Name: dual-dye optical mapping of hearts from ryr2r2474s knock-in mice of catecholaminergic polymorphic ventricular tachycardia
Uploaded: 2023-12-22T12:20:00
Description: Watch this Scientific Journal Video about Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia at JoVE.com

This study is supported by the National Natural Science Foundation of China (81700308 to XO and 31871181 to ML, and 82270334 to XT), Sichuan Province Science and Technology Support Program (CN) (2021YJ0206 to XO, 23ZYZYTS0433, and 2022YFS0607 to XT, and 2022NSFSC1602 to TC) and State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University) (CMEMR2017-B08 to XO), MRC (G10031871181 to ML02647, G1002082, ML), BHF (PG/14/80/31106, PG/16/67/32340, PG/12/21/29473, PG/11/59/29004 ML), BHF CRE at Oxford (ML) grants.

Male 10&#160;to 14-week-old wild-type mice or RyR2-R2474S/+ mice (C57BL/6 background) weighing 20-25 g are used for the experiments. All procedures have been approved by the animal care and use committee of Southwest Medical University, Sichuan, China (approval NO:20160930) in conformity with the national guidelines under which the institution operates.
1. Preparation
<ol>
	<li>Stock solutions
	<ol>
		<li>Blebbistatin stock solution: Add 1 mL of 100% dimethyl sulfox...

