RESUMEN
S-Limonene (s-Lim) is a monocyclic monoterpene found in a variety of plants and has been shown to present antioxidant and cardioprotective activity in experimental models of myocardial infarction. The aim of this study was to evaluate the potential mechanism by which s-Lim exerts its antiarrhythmic effect, focusing on the blockade of ß-adrenoceptor (ß-AR) and its effects on various in vivo and in vitro parameters, including electrocardiogram (ECG) measurements, left ventricular developed pressure (LVDP), the ß-adrenergic pathway, sarcomeric shortening and L-type calcium current (ICa,L). In isolated hearts, 10 µM of s-Lim did not alter the ECG profile or LVPD. s-Lim increased the heart rate corrected QT interval (QTc) (10.8%) at 50 µM and reduced heart rate at the concentrations of 30 (12.4%) and 50 µM (16.6%). s-Lim (10 µM) also inhibited the adrenergic response evoked by isoproterenol (ISO) (1 µM) reducing the increased of heart rate, LVDP and ECG changes. In ventricular cardiomyocyte, s-Lim antagonized the effect of dobutamine by preventing the increase of sarcomeric shortening, demonstrating a similar effect to atenolol (blocker ß1-AR). In vivo, s-Lim antagonized the effect of ISO (agonists ß1-AR), presenting a similar effect to propranolol (a non-selective blocker ß-AR). In ventricular cardiomyocyte, s-Lim did not alter the voltage dependence for ICa,L activation or the ICa,L density. In addition, s-Lim did not affect changes in the ECG effect mediated by 5 µM forskolin (an activator of adenylate cyclase). In an in vivo caffeine/ISO-induced arrhythmia model, s-Lim (1 mg/kg) presented antiarrhythmic action verified by a reduced arrhythmia score, heart rate, and occurrence of ventricular premature beats and inappropriate sinus tachycardia. These findings indicate that the antiarrhythmic activity of s-Lim is related to blockade of ß-AR in the heart.
Asunto(s)
Antiarrítmicos , Limoneno , Ratas Wistar , Receptores Adrenérgicos beta , Transducción de Señal , Animales , Ratas , Antiarrítmicos/farmacología , Masculino , Receptores Adrenérgicos beta/metabolismo , Limoneno/farmacología , Transducción de Señal/efectos de los fármacos , Terpenos/farmacología , Corazón/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Ciclohexenos/farmacología , Arritmias Cardíacas/tratamiento farmacológico , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/inducido químicamente , Arritmias Cardíacas/fisiopatología , Isoproterenol/farmacología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismoRESUMEN
AIMS: It is well established that intracellular cAMP contributes to the relaxation of vas deferens smooth muscle. In many tissues, intracellular cAMP is actively transported to the extracellular space, where it exerts regulatory functions, via its metabolite adenosine. These actions take place through the cAMP conversion to adenosine by ectoenzymes, a process called "extracellular cAMP-adenosine pathway". Herein, we investigated whether, in addition to ATP, extracellular cAMP might be an alternative source of adenosine, influencing the contraction of vas deferens smooth muscle. MAIN METHODS: The effects of cAMP, 8-Br-cAMP and adenosine were analyzed in the isometric contractions of rat vas deferens. cAMP efflux was analyzed by measuring extracellular cAMP levels after exposure of vas deferens segments to isoproterenol and forskolin in the presence or absence of MK-571, an inhibitor of MRP/ABCC transporters. KEY FINDINGS: While 8-Br-cAMP, a cell-permeable cAMP analog, induced relaxation of KCl-precontracted vas deferens, the non-permeant cAMP increased the KCl-induced contractile response, which was mimicked by adenosine, but prevented by inhibitors of ecto-5'-nucleotidase or A1 receptors. Our results also showed that isoproterenol and forskolin increases cAMP efflux via an MRP/ABCC transporter-dependent mechanism, since it is inhibited by MK-571. SIGNIFICANCE: Our data show that activation of ß-adrenoceptors and adenylyl cyclase increases cAMP efflux from vas deferens tissue, which modulates the vas deferens contractile response via activation of adenosine A1 receptors. Assuming that inhibition of vas deferens contractility has been proposed as a strategy for male contraception, the extracellular cAMP-adenosine pathway emerges as a potential pharmacological target that should be considered in studies of male fertility.
