Yosuke Okamoto

Yosuke Okamoto
Akita University · Department of Cell Physiology

MD, PhD

About

30
Publications
1,678
Reads
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350
Citations
Citations since 2016
18 Research Items
279 Citations
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050

Publications

Publications (30)
Article
Full-text available
The heart is a necessary organ for sustaining life in mammals, and it is the first organ to function during early development [...]
Article
Full-text available
The heart is a significant organ in mammalian life, and the heartbeat mechanism has been an essential focus of science. However, few studies have focused on species differences. Accordingly, challenges remain in studying genes that have universal functions across species and genes that determine species differences. Here, we analyzed transcriptome...
Article
Full-text available
Ectopic excitability in pulmonary veins (PVs) is the major cause of atrial fibrillation. We previously reported that the inositol trisphosphate receptor in rat PV cardiomyocytes cooperates with the Na+-Ca2+ exchanger to provoke ectopic automaticity in response to norepinephrine. Here, we focused on adenylyl cyclase (AC) as another effector of norep...
Article
Full-text available
Gain-of-function mutations in voltage-gated sodium channels (NaV1.7, NaV1.8, and NaV1.9) are known causes of inherited pain disorders. Identification and functional assessment of new NaV1.7 mutations could help elucidate the phenotypic spectrum of NaV1.7 channelopathies. We identified a novel NaV1.7 mutation (E44Q in exon 2) that substitutes a glut...
Article
To cryopreserve cells, it is essential to avoid intracellular ice formation during cooling and warming. One way to achieve this is to convert the water inside the cells into a non-crystalline glass. It is currently believed that to accomplish this vitrification, the cells must be suspended in a very high concentration (20–40%) of a glass-inducing s...
Article
Aims Azelnidipine, a third-generation dihydropyridine calcium channel blocker (DHP CCB), has a characteristic hypotensive effect that persists even after it has disappeared from the plasma, which is thought to be due to its high hydrophobicity. However, because azelnidipine is unique, it might have other unknown effects on L-type Cav1.2 channels th...
Article
Full-text available
Pulmonary vein (PV) cardiomyocytes have the potential to generate spontaneous activity, in contrast to working myocytes of atria. Different electrophysiological properties underlie the potential automaticity of PV cardiomyocytes, one being the hyperpolarization-activated inward current (Ih), which facilitates the slow diastolic depolarization. In t...
Article
Extracellular signal-regulated kinase (ERK) 5, a member of mitogen-activated protein kinase, plays important roles in the neuronal development. In our previous studies, we demonstrated that ERK5 mediates neurite/axon outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, the regulation of membrane excitability by E...
Article
Full-text available
Pulmonary veins (PVs) are the major origin of atrial fibrillation. Recently, we recorded hyperpolarization-activated Cl- current (ICl, h) in rat PV cardiomyocytes. Unlike the well-known chloride channel protein 2 (CLCN2) current, the activation curve of ICl, h was hyperpolarized as the Cl- ion concentration ([Cl-] i ) increased. This current could...
Article
Full-text available
Cardiomyocytes and myocardial sleeves dissociated from pulmonary veins (PVs) potentially generate ectopic automaticity in response to noradrenaline (NA), and thereby trigger atrial fibrillation. We developed a mathematical model of rat PV cardiomyocytes (PVC) based on experimental data that incorporates the microscopic framework of the local contro...
Article
Full-text available
Extracellular signal-regulated kinase 5 (ERK5) regulates diverse physiological responses such as proliferation, differentiation, and gene expression. Previously, we demonstrated that ERK5 is essential for neurite outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, it remains unclear how ERK5 regulates the activi...
Article
Full-text available
AMPK is a conserved serine/threonine kinase whose activity maintains cellular energy homeostasis. Eukaryotic AMPK exists as αβγ complexes, whose regulatory γ subunit confers energy sensor function by binding adenine nucleotides. Humans bearing activating mutations in the γ2 subunit exhibit a phenotype including unexplained slowing of heart rate (br...
Data
Fig. S1 ECG recording in vivo and electrogram recording in isolated SAN. Fig. S2 Age‐associated changes in (A) beating interval, (B) coefficient of variance (CV) and (C) low frequency (LF) to high frequency (HF) ratio in awake mice in vivo (n = 3) and during autonomic blockade (DB). Fig. S3 Dose–response of beating rate, coefficient of variance (...