<ol>
	<li>Priori, S. G., Chen, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inherited+dysfunction+of+sarcoplasmic+reticulum+Ca2++handling+and+arrhythmogenesis.">Inherited dysfunction of sarcoplasmic reticulum Ca2+ handling and arrhythmogenesis.</a> Circulation Research. 108 (7), 871-883 (2011).</li><li>Goddard, C. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+consequences+of+the+P2328S+mutation+in+the+ryanodine+receptor+(RyR2)+gene+in+genetically+modified+murine+hearts.">Physiological consequences of the P2328S mutation in the ryanodine receptor (RyR2) gene in genetically modified murine hearts.</a> Acta Physiologica. 194 (2), 123-140 (2008).</li><li>Sabir, I. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alternans+in+genetically+modified+langendorff-perfused+murine+hearts+modeling+catecholaminergic+polymorphic+ventricular+tachycardia.">Alternans in genetically modified langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia.</a> Frontiers in Physiology. 1, 126 (2010).</li><li>Zhang, Y., Matthews, G. D., Lei, M., Huang, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+Ca2++homeostasis,+atrial+arrhythmogenesis,+and+sinus+node+dysfunction+in+murine+hearts+modeling+RyR2+modification.">Abnormal Ca2+ homeostasis, atrial arrhythmogenesis, and sinus node dysfunction in murine hearts modeling RyR2 modification.</a> Frontiers in Physiology. 4, 150 (2013).</li><li>Leenhardt, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catecholaminergic+polymorphic+ventricular+tachycardia+in+children.+A+7-year+follow-up+of+21+patients.">Catecholaminergic polymorphic ventricular tachycardia in children. A 7-year follow-up of 21 patients.</a> Circulation. 91 (5), 1512-1519 (1995).</li><li>Priori, S. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+in+the+cardiac+ryanodine+receptor+gene+(hRyR2)+underlie+catecholaminergic+polymorphic+ventricular+tachycardia.">Mutations in the cardiac ryanodine receptor gene (hRyR2) underlie catecholaminergic polymorphic ventricular tachycardia.</a> Circulation. 103 (2), 196-200 (2001).</li><li>Wehrens, X. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FKBP12.6+deficiency+and+defective+calcium+release+channel+(ryanodine+receptor)+function+linked+to+exercise-induced+sudden+cardiac+death.">FKBP12.6 deficiency and defective calcium release channel (ryanodine receptor) function linked to exercise-induced sudden cardiac death.</a> Cell. 113 (7), 829-840 (2003).</li><li>Novak, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+abnormalities+in+iPSC-derived+cardiomyocytes+generated+from+CPVT1+and+CPVT2+patients+carrying+ryanodine+or+calsequestrin+mutations.">Functional abnormalities in iPSC-derived cardiomyocytes generated from CPVT1 and CPVT2 patients carrying ryanodine or calsequestrin mutations.</a> Journal of Cellular and Molecular Medicine. 19 (8), 2006-2018 (2015).</li><li>Napolitano, C., Mazzanti, A., Bloise, R., Priori, S. G., Adam, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CACNA1C-related+disorders.">CACNA1C-related disorders.</a> GeneReviews. , (1993).</li><li>Makita, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+calmodulin+mutations+associated+with+congenital+arrhythmia+susceptibility.">Novel calmodulin mutations associated with congenital arrhythmia susceptibility.</a> Circulation. Cardiovascular Genetics. 7 (4), 466-474 (2014).</li><li>Gomez-Hurtado, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+CPVT-associated+calmodulin+mutation+in+CALM3+(CALM3-A103V)+activates+arrhythmogenic+Ca+waves+and+sparks.">Novel CPVT-associated calmodulin mutation in CALM3 (CALM3-A103V) activates arrhythmogenic Ca waves and sparks.</a> Circulation, Arrhythmia and Electrophysiology. 9 (8), (2016).</li><li>Wleklinski, M. J., Kannankeril, P. J., Knollmann, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+and+tissue+mechanisms+of+catecholaminergic+polymorphic+ventricular+tachycardia.">Molecular and tissue mechanisms of catecholaminergic polymorphic ventricular tachycardia.</a> Journal of Physiology. 598 (14), 2817-2834 (2020).