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1.
Acta Physiologica Sinica ; (6): 275-285, 2021.
Article in Chinese | WPRIM | ID: wpr-878256

ABSTRACT

This study aimed to explore the positive inotropic effect of phosphodiesterase type 9 (PDE9) inhibitor PF-04449613 in ratsand its cellular and molecular mechanisms. The heart pressure-volume loop (P-V loop) analysis was used to detect the effects of PF-04449613 on rat left ventricular pressure-volume relationship, aortic pressures and peripheral vessel resistance in healthy rats. The Langendorff perfusion of isolated rat heart was used to explore the effects of PF-04449613 on heart contractility. The cardiomyocyte sarcoplasmic reticulum (SR) Ca


Subject(s)
Animals , Calcium/metabolism , Myocardial Contraction , Myocytes, Cardiac/metabolism , Phosphodiesterase Inhibitors , Phosphoric Diester Hydrolases , Rats , Ryanodine Receptor Calcium Release Channel , Sarcoplasmic Reticulum
2.
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
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 Korean | WPRIM | ID: wpr-766770

ABSTRACT

Congenital fiber type disproportion (CFTD) has been related with mutations in ACTA1, SEPN1, RYR1 and tropomyosin 3 (TPM3) genes. Particularly, TPM3 mutation was identified as one of the most frequent cause of CFTD and was also detected in cap myopathy and nemaline myopathy. Herein we report patients of autosomal dominant TPM3 missense mutations with CFTD in a Korean family over twogenerations. Two of our patients, who developed mild muscle weakness in infancy, presented with altered mentality and respiratory distress despite relatively mild limb weakness.


Subject(s)
Extremities , Humans , Muscle Weakness , Muscular Diseases , Mutation, Missense , Myopathies, Nemaline , Myopathies, Structural, Congenital , Respiratory Insufficiency , Ryanodine Receptor Calcium Release Channel , Tropomyosin
5.
Natural Product Sciences ; : 136-142, 2019.
Article in English | WPRIM | ID: wpr-760552

ABSTRACT

Ischemia/reperfusion-induced myocardial injury is the main cause of acute myocardial infarction. Dendropanax morbifera Léveille has been used in traditional medicines for the treatment of various diseases such as headache, infectious diseases, and general debility. However, the effect of extract from D. morbifera (EDM) on myocardial ischemic injury is still unknown. In this study, the effects of EDM on neonatal rat cardiomyocytes with hypoxia/reoxygenation (H/R) injury were investigated. The viability of cardiomyocytes with H (30 min)/R (1 h) decreased; however, treatment with EDM significantly inhibited H/R injury-induced cardiomyocyte death. Further, we observed that reactive oxygen species (ROS) generation and intracellular calcium concentration (Ca²⁺ᵢ) were significantly reduced in EDM-treated cardiomyocytes compared with that in H/R-injured positive control. In addition, western blotting results showed that EDM attenuated abnormal changes of RyR2 and SERCA2a genes in hypoxic cardiomyocytes. These results suggest that EDM ameliorates ROS generation and Ca²⁺ᵢ homeostasis to prevent dysregulation of calcium regulatory proteins in the heart, thereby exerting cardioprotective effects and reducing hypoxia-induced cardiomyocyte damage, which verifies the potential use of EDM as a new therapeutic agent for the treatment of myocardial ischemic injury.


Subject(s)
Animals , Blotting, Western , Calcium , Communicable Diseases , Headache , Heart , Homeostasis , Myocardial Infarction , Myocytes, Cardiac , Rats , Reactive Oxygen Species , Ryanodine Receptor Calcium Release Channel
6.
Korean Circulation Journal ; : 148-158, 2018.
Article in English | WPRIM | ID: wpr-738679

