais de 70% de conformidade: força do dispositivo de compressão (85,1%), processamento dos filmes (72,7%), resposta do filme do serviço (72,7%), detalhes lineares de baixo contraste (92,2%), visualização de massas tumorais (76,5%), ausência de artefatos de imagem (94,1%), existência de processadoras específicas para mamografia (88,2%). Importantes parâmetros apresentaram-se abaixo de 50% de conformidade: realização de testes mensais da qualidade de imagem pelo estabelecimento (28,8%) e detalhes de alto contraste, que dizem respeito à visualização de microcalcificações (47,1%). Conclusão: A análise revelou situações críticas da atuação da vigilância sanitária, cuja prioridade deveria ser dirigida aos estacionários, ou seja, os mamógrafos que permaneceram na situação de não conformidade nas inspeções realizadas com intervalo de um ano. .


Subject(s)
Animals , Rabbits , Calcium Channels, L-Type/metabolism , Muscle Cells/metabolism , Amino Acid Sequence , Calcium Channel Agonists/pharmacology , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Calmodulin/metabolism , Cell Membrane/drug effects , Cell Membrane/metabolism , Electrophysiology , Heart Ventricles/cytology , Heart Ventricles/metabolism , Ion Channel Gating/physiology , Ligands , Molecular Sequence Data , Patch-Clamp Techniques , Peptides/pharmacology
9.
Article in Chinese | WPRIM | ID: wpr-320892

ABSTRACT

This study was amid to construct the pharmacophore model of L-type calcium channel antagonist in the application of screening Drugbank and TCMD. This paper repositions the approved drugs resulting from virtual screening and discusses the relocation-based drug discovery methods, screening antihypertensive drugs with L-type calcium channel function from TCMD. Qualitative hypotheses wre generated by HipHop separately on the basis of 12 compounds with antagonistic action on L-type calcium channel expressed in rabbit cardiac muscle. Datebase searching method was used to evaluate the generated hypotheses. The optimum hypothesis was used to search Drugbank and TCMD. This paper repositions the approved drugs and evaluates the antihypertensive effect of the chemical constituent of traditional Chinese medicine resulting from virtual screening by the matching score and literature. The results showed that optimum qualitative hypothesis is with six features, which were two hydrogen-bond acceptors, four hydrophobic groups, and the CAI value of 2.78. Screening Drugbank achieves 93 approved drugs. Screening TCMD achieves 285 chemical constituents of traditional Chinese medicine. It was concluded that the hypothesis is reliable and can be used to screen datebase. The approved drugs resulting from virtual screening, such as pravastatin, are potentially L-type calcium channels inhibitors. The chemical constituents of traditional Chinese medicine, such as Arctigenin III and Arctigenin are potentially antihypertensive drugs. It indicates that Drug Repositioning based on hypothesis is possible.


Subject(s)
Animals , Antihypertensive Agents , Chemistry , Pharmacology , Calcium Channel Blockers , Chemistry , Pharmacology , Calcium Channels, L-Type , Genetics , Metabolism , Drug Repositioning , Methods , Molecular Structure , Myocardium , Metabolism , Rabbits
10.
Article in English | WPRIM | ID: wpr-21890

ABSTRACT

BACKGROUND/AIMS: Chronic intestinal pseudo-obstruction (CIPO) is a disorder characterized by recurrent symptoms suggestive of obstruction such as abdominal pain, proximal distension with extremely suppressed motility in the absence of lumen-occluding lesion, whose etiology/pathophysiology is poorly understood. In this study we investigated a functionally obstructive lesion that could underlie symptoms of CIPO. METHODS: We studied colons surgically removed from 13 patients exhibiting clinical/pathological features of pseudo-obstruction but were unresponsive to standard medical treatments. The colons were characterized morphologically, functionally and molecularly, which were compared between regions and to 28 region-matched controls obtained from colon cancer patients. RESULTS: The colons with pseudo-obstruction exhibited persistent luminal distension proximally, where the smooth muscle was hypertrophied with changes in the cell phenotypes. Distinct luminal narrowing was observed near the distal end of the dilated region, close to the splenic flexure, previously referred to as the "transition zone (TZ)" between the dilated and non-dilated loops. Circular muscles from the TZ responded less to depolarization and cholinergic stimulation, which was associated with down-regulation of L-type calcium channel expression. Smooth muscle contractile protein was also downregulated. Myenteric ganglia and neuronal nitric oxide synthase (nNOS) positive cells were deficient, more severely in the TZ region. Interstitial cells of Cajal was relatively less affected. CONCLUSIONS: The TZ may be the principal site of functional obstruction, leading to proximal distension and smooth muscle hypertrophy, in which partial nNOS depletion could play a key role. The neuromuscular abnormalities probably synergistically contributed to the extremely suppressed motility observed in the colonic pseudo-obstruction.


