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• W2027320952 abstract "Several vasoactive drugs that lower blood pressure and increase heart rate induce regional cardiotoxicity in the dog, most frequently of right coronary arteries and right atrium. The basis for this selective damage is thought to result from local changes in vascular tone and blood flow. Administration of an endothelin receptor antagonist (ETRA, SB 209670) to dogs induced damage most frequent and severe in the right coronary artery and right atrium. Because site predisposition may correlate with distribution of vasoactive receptors, the objectives of this study were to map endothelin (ET) receptor distribution and density within regions of dog heart using both gene (mRNA) and protein expression endpoints for dog ETA and ETB receptors, and, additionally, correlate ET receptor subtype density with regional cardiac blood flow. A 10- to 15-mmHg reduction in mean arterial pressure with a concomitant increase in heart rate (10–20%), a six- and twofold increase in regional blood flow to the right and left atrium, respectively, and acute hemorrhage, medial necrosis, and inflammation were observed in the right coronary arteries and arteries of the right atrium after ETRA infusion for 5 days. Radioligand protein binding to quantify both ET receptors in normal dog heart indicated a twofold greater density of ET receptors in atrial regions versus ventricular regions. Importantly, ET receptor density in coronary arteries was markedly (about five- to sixfold) increased above that in atrial or ventricular tissues. ET receptor subtype characterization indicated ETB receptors were three times more prevalent in right coronary arteries compared to left coronary arteries and in situ hybridization confirmed localization of ETB in vascular smooth muscle. ETA receptor density was comparable in right and left coronary arteries. Quantitative real-time polymerase chain reaction for ETA and ETB receptor mRNA transcripts supported the site prevalence for message distribution. Consequently, the composite of protein and message expression profiles for ETA and ETB receptors indicated a disproportionate distribution of ETB receptors within right coronary artery of dog and this, along with functional measures of blood flow after ETRA infusion indicated a predisposition for exaggerated pharmacological responses and subsequent damage to right coronary arteries by ET and/or ETRAs. Several vasoactive drugs that lower blood pressure and increase heart rate induce regional cardiotoxicity in the dog, most frequently of right coronary arteries and right atrium. The basis for this selective damage is thought to result from local changes in vascular tone and blood flow. Administration of an endothelin receptor antagonist (ETRA, SB 209670) to dogs induced damage most frequent and severe in the right coronary artery and right atrium. Because site predisposition may correlate with distribution of vasoactive receptors, the objectives of this study were to map endothelin (ET) receptor distribution and density within regions of dog heart using both gene (mRNA) and protein expression endpoints for dog ETA and ETB receptors, and, additionally, correlate ET receptor subtype density with regional cardiac blood flow. A 10- to 15-mmHg reduction in mean arterial pressure with a concomitant increase in heart rate (10–20%), a six- and twofold increase in regional blood flow to the right and left atrium, respectively, and acute hemorrhage, medial necrosis, and inflammation were observed in the right coronary arteries and arteries of the right atrium after ETRA infusion for 5 days. Radioligand protein binding to quantify both ET receptors in normal dog heart indicated a twofold greater density of ET receptors in atrial regions versus ventricular regions. Importantly, ET receptor density in coronary arteries was markedly (about five- to sixfold) increased above that in atrial or ventricular tissues. ET