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Sesena-Rubfiaro A, Prajapati NJ, Paolino L, Lou L, Cotayo D, Pandey P, Shaver M, Hutcheson J, Agarwal A, He J. Membrane Remodeling of Human-Engineered Cardiac Tissue by Chronic Electric Stimulation. ACS Biomater Sci Eng 2023; 9:1644-1655. [PMID: 36765460 PMCID: PMC10542861 DOI: 10.1021/acsbiomaterials.2c01370] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) show immature features, but these are improved by integration into 3D cardiac constructs. In addition, it has been demonstrated that physical manipulations such as electrical stimulation (ES) are highly effective in improving the maturation of human-engineered cardiac tissue (hECT) derived from hiPSC-CMs. Here, we continuously applied an ES in capacitive coupling configuration, which is below the pacing threshold, to millimeter-sized hECTs for 1-2 weeks. Meanwhile, the structural and functional developments of the hECTs were monitored and measured using an array of assays. Of particular note, a nanoscale imaging technique, scanning ion conductance microscopy (SICM), has been used to directly image membrane remodeling of CMs at different locations on the tissue surface. Periodic crest/valley patterns with a distance close to the sarcomere length appeared on the membrane of CMs near the edge of the tissue after ES, suggesting the enhanced transverse tubulation network. The SICM observation is also supported by the fluorescence images of the transverse tubulation network and α-actinin. Correspondingly, essential cardiac functions such as calcium handling and contraction force generation were improved. Our study provides evidence that chronic subthreshold ES can still improve the structural and functional developments of hECTs.
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Affiliation(s)
| | - Navin J. Prajapati
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Lia Paolino
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Lihua Lou
- Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174, USA
| | - Daniel Cotayo
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Popular Pandey
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Mohammed Shaver
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Joshua Hutcheson
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
- Biomolecular Science Institute, Florida International University, Miami FL 33199, USA
| | - Arvind Agarwal
- Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174, USA
| | - Jin He
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Science Institute, Florida International University, Miami FL 33199, USA
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Clark BC, Kopp A, Morey W, Djukic A. Serial follow-up of corrected QT interval in Rett syndrome. Dev Med Child Neurol 2020; 62:833-836. [PMID: 31797351 DOI: 10.1111/dmcn.14419] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/24/2019] [Indexed: 01/14/2023]
Abstract
AIM To identify factors associated with baseline prolonged corrected QT (QTc) and higher risk of QTc prolongation during follow-up in patients with Rett syndrome (RTT). METHOD A retrospective review of patients receiving an electrocardiogram (ECG) between June 2012 and June 2018 was performed. Age, methyl-CpG binding protein 2 gene (MECP2) mutation, RTT Severity Scale (RSSS) score, breathing abnormalities, seizure frequency, medications, and ECG parameters were collected. Prolonged QTc was defined as greater than or equal to 460ms. Comparisons at baseline and during follow-up were made. RESULTS In total, 129 unique patients (all female) had 349 ECGs. At baseline, 12 (9.3%) had a prolonged QTc (median 474ms, interquartile range 470-486ms) and were more likely to have moderate/severe breathing abnormalities (66.7% vs 24.8%; p=0.005) and take selective serotonin reuptake inhibitors (SSRIs) (41.7% vs 15.4%; p=0.04). There was no difference in age, RSSS score, seizures, or mutation. Twenty-six developed prolonged QTc during a median follow-up of 1 year 7 months (interquartile range 0-3y 6mo). QTc prolongation was associated with p.(Thr158Met) mutation versus the remaining six common mutations (hazard ratio 4.1, 95% confidence interval 1.4-12.0; p=0.01) but not with age, RSSS score, seizures, breathing abnormalities, or SSRIs. INTERPRETATION Breathing abnormalities and SSRIs were associated with baseline QTc prolongation and those with p.(Thr158Met) mutation were more likely to develop prolonged QTc over time. Identification of patients with prolonged QTc warrants increased clinical monitoring. WHAT THIS PAPER ADDS Breathing abnormalities and selective serotonin reuptake inhibitors are associated with prolonged baseline corrected QT (QTc). Development of QTc prolongation is associated with the p.(Thr158Met) mutation.