ABSTRACT

BACKGROUND AND OBJECTIVES: Multifocal atrial tachycardia (MAT), in general, has a favorable outcome. However, there are insufficient data regarding MAT in a pediatric population. This study sought to determine the clinical course of MAT and identify potential prognostic factors. METHODS: The medical records of MAT patients from 1997–2015 were reviewed. The arrhythmia control rate and factors for unfavorable outcomes were assessed and compared to those in the literature. RESULTS: Of the 33 included patients (19 boys and 14 girls), 27 were infants less than 1 year of age. The median age at diagnosis was 1.7 months (range, 0 day to 14 years). Fourteen (42%) patients had structural heart disease. Eight (24%) patients had lung disease and 6 (18%) had a syndromic diagnosis belonging to RASopathy. Two patients developed polymorphic ventricular tachycardia, in whom genetic analysis confirmed the presence of the RyR2 mutation several years later. MAT was controlled in 26 patients (84%) within 3.9 months (median; range, 16 days–18.4 years) using an average of 2.4 medications. There were 3 cases of cardiopulmonary mortality. The arrhythmia control rate was higher in the infant group (85%) than in the non-infant group (67%), although this trend was not statistically significant. There was a significantly lower rate of unfavorable outcomes in the idiopathic infant group (n=11) than in the other groups (p=0.008). Considering the findings of previous studies, the mortality rate was significantly higher in patients with structural heart disease than in patients without (21% vs. 5%, p=0.01). CONCLUSIONS: MAT usually affects infants and has a favorable prognosis, particularly in the idiopathic infant group. However, in the presence of other comorbidities, MAT may have a variable clinical course.


Subject(s)
Arrhythmias, Cardiac , Atrial Fibrillation , Atrial Flutter , Comorbidity , Diagnosis , Heart Diseases , Humans , Infant , Lung Diseases , Medical Records , Mortality , Prognosis , Ryanodine Receptor Calcium Release Channel , Tachycardia , Tachycardia, Supraventricular , Tachycardia, Ventricular
7.
Article in English | WPRIM | ID: wpr-739103

ABSTRACT

Long QT syndrome (LQTS) is an inherited cardiac disease characterized by a prolonged heart rate-corrected QT (QTc) interval. We investigated the genetic causes in patients with prolonged QTc intervals who were negative for pathogenic variants in three major LQTS-related genes (KCNQ1, KCNH2, and SCN5A). Molecular genetic testing was performed using a panel including 13 LQTS-related genes and 67 additional genes implicated in other cardiac diseases. Overall, putative genetic causes of prolonged QTc interval were identified in three of the 30 patients (10%). Among the LQTS-related genes, we detected a previously reported pathogenic variant, CACNA1C c.1552C>T, responsible for cardiac-only Timothy syndrome. Among the genes related to other cardiac diseases, a likely pathogenic variant, RYR2 c.11995A>G, was identified in a patient with catecholaminergic polymorphic ventricular tachycardia. Another patient who developed dilated cardiomyopathy with prolonged QTc interval was found to carry a likely pathogenic variant, TAZ c.718G>A, associated with infantile dilated cardiomyopathy. Comprehensive screening of genetic variants using multigene panel sequencing enables detection of genetic variants with a possible involvement in QTc interval prolongation, thus uncovering unknown molecular mechanisms underlying LQTS.


Subject(s)
Cardiomyopathy, Dilated , Heart , Heart Diseases , Humans , Long QT Syndrome , Mass Screening , Molecular Biology , Ryanodine Receptor Calcium Release Channel , Tachycardia, Ventricular
8.
Article in English | WPRIM | ID: wpr-93424

ABSTRACT

Cyclic ADP-ribose (cADPR) releases Ca²⁺ from ryanodine receptor (RyR)-sensitive calcium pools in various cell types. In cardiac myocytes, the physiological levels of cADPR transiently increase the amplitude and frequency of Ca²⁺ (that is, a rapid increase and decrease of calcium within one second) during the cardiac action potential. In this study, we demonstrated that cADPR levels higher than physiological levels induce a slow and gradual increase in the resting intracellular Ca²⁺ ([Ca²⁺](i)) level over 10 min by inhibiting the sarcoendoplasmic reticulum Ca²⁺ ATPase (SERCA). Higher cADPR levels mediate the tyrosine-dephosphorylation of α-actin by protein tyrosine phosphatase 1B (PTP1B) present in the endoplasmic reticulum. The tyrosine dephosphorylation of α-actin dissociates phospholamban, the key regulator of SERCA, from α-actin and results in SERCA inhibition. The disruption of the integrity of α-actin by cytochalasin B and the inhibition of α-actin tyrosine dephosphorylation by a PTP1B inhibitor block cADPR-mediated Ca²⁺ increase. Our results suggest that levels of cADPR that are relatively higher than normal physiological levels modify calcium homeostasis through the dephosphorylation of α-actin by PTB1B and the subsequent inhibition of SERCA in cardiac myocytes.