Asunto(s)
5'-Nucleotidasa , AMP Cíclico , Contracción Muscular , Ratas Wistar , Receptor de Adenosina A1 , Conducto Deferente , Masculino , Animales , Conducto Deferente/efectos de los fármacos , Conducto Deferente/metabolismo , AMP Cíclico/metabolismo , 5'-Nucleotidasa/metabolismo , Receptor de Adenosina A1/metabolismo , Receptor de Adenosina A1/efectos de los fármacos , Ratas , Contracción Muscular/efectos de los fármacos , Adenosina/farmacología , Adenosina/análogos & derivados , Adenosina/metabolismo , Isoproterenol/farmacología , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Colforsina/farmacologíaRESUMEN
Long-term ß-adrenoceptor (ß-AR) stimulation is a pathological mechanism associated with cardiovascular diseases resulting in endothelial and perivascular adipose tissue (PVAT) dysfunction. In this study, we aimed to identify whether ß-adrenergic signaling has a direct effect on PVAT. Thoracic aorta PVAT was obtained from male Wistar rats and cultured ex vivo with the ß-AR agonist isoproterenol (Iso; 1â µM) or vehicle for 24 hours. Conditioned culture medium (CCM) from Iso-treated PVAT induced a marked increase in aorta contractile response, induced oxidative stress, and reduced nitric oxide production in PVAT compared to vehicle. In addition, Iso-treated PVAT and PVAT-derived differentiated adipocytes exhibited higher corticosterone release and protein expression of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), an enzyme responsible for de novo synthesis of corticosterone. Macrophages exposed to Iso also exhibited increased corticosterone release in response to ß-AR stimulation. Incubation of Iso-treated PVAT and PVAT-derived differentiated adipocytes with ß3-AR antagonist restored aorta contractile function modulated by Iso-CCM and normalized 11ß-HSD1 protein expression. These results show that ß3-AR signaling leads to upregulation of 11ß-HSD1 in PVAT, thus increasing corticosterone release and contributing to impair the anticontractile function of this tissue.
Asunto(s)
11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1 , Corticosterona , Isoproterenol , Animales , Masculino , Ratas , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/metabolismo , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/genética , Adipocitos/metabolismo , Adipocitos/efectos de los fármacos , Tejido Adiposo/metabolismo , Agonistas Adrenérgicos beta/farmacología , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Corticosterona/metabolismo , Medios de Cultivo Condicionados/farmacología , Isoproterenol/farmacología , Óxido Nítrico/metabolismo , Estrés Oxidativo/efectos de los fármacos , Ratas Wistar , Receptores Adrenérgicos beta/metabolismoRESUMEN
Cardiac maturation represents the last phase of heart development and is characterized by morphofunctional alterations that optimize the heart for efficient pumping. Its understanding provides important insights into cardiac regeneration therapies. Recent evidence implies that adrenergic signals are involved in the regulation of cardiac maturation, but the mechanistic underpinnings involved in this process are poorly understood. Herein, we explored the role of ß-adrenergic receptor (ß-AR) activation in determining structural and functional components of cardiomyocyte maturation. Temporal characterization of tyrosine hydroxylase and norepinephrine levels in the mouse heart revealed that sympathetic innervation develops during the first 3 wk of life, concurrent with the rise in ß-AR expression. To assess the impact of adrenergic inhibition on maturation, we treated mice with propranolol, isolated cardiomyocytes, and evaluated morphofunctional parameters. Propranolol treatment reduced heart weight, cardiomyocyte size, and cellular shortening, while it increased the pool of mononucleated myocytes, resulting in impaired maturation. No changes in t-tubules were observed in cells from propranolol mice. To establish a causal link between ß-AR signaling and cardiomyocyte maturation, mice were subjected to sympathectomy, followed or not by restoration with isoproterenol treatment. Cardiomyocytes from sympathectomyzed mice recapitulated the salient immaturity features of propranolol-treated mice, with the additional loss of t-tubules. Isoproterenol rescued the maturation deficits induced by sympathectomy, except for the t-tubule alterations. Our study identifies the ß-AR stimuli as a maturation promoting signal and implies that this pathway can be modulated to improve cardiac regeneration therapies.NEW & NOTEWORTHY Maturation involves a series of morphofunctional alterations vital to heart development. Its regulatory mechanisms are only now being unveiled. Evidence implies that adrenergic signaling regulates cardiac maturation, but the mechanisms are poorly understood. To address this point, we blocked ß-ARs or performed sympathectomy followed by rescue experiments with isoproterenol in neonatal mice. Our study identifies the ß-AR stimuli as a maturation signal for cardiomyocytes and highlights the importance of this pathway in cardiac regeneration therapies.