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Affiliation(s)
- Bradley C Clark
- Division of Cardiology, Children's Hospital at Montefiore, Bronx, NY, USA.,Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Adam Kopp
- Albert Einstein College of Medicine, Bronx, NY, USA
| | - Wenzhu Morey
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Aleksandra Djukic
- Albert Einstein College of Medicine, Bronx, NY, USA.,Rett Syndrome Center, Division of Neurology, Children's Hospital at Montefiore, Bronx, NY, USA
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Abstract
Electrocardiography (ECG) in rats is a widely applied experimental method in basic cardiovascular research. The technique of ECG recordings is simple; however, the interpretation of electrocardiographic parameters is challenging. This is because the analysis may be biased by experimental settings, such as the type of anesthesia, the strain or age of animals. Here, we aimed to review electrocardiographic parameters in rats, their normal range, as well as the effect of experimental settings on the parameters variation. Furthermore, differences and similarities between rat and human ECG are discussed in the context of translational cardiovascular research.
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Affiliation(s)
- P Konopelski
- Department of Experimental Physiology and Pathophysiology, Medical University of Warsaw, Warsaw, Poland.
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Mousa SA, Shaqura M, Schäper J, Treskatsch S, Habazettl H, Schäfer M, Abdul-Khaliq H. Developmental expression of δ-opioid receptors during maturation of the parasympathetic, sympathetic, and sensory innervations of the neonatal heart: early targets for opioid regulation of autonomic control. J Comp Neurol 2011; 519:957-71. [PMID: 21280046 DOI: 10.1002/cne.22560] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Evidence is accumulating regarding the local opioid regulation of heart function. However, the exact anatomical location of δ-opioid receptors (DORs) and expression during maturation of the autonomic and sensory innervations of the neonatal heart is unknown. Therefore, we aimed to characterize target sites for opioids in neonatal rat heart intracardiac ganglia at postnatal day (P)1, P7 and adulthood (P56-P84). Rat heart atria were subjected to reverse-transcriptase polymerase chain reaction, Western blot, radioligand binding, and immunofluorescence confocal analysis of DORs with the neuronal markers vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), and substance P (SP). Our results demonstrated DOR mRNA, protein, and binding sites that gradually increased from P1 toward adulthood. Immunofluorescence confocal microscopy showed DOR co-localized with VAChT in large-diameter principal neurons, TH-immunoreactive (IR) small intensely fluorescent (SIF) catecholaminergic cells, and CGRP- or SP-IR afferent nerve terminals arborizing within intracardiac ganglia and atrial myocardium. Co-expression of DOR with VAChT-IR neurons was observed from the first day of birth (P1). In contrast, DORs on TH-IR SIF cells or CGRP-IR fibers were not observed in intracardiac ganglia of P1, but rather in P7 rats. The density of nerve fibers in atrial myocardium co-expressing DORs with different neuronal markers increased from neonatal age toward adulthood. In summary, the enhanced DOR expression parallel to the maturation of cardiac parasympathetic, sympathetic, and sensory innervation of the heart suggests that the cardiac opioid system is an important regulator of neonatal and adult heart function through the autonomic nervous system.
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Affiliation(s)
- Shaaban A Mousa
- Department of Anesthesiology and Intensive Care Medicine, Charité University Berlin, Campus Virchow-Klinikum, Berlin, Germany.
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PRIORI SILVIAG, CORR PETERB. The Importance of α-Adrenergic Stimulation of Cardiac Tissue and its Contribution to Arrhythmogenesis During Ischemia. J Cardiovasc Electrophysiol 2008. [DOI: 10.1111/j.1540-8167.1990.tb01087.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bru-Mercier G, Deroubaix E, Rousseau D, Coulombe A, Renaud JF. Depressed transient outward potassium current density in catecholamine-depleted rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2002; 282:H1237-47. [PMID: 11893557 DOI: 10.1152/ajpheart.00180.2001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of catecholamine depletion (induced by prior treatment with reserpine) was studied in Wistar rat ventricular myocytes using whole cell voltage-clamp methods. Two calcium-independent outward currents, the transient outward potassium current (I(to)) and the sustained outward potassium current (I(sus)), were measured. Reserpine treatment decreased tissue norepinephrine content by 97%. Action potential duration in the isolated perfused heart was significantly increased in reserpine-treated hearts. In isolated ventricular myocytes, I(to) density was decreased by 49% in reserpine-treated rats. This treatment had no effect on I(sus). The I(to) steady-state inactivation-voltage relationship and recovery from inactivation remained unchanged, whereas the conductance-voltage activation curve for reserpine-treated rats was significantly shifted (6.7 mV) toward negative potentials. The incubation of myocytes with 10 microM norepinephrine for 7-10 h restored I(to), an effect that was abolished by the presence of actinomycin D. Norepinephrine (0.5 microM) had no effect on I(to). However, in the presence of both 0.5 microM norepinephrine and neuropeptide Y (0.1 microM), I(to) density was restored to its control value. These results suggest that the sympathetic nervous system is involved in I(to) regulation. Sympathetic norepinephrine depletion decreased the number of functional channels via an effect on the alpha-adrenergic cascade and norepinephrine is able to restore expression of I(to) channels.