Subject(s)
Action Potentials , Adenosine Diphosphate , Adenosine Triphosphatases , Calcium , Cyclic ADP-Ribose , Cytochalasin B , Endoplasmic Reticulum , Homeostasis , Muscle Cells , Myocytes, Cardiac , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Protein Tyrosine Phosphatases , Reticulum , Ryanodine Receptor Calcium Release Channel , Tyrosine
9.
Arch. endocrinol. metab. (Online) ; 60(6): 582-586, Nov.-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-827786

ABSTRACT

ABSTRACT Objective The current study was aimed at analyzing sarcoplasmic reticulum Ca2+ ATPase (Serca2) and ryanodine receptor type 2 (Ryr2) gene expression in rats subjected to surgery that induced HF and were subsequently treated with T4 using physiological doses. Materials and methods HF was induced in 18 male Wistar rats by clipping the ascending thoracic aorta to generate aortic stenosis (HFS group), while the control group (9-sham) underwent thoracotomy. After 21 weeks, the HFS group was subdivided into two subgroups. One group (9 Wistar rats) with HF received 1.0 µg of T4/100 g of body weight for five consecutive days (HFS/T4); the other group (9 Wistar rats) received isotonic saline solution (HFS/S). The animals were sacrificed after this treatment and examined for signs of HF. Samples from the left ventricles of these animals were analyzed by RT-qPCR for the expression of Serca2 and Ryr2 genes. Results Rats with HF developed euthyroid sick syndrome (ESS) and treatment with T4 restored the T3 values to the Sham level and increased Serca2 and Ryr2 gene expression, thereby demonstrating a possible benefit of T4 treatment for heart function in ESS associated with HF. Conclusion The T4 treatment can potentially normalize the levels of T3 as well elevated Serca2 and Ryr2 gene expression in the myocardium in heart failure rats with euthyroid sick syndrome.


Subject(s)
Animals , Male , Thyroxine/administration & dosage , Euthyroid Sick Syndromes/drug therapy , Ryanodine Receptor Calcium Release Channel/drug effects , Aortic Valve Stenosis/complications , Thyroxine/therapeutic use , Triiodothyronine/drug effects , Euthyroid Sick Syndromes/complications , Euthyroid Sick Syndromes/genetics , RNA, Messenger/metabolism , Gene Expression/drug effects , Rats, Wistar , Ryanodine Receptor Calcium Release Channel/genetics , Models, Animal , Sarcoplasmic Reticulum Calcium-Transporting ATPases/drug effects , Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics , Heart Failure/complications
10.
Article in Chinese | WPRIM | ID: wpr-815046

ABSTRACT

OBJECTIVE@#To study the impact of aconitine and Shuang-huang-lian injection on the expression of myocardial ryanodine receptor (RyR2) and to discuss the anti-arrhythmic mechanisms of Shuanghuanglian against aconitine poisoning.
@*METHODS@#A total of 52 SD rats were randomly divided into 3 groups: aconitine group (group A, n=20), Shuang-huang-lian group (group B, n=20) and control group (group C, n=12). Aconitine at a dose of 0.3 mg/kg was firstly administrated to the rats of group A and group B through gavage. 30 minutes later, normal saline was delivered to rats in group A through intraperitoneal injection, while rats in group B received Shuang-huang-lian at a dose of 100 mg/kg through intraperitoneal injection. Group C accepted twice administration of normal saline by gavage and intraperitoneal injection. The disposals for each group were implemented for 10 consecutive days. The rats' electrocardiograms (ECG) were recorded on day 1, 3, 6 and 10. Immunofluorescent staining technique and real-time quantitative PCR technique was used to detect the protein and mRNA expression of myocardial RyR2.
@*RESULTS@#The arrhythmia scores of group B at different time were lower than group A and the difference was statistically significant (P0.05). On day 3, 6 and 10, the expression of RyR2 protein and mRNA in group A was dramatically increased compared to group B and group C (P<0.01). 
@*CONCLUSION@#Shuang-huang-lian injection can effectively prevent the arrhythmia caused by aconitine, which is related to suppressing the aconitine-induced RyR2 expression.