</li><li>Neco, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paradoxical+effect+of+increased+diastolic+Ca2++release+and+decreased+sinoatrial+node+activity+in+a+mouse+model+of+catecholaminergic+polymorphic+ventricular+tachycardia.">Paradoxical effect of increased diastolic Ca2+ release and decreased sinoatrial node activity in a mouse model of catecholaminergic polymorphic ventricular tachycardia.</a> Circulation. 126 (4), 392-401 (2012).</li><li>Bogdanov, K. Y., Vinogradova, T. M., Lakatta, E. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sinoatrial+nodal+cell+ryanodine+receptor+and+Na(+)-Ca(2+)+exchanger:+molecular+partners+in+pacemaker+regulation.">Sinoatrial nodal cell ryanodine receptor and Na(+)-Ca(2+) exchanger: molecular partners in pacemaker regulation.</a> Circulation Research. 88 (12), 1254-1258 (2001).</li><li>O'Shea, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ElectroMap:+High-throughput+open-source+software+for+analysis+and+mapping+of+cardiac+electrophysiology.">ElectroMap: High-throughput open-source software for analysis and mapping of cardiac electrophysiology.</a> Scientific Reports. 9 (1), 1389 (2019).</li><li>O'Shea, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+analysis+of+optical+mapping+data+using+ElectroMap.">High-throughput analysis of optical mapping data using ElectroMap.</a> Journal of Visualized Experiments: JoVE. (148), e59663 (2019).</li><li>Choi, B. R., Salama, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+maps+of+optical+action+potentials+and+calcium+transients+in+guinea-pig+hearts:+mechanisms+underlying+concordant+alternans.">Simultaneous maps of optical action potentials and calcium transients in guinea-pig hearts: mechanisms underlying concordant alternans.</a> Journal of Physiology. 529, 171-188 (2000).</li><li>Rybashlykov, D., Brennan, J., Lin, Z., Efimov, I. R., Syunyaev, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Open-source+low-cost+cardiac+optical+mapping+system.">Open-source low-cost cardiac optical mapping system.</a> PLoS One. 17 (3), 0259174 (2022).</li><li>Lucas-Lopez, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absolute+stereochemical+assignment+and+fluorescence+tuning+of+the+small+molecule+tool,+(-)-blebbistatin.">Absolute stereochemical assignment and fluorescence tuning of the small molecule tool, (-)-blebbistatin.</a> European Journal of Organic Chemistry. 2005 (9), 1736-1740 (2005).</li><li>Ponsaerts, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+myosin+II+ATPase+inhibitor+blebbistatin+prevents+thrombin-induced+inhibition+of+intercellular+calcium+wave+propagation+in+corneal+endothelial+cells.">The myosin II ATPase inhibitor blebbistatin prevents thrombin-induced inhibition of intercellular calcium wave propagation in corneal endothelial cells.</a> Investigative Ophthalmology &amp; Visual Science. 49 (11), 4816-4827 (2008).</li><li>Jou, C., Spitzer, K., Tristani-Firouzi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blebbistatin+effectively+uncouples+the+excitation-contraction+process+in+zebrafish+embryonic+heart.">Blebbistatin effectively uncouples the excitation-contraction process in zebrafish embryonic heart.</a> Cellular Physiology &amp; Biochemistry. 25 (4-5), 419-424 (2010).</li><li>Brack, K. E., Narang, R., Winter, J., Ng, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanical+uncoupler+blebbistatin+is+associated+with+significant+electrophysiological+effects+in+the+isolated+rabbit+heart.">The mechanical uncoupler blebbistatin is associated with significant electrophysiological effects in the isolated rabbit heart.</a> Experimental Physiology. 98 (5), 1009-1027 (2013).</li><li>O'Shea, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+analysis+of+optical+mapping+data+using+ElectroMap.">High-throughput analysis of optical mapping data using ElectroMap.</a> Journal of Visualized Experiments: JoVE. (148), e59663 (2019).</li><li>He, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+dataset+of+dual+calcium+and+voltage+optical+mapping+in+healthy+and+hypertrophied+murine+hearts.">A dataset of dual calcium and voltage optical mapping in healthy and hypertrophied murine hearts.