Subject(s)
Abdominal Pain , Calcium Channels, L-Type , Colon , Colon, Transverse , Colonic Neoplasms , Colonic Pseudo-Obstruction , Constipation , Down-Regulation , Ganglia , Humans , Hypertrophy , Interstitial Cells of Cajal , Intestinal Pseudo-Obstruction , Muscle, Smooth , Muscles , Nitric Oxide , Nitric Oxide Synthase Type I , Phenobarbital , Phenotype
11.
Article in Chinese | WPRIM | ID: wpr-748530

ABSTRACT

OBJECTIVE@#To learn the influence the gentamycin on C57BL/6J mice hear and cochlear hair cell ribbon synapses CaV1.3 calcium protein amount. To explore the relationship between hear loss and its dosage correlation change and significance.@*METHOD@#The fixed amino glucoside to C57BL/6J mice was used to make abdominal cavity injection mold every day. The auditory brain-stem response ABR was used to measure the hear of mice in 7th, 14th, 28th after the injection. Immunofluorescence method was used to observe cochlear basement membrane of hair ribbon synapse CaV1.3 calcium channel proteins in the distribution and expression. Inner hair cells synaptic membrane was immune fluorescent tags with CtbP2 and CaV1. 3.@*RESULT@#With the growth of the injected drugs, ABR threshold increased,but all the hair cells and shape had no obvious change. However the amount of hair rib bon synapse CaV1.3 calcium ion channel proteins in the expression had significant differences (P < 0.01). CaV1.3 calcium ion channel proteins increased slightly lower than normal at 7th day, significantly decreased at 14th day, had increased, increased quantity compare with 14th day, but at 28th day after intraperitoneal injection of gentamicin.@*CONCLUSION@#The increasing,decreasing and increasing trend of cochlear hair cells CaV1.3 proteins in the environment of amino glucoside drug toxicity showed that the increase of hair ribbon synapse CaV1.3 proteins may have a compensatory effect on the drug toxicity. With the increase of the drug toxicity effect, this kind of decompensated function could be the listening decline, which may be one of the mechanism of damage to hearing.


Subject(s)
Animals , Calcium Channels, L-Type , Metabolism , Evoked Potentials, Auditory, Brain Stem , Gentamicins , Pharmacology , Hair Cells, Auditory, Inner , Metabolism , Mice , Mice, Inbred C57BL , Proteomics
12.
Acta Physiologica Sinica ; (6): 718-722, 2014.
Article in Chinese | WPRIM | ID: wpr-255982

ABSTRACT

This study is aimed to investigate the effects of high intracellular Mg²⁺ on L-type calcium channel in guinea-pig ventricular myocytes. The cardiomyocytes were acutely isolated with enzyme digestion method. By adopting inside-out configuration of patch clamp technique, single channel currents of the L-type calcium channel were recorded under different intracellular Mg²⁺ concentrations ([Mg²⁺]i). In control group, which was treated with 0.9 mmol/L Mg²⁺, the relative activity of calcium channel was (176.5 ± 34.1)% (n = 7). When [Mg²⁺]i was increased from 0.9 to 8.1 mmol/L (high Mg²⁺ group), the relative activities of calcium channel decreased to (64.8 ± 18.1)% (n = 6, P < 0.05). Moreover, under 8.1 mmol/L Mg²⁺, the mean open time of calcium channel was shortened to about 25% of that under control condition (P < 0.05), but the mean close time of calcium channel was not altered. These results suggest that high intracellular Mg²⁺ may inhibit the activities of L-type calcium channel, which is mainly due to the shortening of the mean open time of single L-type calcium channel.