Subject(s)
Aconitine , Animals , Anti-Arrhythmia Agents , Drugs, Chinese Herbal , Therapeutic Uses , Rats , Rats, Sprague-Dawley , Ryanodine Receptor Calcium Release Channel
11.
Article in English | WPRIM | ID: wpr-72758

ABSTRACT

This study aimed at constructing a draft genome of the adult female worm Toxocara canis using next-generation sequencing (NGS) and de novo assembly, as well as to find new genes after annotation using functional genomics tools. Using an NGS machine, we produced DNA read data of T. canis. The de novo assembly of the read data was performed using SOAPdenovo. RNA read data were assembled using Trinity. Structural annotation, homology search, functional annotation, classification of protein domains, and KEGG pathway analysis were carried out. Besides them, recently developed tools such as MAKER, PASA, Evidence Modeler, and Blast2GO were used. The scaffold DNA was obtained, the N50 was 108,950 bp, and the overall length was 341,776,187 bp. The N50 of the transcriptome was 940 bp, and its length was 53,046,952 bp. The GC content of the entire genome was 39.3%. The total number of genes was 20,178, and the total number of protein sequences was 22,358. Of the 22,358 protein sequences, 4,992 were newly observed in T. canis. Following proteins previously unknown were found: E3 ubiquitin-protein ligase cbl-b and antigen T-cell receptor, zeta chain for T-cell and B-cell regulation; endoprotease bli-4 for cuticle metabolism; mucin 12Ea and polymorphic mucin variant C6/1/40r2.1 for mucin production; tropomodulin-family protein and ryanodine receptor calcium release channels for muscle movement. We were able to find new hypothetical polypeptides sequences unique to T. canis, and the findings of this study are capable of serving as a basis for extending our biological understanding of T. canis.


Subject(s)
Adult , B-Lymphocytes , Base Composition , Classification , DNA , Female , Genome , Genomics , Humans , Larva Migrans, Visceral , Metabolism , Mucins , Peptides , Protein Structure, Tertiary , Receptors, Antigen, T-Cell , RNA , Ryanodine Receptor Calcium Release Channel , T-Lymphocytes , Toxocara canis , Toxocara , Transcriptome , Ubiquitin-Protein Ligases
12.
Article in English | WPRIM | ID: wpr-149849

ABSTRACT

Sildenafil relaxes vascular smooth muscle cells and is used to treat pulmonary artery hypertension as well as erectile dysfunction. However, the effectiveness of sildenafil on skeletal muscle and the benefit of its clinical use have been controversial, and most studies focus primarily on tissues and organs from disease models without cellular examination. Here, the effects of sildenafil on skeletal muscle at the cellular level were examined using mouse primary skeletal myoblasts (the proliferative form of skeletal muscle stem cells) and myotubes, along with single-cell Ca2+ imaging experiments and cellular and biochemical studies. The proliferation of skeletal myoblasts was enhanced by sildenafil in a dose-independent manner. In skeletal myotubes, sildenafil enhanced the activity of ryanodine receptor 1, an internal Ca2+ channel, and Ca2+ movement that promotes skeletal muscle contraction, possibly due to an increase in the resting cytosolic Ca2+ level and a unique microscopic shape in the myotube membranes. Therefore, these results suggest that the maintenance ability of skeletal muscle mass and the contractility of skeletal muscle could be improved by sildenafil by enhancing the proliferation of skeletal myoblasts and increasing the Ca2+ availability of skeletal myotubes, respectively.


Subject(s)
Animals , Cytosol , Erectile Dysfunction , Hypertension , Maintenance , Male , Membranes , Mice , Muscle Fibers, Skeletal , Muscle, Skeletal , Muscle, Smooth, Vascular , Myoblasts, Skeletal , Pulmonary Artery , Ryanodine Receptor Calcium Release Channel , Sildenafil Citrate
13.
Article in Korean | WPRIM | ID: wpr-42181

ABSTRACT

Nitric Oxide (NO) is an important signaling molecule in the nociceptive process. Our previous study suggested that high concentrations of sodium nitroprusside (SNP), a NO donor, induce a membrane hyperpolarization and outward current through large conductances calcium-activated potassium (BKca) channels in substantia gelatinosa (SG) neurons. In this study, patch clamp recording in spinal slices was used to investigate the sources of Ca2+ that induces Ca2+-activated potassium currents. Application of SNP induced a membrane hyperpolarization, which was significantly inhibited by hemoglobin and 2-(4-carboxyphenyl) -4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide potassium salt (c-PTIO), NO scavengers. SNP-induced hyperpolarization was decreased in the presence of charybdotoxin, a selective BKCa channel blocker. In addition, SNP-induced response was significantly blocked by pretreatment of thapsigargin which can remove Ca2+ in endoplasmic reticulum, and decreased by pretreatment of dentrolene, a ryanodine receptors (RyR) blocker. These data suggested that NO induces a membrane hyperpolarization through BKca channels, which are activated by intracellular Ca2+ increase via activation of RyR of Ca2+ stores.