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Affiliation(s)
- Gilles Bru-Mercier
- Département de Physiologie Cardiovasculaire et Thymique, Centre National de la Recherche Scientifique, and Hôpital Marie Lannelongue, 92350 Le Plessis Robinson, France
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Horackova M, Slavikova J, Byczko Z. Postnatal development of the rat intrinsic cardiac nervous system: a confocal laser scanning microscopy study in whole-mount atria. Tissue Cell 2000; 32:377-88. [PMID: 11201277 DOI: 10.1054/tice.2000.0126] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We used confocal laser scanning microscopy and fluorescent immunohistochemistry to study the developmental pattern and distribution of specific neuronal phenotypes within the intrinsic cardiac nervous system in whole-mount atrial preparations from newborn to 5 week old rats. Individual ganglia and neuronal cell bodies were localized by means of two general neuronal markers: protein gene product 9.5 (PGP) and microtubule-associated protein two (MAP). In rats < or =2 weeks old there were two main subpopulations of intrinsic neurons located in the intraatrial septum and around the origin of the superior vena cava. The more abundant was a population of strongly tyrosine hydroxylase (TH) immunoreactive (IR) neurons (10-40 microm in diameter) most of which were also PGP-IR. The second, less numerous (approximately 60-70% than the TH-IR group) type of neurons exhibited ChAT-IR which colocalized with MAP-IR. Towards the end of the second postnatal week and during the third, the ganglia containing these neurons became more numerous and their localization also included tissues around the origins of the inferior vena cava and the pulmonary veins, as well as both atrial walls close to the AV junction. During the second and third postnatal weeks, when the extrinsic innervation of the adrenergic and cholinergic phenotypes largely increases, the intrinsic innervation also changed greatly, and around the 21st postnatal day it appeared to acquire mature characteristics. The TH-IR neurons changed their characteristics and formed two types of ganglia. The larger ganglia containing large cells (20-40 microm in diameter) expressed TH-IR mostly close to their inner body surface (approximately 80-90% of identified neurons). Most of these neurons also expressed neuropeptide Y (NPY)-IR, specifically around their nuclei. The second type of small strongly TH-IR neurons (approximately 10% of all identified neurons) were contained in smaller groups (20-50 cells) which were usually embedded into much larger ganglia (100-400 cells), containing large (20-50 microm) neurons. Unlike all other intrinsic neurons, these small TH-IR cells did not exhibit any PGP-IR or MAP-IR. The number of ChAT-IR neurons increased at this stage, reaching approximately 90% of the neurons identified by the general neuronal markers. These neurons were surrounded by a rich network of cholinergic varicose nerve fibers, some of which were likely of an extrinsic origin. We have also identified relatively small ganglia expressing immunoreactivity to vasoactive intestinal polypeptide (VIP), and to substance P (SP). The presented data indicate that the phenotypes of intrinsic neurons in the rat heart change greatly during the first month of postnatal development. This may be at least partially related to the development and maturation of functional extrinsic nervous control of the heart.
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Affiliation(s)
- M Horackova
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhouise University, Halifax, Nova Scotia, Canada.