Asunto(s)
Miocitos Cardíacos , Propranolol , Transducción de Señal , Animales , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Ratones , Propranolol/farmacología , Receptores Adrenérgicos beta/metabolismo , Ratones Endogámicos C57BL , Isoproterenol/farmacología , Masculino , Corazón/efectos de los fármacos , Células Cultivadas , Agonistas Adrenérgicos beta/farmacología , Norepinefrina/metabolismo , Norepinefrina/farmacología , Antagonistas Adrenérgicos beta/farmacologíaRESUMEN
Several reports have demonstrated that depressive disorder is related to somatic symptoms including gastrointestinal or genitourinary alterations. The pathophysiological mechanisms underlying the gastrointestinal or genitourinary alterations associated with the depression are still not fully understood. Therefore, this study aimed to evaluate the motor activity of gastrointestinal (fundus of stomach and duodenum) and genitourinary tract (bladder) in a stress-based animal model of depression. Adult male mice were submitted to uncontrollable and unpredictable stress (learned helplessness model), controllable stress and non-stressful situations (control). Then, animals were euthanized and the fundus of stomach, duodenum segments or whole bladder were isolated and mounted in a standard organ bath preparation. We evaluated the contractile effects induced by KCl 80 mM for 5 min or carbachol (acetylcholine receptor agonist). The relaxant effects of isoproterenol (ß-adrenoceptor agonist) were also checked. Animals submitted to the learned helplessness model developed a helpless (depressive-like behavior) or resilient (does not exhibit depressive-like behavior) phenotype. The contractions induced by carbachol were diminished in fundus of stomach isolated from helpless and resilient animals. The isoproterenol-induced fundus of stomach relaxation was reduced in resilient but not helpless mice. The contractions/relaxation of duodenum segments isolated from helpless or resilient animals were not altered. Both helpless and resilient animals showed an increase in the bladder contractions induced by carbachol while the relaxant effects of isoproterenol were reduced when compared to control. Conversely, mice underwent a controllable stress situation did not exhibit alterations in the fundus of stomach or duodenum contraction/relaxation induced by pharmacological agents although a decrease in the bladder contraction induced by carbachol was found. In conclusion, incontrollable and unpredictable stress and not depressive phenotype (helpless animals) or controllable stress could be related to the alterations in motor activity of the fundus of stomach and bladder.
Asunto(s)
Depresión , Vejiga Urinaria , Ratones , Masculino , Animales , Carbacol/farmacología , Isoproterenol/farmacología , Estómago/fisiología , Contracción Muscular/fisiología , DuodenoRESUMEN
Altered sensitivity to the chronotropic and inotropic effects of catecholamines and reduction in ß1/ß2-adrenoceptor (ß1/ß2-AR) ratio were reported in failing and in senescent human heart, as well as in isolated atria and ventricle of rats submitted to stress. This was due to downregulation of ß1-AR with or without up-regulation of ß2-AR. AIMS: To investigate the stress-induced behavior of ß1-AR in the heart of mice expressing a non-functional ß2-AR subtype. The guiding hypothesis is that the absence of ß2-AR signaling will not affect the behavior of ß1-AR during stress and that those are independent processes. MATERIALS AND METHODS: The chronotropic and inotropic responses to ß-AR agonists in isolated atria of stressed mice expressing a non-functional ß2-AR were analyzed. The mRNA and protein expressions of ß1- and ß2-AR were also determined. KEY FINDINGS: No deaths were observed in mice under stress protocol. Atria of stressed mice displayed reduced sensitivity to isoprenaline compared to the controls, an effect that was abolished by the ß2- and ß1-AR antagonists 50 nM ICI118,551 and 300 nM CGP20712A, respectively. Sensitivity and maximum response to the ß-agonists dobutamine and salbutamol were not altered by stress or ICI118,551. The responses to dobutamine and salbutamol were prevented by CGP20712A. The expression of ß1-AR was reduced at protein levels. SIGNIFICANCE: Collectively, our data provide evidence that the cardiac ß2-AR is not essential for survival in a stressful situation and that the stress-induced reduction of ß1-AR expression was independent of the ß2-AR presence.
