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Comparison of Thiopental, Urethane, and Pentobarbital in the Study of Experimental Cardiology in Rats In Vivo. J Cardiovasc Pharmacol 2010; 56:38-44. [DOI: 10.1097/fjc.0b013e3181dd502c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Leiro JM, Alvarez E, Arranz JA, Cano E, Orallo F. Antioxidant activity and inhibitory effects of hydralazine on inducible NOS/COX-2 gene and protein expression in rat peritoneal macrophages. Int Immunopharmacol 2004; 4:163-77. [PMID: 14996408 DOI: 10.1016/j.intimp.2003.10.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Revised: 09/23/2003] [Accepted: 10/07/2003] [Indexed: 11/22/2022]
Abstract
This study investigated the effects of the peripheral vasodilator hydralazine on in vitro generation of reactive species of oxygen (ROS), nitrogen (RNS) and prostaglandin (PG) biosynthesis in elicited murine peritoneal macrophages, and on the gene expression and protein synthesis of two key enzymes in the inflammatory process, inducible NO(*) synthase (NOS-2) and inducible cyclooxygenase 2 (COX-2). Hydralazine at 0.1-10 mM inhibited both extracellular and intracellular ROS production by inflammatory macrophages, by a ROS-scavenging mechanism probably affecting superoxide radical (O(2)(*-))-generation by xanthine oxidase (XO) and nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) oxidase. Hydralazine at 0.1-10 mM significantly reduced NO(*) generation, and this effect was attributable to an inhibition of NOS-2 gene expression and protein synthesis. At 1-10 mM, hydralazine also effectively blocked COX-2 gene expression which perfectly correlated with a reduction of protein levels and PGE(2) synthesis. These data suggest that hydralazine, at the concentrations tested, show antioxidant properties and strongly attenuates the macrophage activation.
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Affiliation(s)
- José M Leiro
- Laboratorio de Parasitología, Instituto de Investigación y Análisis Alimentanós, Universidad de Santiago de Compostela, c/Constantino Candeira s/n, 15782, Santiago de Compostela, (A Coruña), Spain.
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Sánchez-Salvatori MA, Vidrio H. Reflex bradycardia induced by hydralazine in sino-aortic deafferented conscious rats. AUTONOMIC & AUTACOID PHARMACOLOGY 2003; 23:63-71. [PMID: 14565540 DOI: 10.1046/j.1474-8673.2003.00278.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
1. It is generally recognized that the vasodilator hydralazine produces hypotension accompanied by baroreflex-mediated tachycardia. In some experimental conditions, however, the accompanying heart rate change is bradycardia, a paradoxical response which has not been satisfactorily explained. The present study examined the possibility of hydralazine-induced bradycardia being mediated by vagal or sympathetic afferents activated by changes in left ventricular pressure. 2. Systolic blood pressure and heart rate responses to hydralazine were recorded in conscious normotensive intact rats by a tail cuff method and compared with responses in animals subjected to previous sino-aortic deafferentation (SAD) to remove the influence of the arterial baroreflex. Responses were also obtained after blockade of myocardial afferent vagal C-fibres with urethane, of efferent vagal impulses to the heart with methylatropine, of positive inotropic effects of hydralazine with atenolol, and of prostanoid sensitization of myocardial nerve fibres with indomethacin. 3. Hydralazine produced hypotension and tachycardia in intact rats, and hypotension and bradycardia in SAD animals. In intact rats, this pattern was not affected by any of the pretreatments, while in SAD rats, all pretreatments reversed the bradycardia to hydralazine. 4. The present results indicate that suppression of the arterial baroreflex by SAD propitiates the appearance of a bradycardiac response to hydralazine. This reaction probably results from activation of a vagal cardiodepressant reflex originating in the heart, as suggested by its blockade by drugs acting at various sites along the reflex arch.