receptor subtype characterization indicated ETB receptors were three times more prevalent in right coronary arteries compared to left coronary arteries and in situ hybridization confirmed localization of ETB in vascular smooth muscle. ETA receptor density was comparable in right and left coronary arteries. Quantitative real-time polymerase chain reaction for ETA and ETB receptor mRNA transcripts supported the site prevalence for message distribution. Consequently, the composite of protein and message expression profiles for ETA and ETB receptors indicated a disproportionate distribution of ETB receptors within right coronary artery of dog and this, along with functional measures of blood flow after ETRA infusion indicated a predisposition for exaggerated pharmacological responses and subsequent damage to right coronary arteries by ET and/or ETRAs. Cardiovascular toxicity frequently occurs at specific anatomical sites and generally has characteristic histopathological features. Lesion location and the combination of vascular and myocardial damage is an indicator of vasopressor or vasodilator activity of an insulting agent.1Dogterom P Zbinden G Reznik GK Cardiotoxicity of vasodilators and positive inotropic/vasodilating drugs in dogs: an overview.CRC Crit Rev Toxicol. 1992; 22: 203-241Crossref Scopus (63) Google Scholar Various vasodilators, when given to dogs induce hemorrhage, medial necrosis, and acute inflammation predominantly of the right coronary arteries and/or right atrium.1Dogterom P Zbinden G Reznik GK Cardiotoxicity of vasodilators and positive inotropic/vasodilating drugs in dogs: an overview.CRC Crit Rev Toxicol. 1992; 22: 203-241Crossref Scopus (63) Google Scholar, 2Gans JH Korson R Cates MR Ackerly CC Effects of short-term and long term theobromine administration to male dogs.Toxicol Appl Pharmacol. 1980; 53: 481-496Crossref PubMed Scopus (52) Google Scholar, 3Harlem JH Joseph EC Eden RJ Walker TF Major IR Lamb MS Cardiotoxicity of a new inotrope/vasodilator drug (SK&F 94120) in the dog.Arch Toxicol. 1986; 59: 51-55Crossref PubMed Scopus (34) Google Scholar, 4Herman EH Balazs T Young R Earl FL Krop S Ferrans VJ Acute cardiomyopathy induced by vasodilating antihypertensive agent minoxidil.Toxicol Appl Pharmacol. 1979; 47: 493-503Crossref PubMed Scopus (43) Google Scholar, 5Mesfin GM Shawaryn GG Higgins MJ Cardiovascular alterations in dogs treated with hydralazine.Toxicol Pathol. 1987; 15: 409-416Crossref PubMed Scopus (33) Google Scholar For example, when endothelin receptor antagonists (ETRA) are given to dogs, characteristic lesions occur in the atrium and coronary arteries, even in the absence of meaningful clinical signs.6Louden C Nambi P Branch C Gossett K Pullen M Eustis S Solleveld H Coronary arterial lesions in dogs treated with an endothelin receptor antagonist.J Cardiovasc Pharmacol. 1998; 31: S384-S385Crossref PubMed Scopus (18) Google Scholar, 7Louden C Tierney L Thomas R Branch C Schwartz L Solleveld H Coronary arterial lesions in dogs caused by endothelin receptor blockade are associated with regional differences in endothelin receptor distribution and blood flow.FASEB J. 1999; 13: A156Google Scholar Because endothelin (ET) is a potent vasoconstrictor,8Yanagisawa M Masaki T Pharmacological activities, regulation and possible roles in cardiovascular control.Biochem Pharmacol. 1989; 38: 1877-1883Crossref PubMed Scopus (370) Google Scholar, 9Yanagisawa M Kurihara H Kimura S Tomobe Y Kobayashi M Mitsui Y Yazaki Y Goto K Masaki T A novel potent vasoconstrictor peptide produced by vascular endothelial cells.Nature. 