Asunto(s)
Agonistas Adrenérgicos beta , Dobutamina , Humanos , Ratones , Ratas , Animales , Dobutamina/farmacología , Dobutamina/metabolismo , Agonistas Adrenérgicos beta/farmacología , Atrios Cardíacos/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Isoproterenol/farmacología , Isoproterenol/metabolismo , Albuterol/farmacología , Receptores Adrenérgicos beta 1/genética , Receptores Adrenérgicos beta 1/metabolismo , Antagonistas Adrenérgicos beta/farmacología , Antagonistas Adrenérgicos beta/metabolismoRESUMEN
To investigate the role of adrenergic signalling (AS) in the host immune response and Porphyromonas gingivalis virulence, we compared norepinephrine (NE) and isoproterenol (ISO) responses in Galleria mellonella. P. gingivalis infection was evaluated by survival; humoral immune responses (i.e. melanization and cecropin and gloverin mRNA expression); cellular immune responses (i.e. haemocyte count, nodulation by histology); and P. gingivalis recovery (CFU/mL). P. gingivalis was cultivated in the presence of ISO (PgISO) or NE and injected into the larvae for survival evaluation. Finally, we co-injected ISO and PgISO to evaluate the concomitant effects on the immune response and bacterial virulence. None of the ligands were toxic to the larvae; ISO increased haemocyte number, even after P. gingivalis infection, by mobilizing sessile haemocytes in a ß-adrenergic-specific manner, while NE showed the opposite effect. ISO treatment reduced larval mortality and the number of recovered bacteria, while NE increased mortality and showed no effect on bacterial recovery. ISO and NE had similar effects on melanization and decreased the expression of cecropin. Although co-cultivation with NE and ISO increased the gene expression of bacterial virulence factors in vitro, only the injection of PgISO increased larval death, which was partially reversed by circulating ISO. Therefore, α- and ß-adrenergic signalling had opposite effects after P. gingivalis infection. Ultimately, the catecholamine influence on the immune response overcame the effect of more virulent strains. The effect of AS directly on the pathogen found in vitro did not translate to the in vivo setting.
Asunto(s)
Cecropinas , Mariposas Nocturnas , Adrenérgicos , Animales , Inmunidad Innata , Isoproterenol/farmacología , Larva/microbiología , Norepinefrina/farmacología , Porphyromonas gingivalis , ARN Mensajero , Virulencia , Factores de VirulenciaRESUMEN
The cardiac circadian clock is responsible for the modulation of different myocardial processes, and its dysregulation has been linked to disease development. How this clock machinery is regulated in the heart remains an open question. Because noradrenaline (NE) can act as a zeitgeber in cardiomyocytes, we tested the hypothesis that adrenergic signaling resets cardiac clock gene expression in vivo. In its anti-phase with Clock and Bmal1, cardiac Per1 abundance increased during the dark phase, concurrent with the rise in heart rate and preceded by an increase in NE levels. Sympathetic denervation altered Bmal1 and Clock amplitude, while Per1 was affected in both amplitude and oscillatory pattern. We next treated mice with a ß-adrenergic receptor (ß-AR) blocker. Strikingly, the ß-AR blockade during the day suppressed the nocturnal increase in Per1 mRNA, without altering Clock or Bmal1. In contrast, activating ß-AR with isoproterenol (ISO) promoted an increase in Per1 expression, demonstrating its responsiveness to adrenergic input. Inhibitors of ERK1/2 and CREB attenuated ISO-induced Per1 expression. Upstream of ERK1/2, PI3Kγ mediated ISO induction of Per1 transcription, while activation of ß2-AR, but not ß1-AR induced increases in ERK1/2 phosphorylation and Per1 expression. Consistent with the ß2-induction of Per1 mRNA, ISO failed to activate ERK1/2 and elevate Per1 in the heart of ß2-AR-/- mice, whereas a ß2-AR antagonist attenuated the nocturnal rise in Per1 expression. Our study established a link between NE/ß2-AR signaling and Per1 oscillation via the PI3Ky-ERK1/2-CREB pathway, providing a new framework for understanding the physiological mechanism involved in resetting cardiac clock genes.