Subject(s)
Animals , Calcium , Charybdotoxin , Endoplasmic Reticulum , Humans , Membranes , Neurons , Nitric Oxide , Nitroprusside , Potassium , Rats , Ryanodine Receptor Calcium Release Channel , Ryanodine , Substantia Gelatinosa , Thapsigargin , Tissue Donors
14.
Article in English | WPRIM | ID: wpr-179191

ABSTRACT

BACKGROUND: Central core disease (CCD) is a congenital myopathy characterized by distinctive cores in muscle fibers. Mutations in the gene encoding ryanodine receptor 1 (RYR1) have been identified in most CCD patients. CASE REPORT: Two unrelated patients presented with slowly progressive or nonprogressive proximal muscle weakness since childhood. Their family history revealed some members with the same clinical problem. Histological analysis of muscle biopsy samples revealed numerous peripheral cores in the muscle fibers. RYR1 sequence analysis disclosed a novel mutation in exon 101 (c.14590T>C) and confirmed a previously reported mutation in exon 102 (c.14678G>A). CONCLUSIONS: We report herein two families with CCD in whom missense mutations at the C-terminal of RYR1 were identified. Although it has been accepted that such mutations are usually associated with a severe clinical phenotype and clearly demarcated central cores, our patients exhibited a mild clinical phenotype without facial muscle involvement and skeletal deformities, and atypical cores in their muscle biopsy specimens.


Subject(s)
Biopsy , Congenital Abnormalities , Exons , Facial Muscles , Humans , Muscle Weakness , Muscular Diseases , Mutation, Missense , Myopathy, Central Core , Phenotype , Ryanodine Receptor Calcium Release Channel , Sequence Analysis
15.
Braz. j. med. biol. res ; 47(11): 960-965, 11/2014. tab, graf
Article in English | LILACS | ID: lil-723901

ABSTRACT

In cardiomyocytes, calcium (Ca2+) release units comprise clusters of intracellular Ca2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F0), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes.


Subject(s)
Animals , Male , Calcium/physiology , Heart Ventricles/metabolism , Hypertension/therapy , Motor Activity/physiology , Myocytes, Cardiac/metabolism , Physical Conditioning, Animal/methods , Calcium Signaling/physiology , Exercise Test/methods , Heart Ventricles/cytology , Hypertension/metabolism , Rats, Inbred SHR , Rats, Wistar , Ryanodine Receptor Calcium Release Channel/genetics , Ryanodine Receptor Calcium Release Channel/metabolism , Tacrolimus Binding Proteins/genetics , Tacrolimus Binding Proteins/metabolism
16.
Arch. cardiol. Méx ; 84(3): 191-201, jul.-sep. 2014. ilus
Article in Spanish | LILACS | ID: lil-732027

ABSTRACT

La participación del canal de Ca2+/receptor de rianodina en el acoplamiento excitación-contracción cardiaco se conoce desde finales de los años ochenta, cuando en varios trabajos trascendentales se comunicó por primera vez su purificación y se encontró que correspondía a las estructuras conocidas como «pies¼ localizadas en las cisternas terminales del retículo sarcoplásmico. Adicionalmente a su papel como canal responsable del aumento global y transitorio de Ca2+ que activa a la maquinaria contráctil durante el ciclo cardiaco, el receptor de rianodina también libera Ca2+ durante la fase de relajación, dando lugar a la fuga de Ca2+ en la diástole que en condiciones fisiológicas regula el nivel de Ca2+ luminal, pero cuando se encuentra alterada participa en la generación de arritmias adquiridas o hereditarias. Recientemente, el esfuerzo de diversos grupos de investigación se ha enfocado en el desarrollo de herramientas farmacológicas para controlar la fuga diastólica de Ca2+ que se presenta alterada en algunas enfermedades cardiacas. En esta revisión nos enfocamos en describir la participación del receptor de rianodina cardiaco en la fuga diastólica de Ca2+ así como los diversos enfoques terapéuticos que se han implementado para controlar su actividad exacerbada en la diástole.