1988; 332: 411-415Crossref PubMed Scopus (10219) Google Scholar blockade of ET receptors should mediate vasodilation. However, the final biological outcome of ET receptor blockade is variable and influenced by a several factors, including (i) ET receptor subtypes involved, (ii) association of ET subtypes with specific cells (endothelium or vascular smooth muscle), (iii) ratios of ET receptor subtypes at affected sites, and (iv) specific signal transduction systems conducting responses in particular species or tissue types. Two major ET receptors, ETA and ETB, are recognized; however, pharmacological evidence suggests additional subtypes are present but not well characterized.10Adachi M Yang YY Furuichi Y Miyamoto C Cloning and characterization of cDNA encoding human A-type endothelin receptor.Biochem Biophys Res Commun. 1991; 180: 1265-1272Crossref PubMed Scopus (94) Google Scholar, 11Arai H Hori S Aramori I Ohkubo H Nakanishi S Cloning and expression of a cDNA encoding an endothelin receptor.Nature. 1990; 348: 730-732Crossref PubMed Scopus (2509) Google Scholar, 12Battistini B D'Orleans-Juste P Sirois P Endothelins: circulating plasma levels and presence in other biologic fluids.Lab Invest. 1993; 68: 600-628PubMed Google Scholar, 13Fukuroda T Nishikibe M Ohta Y Ihara M Yano M Ishikawa K Fukami Ikemoto F Analysis of responses to endothelins in isolated porcine blood vessels by using a novel endothelin antagonist BQ153.Life Sci. 1992; 50: PL107-PL112Crossref PubMed Scopus (74) Google Scholar, 14Harrison VJ Randriantsoa A Schoeffter P Heterogeneity of endothelin-sarafotoxin receptors mediating contraction of pig coronary artery.Br J Pharmacol. 1992; 105: 511-513Crossref PubMed Scopus (95) Google Scholar, 15Inoue A Yanagisawa M Kimura S Kasuya Y Miyauchi T Goto K Masaki T The human endothelin family: Three structurally and pharmacologically distinct isopeptides predicted by three separate genes.Proc Natl Acad Sci USA. 1989; 86: 2863-2867Crossref PubMed Scopus (2567) Google Scholar Classically, vascular smooth muscle cells express ET receptors ETA and ETB,12Battistini B D'Orleans-Juste P Sirois P Endothelins: circulating plasma levels and presence in other biologic fluids.Lab Invest. 1993; 68: 600-628PubMed Google Scholar, 16Clozel M Gray GA Breu V Loffler BM Osterwalder R The endothelin ETB receptor mediates both vasodilatation and vasoconstriction in vivo.Biochem Biophys Res Commun. 1992; 186: 867-873Crossref PubMed Scopus (398) Google Scholar whereas endothelial cells express only ETB.15Inoue A Yanagisawa M Kimura S Kasuya Y Miyauchi T Goto K Masaki T The human endothelin family: Three structurally and pharmacologically distinct isopeptides predicted by three separate genes.Proc Natl Acad Sci USA. 1989; 86: 2863-2867Crossref PubMed Scopus (2567) Google Scholar In general, ETA mediates vasoconstriction and ETB receptors on endothelium, through release of nitric oxide, indirectly mediate vasorelaxation.17Pernow J Modin A Endothelial regulation of coronary vascular tone in vitro: contribution of endothelin receptor subtypes and nitric oxide.Eur J Pharmacol. 1993; 243: 281-286Crossref PubMed Scopus (26) Google Scholar, 18Chabrier PE The role of endothelin in the vessel wall.Bailliere's Clin Haematol. 1993; 6: 577-591Abstract Full Text PDF PubMed Scopus (14) Google Scholar However, an ETB receptor subtype of vascular smooth muscle directly mediates smooth muscle contraction.14Harrison VJ Randriantsoa A Schoeffter P Heterogeneity of endothelin-sarafotoxin receptors mediating contraction of pig coronary artery.Br J Pharmacol. 1992; 105: 511-513Crossref PubMed Scopus (95) Google Scholar, 19Sokolovsky M Endothelins and sarafotoxins: physiological regulation, receptor subtypes and transmembrane signaling.Trends Biochem Sci. 1991; 16: 261-264Abstract Full Text PDF PubMed Scopus (57) Google Scholar, 20Igarashi Y Aizawa Y Tamura M Ebe K Yamaguchi T Shibata A Vasoconstrictor effect of endothelin on the canine coronary artery: is a novel endogenous peptide involved in regulating myocardial blood flow and coronary spasm?.Am Heart J. 1989; 118: 674-678Abstract Full Text PDF PubMed Scopus (35) Google Scholar, 21Moreland S McMullen DM Delaney CL Lee VG Hunt JT Venous smooth muscle contains vasoconstrictor ETB-like receptors.Biochem Biophys Res Commun. 