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Affiliation(s)
- M A Sánchez-Salvatori
- Department of Pharmacology, School of Medicine, Universidad Nacional Autónoma de México, Apartado Postal 70297, 04510 Mexico, DF, Mexico
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Vidrio H, Medina M, Fernandez G, Lorenzana-Jimenez M, Campos AE. Enhancement of hydralazine hypotension by low doses of isoniazid. Possible role of semicarbazide-sensitive amine oxidase inhibition. GENERAL PHARMACOLOGY 2000; 35:195-204. [PMID: 11827726 DOI: 10.1016/s0306-3623(01)00106-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The influence of pretreatment with 1 through 300 mg/kg ip of isoniazid (ISO) on blood pressure and heart rate responses to 0.1 mg/kg iv of hydralazine (HYD) was assessed in rats anesthetized with chloralose--urethane. HYD hypotension was significantly enhanced by ISO at doses between 3 and 300 mg/kg ip. Heart rate was not influenced by HYD in control or pretreated animals. Depressor responses to 0.2 mg/kg iv of pinacidil (PIN) were also potentiated by ISO at 100 and 300, but not at 30 mg/kg. Similarly, ISO decreased cerebral gamma-aminobutyric acid (GABA) at the two highest doses; 30 mg/kg was without effect. Pretreatment of rats with ISO at 1 through 300 mg/kg failed to influence HYD-induced relaxation of aortic rings. These results were interpreted as indicating that potentiation of HYD hypotension by high doses of ISO is not specific for that vasodilator and is related to decreased cerebral GABA, as postulated previously. Lower doses could specifically potentiate the HYD-induced hypotensive effect by inhibition of semicarbazide-sensitive amine oxidase (SSAO), since both ISO and HYD are potent inhibitors of this enzyme. In support of this hypothesis, the SSAO inhibitors, benserazide (100 mg/kg ip) and mexiletine (50 mg/kg ip), were also found to enhance HYD hypotension.
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Affiliation(s)
- H Vidrio
- Department of Pharmacology, School of Medicine, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-297, 04510, D.F., Mexico, Mexico.
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Princi T, Delbello G, Grill V. Experimental urethane anaesthesia prevents digoxin intoxication: electrocardiographic and histological study in rabbit. Pharmacol Res 2000; 42:355-9. [PMID: 10987996 DOI: 10.1006/phrs.2000.0698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An electrocardiographic and histological study was performed in rabbit to detect the effects of urethane (ethyl carbamate) intraperitoneal (i.p.) anaesthesia in digoxin intoxication, since it has been previously shown that this anaesthetic and digitalis glycosides exert specific peripheral effects on the cardiovascular system involving central structures of the autonomic nervous system. We observed that i.p. urethane anaesthesia prevented the onset of the electrocardiographic signs of digitalis intoxication, as well as inhibiting the appearance of histological myocardial alterations after treatment with toxic digoxin doses. On the other hand, lethal arrhythmias and severe myocardial damage were observed in animals that had not undergone preliminary urethane anaesthesia. These results indicate that the effect exerted by urethane in preventing the toxic action of digoxin is probably due to a decrease of sympathetic activity in anaesthetized animals by centrally mediated sympathetic inhibition.
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Affiliation(s)
- T Princi
- Dipartimento di Fisiologia e Patologia, Università degli Studi di Trieste, Italy
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Holland HL, Gu JX, Orallo F, Camiña M, Fabeiro P, Willetts AJ. Enantioselective synthesis and pharmacological evaluation of a new type of verapamil analog with hypotensive and calcium antagonist activities. Pharm Res 1999; 16:281-7. [PMID: 10100315 DOI: 10.1023/a:1018888711071] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The syntheses and evaluation for cardiovascular activity in the rat of both enantiomers of a verapamil analog in which the cyano group has been replaced by hydroxyl. METHODS (+)- and (-)-alpha-[3-[[2-(3,4-Dimethoxyphenyl)ethyl]methylamino]propyl]- 3,4-dimethoxy-alpha-(1-methyl ethyl)benzyl alcohol were prepared from chiral sulfoxides produced by microbial biotransformations using Mortierella isabellina ATCC 42613 or Helminthsporium species NRRL 4671, and were examined for hypotensive and calcium antagonist activity using anaesthetized normotensive rats and isolated rat aorta and atria. RESULTS The analogs showed a pharmacological profile similar to that exhibited by verapamil, possessing a remarkable hypotensive activity, accompanied by a significant bradycardia, in anaesthetized normotensive rats. In vitro, these analogs displayed clear inhibitory effects: in isolated rat aorta they inhibited, in a concentration-dependent fashion, the contractions and 45Ca2+ uptake induced by norepinephrine and high KCl, and in isolated rat atria the analogs considerably decreased the rate of contraction (negative chronotropic effects). No significant differences between the quantitative cardiovascular effects produced by the two enantiomers of the verapamil analogs were observed. CONCLUSIONS The results suggest that, like that of verapamil, the cardiovascular activity exhibited by the new compounds seems to be due, at least in part, to a blockage of transmembrane calcium channels present in vascular smooth muscle cells.
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Affiliation(s)
- H L Holland
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada.