</a> Scientific Data. 8 (1), 314 (2021).</li><li>Lei, M., Huang, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+arrhythmogenesis:+a+tale+of+two+clocks.">Cardiac arrhythmogenesis: a tale of two clocks.</a> Cardiovascular Research. 116 (14), e205-e209 (2020).</li><li>Mal Baudot, ., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concomitant+genetic+ablation+of+L-type+Cav1.3+&#945;1D+and+T-type+Cav3.1+&#945;1G+Ca2++channels+disrupts+heart+automaticity.">Concomitant genetic ablation of L-type Cav1.3 &#945;1D and T-type Cav3.1 &#945;1G Ca2+ channels disrupts heart automaticity.</a> Scientific Reports. 10 (1), 18906 (2020).</li><li>Dai, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ZO-1+regulates+intercalated+disc+composition+and+atrioventricular+node+conduction.">ZO-1 regulates intercalated disc composition and atrioventricular node conduction.</a> Circulation Research. 127 (2), e28-e43 (2020).</li><li>Glukhov, A. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calsequestrin+2+deletion+causes+sinoatrial+node+dysfunction+and+atrial+arrhythmias+associated+with+altered+sarcoplasmic+reticulum+calcium+cycling+and+degenerative+fibrosis+within+the+mouse+atrial+pacemaker+complex1.">Calsequestrin 2 deletion causes sinoatrial node dysfunction and atrial arrhythmias associated with altered sarcoplasmic reticulum calcium cycling and degenerative fibrosis within the mouse atrial pacemaker complex1.</a> European Heart Journal. 36 (11), 686-697 (2015).</li><li>Torrente, A. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burst+pacemaker+activity+of+the+sinoatrial+node+in+sodium-calcium+exchanger+knockout+mice.">Burst pacemaker activity of the sinoatrial node in sodium-calcium exchanger knockout mice.</a> Proceedings of the National Academy of Sciences of the United States of America. 112 (31), 9769-9774 (2015).</li><li>Yang, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+SK2+upregulation+following+angiotensin+II+challenge:+Modulation+by+p21-activated+kinase-1.">Ventricular SK2 upregulation following angiotensin II challenge: Modulation by p21-activated kinase-1.</a> Journal of Molecular and Cellular Cardiology. 164, 110-125 (2022).</li><li>Dong, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protocol+for+dual+calcium-voltage+optical+mapping+in+murine+sinoatrial+preparation+with+optogenetic+pacing.">A protocol for dual calcium-voltage optical mapping in murine sinoatrial preparation with optogenetic pacing.</a> Frontiers in Physiology. 10, 954 (2019).</li><li>He, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protocol+for+transverse+cardiac+slicing+and+optical+mapping+in+murine+heart.">A protocol for transverse cardiac slicing and optical mapping in murine heart.</a> Frontiers in Physiology. 10, 755 (2019).</li><li>Hoeker, G. S., Katra, R. P., Wilson, L. D., Plummer, B. N., Laurita, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+calcium+release+in+tissue+from+the+failing+canine+heart.">Spontaneous calcium release in tissue from the failing canine heart.</a> American Journal of Physiology. Heart and Circulatory Physiology. 297 (4), H1235-H1242 (2009).</li><li>Laurita, K. R., Singal, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+action+potentials+and+calcium+transients+simultaneously+from+the+intact+heart.">Mapping action potentials and calcium transients simultaneously from the intact heart.</a> American Journal of Physiology. Heart and Circulatory Physiology. 280 (5), H2053-H2060 (2001).</li><li>Johnson, P. L., Smith, W., Baynham, T. C., Knisley, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Errors+caused+by+combination+of+Di-4+ANEPPS+and+Fluo3/4+for+simultaneous+measurements+of+transmembrane+potentials+and+intracellular+calcium.">Errors caused by combination of Di-4 ANEPPS and Fluo3/4 for simultaneous measurements of transmembrane potentials and intracellular calcium.</a> Annals of Biomedical Engineering. 27 (4), 563-571 (1999).</li></ol>