1992; 184: 100-106Crossref PubMed Scopus (255) Google Scholar, 22Teerlink JR Breu V Sprecher U Clozel M Clozel JP Potent vasoconstriction mediated by endothelin ETB receptors in canine coronary arteries.Circ Res. 1994; 74: 105-114Crossref PubMed Scopus (123) Google Scholar, 23Summer MJ Cannon TR Mundin JW White DG Watts IS Endothelin ETA and ETB receptors mediate vascular smooth muscle contraction.Br J Pharmacol. 1992; 107: 858-860Crossref PubMed Scopus (267) Google Scholar In the dog, ETB receptors of coronary arteries are potent vasoconstrictors.22Teerlink JR Breu V Sprecher U Clozel M Clozel JP Potent vasoconstriction mediated by endothelin ETB receptors in canine coronary arteries.Circ Res. 1994; 74: 105-114Crossref PubMed Scopus (123) Google Scholar, 24Rigel DF Lappe RW Differential responsiveness of conduit and resistance coronary arteries to endothelin A and B receptor stimulation in anesthetized dogs.J Cardiovasc Pharmacol. 1993; 22: S243-S247Crossref PubMed Scopus (36) Google Scholar, 25Awane-Igata Y Ikeda S Watanabe T Inhibitory effects of TAK-044 on endothelin induced vasoconstriction in various canine arteries and porcine coronary arteries: a comparison with selective ETA and ETB receptor antagonists.Br J Pharmacol. 1997; 120: 516-522Crossref PubMed Scopus (23) Google Scholar SB 209670, a novel nonpeptide ETRA, has high affinity for human cloned ETA and ETB receptors (KiS of 0.2 and 18 nmol/L, respectively) which, in a variety of model systems, competitively inhibits both ETA- and ETB-mediated arterial contractions.26Ohlstein EH Nambi P Douglas SA Edwards RM Gellai M Lago A Leber JD Cousins RD Gao A Peishoff CE Bean JW Eggleston D Elshourbagy N Kumar C Lee JA Brooks DP Ruffolo Jr, RR Feuerstein G Weinstock J Gleason JG Elliott JD SB 209670, a rationally designed potent nonpeptide endothelin receptor antagonist.Proc Natl Acad Sci USA. 1994; 91: 8052-8056Crossref PubMed Scopus (178) Google Scholar SB 209670, when given to dogs as an intravenous infusion for 5 days (50 μg/kg/minute), increased heart rate (HR), decreased mean arterial pressure (MAP), and caused atrial hemorrhage and acute coronary arterial injury (medial hemorrhage, necrosis, and perivascular inflammation), predominantly of the right heart. These right heart lesions after administration of selective ETRA indicated that ET receptors predispose specific locations to damage. The objectives of this study were, first, to quantify ET receptor subtypes in specific anatomical regions of the normal dog heart; second, to quantify regional blood flow in dog heart during periods of ET receptor blockade by SB 209670 as a measure of vascular function; and third, to correlate ET receptor density with regional blood flow and severity and frequency of cardiovascular damage. ET receptor mRNA and protein expression were quantified in selected areas of dog heart including right and left atria, ventricles, and coronary arteries. Quantitative real time reverse transcriptase-polymerase chain reaction (RT-PCR) and radiolabeled ligands were used to measure ETA and ETB mRNA, and ETA and ETBreceptor proteins, respectively. Dog-specific radiolabeled ET receptor riboprobes in conjunction with in situ hybridization were used to anatomically characterize receptor distribution within dog coronary arteries. Right and left atria and ventricular blood flow was determined both before and after administration of SB 209670 using fluorescent microspheres. Purebred beagle dogs 12 to 14 months old (Marshall Farms, Inc., North Rose, NY) were used. Dogs were housed individually in stainless steel cages and fed Purina Certified Canine Diet 5007 (Purina Mills Inc., Richmond, IN) and water ad libitum. Animal care, husbandry, and cage specifications conformed to the current guidelines of ILAR/AALAC and the “Guide for the Care and Use of Laboratory Animals.” In preparation for intravenous infusion, dogs received a jugular catheter and were jacketed for protection. Dogs (3 males and 3 females/group) were given 50 μg/kg/minute SB 209670 (5 mg/ml) or 0.9% sodium chloride (saline) as a continuous intravenous infusion for up to 5 days. The solutions were sterile-filtered through a 0.22-μm Sterivex-GV filter into clear PVC Viaflex infusion bags and an ambulatory peristaltic pump (CADD plus, Model 5400, Sims Deltec, St. Paul, MN) was used for delivery through polyvinyl catheters. The study design is shown in Table 1.Table 1Study Design, Toxicokinetic Data, and Frequency of Coronary Arterial LesionsLength of ETRA infusionTotal dose (mg/kg/day)Infusion rate (μg/kg/min)Mean Css (μg/mL)Arterial lesion5 days72505.06 /6*Each group consisted of 3 males and 3 females.24 hours72505.02 /612 hours36505.01 /612 hours7.2101.00 /6Css, concentration at steady state.* Each group consisted of 3 males and 3 females. Open table in a new tab Css, concentration at steady state. A series of MAP and HR plots were obtained before, during, and after dosing using Dataquest (Data Sciences International, St. Paul, MN) from surgically implanted radiotelemetry transmitters. Plots were constructed from averaged intervals. Average values, standard deviations, number of observations, and minimum and maximum values were summarized for 24-hour time periods. Regional myocardial blood flow (RBF) was measured using color-coated fluorescent microspheres27Bassingthwaighte JB Malone MA Moffett TC King RB Little SE Link JM Krohn KA Validity of microsphere depositions for regional myocardial flows.Am J Physiol. 1987; 253: H184-H193PubMed Google Scholar, 28Chien GL Anselone CG Davis RF Van Winkle DM Fluorescent vs. radioactive microsphere measurement of regional myocardial blood flow.Cardiovasc Res. 1995; 30: 405-412Crossref PubMed Scopus (31) Google Scholar, 29Glenny RW Bernard S Brinkley M Validation of fluorescent-labeled microspheres for measurement of regional organ perfusion.J Appl Physiol. 1993; 74: 2585-2597Crossref PubMed Scopus (326) Google Scholar before and after infusion of ETRA (SB 209670). Briefly, multiple sets of NuFlow microspheres (15 μm in diameter, Triton Technology, San Diego, CA), each having a distinct fluorescent color emission, were supplied in sterile saline containing 0.05% Tween 80 and 0.01% Thimersal. Microsphere suspensions were diluted in 0.5% (w/v) dextrose and microspheres/100 μl quantified. Before ETRA infusion, dogs were pretreated with 0.01% Tween 80 to preclude Tween-related hemodynamic effects during study.30Millard RW Baig H Vatner VF Cardiovascular effects of radioactive microsphere suspensions and Tween 80 solutions.Am J Physiol. 1977; 232: 331-334Google Scholar Dogs were also acclimated to stabilize MAP and HR before microsphere injection. Vascular access ports (VAP) to the left atrium were used for microsphere injection and reference blood samples obtained from an aortic VAP immediately after microsphere administration. One color-set of microspheres was given on day 1, before ETRA infusion, and another color-set was given on day 5 during completion of ETRA infusion, allowing each dog to serve as its own control, thereby reducing interanimal variability. Regional myocardial tissues were collected at necropsy, weighed, homogenized, and analyzed by flow cytometry for quantification of each set of microspheres per gram of tissue. Serial jugular vein blood samples were collected at 0, 2, 4, and 8 hours of ETRA infusion and at the end of days 1, 2, 3, 4, and 5 to analyze SB 209670 concentration using a high pressure liquid chromatography method. Heart and coronary arteries were examined at necropsy. Atria, ventricles, and coronary arteries were collected and identified as right or left chambers; this identity was maintained throughout processing and examination. Light microscopic assessment was completed after paraffin embedding and staining with hematoxylin and eosin. Expression of ETA and ETB receptor mRNA was localized using isotopic in situ hybridization procedures.31Lu L Gillet NA An optimized protocol for an in situ hybridization using PCR-generated 33P-labeled riboprobes.Cell Vis. 1994; 1: 