The participation of the ionic Ca2+ release channel/ryanodine receptor in cardiac excitation-contraction coupling is well known since the late '80s, when various seminal papers communicated its purification for the first time and its identity with the "foot" structures located at the terminal cisternae of the sarcoplasmic reticulum. In addition to its main role as the Ca2+ channel responsible for the transient Ca2+ increase that activates the contractile machinery of the cardiomyocytes, the ryanodine receptor releases Ca2+ during the relaxation phase of the cardiac cycle, giving rise to a diastolic Ca2+ leak. In normal physiological conditions, diastolic Ca2+ leak regulates the proper level of luminal Ca2+, but in pathological conditions it participates in the generation of both, acquired and hereditary arrhythmias. Very recently, several groups have focused their efforts into the development of pharmacological tools to control the altered diastolic Ca2+ leak via ryanodine receptors. In this review, we focus our interest on describing the participation of cardiac ryanodine receptor in the diastolic Ca2+ leak under physiological or pathological conditions and also on the therapeutic approaches to control its undesired exacerbated activity during diastole.


Subject(s)
Humans , Arrhythmias, Cardiac/etiology , Calcium/physiology , Ryanodine Receptor Calcium Release Channel/physiology , Diastole
17.
Yonsei Medical Journal ; : 660-668, 2014.
Article in English | WPRIM | ID: wpr-58592

ABSTRACT

PURPOSE: The underlying cause of myasthenia gravis (MG) is unknown, although it likely involves a genetic component. However, no common genetic variants have been unequivocally linked to autoimmune MG. We sought to identify the genetic variants associated with an increased or decreased risk of developing MG in samples from a Korean Multicenter MG Cohort. MATERIALS AND METHODS: To determine new genetic targets related to autoimmune MG, a whole genome-based single nucleotide polymorphisms (SNP) analysis was conducted using an Axiom(TM) Genome-Wide ASI 1 Array, comprising 598375 SNPs and samples from 109 MG patients and 150 neurologically normal controls. RESULTS: In total, 641 SNPs from five case-control associations showed p-values of less than 10(-5). From regional analysis, we selected seven candidate genes (RYR3, CACNA1S, SLAMF1, SOX5, FHOD3, GABRB1, and SACS) for further analysis. CONCLUSION: The present study suggests that a few genetic polymorphisms, such as in RYR3, CACNA1S, and SLAMF1, might be related to autoimmune MG. Our findings also encourage further studies, particularly confirmatory studies with larger samples, to validate and analyze the association between these SNPs and autoimmune MG.


Subject(s)
Antigens, CD/genetics , Asian Continental Ancestry Group/genetics , Calcium Channels/genetics , Female , Genetic Predisposition to Disease/genetics , Genotype , Humans , Male , Myasthenia Gravis/etiology , Polymorphism, Single Nucleotide/genetics , Receptors, Cell Surface/genetics , Ryanodine Receptor Calcium Release Channel/genetics
18.
Article in English | WPRIM | ID: wpr-727590

ABSTRACT

DA-6034, a eupatilin derivative of flavonoid, has shown potent effects on the protection of gastric mucosa and induced the increases in fluid and glycoprotein secretion in human and rat corneal and conjunctival cells, suggesting that it might be considered as a drug for the treatment of dry eye. However, whether DA-6034 induces Ca2+ signaling and its underlying mechanism in epithelial cells are not known. In the present study, we investigated the mechanism for actions of DA-6034 in Ca2+ signaling pathways of the epithelial cells (conjunctival and corneal cells) from human donor eyes and mouse salivary gland epithelial cells. DA-6034 activated Ca2+-activated Cl- channels (CaCCs) and increased intracellular calcium concentrations ([Ca2+]i) in primary cultured human conjunctival cells. DA-6034 also increased [Ca2+]i in mouse salivary gland cells and human corneal epithelial cells. [Ca2+]i increase of DA-6034 was dependent on the Ca2+ entry from extracellular and Ca2+ release from internal Ca2+ stores. Interestingly, these effects of DA-6034 were related to ryanodine receptors (RyRs) but not phospholipase C/inositol 1,4,5-triphosphate (IP3) pathway and lysosomal Ca2+ stores. These results suggest that DA-6034 induces Ca2+ signaling via extracellular Ca2+ entry and RyRs-sensitive Ca2+ release from internal Ca2+ stores in epithelial cells.