Subject(s)
Animals , Calcium Channels, L-Type , Physiology , Guinea Pigs , Magnesium , Physiology , Myocytes, Cardiac , Physiology , Patch-Clamp Techniques
13.
Article in Chinese | WPRIM | ID: wpr-237253

ABSTRACT

<p><b>OBJECTIVE</b>To assess the association between single nucleotide polymorphisms (SNPs) of calcium channel β 2 subunit (CACNB2) gene and essential hypertension (EH) in ethnic Han Chinese in Wenzhou area, and to study the influence of rs7069292 alleles on gene expression with luciferase reporter technique.</p><p><b>METHODS</b>Sixty hundred and thirty seven Han Chinese with EH and 600 normal controls were enrolled. Genotypes of 6 SNP within CACNB2 gene including rs2228645, rs2357928, rs7069292, rs7099380, rs10764319 and rs11014166 were determined with matrix assisted laser desorption ionization/time of flight mass spectrometer (MALDI-TOF MS). A luciferase reporter gene plasmid containing the fragment flanking rs7069292 (-2831 bp to -2460 bp) in the 5' regulatory region of CACNB2 was constructed.</p><p><b>RESULTS</b>Compared with the control, CT and TT genotypes for the rs7069292 locus were significantly more common in EH group (5.20% vs. 2.17%, 2.59% vs. 1.08%, P< 0.05). CC genotype was not found. Promoter activity for allele C of the rs7069292 locus was significantly increased compared with allele T (P< 0.05). No significant difference was detected for other 5 SNPs in terms of genotypes and allele frequency.</p><p><b>CONCLUSION</b>The rs7069292 CT polymorphism of the CACNB2 gene is associated with EH in ethnic Han Chinese from Wenzhou area. A T>C mutation may affect the expression of CACNB2.</p>


Subject(s)
Aged , Alleles , Base Sequence , Calcium Channels, L-Type , Genetics , Case-Control Studies , Cell Line , Female , Gene Frequency , Genetic Predisposition to Disease , Genotype , Humans , Hypertension , Genetics , Male , Middle Aged , Polymorphism, Single Nucleotide
14.
Article in English | WPRIM | ID: wpr-28628

ABSTRACT

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor family of cytokines. TRAIL selectively induces apoptotic cell death in various tumors and cancer cells, but it has little or no toxicity in normal cells. Agonism of TRAIL receptors has been considered to be a valuable cancer-therapeutic strategy. However, more than 85% of primary tumors are resistant to TRAIL, emphasizing the importance of investigating how to overcome TRAIL resistance. In this report, we have found that nemadipine-A, a cell-permeable L-type calcium channel inhibitor, sensitizes TRAIL-resistant cancer cells to this ligand. Combination treatments using TRAIL with nemadipine-A synergistically induced both the caspase cascade and apoptotic cell death, which were blocked by a pan caspase inhibitor (zVAD) but not by autophagy or a necrosis inhibitor. We further found that nemadipine-A, either alone or in combination with TRAIL, notably reduced the expression of survivin, an inhibitor of the apoptosis protein (IAP) family of proteins. Depletion of survivin by small RNA interference (siRNA) resulted in increased cell death and caspase activation by TRAIL treatment. These results suggest that nemadipine-A potentiates TRAIL-induced apoptosis by down-regulation of survivin expression in TRAIL resistant cells. Thus, combination of TRAIL with nemadipine-A may serve a new therapeutic scheme for the treatment of TRAIL resistant cancer cells, suggesting that a detailed study of this combination would be useful.