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Qu J, Cohen IS, Robinson RB. Sympathetic innervation alters activation of pacemaker current (If) in rat ventricle. J Physiol 2000; 526 Pt 3:561-9. [PMID: 10922008 PMCID: PMC2270045 DOI: 10.1111/j.1469-7793.2000.t01-1-00561.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Pacemaker current (If) exists in both neonatal and adult ventricles, but activates at more negative voltages in the adult. This study uses whole-cell patch clamp to investigate the factors that may contribute to the maturational shift of If, comparing neonatal rat ventricular myocytes that were cultured for 4-6 days either alone, in co-culture with sympathetic nerves, or with neurotransmitters chronically present in culture. If recorded from nerve-muscle co-cultures had a significantly more negative and shallower activation-voltage relation than that from control muscle cultures, which was reflected in the midpoint potential (V50) and slope factor (K) of activation. This effect of innervation was prevented by the sustained presence in the culture of the alpha1-adrenergic antagonist prazosin (Pz) at 10(-7) M. In parallel experiments, myocytes treated with noradrenaline (NA) at 10(-7) M or neuropeptide Y (NPY) at 10(-7) M during culture had the same If activation as control cells, but cells treated with NA and NPY together had a significantly more negative and shallower activation curve. Maximum conductance and reversal potential were unchanged. The effect of chronic exposure to NA + NPY was prevented by the sustained presence of either Pz or the NPY Y2 selective antagonist T4-[NPY(33-36)]4 (3.5 x 10(-7) M) in the culture, indicating a requirement for both alpha1-adrenergic and NPY Y2 activation. Substituting NA with the alpha1A-adrenergic selective agonist A61603 (5(-10) x 10(-9) M), in the presence of NPY, did not alter If, suggesting the involvement of alpha1B- rather than alpha1A-adrenoceptors. Further, sequential exposure to NPY followed by NA was effective in reproducing the action of chronic simultaneous exposure to these agonists, but sequential exposure to NA followed by NPY was ineffective. The results are consistent with past studies indicating that NPY affects the functional expression of the alpha1B-adrenergic cascade and suggest that sympathetic innervation induces a negative shift of If in ventricle via a combined action at alpha1B-adrenergic and NPY Y2 receptors. This effect of innervation probably contributes to the developmental maturation of If activation.
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Affiliation(s)
- J Qu
- Department of Pharmacology, Columbia University, New York and Institute of Molecular Cardiology, Department of Physiology & Biophysics, SUNY at Stony Brook, NY, USA
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Varma DR, Deng XF. Cardiovascular α1-adrenoceptor subtypes: functions and signaling. Can J Physiol Pharmacol 2000. [DOI: 10.1139/y99-142] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
α1-Adrenoceptors (α1AR) are G protein-coupled receptors and include α1A, α1B, and α1D subtypes corresponding to cloned α1a, α1b, and α1d, respectively. α1AR mediate several cardiovascular actions of sympathomimetic amines such as vasoconstriction and cardiac inotropy, hypertrophy, metabolism, and remodeling. α1AR subtypes are products of separate genes and differ in structure, G protein-coupling, tissue distribution, signaling, regulation, and functions. Both α1AAR and α1BAR mediate positive inotropic responses. On the other hand, cardiac hypertrophy is primarily mediated by α1AAR. The only demonstrated major function of α1DAR is vasoconstriction. α1AR are coupled to phospholipase C, phospholipase D, and phospholipase A2; they increase intracellular Ca2+ and myofibrillar sensitivity to Ca2+ and cause translocation of specific phosphokinase C isoforms to the particulate fraction. Cardiac hypertrophic responses to α1AR agonists might involve activation of phosphokinase C and mitogen-activated protein kinase via Gq. α1AR subtypes might interact with each other and with other receptors and signaling mechanisms.Key words: cardiac hypertrophy, inotropic responses, central α1-adrenoreceptors, arrythmias.