Subject(s)
Animals , Calcium , Calcium Signaling , Epithelial Cells , Gastric Mucosa , Glycoproteins , Humans , Mice , Phospholipases , Rats , Ryanodine Receptor Calcium Release Channel , Salivary Glands , Tissue Donors
19.
São Paulo; s.n; 2014. [208] p. ilus, tab.
Thesis in Portuguese | LILACS | ID: lil-750119

ABSTRACT

Introdução: A miopatia centronuclear é uma doença muscular congênita com apresentação clínica heterogênea, caracterizada histologicamente pela proeminência de fibras musculares com núcleos centralizados. Três formas são reconhecidas: neonatal grave, com herança ligada ao X e envolvimento do gene MTM1; autossômica dominante, com início geralmente tardio e curso mais leve, associada a mutações no gene DNM2; e autossômica recessiva, com gravidade intermediária entre as outras formas e envolvimento dos genes BIN1, RYR1 ou TTN. Apesar da identificação dos principais genes responsáveis pela doença, os métodos usuais de diagnóstico genético não encontram mutações em cerca da metade dos casos. Objetivo: O objetivo deste estudo foi a caracterização clínica, histológica e molecular de pacientes brasileiros portadores de miopatia centronuclear. Métodos: Laudos de dois bancos de biópsia muscular foram usados para identificar pacientes com diagnóstico de miopatia centronuclear nos últimos dez anos. As lâminas das biópsias foram revisadas e analisadas, e as famílias correspondentes convocadas para aplicação de protocolo clínico e coleta de sangue periférico para extração de DNA genômico. As famílias foram estudadas para os genes conhecidos por sequenciamento Sanger, MLPA, painel de genes implicados em doenças neuromusculares ou sequenciamento de exoma. Resultados: Foram convocados 24 pacientes provenientes de 21 famílias, em 16 das quais foi possível estabelecer o diagnóstico molecular. As 7 famílias com a forma neonatal grave constituíam um grupo homogêneo clínica e histologicamente, e mutações novas e conhecidas foram encontradas no gene MTM1 em 6 destas. Dois meninos deste grupo, com evolução estável, tiveram óbito súbito por choque hipovolêmico subsequente a rompimento de cisto hepático. O gene MTM1 também foi implicado em uma menina portadora manifestante, com quadro mais leve, na forma de uma macrodeleção em heterozigose, detectada por MPLA...


Introduction: Centronuclear myopathy is a heterogeneous congenital muscle disease, characterized by the prominence of centralized nuclei in muscle fibers. Three disease forms are recognized: a severe neonatal, X-linked form caused by mutations in the MTM1 gene; an autosomal dominant, late-onset milder form, associated to the DNM2 gene; and an autosomal recessive form, with intermediate severity, so far with the BIN1, RYR1 or TTN genes implicated. In spite of the identification of these genes, usual molecular diagnostic methods don't yield a molecular diagnosis in about half of cases. Objetives: The aim of this work was to study clinical, histological, and molecular aspects of centronuclear myopathy Brazilian patients. Methods: Reports taken from two muscle biopsy banks were used to identify centronuclear myopathy patients in the last ten years. Biopsy slides were reviewed and analyzed, and corresponding families recruited to apply a clinical protocol and to draw peripheral blood to extract genomic DNA. Families were studied for known genes via Sanger sequencing, MLPA, panel of genes implicated in neuromuscular diseases, or exome sequencing. Results: Twentyfour patients out of 21 families were recruited, and in 16 families molecular diagnosis was established. The 7 families with the severe neonatal form amounted to a clinically and histologically homogeneous group, and mutations, both known and novel, were found in the MTM1 gene in 6 of these. Two boys of this group, with a stable course, died suddenly of hypovolemic shock due to a hepatic cyst rupture. The MTM1 gene was also implicated in the case of a mild manifesting carrier girl with a heterozygous macrodeletion detected via MLPA...


Subject(s)
Humans , Male , Female , Infant , Child, Preschool , Child , Adolescent , Young Adult , Middle Aged , Biopsy , Dynamin II , Exome , High-Throughput Nucleotide Sequencing , Muscle Hypotonia , Myopathies, Structural, Congenital , Ryanodine Receptor Calcium Release Channel
20.
Rev. bras. anestesiol ; 62(6): 828-837, nov.-dez. 2012. ilus, tab
Article in Portuguese | LILACS | ID: lil-659013