Subject(s)
Apoptosis , Autophagy , Calcium Channels, L-Type , Cell Death , Cytokines , Down-Regulation , Felodipine , Humans , Necrosis , Receptors, TNF-Related Apoptosis-Inducing Ligand , RNA Interference , Tumor Necrosis Factor-alpha
15.
Article in English | WPRIM | ID: wpr-80565

ABSTRACT

Timothy syndrome, long QT syndrome type 8, is highly malignant with ventricular tachyarrhythmia. A 30-month-old boy had sudden cardiac arrest during anesthesia induction before plastic surgery for bilateral cutaneous syndactyly. After successful resuscitation, prolonged QT interval (QTc, 0.58-0.60 sec) and T-wave alternans were found in his electrocardiogram. Starting beta-blocker to prevent further tachycardia and collapse event, then there were no more arrhythmic events. The genes KCNQ1, KCNH2, KCNE1 and 2, and SCN5A were negative for long QT syndrome. The mutation p.Gly406Arg was confirmed in CACNA1C, which maintains L-type calcium channel depolarization in the heart and other systems.


Subject(s)
Anesthesia/adverse effects , Calcium Channels, L-Type/genetics , Death, Sudden, Cardiac/etiology , Electroencephalography , Humans , Infant , Long QT Syndrome/genetics , Magnetic Resonance Imaging , Male , Methyl Ethers/adverse effects , Nitric Oxide/adverse effects , Polymorphism, Single Nucleotide , Sequence Analysis, DNA , Surgery, Plastic , Syndactyly/diagnosis
16.
Article in English | WPRIM | ID: wpr-13113

ABSTRACT

The aim of this study was to investigate the effects of Red L. platyphylla (RLP) on calcium and glucose levels during insulin secretion. To achieve this, alteration of insulin and calcium concentrations was measured in rat insulinoma-1 (INS-1) cells and animal models in response to RLP treatment. In INS-1 cells, maximum secretion of insulin was detected upon treatment with 200 microg/mL of RLP for 20 min. Nifedipine, an L-type calcium channel blocker, effectively inhibited insulin secretion from INS-1 cells. Regarding calcium levels, the maximum concentration of intracellular calcium in INS-1 cells was obtained by treatment with 100 microg/mL of RLP, whereas this level was reduced under conditions of 200 microg/mL of RLP. Further, RLP-treated INS-1 cells showed a higher level of intracellular calcium than that of L. platyphylla (LP), Korea White Ginseng (KWG), or Korea Red Ginseng (KRG)-treated cells. This RLP-induced increase in intracellular calcium was abrogated but not completely abolished upon treatment with 40 microM nifedipine in a dose-dependent manner. Furthermore, the insulin level was dramatically elevated upon co-treatment with high concentrations of glucose and RLP, whereas it was maintained at a low level in response to glucose and RLP co-treatment at low concentrations. In an animal experiment, the serum concentration of calcium increased or decreased upon RLP treatment according to glucose level compared to vehicle treatment. Therefore, these results suggest that insulin secretion induced by RLP treatment may be tightly correlated with calcium regulation, which suggests RLP is an excellent candidate for diabetes treatment.


Subject(s)
Animal Experimentation , Animals , Calcium , Calcium Channels, L-Type , Whites , Glucose , Humans , Insulin , Insulinoma , Korea , Models, Animal , Nifedipine , Panax , Rats
17.
Acta Pharmaceutica Sinica ; (12): 38-44, 2013.
Article in Chinese | WPRIM | ID: wpr-274593

ABSTRACT

To investigate the electrophysiology mechanisms of new anxiolytic and antidepressant drug: 4-butyl-alpha-agarofuran (AF-5), patch clamp-recording was used to test the effects of AF-5 on voltage-dependent sodium currents, voltage-dependent potassium currents, L-type voltage-dependent calcium currents and GABA dependent Cl(-) currents in primary cultured rat cortical neurons. Effects of AF-5 on Kv2.1 currents, expressed stably in HEK293 cells, were also tested. Our results showed that, delayed rectifier potassium currents (I(K(DR, L-type voltage-dependent calcium currents (I(LC-ca)) in primary cultured rat cortical neurons and Kv2.1 currents in HEK293 cells were significantly inhibited by AF-5, with IC50 as 6.17, 4.4 and 5.29 micromol x L(-1) respectively. However, voltage-dependent sodium currents (I(Na)), GABA dependent Cl(-) currents and transient outward potassium currents (I(K(A)) in primary cultured rat cortical neurons were not significantly blocked by AF-5. Our results concluded that, blocked I(K(DR)) and I(L-Ca) currents may be one of the mechanisms of anxiolytic and antidepression actions of AF-5.