Article
Full-text available
We aimed to determine how age-associated changes in mechanisms extrinsic and intrinsic to pacemaker cells relate to basal beating interval variability (BIV) reduction in vivo. Beating intervals (BIs) were measured in aged (23-25 months) and adult (3-4 months) C57BL/6 male mice (i) via ECG in vivo during light anesthesia in the basal state, or in th...
Article
Novel functional analyses and numerical models have led to a paradigm shift in sinoatrial nodal pacemaker cell biology. Recent reports of transcriptional profiles of SAN, however, have focused on a limited number of pre-selected transcripts, while the large-scale transcriptome profile of SAN pacemaker cells remains unknown. Using Illumina Ref8v2 be...
Article
Recent evidence indicates that the spontaneous action potential (AP) of isolated sinoatrial node cells (SANC) is regulated by a system of stochastic mechanisms embodied within two clocks: ryanodine receptors of the “Ca2 + clock” within the sarcoplasmic reticulum, spontaneously activate during diastole and discharge local Ca2 + releases (LCRs) benea...
Article
A reduction of complexity of heart-beat interval variability (BIV) that is associated with an increased morbidity and mortality in cardiovascular disease states is thought to derive from the balance of sympathetic and parasympathetic neural impulses to the heart. But rhythmic clock-like behavior intrinsic to pacemaker cells within the sinoatrial no...
Article
The heart rate and rhythm are controlled by complex chaotic neural, chemical and hormonal networks which are not strictly regular, but exhibit fluctuations across multiple-time scales. Therefore, it is not surprising that decoding of the ECG in mammals, even under resting conditions, reveals scale-invariant dynamics and beat-interval variability (B...
Article
Normal automaticity of the sinatrial-node cells (SANC) is regulated by integrated molecular functions within a system of two clock-like oscillators: the sarcoplasmic reticulum, acting as a “Ca2+ clock,” rhythmically discharges diastolic local-Ca2+ releases (LCRs) beneath the cell surface membrane; LCRs activate an inward Na+/Ca2+ exchanger current...
Article
Full-text available
Pulmonary veins (PVs) are believed to be a crucial origin of atrial fibrillation. We recently reported that rat PV cardiomyocytes exhibit arrhythmogenic automaticity in response to norepinephrine. Herein, we further characterized the electrophysiological properties underlying the potential arrhythmogenicity of PV cardiomyocytes. Patch clamping stud...
Article
Full-text available
Heart rate (HR) of mammalian species changes postnatally, i.e., HR of large animals including humans decreases, while HR in small animals such as mice and rats increases. To clarify cellular mechanisms underlying the postnatal HR changes, we performed in vivo HR measurement and electrophysiological analysis on sinoatrial node (SAN) cells in mice. T...
Article
Full-text available
The ultra-short acting, selective β(1)-adrenergic antagonists landiolol and esmolol are widely used perioperatively; however, little is known about their acute direct actions on the heart. The current study utilized the Langendorff perfused heart system to measure changes in cardiac function and hemodynamics in response to each drug. Furthermore, e...
Article
Atrial fibrillation, the most common sustained arrhythmia, is believed to be triggered by ectopic electrical activity originating in the myocardial sleeves surrounding the pulmonary veins (PVs). It has been reported that myocardial sleeves have the potential to generate automaticity in response to norepinephrine. This study investigated the cellula...
Article
Full-text available
We carried out a screening of survival factors released from cells exposed to simulated ischaemia and reperfusion (sI/R) using the embryonic rat heart-derived cell line, H9c2 cells, and examined the physiological role of the identified factor. The culture medium supernatant of H9c2 cells exposed to sI/R was separated by column chromatography and th...
Article
A 58-year-old woman with rheumatoid arthritis (RA) developed fever, skin eruptions, leukocytopenia, and thrombocytopenia, 3 weeks after treatment with sulfasalazine. A skin biopsy showed hydropic degeneration of keratinocytes and lymphocytic infiltrate. A bone marrow aspiration demonstrated an increased number of macrophages with hemophagocytosis....

Questions

Question (1)
Question
Sometimes IP/MS identify protein-protein interactions. Is it possible to find exact regions where they are interacting?

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