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Schwartz PJ, Stramba-Badiale M, Segantini A, Austoni P, Bosi G, Giorgetti R, Grancini F, Marni ED, Perticone F, Rosti D, Salice P. Prolongation of the QT interval and the sudden infant death syndrome. N Engl J Med 1998; 338:1709-14. [PMID: 9624190 DOI: 10.1056/nejm199806113382401] [Citation(s) in RCA: 529] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The sudden infant death syndrome (SIDS) is multifactorial in origin, but its causes remain unknown. We previously proposed that prolongation of the QT interval on the electrocardiogram, possibly resulting from a developmental abnormality in cardiac sympathetic innervation, may increase the risk of life-threatening ventricular arrhythmias and contribute to this devastating disorder. We prospectively tested this hypothesis. METHODS Between 1976 and 1994, we recorded electrocardiograms on the third or fourth day of life in 34,442 newborns and followed them prospectively for one year. The QT interval was analyzed with and without correction for the heart rate. RESULTS One-year follow-up data were available for 33,034 of the infants. There were 34 deaths, of which 24 were due to SIDS. The infants who died of SIDS had a longer corrected QT interval (QTc) than did the survivors (mean [+/-SD], 435+/-45 vs. 400+/-20 msec, P<0.01) and the infants who died from causes other than SIDS (393+/-24 msec, P<0.05). Moreover, 12 of the 24 SIDS victims but none of the other infants had a prolonged QTc (defined as a QTc greater than 440 msec). When the absolute QT interval was determined for similar cardiac-cycle lengths, it was found that 12 of the 24 infants who died of SIDS had a QT value exceeding the 97.5th percentile for the study group as a whole. The odds ratio for SIDS in infants with a prolonged QTc was 41.3 (95 percent confidence interval, 17.3 to 98.4). CONCLUSIONS Prolongation of the QT interval in the first week of life is strongly associated with SIDS. Neonatal electrocardiographic screening may permit the early identification of a substantial percentage of infants at risk for SIDS, and the institution of preventive measures may therefore be possible.
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Affiliation(s)
- P J Schwartz
- Department of Cardiology, Policlinico San Matteo Istituto di Ricovero e Cura a Carattene Scientifico, University of Pavia, Italy
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Sun LS, Rybin VO, Steinberg SF, Robinson RB. Characterization of the alpha1-adrenergic chronotropic response in neuropeptide Y-treated cardiomyocytes. Eur J Pharmacol 1998; 349:377-81. [PMID: 9671120 DOI: 10.1016/s0014-2999(98)00311-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The cardiac alpha1-adrenergic chronotropic response changes from stimulatory to inhibitory post-natally. The mature inhibitory response is mediated by the alpha1B-adrenoceptor and a pertussis toxin sensitive G protein. In vivo and in vitro studies identify sympathetic innervation as critical for the maturation of this inhibitory response. Additional experiments in a culture model indicate the effect of innervation is dependent on neurally released neuropeptide Y. The present study establishes that the individual signaling elements in the neuropeptide Y induced alpha1-adrenergic cascade are the same as those appearing during normal in vivo development. In addition, the data demonstrate that the effect of neuropeptide Y does not result from activation of the putative cardiac Y3 neuropeptide Y receptor subtype, since it is reproduced by the peptide fragment neuropeptide Y-(13-36) but not by [Leu31, Pro34]neuropeptide Y.
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Affiliation(s)
- L S Sun
- Department of Anesthesiology, Columbia University, New York, NY 10032, USA
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Liu QY, Rosen MR, McKinnon D, Robinson RB. Sympathetic innervation modulates repolarizing K+ currents in rat epicardial myocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:H915-22. [PMID: 9530204 DOI: 10.1152/ajpheart.1998.274.3.h915] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During postnatal development, sympathetic innervation of the heart evolves, and repolarization accelerates. Our goal in this study was to test whether sympathetic innervation modulates the ion channels that regulate repolarization. We studied action potentials and repolarizing K+ currents in epicardial myocytes from rats in which sympathetic innervation was accelerated or delayed, respectively, by subcutaneous injection of nerve growth factor (NGF) or NGF antibody (Ab) for the first 15 days of life. A placebo group was included as well. Action potential duration (APD) to 90% repolarization was greater in the Ab (158 +/- 18 ms)-treated than the NGF (106 +/- 10 ms)-treated animals (P < 0.05); the APD at 90% repolarization for the placebo group was intermediate (125 +/- 30 ms). The transient outward (Ito) and inward rectifier (IK1) K+ currents were recorded in freshly dissociated cells using the whole cell patch-clamp technique. Ito was decreased in density at potentials positive to +40 mV in Ab-treated rats when compared with rats treated with NGF (P < 0.05). In addition, the inactivation curve of Ito in Ab-treated rats was shifted 13 mV positive to that of NGF-treated rats. IK1 also decreased in the Ab-treated group compared with the NGF group in the potential ranges of -100 to -90 mV (P < 0.05). However, the channel transcript abundance (RNA) in NGF-, Ab-, or placebo-treated rat hearts did not differ. Our results suggest that sympathetic innervation contributes to the developmental differences in K+ currents and APD postnatally in the rat.