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Orallo F. Study of the in vivo and in vitro cardiovascular effects of a hydralazine-like vasodilator agent (HPS-10) in normotensive rats. Br J Pharmacol 1997; 121:1627-36. [PMID: 9283696 PMCID: PMC1564871 DOI: 10.1038/sj.bjp.0701314] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. In this work, the cardiovascular effects of HPS-10, a new vasodilator agent, were studied in rats. 2. In conscious normotensive rats, oral administration of HPS-10 (4-9 mg kg-1) produced a dose-related and long-lasting fall in systolic arterial blood pressure (ED30 of 5.32 mg kg-1), accompanied by an increase in heart rate (ED30 of 8.43 mg kg-1). This tachycardia was totally inhibited by pretreatment with (+/-)-propranolol (10 mg kg-1, p.o.). 3. In anaesthetized normotensive rats, HPS-10 (0.3-0.6 mg kg-1, i.v.) produced a gradual, dose-dependent and sustained decrease in systolic, diastolic and mean arterial pressure (MAP) (ED30 for MAP of 0.41 mg kg-1, i.v.), accompanied by a significant bradycardia at high doses (> 0.4 mg kg-1; ED20 of 0.61 mg kg-1, i.v.). HPS-10 (0.5 mg kg-1, i.v.) did not modify the positive chronotropic effects induced by intravenous administration of noradrenaline (NA; 5 micrograms kg-1), angiotensin II (AII; 0.2 microgram kg-1) and nicotine (200 micrograms kg-1) but markedly inhibited the hypertensive response produced by these agents. 4. In rat isolated rubbed aorta, HPS-10 (0.1-1 mM) non-competitively and with almost equal effectiveness antagonized the contractions induced by NA, AII (in normal Krebs solution) and Ca2+ (in depolarizing Ca(2+)-free high-K+ 50 mM solution). In the experiments in Ca(2+)-free medium, HPS-10 (1 mM) considerably inhibited the contractions induced by NA, AII and caffeine in rat aorta. 5. Furthermore, in the studies with radioactive Ca2+, HPS-10 (1 mM) did not modify the basal uptake of 45Ca2+ but strongly decreased the influx of 45Ca2+ induced by NA, AII and K+ in rat aortic rings. 6. In rat isolated atria, HPS-10 (1 mM) produced a positive inotropic/negative chronotropic effect. 7. HPS-10 (0.3 mM) significantly inhibited the sustained and transient Ba2+ inward current (IBa) recorded in whole-cell clamped rat aortic myocytes. 8. These results indicate that the non-selective vasorelaxant effects of HPS-10 in rat aortic rings can be attributed to transmembrane Ca(2+)-antagonist activity and an intracellular action on smooth muscle cells. The direct vasodilator action of HPS-10 observed in rat isolated aorta may be responsible for the HPS-10 hypotensive activity in anaesthetized normotensive rats.
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Affiliation(s)
- F Orallo
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, España
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Kotanidou A, Choi AMK, Winchurch RA, Otterbein L, Fessler HE. Urethan anesthesia protects rats against lethal endotoxemia and reduces TNF-α release. J Appl Physiol (1985) 1996. [DOI: 10.1152/jappl.1996.81.5.2304] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Kotanidou, Anastasia, Augustine M. K. Choi, Richard A. Winchurch, Leo Otterbein, and Henry E. Fessler. Urethan anesthesia protects rats against lethal endotoxemia and reduces TNF-α release. J. Appl. Physiol. 81(5): 2304–2311, 1996.—Urethan is a commonly used animal anesthetic for nonrecovery laboratory surgery. However, urethan has diverse biological effects that may complicate the interpretation of experimental findings. This study examined the effect of urethan on the response to an intravenous bolus of lipopolysaccharide (LPS; 30 mg/kg) in rats. In instrumented rats, urethan (1.2 gm/kg ip) completely prevented the fall in arterial pressure immediately after LPS administration but did not prevent late cardiovascular collapse. In uninstrumented rats, urethan also attenuated indexes of organ injury measured 4 h after LPS administration, including mural bowel hemorrhage, hemoconcentration, hypoglycemia, metabolic acidosis, and lung myeloperoxidase activity, a measure of neutrophil sequestration. The peak increase in tumor necrosis factor-α (TNF-α) 90 min after LPS administration was reduced 88% by urethan (2,060 ± 316 vs. 16,934 ± 847 pg/ml; P < 0.001). In uninstrumented animals, urethan at 1.2 gm/kg reduced the 90% mortality rate of a lethal dose of LPS to 0–10% when given up to 24 h before LPS administration but did not reduce mortality when given 2 h after LPS. Urethan neither directly bound LPS by Limulus assay nor inhibited LPS-stimulated TNF-α mRNA expression in cultured mouse peritoneal macrophages, but TNF-α mRNA expression was suppressed by serum from a urethan-treated rat. Moreover, rauwolscine, which shares α2-adrenoceptor-blocking activity with urethan, also prevented death from a subsequent 90% lethal dose LPS bolus. We conclude that urethan or its metabolites protect against LPS, in part, by reducing TNF-α release and speculate that this may be mediated by α2-adrenoceptors. These actions of urethan make it an undesirable anesthetic agent for in vivo studies of sepsis or LPS.