Based on our experience, the keys to a successful dual-dye optical mapping of a mouse heart include a well-prepared solution and heart, dye loading, achieving the best signal-to-noise ratio, and reducing the motion artifact.
Preparation of solution 
Krebs solution is essential for a successful heart experiment. MgCl2 and CaCl2 stock solutions (1 mol/L) are prepared in advance considering their water absorption and added to the Krebs solution after al...

Inherited cardiac disorder catecholaminergic polymorphic ventricular tachycardia (CPVT) manifests as polymorphic ventricular tachycardia (PVT) episodes following physical activity, stress, or catecholamine challenge, which can deteriorate into potentially fatal ventricular fibrillation1,2,3,4. Recent evidence following its first report as a clinical syndrome in 1995 implicated mutations in seven genes, all involved in sarcoplasmic reticular (SR) store Ca2+ release in this condition: the most frequently reported RYR2 encoding ryanodine receptor 2 (RyR2) of Ca2+ release channels5,6, FKBP12.67, CASQ2 encoding cardiac calsequestrin8, TRDN encoding the junctional SR protein triadin9, and CALM19, CALM210, and CALM3 identically encoding calmodulin11,12. These genotypic patterns attribute the arrhythmic events to the unregulated pathological release of SR store Ca2+12.
Spontaneous Ca2+ release from SR can be detected as Ca2+ sparks or Ca2+ waves, which activates the Na+/Ca2+ exchanger (NCX). The exchanger of one Ca2+ for three Na+ generates an inward current, which speeds up the diastolic depolarization and drives the membrane voltage to the threshold of action potential (AP). In RyR2 knock-in mice, the increased activity of RyR2R4496C in the sinoatrial node (SAN) leads to an unanticipated decrease in SAN automaticity by Ca2+-dependent decrease of ICa,L and SR Ca2+ depletion during diastole, identifying subcellular pathophysiologic alterations contributing to the SAN dysfunction in CPVT patients13,14. Occurrence of the related cardiomyocyte cytosolic Ca2+ waves is more likely following increases in background cytosolic [Ca2+] following RyR sensitization by catecholamine, including isoproterenol (ISO), challenge.
Detailed kinetic changes in Ca2+ signaling following RyR2-mediated Ca2+ release in response to action potential (AP) activation that may be the cause of the observed ventricular arrhythmias in intact cardiac CPVT models remain to be determined for the full range of reported RyR2 genotypes12. This paper presents the instrumentation setup and experimental procedure for high-throughput mapping of Ca2+ signals and transmembrane potentials (Vm) in murine wild-type (WT) and heterozygous RyR2-R2474S/+ hearts, combined with programmed electrical pacing before and after isoproterenol challenge. This protocol provides a method for the mechanistic study of CPVT disease in isolated mouse hearts.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.2 &#956;m syringe filter</td>
			<td>Medical equipment factory of Shanghai Medical Instruments Co., Ltd., Shanghai, China</td>
			<td>N/A</td>
			<td>To filter solution</td>
		</tr>
		<tr>
			<td>15 mL centrifuge tube</td>
			<td>Guangzhou Jet Bio-Filtration Co., Ltd. China</td>
			<td>CFT011150</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Pasteur pipette</td>
			<td>Beijing Labgic Technology Co., Ltd. China</td>
			<td>00900026</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Syringe</td>
			<td>B. Braun Medical Inc.</td>
			<td>YZB/GER-5474-2014</td>
			<td></td>
		</tr>
		<tr>
			<td>200 &#956;L PCR tube</td>
			<td>Sangon Biotech Co., Ltd. Shanghai. China</td>
			<td>F611541-0010</td>
			<td>Aliquote the stock solutions&#160; to avoid repeated freezing and thawing</td>
		</tr>
		<tr>
			<td>50 mL centrifuge tube</td>
			<td>Guangzhou Jet Bio-Filtration Co., Ltd. China</td>
			<td>CFT011500</td>
			<td>Store Tyrode&#39;s solution at 4 &#176;C for follow-up heart isolation</td>
		</tr>
		<tr>
			<td>585/40 nm filter</td>
			<td>Chroma Technology</td>
			<td>N/A</td>
			<td>Filter for calcium signal</td>
		</tr>
		<tr>
			<td>630 nm long-pass filter</td>
			<td>Chroma Technology</td>
			<td>G15604AJ</td>
			<td>Filter for voltage signal</td>
		</tr>
		<tr>
			<td>Avertin (2,2,2-tribromoethanol)</td>
			<td>Sigma-Aldrich Poole, Dorset, United Kingdom</td>
			<td>T48402-100G</td>
			<td>To minimize suffering and pain reflex</td>
		</tr>
		<tr>
			<td>Blebbistatin</td>
			<td>Tocris Bioscience, Minneapolis, MN, United States</td>
			<td>SLBV5564</td>
			<td>Excitation-contraction uncoupler to&#160; eliminate motion artifact during mapping</td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>SLBK1794V</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>Custom-made thermostatic bath</td>
			<td>MappingLab, United Kingdom</td>
			<td>TBC-2.1</td>
			<td>To keep temperature of perfusion solution</td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>(RNBT7442)</td>