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Affiliation(s)
- Q Y Liu
- Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York 10032, USA
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Taguchi N, Nishikawa T, Inomata S, Taguchi M, Yamashita S, Naito H. Hemodynamic Effects of Intravenous Ephedrine in Infants and Children Anesthetized with Halothane and Nitrous Oxide. Anesth Analg 1996. [DOI: 10.1213/00000539-199603000-00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Taguchi N, Nishikawa T, Inomata S, Taguchi M, Yamashita S, Naito H. Hemodynamic effects of intravenous ephedrine in infants and children anesthetized with halothane and nitrous oxide. Anesth Analg 1996; 82:568-73. [PMID: 8623963 DOI: 10.1097/00000539-199603000-00025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The aim of this study was to evaluate the effect of age on the hemodynamic responses to intravenous (IV) ephedrine in pediatric patients anesthetized with halothane, nitrous oxide, and oxygen. One hundred ten pediatric patients, ranging in age from 0.1 to 15 yr, were assigned to receive 0.1 mg/kg (n = 55) or 0.2 mg/kg (n = 55) IV ephedrine. General anesthesia was maintained with 1.0 minimum alveolar anesthetic concentration (MAC) of halothane and 67% nitrous oxide in oxygen after tracheal intubation. Measurements of arterial blood pressure and heart rate were made at 1-min intervals for 10 min after ephedrine 0.1 or 0.2 mg/kg was injected IV as a bolus. Significant correlations were noted between age and changes in mean blood pressure (r = 0.37, P < 0.01 for the subjects receiving ephedrine 0.1 mg/kg; r = 0.63, P < 0.001 for the subjects receiving ephedrine 0.2 mg/kg), but not between age and changes in heart rate. The present results indicate that age correlates with the pressor but not the chronotropic effects of ephedrine in pediatric patients anesthetized with 1 MAC halothane and nitrous oxide.
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Affiliation(s)
- N Taguchi
- Department of Anesthesiology, University of Tsukuba, Ibaraki, Japan
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[22] G protein dependence of α1-adrenergic receptor subtype action in cardiac myocytes. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1043-9471(96)80058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Tanaka H, Manita S, Matsuda T, Adachi M, Shigenobu K. Sustained negative inotropism mediated by alpha-adrenoceptors in adult mouse myocardia: developmental conversion from positive response in the neonate. Br J Pharmacol 1995; 114:673-7. [PMID: 7735694 PMCID: PMC1510019 DOI: 10.1111/j.1476-5381.1995.tb17191.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. Inotropic responses to alpha-adrenoceptor stimulation and the effects of antagonists were examined in isolated ventricular preparations from neonatal and adult mice. 2. Phenylephrine, in the presence of propranolol, produced positive inotropic responses in neonates up to 1 week after birth, while it produced negative inotropic responses in mice older than 3 weeks. 3. Both positive and negative responses to phenylephrine in neonates and adults, respectively, were antagonized by prazosin, WB4101 (2-([2,6-dimethoxyphenoxyethyl]aminomethyl)-1,4-benzodioxane) and 5-methylurapidil, but not by atropine, yohimbine or chlorethylclonidine. 4. Noradrenaline (NA) produced positive inotropic responses both in the neonate and adult; the responses were observed in a lower concentration-range in the neonate than in the adult. WB4101 produced a significant leftward shift of the concentration-response curve for noradrenaline in adult preparations while only a slight rightward shift was observed in the neonate. 5. Our results demonstrate the presence of alpha-adrenoceptor-mediated inotropic responses in the mouse ventricular myocardia. The response to phenylephrine changes from a positive to a negative effect during postnatal development. The responses are mediated by alpha 1-adrenoceptors, and modulate the overall inotropic response to NA in the adult.