169-176Google Scholar [33P]-UTP-labeled riboprobes were synthesized from PCR-generated cDNA templates containing flanking T3 and T7 promoter sequences for sense and antisense riboprobes, respectively. Primer sequences are illustrated in Table 2.Table 2Primers and Fluorogenic ProbesReagentSequenceSizeQuantitative RT-PCRETA101 bp Forward Primer5′-TCG AGA AGT GGC AAA AAC AGT TT-3′ Reverse Primer5′-CAT CGT ACA CGG TTT TCT TCA A-3′ Probe*FAM (6-carboxy-fluorescein) and TAMRA (6-carboxytetramethyl-rhodamine) are the detection and quencher dyes, respectively.5′-FAM-TGG TTC CCG CTT CAC TTA AGC CGT-TAMRA-3′ETB†GenBank Accession number AF034530.107 bp Forward Primer5′-TCA GAA TGA TCC CAA TAG ATG TGA A-3′ Reverse Primer5′-ACA GAG CTA TAG GAT TAA TGC AGG AAT-3′ Probe*FAM (6-carboxy-fluorescein) and TAMRA (6-carboxytetramethyl-rhodamine) are the detection and quencher dyes, respectively.5′-FAM-TGC CGA TAT AAT CCA ACA CCA ACA AAA AGC T-TAMRA-3′β-Actin‡GenBank Accession number Z700440.86 bp Forward Primer5′-GAT GAG GCC CAG AGC AAG AG-3′ Reverse Primer5′-TTC TCC ATG TCG TCC CAG TTG-3′ Probe5′-FAM-TGA CCC TGA AGT ACC CCA TTG AGC ACG GCA T-TAMRA-3′In Situ HybridizationETA389 bp Forward Primer5′-AAG GAC TGG TGG CT-3′ (sense) Reverse Primer5′-GGC ATG ACT GGA AA-3′ (antisense)ETB†GenBank Accession number AF034530.565 bp Forward Primer5′-TAA TGA CGC CAC CCA CTA AGA CCT-3′ (sense) Reverse Primer5′-GCC AGA ACC ACG GAG ACC A-3′ (antisense)* FAM (6-carboxy-fluorescein) and TAMRA (6-carboxytetramethyl-rhodamine) are the detection and quencher dyes, respectively.† GenBank Accession number AF034530.‡ GenBank Accession number Z700440. Open table in a new tab Regions of femoral, right (RCA) and left (LCA) coronary arteries, and heart (right and left atria and ventricles) were collected from untreated dogs (n = 4). Cell membranes were prepared following the procedure of Brooks et al32Brooks DP DePalma PD Pullen M Nambi P Characterization of canine renal endothelin receptor subtypes and function.J Pharmacol Exp Ther. 1994; 268: 1091-1097PubMed Google Scholar for radioligand binding studies. Briefly, dissected tissues were homogenized in buffer containing 20 mmol/L Tris-HCl pH 7.5, 5 mmol/L EDTA, 0.25 mol/L sucrose, 100 μg/ml phenylmethyl sulfonyl fluoride, 10 μg/ml aprotinin, and 10 μg/ml leupeptin. After low-speed centrifugation (1000 × g) for 10 minutes at 4°C, supernatants were collected and centrifuged again for 30 minutes at 45,000 × g at 4°C. Resulting pellets were re-suspended in buffer containing 50 mmol/L Tris-HCl, pH 7.5, and 20 mmol/L MgCl2 and frozen. [125I]-ET-1 (specific activity 2200 Ci/mmol) and [125I]-ET-3 (specific activity 2200 Ci/mmol) were obtained from New England Nuclear (Boston, MA); unlabeled ET-1 and ET-3 were obtained from American Peptides (Sunnyvale, CA). For radioligand binding, 0.3 nmol/L of [125I]-ET-1 or [125I]-ET-3 was added to membrane preparations (5–10 μg/tube) and incubated at 30°C for 60 minutes. Reactions were quenched with cold buffer. Bound and free ligands were separated by filtering and counted using a γ counter. Nonspecific binding was determined in the presence of 100 nmol/L unlabeled ET-1 or ET-3. Because ET-1 binds to both ETA and ETB receptors and ET-3 binds only to ETB, ETB receptor density was measured directly and ETA receptor density was calculated. Using normal dog tissues, total RNA was isolated from right coronary artery (RCA) and left coronary artery (LCA), atrial and ventricular myocardium, kidney, and femoral artery. RNA was treated with 0.8 units RQ1 RNase-free DNase (Promega, Madison, WI) before extraction with phenol/chloroform to reduce DNA contamination.33Chomczynski P Sacchi N Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction.Anal Biochem. 