			<td>Solvent for dyes</td>
		</tr>
		<tr>
			<td>Dumont forceps</td>
			<td>Medical equipment factory of Shanghai Medical Instruments Co.,Ltd.,Shanghai, China</td>
			<td>YAF030</td>
			<td></td>
		</tr>
		<tr>
			<td>ElectroMap software</td>
			<td>University of Birmingham</td>
			<td>N/A</td>
			<td>Quantification of electrical parameters</td>
		</tr>
		<tr>
			<td>EMCCD camera</td>
			<td>Evolve 512 Delta, Photometrics, Tucson, AZ, United States</td>
			<td>A18G150001</td>
			<td>Acquire images for optical signals</td>
		</tr>
		<tr>
			<td>ET525/36 sputter coated filter</td>
			<td>Chroma Technology</td>
			<td>319106</td>
			<td>Excitation filter</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>SLBT4811V</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>Heparin Sodium</td>
			<td>Chengdu Haitong Pharmaceutical Co., Ltd., Chengdu, China</td>
			<td>(H51021209)</td>
			<td>To prevent blood clots in the coronary artery</td>
		</tr>
		<tr>
			<td>&#160;Iris forceps</td>
			<td>Medical equipment factory of Shanghai Medical Instruments Co.,Ltd.,Shanghai, China</td>
			<td>YAA010</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoproterenol</td>
			<td>MedChemExpress, Carlsbad, CA, United States</td>
			<td>HY-B0468/CS-2582</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>SLBS5003</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>MacroLED</td>
			<td>Cairn Research, Faversham, United Kingdom</td>
			<td>7355/7356</td>
			<td>The excitation light of fluorescence probes</td>
		</tr>
		<tr>
			<td>MacroLED light source</td>
			<td>Cairn Research, Faversham, United Kingdom</td>
			<td>7352</td>
			<td>Control the LEDs</td>
		</tr>
		<tr>
			<td>Mayo scissors</td>
			<td>Medical equipment factory of Shanghai Medical Instruments Co.,Ltd.,Shanghai, China</td>
			<td>YBC010</td>
			<td></td>
		</tr>
		<tr>
			<td>MetaMorph</td>
			<td>Molecular Devices</td>
			<td>N/A</td>
			<td>Optical signals sampling</td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>BCBS6841V</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>MICRO3-1401</td>
			<td>Cambridge Electronic Design limited, United Kingdom</td>
			<td>M5337</td>
			<td>Connect the electrical stimulator and Spike2 software</td>
		</tr>
		<tr>
			<td>MyoPacer EP field stimulator</td>
			<td>Ion Optix Co, Milton, MA, United States</td>
			<td>S006152</td>
			<td>Electric stimulator</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>SLBS2340V</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>NaH2PO4&#160;</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>BCBW9042</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sigma-Aldrich, St. Louis, MO, United States</td>
			<td>SLBX3605</td>
			<td>For Tyrode&#39;s solution</td>
		</tr>
		<tr>
			<td>NeuroLog System</td>
			<td>Digitimer</td>
			<td>NL905-229</td>
			<td>For ECG amplifier</td>
		</tr>
		<tr>
			<td>OmapScope5</td>
			<td>MappingLab, United Kingdom</td>
			<td>N/A</td>
			<td>Calcium alternans and arrhythmia analysis</td>
		</tr>
		<tr>
			<td>Ophthalmic scissors</td>
			<td>Huaian Teshen Medical Instruments Co., Ltd., Jiang Su, China</td>
			<td>T4-3904</td>
			<td></td>
		</tr>
		<tr>
			<td>OptoSplit</td>
			<td>Cairn Research, Faversham, United Kingdom</td>
			<td>6970</td>
			<td>Split the emission light for detecting Ca2+ and Vm&#160; simultaneously</td>
		</tr>
		<tr>
			<td>Peristalic pump</td>
			<td>Longer Precision Pump Co., Ltd., Baoding, China,</td>
			<td>BT100-2J</td>
			<td>To pump the solution</td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>BIOFIL</td>
			<td>TCD010060</td>
			<td></td>
		</tr>
		<tr>
			<td>Pluronic F127</td>
			<td>Invitrogen, Carlsbad, CA, United States</td>
			<td>1899021</td>
			<td>To enhance the loading with Rhod2AM</td>
		</tr>
		<tr>
			<td>RH237</td>
			<td>Thermo Fisher Scientifific, Waltham, MA, United States</td>
			<td>1971387</td>
			<td>Voltage-sensitive dye</td>
		</tr>
		<tr>
			<td>Rhod-2 AM</td>
			<td>Invitrogen, Carlsbad, CA, United States</td>
			<td>1890519</td>
			<td>Calcium indicator</td>
		</tr>
		<tr>
			<td>Silica gel tube</td>
			<td>Longer Precision Pump Co., Ltd., Baoding, China,</td>
			<td>96402-16</td>
			<td>Connect with the peristaltic pump</td>
		</tr>
		<tr>
			<td>Silk suture</td>
			<td>Yuankang Medical Instrument Co., Ltd.,Yangzhou, China</td>
			<td>20172650032</td>
			<td>To fix the aorta</td>
		</tr>
		<tr>
			<td>Spike2</td>
			<td>Cambridge Electronic Design limited, United Kingdom</td>
			<td>N/A</td>
			<td>To record and analyze ECG data</td>
		</tr>
		<tr>
			<td>Stimulation electrode</td>
			<td>MappingLab, United Kingdom</td>
			<td>SE1600-35-2020</td>
			<td></td>
		</tr>
		<tr>
			<td>T510lpxr</td>
			<td>Chroma Technology</td>
			<td>312461</td>
			<td>For light source</td>
		</tr>
		<tr>
			<td>T565lpxr</td>
			<td>Chroma Technology</td>
			<td>321343</td>
			<td>For light source</td>
		</tr>
	</tbody>
</table>