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Affiliation(s)
- H Tanaka
- Department of Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan
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Affiliation(s)
- S F Steinberg
- Department of Medicine, Columbia University, New York, NY 10032, USA
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Antzelevitch C, Sicouri S. Clinical relevance of cardiac arrhythmias generated by afterdepolarizations. Role of M cells in the generation of U waves, triggered activity and torsade de pointes. J Am Coll Cardiol 1994; 23:259-77. [PMID: 8277090 DOI: 10.1016/0735-1097(94)90529-0] [Citation(s) in RCA: 356] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent findings point to an important heterogeneity in the electrical behavior of cells spanning the ventricular wall as well as important differences in the response of the various cell types to cardioactive drugs and pathophysiologic states. These observations have permitted a fine tuning and, in some cases, a reevaluation of basic concepts of arrhythmia mechanisms. This brief review examines the implications of some of these new findings within the scope of what is already known about early and delayed afterdepolarizations and triggered activity and discusses the possible relevance of these mechanisms to clinical arrhythmias.
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Affiliation(s)
- C Antzelevitch
- Masonic Medical Research Laboratory, Utica, New York 13504
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Nyquist-Battie C, Cochran PK, Sands SA, Chronwall BM. Development of neuropeptide Y and tyrosine hydroxylase immunoreactive innervation in postnatal rat heart. Peptides 1994; 15:1461-9. [PMID: 7700848 DOI: 10.1016/0196-9781(94)90124-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuropeptide Y (NPY), immunoreactive (IR), and tyrosine hydroxylase (TH)-IR nerve fibers were scarce at birth in rat heart, but increased rapidly during the first 2 postnatal weeks, reaching approximately adult levels by the third week. The sequence of development was: interatrial septum and atrial wall, free ventricular wall starting from the epicardium, and finally the atrial appendages and interventricular septum. In ventricles and atrial appendages both fiber types developed similarly. In interatrial septum and atrial walls more NPY-IR than TH-IR fibers were evident, and NPY-IR, but not TH-IR, neurons were detected in intrinsic ganglia. Double-label immunohistochemistry provided further evidence that NPY is located in ventricular and atrial noradrenergic nerves, but is also located in nonnoradrenergic nerves in atria.
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Affiliation(s)
- C Nyquist-Battie
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City 64108
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García-Calvo R, Chorro FJ, Sendra M, Alberola A, Sanchis J, Navarro J, Valentín V, López-Merino V, Such L. The effects of selective stellate ganglion manipulation on ventricular refractoriness and excitability. Pacing Clin Electrophysiol 1992; 15:1492-503. [PMID: 1383961 DOI: 10.1111/j.1540-8159.1992.tb02923.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effects of selective stellate ganglion stimulation or stellectomy on ventricular excitability were studied in 30 open chest mongrel dogs anesthetized with alpha-chloralose. The effective refractory period (ERP) and strength interval curves (stimulus intensity [S2] = twice the diastolic threshold [ERP], and 2, 3, 5, 7, and 14 mA) were determined using bipolar epicardial electrodes placed in the mid-anterior wall of the right ventricle (RV) and the mid-posterolateral wall of the left ventricle (LV) during left stellate ganglion stimulation (LSGSt, n = 8) or right stellate ganglion stimulation (RSGSt, n = 8), or after left stellectomy (LSGEx, n = 7) or right stellectomy (RSGEx, n = 7). LSGEx prolonged ERP-LV (172 +/- 9 vs 167 +/- 8 msec, P < 0.05) and ERP-RV (163 +/- 10 vs 158 +/- 14 msec, P < 0.05). RSGEx prolonged ERP-LV (168 +/- 17 vs 162 +/- 15 msec, P < 0.01) and ERP-RV (166 +/- 14 vs 160 +/- 13 msec, P < 0.01), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. LSGSt decreased ERP-LV (157 +/- 11 vs 163 +/- 12 msec, P < 0.01) and ERP-RV (147 +/- 18 vs 157 +/- 17 msec, P < 0.05), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. RSGSt did not significantly decreased ERP-LV (152 +/- 11 vs 156 +/- 9 msec); however, it significantly shortened the times of the strength interval curves obtained for S2 intensities of 2 and 7 mA in the LV, and shortened ERP-RV (139 +/- 10 vs 145 +/- 7 msec, P < 0.01) and the times of the strength interval curve for S2 intensities of 2, 3, and 5 mA in the RV. A significant interaction (MANOVA test) was observed between the ventricle studied and the ganglion stimulated for S2 intensities of 2 and 3 mA, and between the effect of stimulation and the ganglion stimulated for S2 intensities of 3 and 14 mA. To conclude, selective stellectomy prolonged epicardial ventricular refractoriness in both the mid-anterior wall of the RV and the mid-posterolateral wall of the LV; the magnitude of the epicardial excitability variations in both areas was different during selective stellate ganglion stimulation.