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Affiliation(s)
- Anastasia Kotanidou
- Division of Pulmonary and Critical Care Medicine and Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205-2196; and Department of Critical Care, Medical School of Athens University, Evangelismos Hospital, Athens, Greece GR106 76
| | - Augustine M. K. Choi
- Division of Pulmonary and Critical Care Medicine and Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205-2196; and Department of Critical Care, Medical School of Athens University, Evangelismos Hospital, Athens, Greece GR106 76
| | - Richard A. Winchurch
- Division of Pulmonary and Critical Care Medicine and Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205-2196; and Department of Critical Care, Medical School of Athens University, Evangelismos Hospital, Athens, Greece GR106 76
| | - Leo Otterbein
- Division of Pulmonary and Critical Care Medicine and Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205-2196; and Department of Critical Care, Medical School of Athens University, Evangelismos Hospital, Athens, Greece GR106 76
| | - Henry E. Fessler
- Division of Pulmonary and Critical Care Medicine and Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205-2196; and Department of Critical Care, Medical School of Athens University, Evangelismos Hospital, Athens, Greece GR106 76
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Orallo F, Fernández Alzueta A, Campos-Toimil M, Calleja JM. Study of the in vivo and in vitro cardiovascular effects of (+)-glaucine and N-carbethoxysecoglaucine in rats. Br J Pharmacol 1995; 114:1419-27. [PMID: 7606346 PMCID: PMC1510273 DOI: 10.1111/j.1476-5381.1995.tb13364.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The cardiovascular and vasorelaxant effects of (+)-glaucine and of a semisynthetic derivative (N-carbethoxysecoglaucine) were studied in rats. 2. N-carbethoxysecoglaucine did not modify either systolic arterial pressure or heart rate values in conscious (25 mg kg-1, p.o.) and anaesthetized normotensive rats (5 mg kg-1, i.v.). Furthermore, this compound showed no activity in the experiments carried out on rat isolated aorta [contractility and 45Ca2+ influx assays (5 microM)] and did not modify the rate and force of contraction in rat isolated atria (5 microM). 3. In conscious normotensive rats, oral administration of (+)-glaucine (25 mg kg-1) did not modify either systolic arterial pressure or heart rate. 4. In anaesthetized normotensive rats, (+)-glaucine (5 mg kg-1, i.v.) produced a remarkable fall in mean arterial pressure (MAP) accompanied by a significant decrease in heart rate. In the same preparation, (+)-glaucine (5 mg kg-1, i.v.) did not modify the cardiovascular effects induced by noradrenaline (NA) (5 micrograms kg-1) and 5-hydroxytryptamine (5-HT) (300 micrograms kg-1) but markedly inhibited those induced by nicotine (200 micrograms kg-1). 5. In isolated intact aorta of rat, (+)-glaucine (0.15-5 microM) competitively inhibited the contractions induced by NA (with a pA2 value of 7.14) and non-competitively those induced by 5-HT (in normal Krebs solution) and Ca2+ (in depolarizing Ca(2+)-free high-K+ 50 mM solution), with depression of the maximal response and with pD2 values of 5.56 and 5.26, respectively. 6. In experiments in Ca2+-free medium, (+)-glaucine (3 microM) inhibited the contractions induced by NA and had no effect on either 5-HT- or caffeine-induced contractions.7. Furthermore, in the experiments with radioactive Ca2+, (+)-glaucine (3 microM) did not modify the basal uptake of 45Ca2+ but strongly inhibited the influx of 45Ca2+ induced by NA, 5-HT and K+.8. (+)-Glaucine (5microM) had no effect on rate and force of contraction in rat isolated atria.9. These results indicate that: (a) the cardiovascular effects (hypotension and bradycardia) of (+)-glaucine in anaesthetized normotensive rats (5 mg kg-1) may be due, at least in part, to a ganglioplexic effect; (b) the vasorelaxant action of ( + )-glaucine (0.15-5 microM) in rat isolated aorta can be attributed to an alpha1-adrenoceptor blocking property (which may explain its inhibition of noradrenaline-induced 45Ca2+influx and contractions in normal Krebs solution and noradrenaline-induced contractions in Ca2+-free medium) and to a Ca2+-antagonist activity (which may be responsible, at least in part, for the inhibition of 45Ca2+ uptake induced by NA, 5-HT and K+ and the contractions induced by both NA and 5-HT in normal Krebs solution and by Ca2+ in Ca2+-free high-K+ medium) and (c) there is no correlation between the mechanisms of action observed for (+ )-glaucine in vivo and in vitro, which suggests that the vasorelaxant activity of this alkaloid does not contribute to its hypotensive activity.
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Affiliation(s)
- F Orallo
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, Spain
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