1987; 162: 156Crossref PubMed Scopus (63082) Google Scholar RNA integrity was verified by fractionation on 1% agarose-formaldehyde gel containing 0.5 μg/ml of ethidium bromide followed by ultraviolet visualization. To partially clone the dog ETA receptor gene, PCR primers were designed from conserved regions (GenBank Accession numbers U20577, S67127, X57765, M60786, AF039892, U06633) using the Basic Local Alignment Search Tool (National Center for Biotechnological Information, Washington, D.C.). Sequences of forward and reverse primers were 5′-AAGGACTGGTGGCT-3′ and 5′-GGCATGACTGGAAA-3′, respectively. Based on previous reports describing ETA receptor localization in the dog,32Brooks DP DePalma PD Pullen M Nambi P Characterization of canine renal endothelin receptor subtypes and function.J Pharmacol Exp Ther. 1994; 268: 1091-1097PubMed Google Scholar RT-PCR was performed using total RNA isolated from the dog kidney. Single-stranded cDNA synthesis was accomplished using the Superscript pre-amplification system for first strand cDNA synthesis (Life Technologies, Gaithersburg, MD); random hexamers were used to prime cDNA synthesis. PCR was performed in a total volume of 50 μl consisting of 1.5 mmol/L MgCl2, 200 μmol/L each ATP, CTP, GTP, and TTP, 200 nmol/L of each primer, 2.5 U of AmpliTaq DNA polymerase (PE Applied Biosystems, Foster City, CA) and 1× PCR buffer containing 20 mmol/L Tris-HCl, pH 8.4, and 50 mmol/L KCl. All reactions were performed in a PE Applied Biosystems GeneAmp PCR System 2400. PCR products were analyzed by gel electrophoresis and subsequently recovered using the QIAquick gel extraction kit (Qiagen Inc., Valencia, CA). Purified PCR products were ligated into a bidirectional TA cloning vector, pCRII, and transferred into INVαF′ cells (Invitrogen, San Diego, CA). Minipreps of 20 clones were prepared using the Wizard Plus Minipreps DNA Purification System (Promega). Clones containing inserts were identified by restriction enzyme digestion with EcoRI (Promega) and subsequent agarose gel analysis. Sequencing and analysis of clones were performed using PE Applied Biosystems 373A Automated DNA Sequencer and Basic Local Alignment Search Tool and Lasergene biocomputing software for Windows (DNASTAR Inc., Madison, WI). The nucleic acid sequence obtained had a 93% homology to the human ETA receptor gene (Figure 1).34Cyr C Huebner K Druck T Kris R Cloning and chromosomal localization of a human endothelin ETA receptor.Biochem Biophys Res Commun. 1991; 181: 184-190Crossref PubMed Scopus (41) Google Scholar This cloned ETA sequence was subsequently used in the quantitative real-time PCR (Taqman) and in situ hybridization analysis. Primer and probe sequences for dog ETA and ETB receptor genes and β-actin genes are shown in Table 2. Single-stranded cDNA templates were made from the selected tissues and Taqman analysis used to determine relative differences in PCR products.35Heid CA Stevens J Livak KJ Williams PM Real time quantitative PCR.Genome Res. 1996; 6: 986-994Crossref PubMed Scopus (4981) Google Scholar, 36Holland PM Abramson R Watson R Gelfand DH Detection of specific polymerase chain reaction product by utilizing the 5′-3′ exonuclease activity of Thermus aquaticus DNA polymerase.Proc Natl Acad Sci USA. 1991; 88: 7276-7280Crossref PubMed Scopus (2163) Google Scholar Briefly, fluorogenic probes designed to hybridize to the amplicon had a reporter dye (6-FAM) conjugated to the 5′ end and a quencher dye (TAMRA) conjugated to the 3′ end. Fluorescence for each cycle was quantitatively analyzed on an ABI Prism 7700 Sequence Detection System (PE Applied Biosystems). Each reaction consisted of 1× Taqman Buffer A, 200 μmol/L each of dATP, dCTP, and dGTP, 400 μmol/L dUTP, 100 nmol/L fluorogenic probe, 200 nmol/L each of forward and reverse primers, 0.01 U/μl AmpErase uracil-N-glycosylase, 0.025 U/μl Taq Gold (PE Applied Biosystems), and either 0.5, 1, 10, 100, or 200 ng of template. Standard curves were generated from dog femoral artery cDNA. β-Actin was used as an endogenous control and active reference to normalize quantities of cDNA. Target quantities were normalized to β-actin and all quantities expressed as a fold difference from the femoral artery