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Affiliation(s)
- R García-Calvo
- Department of Medicine, Faculty of Medicine, University of Valencia, Spain
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25
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ROSEN MICHAELR, JECK CYNTHIAD, STEINBERG SUSANF. Autonomic Modulation of Cellular Repolarization and of the Electrocardiographic QT Interval. J Cardiovasc Electrophysiol 1992. [DOI: 10.1111/j.1540-8167.1992.tb00991.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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MALFATTO GABRIELLA, ROSEN MICHAELR, FORESTI AUGUSTO, SCHWARTZ PETERJ. Idiopathic Long QT Syndrome Exacerbated by Beta-Adrenergic Blockade and Responsive to Left Cardiac Sympathetic Denervation: Implications Regarding Electrophysiologic Substrate and Adrenergic Modulation. J Cardiovasc Electrophysiol 1992. [DOI: 10.1111/j.1540-8167.1992.tb00975.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Schwartz PJ, Bonazzi O, Locati E, Napolitano C, Sala S. Pathogenesis and Therapy of the Idiopathic Long QT Syndrome. Ann N Y Acad Sci 1992; 644:112-41. [PMID: 1348609 DOI: 10.1111/j.1749-6632.1992.tb31007.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P J Schwartz
- Dipartimento di Medicina, Università di Pavia, Italy
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29
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Affiliation(s)
- G Malfatto
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York 10032
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30
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ZIPES DOUGLASP. Arrhythmogenic Role of Autonomic Innervation During Ischemia/Infarction and the Long QT Syndrome. J Cardiovasc Electrophysiol 1991. [DOI: 10.1111/j.1540-8167.1991.tb01377.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Corr PB, Yamada KA, DaTorre SD. Modulation of alpha-adrenergic receptors and their intracellular coupling in the ischemic heart. Basic Res Cardiol 1991; 85 Suppl 1:31-45. [PMID: 1965402 DOI: 10.1007/978-3-662-11038-6_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The alpha 1-adrenergic receptor exists as at least two distinct subtypes, alpha 1a and alpha 1b. Based on hydrophobic exclusion studies and limited proteolysis of the cloned receptor, it appears to possess characteristics analogous to other membrane-bound receptors including seven membrane spanning domains, three extracellular, and three intracellular loops, with extensive glycosylation near the extracellular amino terminus. Although the receptor is coupled to phospholipase C in cardiac myocytes, with activation resulting in the production of inositol trisphosphate (IP3) and diacylglycerol, recent findings suggest that the receptor may also be linked to phospholipase A2, phospholipase D, and cyclic nucleotide phosphodiesterase. The alpha 1-adrenergic receptor has been shown to increase in response to myocardial ischemia in a number of different species and to mediate not only positive inotropic effects, but also to contribute substantially to arrhythmogenesis. The increase in alpha 1-adrenergic receptors can also occur in isolated adult ventricular myocytes in response to hypoxia, a mechanism which appears to be secondary to the sarcolemmal accumulation of long-chain acylcarnitines. This increase in alpha 1-adrenergic receptors in hypoxic myocytes is also linked to an enhanced increase in IP3 in response to receptor stimulation. These and other findings obtained in vivo during ischemia suggest that alpha 1-adrenergic mechanisms can become prominent in myocardium under pathophysiologic conditions in which a depressed contractile state exists and may therefore serve as a secondary inotropic system. However, the arrhythmogenic effects of stimulation of the alpha 1-adrenergic receptor in the ischemic heart in man may contribute substantially to arrhythmogenesis and, thereby, to the incidence of sudden cardiac death.
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Affiliation(s)
- P B Corr
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
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Malfatto G, Sun LS, Rosen TS. Bradycardia and long QT interval in neonate rats with delayed cardiac sympathetic innervation. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1990; 30 Suppl:S101-2. [PMID: 2212470 DOI: 10.1016/0165-1838(90)90110-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- G Malfatto
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, NY
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