dual-dye optical mapping of hearts from ryr2r2474s knock-in mice of catecholaminergic polymorphic ventricular tachycardia

The pro-arrhythmic cardiac disorder catecholaminergic polymorphic ventricular tachycardia (CPVT) manifests as polymorphic ventricular tachycardia episodes following physical activity, stress, or catecholamine challenge, which can deteriorate into potentially fatal ventricular fibrillation. The mouse heart is a widespread species for modeling inherited cardiac arrhythmic diseases, including CPVT. Simultaneous optical mapping of transmembrane potential (Vm) and calcium transients (CaT) from Langendorff-perfused mouse hearts has the potential to elucidate mechanisms underlying arrhythmogenesis. Compared with the cellular level investigation, the optical mapping technique can test some electrophysiological parameters, such as the determination of activation, conduction velocity, action potential duration, and CaT duration. This paper presents the instrumentation setup and experimental procedure for high-throughput optical mapping of CaT and Vm in murine wild-type and heterozygous RyR2-R2474S/+ hearts, combined with programmed electrical pacing before and during the isoproterenol challenge. This approach has demonstrated a feasible and reliable method for mechanistically studying CPVT disease in an ex vivo mouse heart preparation.

Optical mapping has been a popular approach in studying complex cardiac arrhythmias in the past decade. The optical mapping setup consists of an EMCCD camera, giving a sampling rate of up to 1,000 Hz and a spatial resolution of 74 x 74 &#181;m for each pixel. It enables a rather high signal-noise ratio during signal sampling (Figure 1). Once the Langendorff-perfused heart reaches a stable state and the dye loading finishes, the heart is placed in the homoeothermic chamber under the illuminat...

Watch this Scientific Journal Video about Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia at JoVE.com

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia

This protocol introduces dual-dye optical mapping of mouse hearts obtained from wild-type and knock-in animals affected by catecholaminergic polymorphic ventricular tachycardia, including electrophysiological measurements of transmembrane voltage and intracellular Ca2+ transients with high temporal and spatial resolution.

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia

The pro-arrhythmic cardiac disorder catecholaminergic polymorphic ventricular tachycardia (CPVT) manifests as polymorphic ventricular tachycardia episodes ...

Research

JoVE Journal

Biology

Proper Care and Cleaning of the Microscope

Keeping the microscope optics clean is important for high-quality imaging. Dust, fingerprints, excess immersion oil, or mounting medium on or in a ...

Major Components of the Light Microscope

The light microscope is a basic tool for the cell biologist, who should have a thorough understanding of how it works, how it should be aligned for ...

Phase Contrast and Differential Interference Contrast (DIC) Microscopy

Phase Contrast and Differential Interference Contrast DIC Microscopy

Phase-contrast microscopy is often used to produce contrast for transparent, non light-absorbing, biological specimens. The technique was discovered by ...

Optical Mapping of Langendorff-perfused Rat Hearts

Optical mapping of the cardiac surface with voltage-sensitive fluorescent dyes has become an important tool to investigate electrical excitation in ...

Semi-automated Optical Heartbeat Analysis of Small Hearts

We have developed a method for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts (Fink, et. al., 2009). Our ...

Isolation of Embryonic Ventricular Endothelial Cells

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines ...

Voltage and Calcium Dual Channel Optical Mapping of Cultured HL-1 Atrial Myocyte Monolayer

Optical mapping has proven to be a valuable technique to detect cardiac electrical activity on both intact ex vivo hearts and in cultured myocyte ...

Optical Mapping of Intra-Sarcoplasmic Reticulum Ca2+ and Transmembrane Potential in the Langendorff-perfused Rabbit Heart

Optical Mapping of Intra-Sarcoplasmic Reticulum Ca2+ and Transmembrane Potential in the Langendorff-perfused Rabbit Heart

Sarcoplasmic reticulum (SR) Ca2+ handling plays a key role in normal excitation-contraction coupling and aberrant SR Ca2+ handling is known to play a ...