value. Statistical analyses of RBF, HR, and MAP were completed. Baseline (predosing) and post-dosing values from control and drug-treated dogs were analyzed using a repeated measures analysis of variance and pairwise comparisons to determine drug effect. Differences were considered significant if the P value was less than 0.05. Intravenous infusion of SB 209670 induced a slight but persistent decrease in MAP (10–15 mmHg), which was apparent 1 to 3 hours after start of infusion. This decrease in MAP persisted for 24 hours (last time point measured) after infusion termination (Figure 2), and the magnitude of change was considered within normal physiological range for MAP in the dog. During the 5-day infusion period, HR increased over time and was maximally increased (10 to 20% over pre-infusion values) on day 4 (Figure 2). A statistically significant increase in HR (P < 0.05) above baseline values occurred on days 2–5. HR returned to near pre-infusion values 24 hours after termination of infusion. Quantification of RBF in right and left atria and ventricles is summarized in Figure 3. Baseline values represent flow measured on day 1, just before the start of ETRA infusion, and was compared to flow measure after 5 days of infusion. Infusion of vehicle for 5 days did not alter flow characteristics from those of day 1 (Figure 3, insert). Baseline flow in ventricular chambers was approximately three- to fourfold greater than baseline flow in atria. After ETRA infusion for 5 days, right atrial blood flow increased (P < 0.05) approximately sixfold when compared to pre-infusion values (Figure 3). In contrast, there were only marginal increases in blood flow to other cardiac chambers. The duration of ETRA infusion also appeared to influence myocardial flow rates, since flow was increased only 0.5- to 1.8-fold after only 3 hours of SB 207960 infusion (data not shown) but increased up to sixfold by day 5. All dogs given 50 μg/kg/minute SB" @default.
• W2027320952 created "2016-06-24" @default.
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• W2027320952 date "2000-07-01" @default.
• W2027320952 modified "2023-10-16" @default.
• W2027320952 title "Endothelin Receptor Subtype Distribution Predisposes Coronary Arteries to Damage" @default.
• W2027320952 cites W1516809639 @default.
• W2027320952 cites W1638665100 @default.
• W2027320952 cites W1929410915 @default.
• W2027320952 cites W1968857862 @default.
• W2027320952 cites W1971397851 @default.
• W2027320952 cites W1980762198 @default.
• W2027320952 cites W1983184640 @default.
• W2027320952 cites W1987087962 @default.
• W2027320952 cites W1993257446 @default.
• W2027320952 cites W1999560936 @default.
• W2027320952 cites W2002874492 @default.
• W2027320952 cites W2009248393 @default.
• W2027320952 cites W2011628824 @default.
• W2027320952 cites W2013082229 @default.
• W2027320952 cites W2013733856 @default.
• W2027320952 cites W2030087021 @default.
• W2027320952 cites W2050359771 @default.
• W2027320952 cites W2054381541 @default.
• W2027320952 cites W2057996609 @default.
• W2027320952 cites W2059369537 @default.
• W2027320952 cites W2062072219 @default.
• W2027320952 cites W2064946616 @default.
• W2027320952 cites W2070233169 @default.
• W2027320952 cites W2070721758 @default.
• W2027320952 cites W2073745930 @default.
• W2027320952 cites W2078199328 @default.
• W2027320952 cites W2082344968 @default.
• W2027320952 cites W2082686123 @default.
• W2027320952 cites W2090019796 @default.
• W2027320952 cites W2111112233 @default.
• W2027320952 cites W2124101537 @default.
• W2027320952 cites W2134812217 @default.
• W2027320952 cites W2138722044 @default.
• W2027320952 cites W2144243188 @default.
• W2027320952 cites W2151204403 @default.
• W2027320952 cites W2151869895 @default.
• W2027320952 cites W2155705390 @default.
• W2027320952 cites W2162804111 @default.
• W2027320952 cites W2164578725 @default.
• W2027320952 cites W2171304897 @default.
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