Subject(s)
Animals , Antidepressive Agents , Pharmacology , Calcium Channels, L-Type , Cells, Cultured , Cerebral Cortex , Cell Biology , Chloride Channels , Delayed Rectifier Potassium Channels , HEK293 Cells , Humans , Neurons , Cell Biology , Patch-Clamp Techniques , Potassium Channels, Voltage-Gated , Rats , Rats, Wistar , Sesquiterpenes , Pharmacology , Shab Potassium Channels , Voltage-Gated Sodium Channels
18.
Chinese Journal of Cardiology ; (12): 507-513, 2013.
Article in Chinese | WPRIM | ID: wpr-261522

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effects of microRNA-133a on isoproterenol (ISO)-induced neonatal rat cardiomyocyte hypertrophy and related molecular mechanism focusing on the changes of L-type calcium channel α1C subunit.</p><p><b>METHODS</b>Neonatal rat cardiomyocytes were cultured, cardiomyocyte hypertrophy was induced by isoproterenol (ISO, 10 µmol/L). The cell surface area was measured by phase contrast microscope and Leica image analysis system. The mRNA expressions of atrial natriuretic peptide (ANP), β-myosin heavy chain (β-MHC), miR-133a and the α1C were detected by qRT-PCR. The protein expression of α1C was evaluated by Western blot. MiR-133a mimic was transfected into cardiomyocytes to investigate the effects of miR-133a on ISO-induced cardiomyocyte hypertrophy. The targets of miR-133a were predicted by online database Targetscan. The 3' untranslated region sequence of α1C was cloned into luciferase reporter vector and then transiently transfected into HEK293 cells. The luciferase activities of samples were measured to verify the expression of luciferase reporter vector. The expression level of α1C was inhibited by RNAi to determine the effects of α1C on cardiomyocyte hypertrophy. Intracellular Ca(2+) content was measured by confocal laser microscope.</p><p><b>RESULTS</b>(1) The expression of miR-133a was significantly reduced in ISO-induced cardiomyocyte hypertrophy (P < 0.01) . Upregulating miR-133a level could suppress the increase of cell surface area, the mRNA expression of ANP and β-MHC (P < 0.01) . (2) α1C was the one of potential target of miR-133a by prediction using online database Targetscan. The luciferase activities of HEK293 cells with the plasmid containing wide type α1C 3'UTR sequence were significantly decreased compared with control group (P < 0.01) . Upregulation of the miR-133a level by miR-133a mimic transfection could suppress the protein expression of α1C (P < 0.05) . (3) The expression of α1C was significantly increased in ISO treated cardiomyocytes (P < 0.05) . Downregulation of α1C by RNAi could markedly inhibit the increase of cell surface area, the mRNA expression of ANP and β-MHC (P < 0.01, P < 0.05, P < 0.05). (4) Downregulation of α1C expression by RNAi or upregulation of miR-133a level by miR-133a mimic transfection significantly inhibited intracellular Ca(2+) content (P < 0.01) .</p><p><b>CONCLUSIONS</b>Our data confirms that α1C is the target of miR-133a. MiR-133a can negatively regulate the expression of L-type calcium α1C subunit, resulting in the decrease of intracellular Ca(2+) content and the attenuation of ISO-induced cardiomyocyte hypertrophy.</p>


Subject(s)
Animals , Calcium Channels, L-Type , Metabolism , Cell Enlargement , Cells, Cultured , Isoproterenol , Pharmacology , MicroRNAs , Genetics , Myocytes, Cardiac , Metabolism , Pathology , Rats , Rats, Sprague-Dawley , Transfection
19.
Article in Chinese | WPRIM | ID: wpr-358670