ABSTRACT

CONTEÚDO: A hipertermia maligna (HM) é uma doença farmacogenética potencialmente letal que acomete indivíduos geneticamente predispostos. Manifesta-se em indivíduos susceptíveis em resposta à exposição a anestésicos inalatórios, relaxantes musculares despolarizantes ou atividade física extrema em ambientes quentes. Durante a exposição a esses agentes desencadeadores, há um aumento rápido e sustentado da concentração de cálcio mioplasmático (Ca2+) induzido pela hiperativação dos receptores de rianodina (RYR1) do músculo esquelético, causando uma alteração profunda na homeostase de Ca2+, caracterizando um estado hipermetabólico. RYR1, canais de libertação de Ca2+ do retículo sarcoplasmático, é o principal local de susceptibilidade à HM. Várias mutações no gene que codifica a proteína RYR1 foram identificadas, mas outros genes podem estar envolvidos. Atualmente, o método padrão para o diagnóstico de sensibilidade à HM é o teste de contratura muscular para exposição ao halotano-cafeína (CHCT) e o único tratamento é o uso de dantroleno. No entanto, com os avanços no campo da genética molecular, um pleno entendimento da etiologia da doença pode ser fornecido, favorecendo o desenvolvimento de um diagnóstico preciso, menos invasivo, com o teste de ADN, e também proporcionar o desenvolvimento de novas estratégias terapêuticas para o tratamento da HM. Logo, esta breve revisão tem como objetivo integrar os aspectos clínicos e moleculares da HM, reunindo informações para uma melhor compreensão desta canalopatia.


CONTENT: Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disorder that affects genetically predisposed individuals. It manifests in susceptible individuals in response to exposure to Inhalant anesthetics, depolarizing muscle relaxants or extreme physical activity in hot environments. During exposure to these triggering agents, there is a rapid and sustained increase of myoplasmic calcium (Ca2+) concentration induced by hyperactivation of ryanodine receptor of skeletal muscle (RyR1), causing a profound change in Ca2+ homeostasis, featuring a hypermetabolic state. RyR1, Ca2+ release channels of sarcoplasmic reticulum, is the primary locus for MH susceptibility. Several mutations in the gene encoding the protein RyR1 have been identified; however, other genes may be involved. Actually, the standard method for diagnosing MH susceptibility is the muscle contracture test for exposure to halothane-caffeine (CHCT) and the only treatment is the use of dantrolene. However, with advances in molecular genetics, a full understanding of the disease etiology may be provided, favoring the development of an accurate diagnosis, less invasive, with DNA test, and also will provide the development of new therapeutic strategies for treatment of MH. Thus, this brief review aims to integrate molecular and clinical aspects of MH, gathering input for a better understanding of this channelopathy.


CONTENIDO: La hipertermia maligna (HM) es una enfermedad farmacogenética potencialmente letal que afecta a individuos genéticamente predispuestos. Se manifiesta en los individuos susceptibles en respuesta a la exposición a los anestésicos inhalatorios, relajantes musculares despolarizantes o actividad física extrema en ambientes calientes. Durante la exposición a esos agentes desencadenantes, existe un aumento rápido y constante de la concentración de calcio mioplasmático (Ca2+) inducido por la hiperactivación de los receptores de rianodina (RYR1) del músculo esquelético, causando una alteración profunda en la homeostasa de Ca2+, y caracterizando un estado hipermetabólico. RYR1, canales de liberación de Ca2+ del retículo sarcoplasmático, es la principal región de susceptibilidad a la HM. Varias mutaciones en el gen que codifica la proteína RYR1 han sido identificadas, pero otros genes pueden estar involucrados también. Actualmente, el método estándar para el diagnóstico de la sensibilidad a la HM es el test de contractura muscular para la exposición al halotano-cafeína (CHCT) y el único tratamiento es el uso de dantroleno. Sin embargo, con los avances en el campo de la genética molecular, un pleno entendimiento de la etiología de la enfermedad puede ser suministrado, favoreciendo así el desarrollo de un diagnóstico preciso, menos invasivo, con el test de ADN, y también proporcionar el desarrollo de nuevas estrategias terapéuticas para el tratamiento de la HM. Por eso, esta breve revisión intenta integrar los aspectos clínicos y moleculares de la HM, reuniendo informaciones para lograr una mejor comprensión de esa canalopatía.


Subject(s)
Humans , Malignant Hyperthermia , Malignant Hyperthermia/diagnosis , Malignant Hyperthermia/genetics , Malignant Hyperthermia/therapy , Ryanodine Receptor Calcium Release Channel/physiology
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