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the molecular and functional changes in L-type Ca2+ channel of hypertrophied cardiomyocytes in neonatal rats induced by angiotensin II (Ang II).</p><p><b>METHODS</b>The in vitro model of cardiomyocyte hypertrophy was established in cultured cardiomyocytes from neonatal rats. Whole cell patch clamp was used to measure the L-type Ca2+ currents. Semi-quantitative RT-PCR was used to determine the mRNA expression of L-type Ca2+ channel alpha1C subunits.</p><p><b>RESULTS</b>In the hypertrophied cardiomyocytes induced by Ang II, I(Ca, L) densities were increased, whereas the features of I(Ca,L) activation, inactivation or recovery from inactivation were not affected. Meanwhile, Ang II increased the mRNA expression of L-type Ca2+ channel alpha1C subunits in cardiomyocytes. All these actions of Ang II could be blocked by the angiotensin II 1 type receptor blocker losartan.</p><p><b>CONCLUSION</b>During cardiomyocyte hypertrophy induced by Ang II, there are significant changes in the molecule and function of L-type Ca2+ channels, which are mediated by the angiotensin II 1 type receptor.</p>


Subject(s)
Angiotensin II , Animals , Calcium , Metabolism , Calcium Channels, L-Type , Metabolism , Female , Hypertrophy , Metabolism , Male , Membrane Potentials , Myocytes, Cardiac , Metabolism , Pathology , Physiology , Rats , Rats, Sprague-Dawley
20.
Article in Chinese | WPRIM | ID: wpr-358660

ABSTRACT

<p><b>OBJECTIVE</b>To explore the modulatory effect of niflumic acid and blocker of calcium channel on the desensitization of gamma aminobutyric acid (GABA)-activated currents in dorsal root ganglion(DRG) neurons from rat.</p><p><b>METHODS</b>The whole-cell patch-clamp technique was used to observe the modulatory effect of niflumic acid and blocker of calcium channel on the desensitization of GABA-activated currents in neurons freshly dissociated from rat DRG neurons.</p><p><b>RESULTS</b>Application of GABA (0.1-1 000 micromol/L) could induce concentration-dependent inward currents in some cells (212/223, 95.11%). GABA-(100 micromol/L) activated currents was (1.32 +/- 0.74) nA (n = 84). However, pre-application of niflumic acid (1-100 micromol/L) and nitrendipine (specific blocker of L-calcium channel)(0.1-30 micromol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects of niflumic acid and nitrendipine were concentration-dependent. The suppression rate of 10 micromol/L niflumic acid and nitrendipine to GABA-activated currents were (31.60% +/- 4.87%) (n = 19) and (43.60% < or = 5.10%) (n = 5), respectively. The desensitization of GABA-activated currents had double exponential characteristic. Tau value was (14.68 +/- 5.11) s (n = 6) and (175.8 +/- 42.67) s (n = 6, r = 0.9647), respectively. Pre-application of niflumic acid (100 micromol/L) and nickel chloride (nonspecific blocker of L-calcium channel) (100 micromol/L) altered tau value of the desensitization of GABA-activated currents, tau value reduced for (4.64 +/- 2.21) s (n = 3), (43.70 +/- 14.34) s ( n = 3, r = 0.9548) and (4.64 +/- 2.21) s (n = 3), (43.70 +/- 14.34) s (n = 3, r = 0.9721).</p><p><b>CONCLUSION</b>Pre-application of niflumic acid exerts a more strong inhibitory effect on the peak value of GABA-activated current, which possibly is through blocking the calcium-activated chloride ion channel to accelerate the desensitization of GABA-activated currents.</p>


Subject(s)
Animals , Animals, Newborn , Calcium Channel Blockers , Pharmacology , Calcium Channels, L-Type , Ganglia, Spinal , Physiology , Membrane Potentials , Physiology , Neurons , Physiology , Niflumic Acid , Pharmacology , Nitrendipine , Pharmacology , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , gamma-Aminobutyric Acid , Pharmacology
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