Asunto(s)
Regulación de la Expresión Génica , Sistema de Señalización de MAP Quinasas , Miocardio/metabolismo , Proteínas Circadianas Period/biosíntesis , Receptores Adrenérgicos beta 2/metabolismo , Factores de Transcripción ARNTL/biosíntesis , Factores de Transcripción ARNTL/genética , Antagonistas de Receptores Adrenérgicos beta 2/farmacología , Animales , Proteínas CLOCK/biosíntesis , Isoproterenol/farmacología , Masculino , Ratones , Ratones Noqueados , Proteínas Circadianas Period/genética , Receptores Adrenérgicos beta 2/genéticaRESUMEN
AIMS: Nitric oxide synthases (NOSs) are key enzymes regulating vascular function. Previously, we reported that ß-adrenergic (ß-AR) overstimulation, a common feature of cardiovascular diseases, did not impair endothelium-dependent vasodilation, although it resulted in endothelial NOS (eNOS) uncoupling and reduced NO bioavailability. In addition to NO, neuronal NOS (nNOS) produces H2O2, which contributes to vasodilation. However, there is limited information regarding vascular ß-AR signaling and nNOS. In the present study, we assessed the possible role of nNOS-derived H2O2 and caveolins on endothelial vasodilation function following ß-AR overstimulation. MAIN METHODS: Male C57BL/6 wild-type and nNOS knockout mice (nNOS-/-) were treated with the ß-AR agonist isoproterenol (ISO, 15 mg·kg-1·day-1, s.c.) or vehicle (VHE) for seven days. Relaxation responses of aortic rings were evaluated using wire myograph and H2O2 by Amplex Red. KEY FINDINGS: Acetylcholine- or calcium ionophore A23187-induced endothelium-dependent relaxation was similar in aortic rings from VHE and ISO. However, this relaxation was significantly reduced in aortas from ISO compared to VHE when (1) caveolae were disrupted, (2) nNOS was pharmacologically inhibited or genetically suppressed and (3) H2O2 was scavenged. NOS-derived H2O2 production was higher in the aortas of ISO mice than in those of VHE mice. Aortas from ISO-treated mice showed increased expression of caveolin-1, nNOS and catalase, while caveolin-3 expression did not change. SIGNIFICANCE: The results suggest a role of caveolin-1 and the nNOS/H2O2 vasodilatory pathway in endothelium-dependent relaxation following ß-AR overstimulation and reinforce the protective role of nNOS in cardiovascular diseases associated with high adrenergic tone.
Asunto(s)
Caveolina 1/fisiología , Óxido Nítrico Sintasa de Tipo I/fisiología , Receptores Adrenérgicos alfa/metabolismo , Vasodilatación/fisiología , Agonistas Adrenérgicos beta/farmacología , Animales , Calcimicina/farmacología , Ionóforos de Calcio/farmacología , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/fisiopatología , Caveolina 1/genética , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Peróxido de Hidrógeno/metabolismo , Isoproterenol/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Óxido Nítrico Sintasa de Tipo I/genética , Vasodilatación/efectos de los fármacos , Vasodilatación/genéticaRESUMEN
AIMS: Stimulation of ß-adrenergic receptors (ßAR) in osteoblasts by isoproterenol (ISO) was shown to induce Vascular Endothelial Growth Factor (VEGF) and angiogenesis in long bones. We thus aimed to determine the vascular response of mandibular tissues to ßAR stimulation regarding blood vessel formation. MAIN METHODS: Six-week-old wild-type C57BL6 female mice received daily intraperitoneal injections of ISO or phosphate buffered saline (PBS) for 1 month. Hemimandibles and tibias were collected for immunolocalization of endomucin, tyrosine hydroxylase (TH), neuropeptide Y (NPY) and norepinephrine transporter (NET). Moreover, Vegfa, Il-1 ß, Il-6, Adrb2 and Rankl mRNA expression was assessed in mandibles and tibias 2 h after PBS or ISO treatment. KEY FINDINGS: Despite similar sympathetic innervation and Adrb2 expression between mandibular tissues and tibias, with TH and NPY+ nerve fibers distributed around blood vessels, ISO treatment did not increase endomucin+ vessel area or the total number of endomucin+ vessels in any of the regions investigated (alveolar bone, periodontal ligament, and dental pulp). Consistent with these results, the expression of Vegfα, Il-6, Il-1ß, and Rankl in the mandibular molar region did not change following ISO administration. We detected high expression of NET by immunofluorescence in mandible alveolar osteoblasts, osteocytes, and periodontal ligament fibroblasts, in addition to significantly higher Net expression by qPCR compared to the tibia from the same animals. SIGNIFICANCE: These findings indicate a differential response to ßAR agonists between mandibular and tibial tissues, since the angiogenic potential of sympathetic outflow observed in long bones is absent in periodontal tissues.
Asunto(s)
Agonistas Adrenérgicos beta/farmacología , Isoproterenol/farmacología , Ligamento Periodontal/efectos de los fármacos , Animales , Femenino , Ratones , Ratones Endogámicos C57BL , Ligamento Periodontal/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.
El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).
Asunto(s)
Síncope Vasovagal/diagnóstico , Síncope/diagnóstico , Pruebas de Mesa Inclinada/métodos , Niño , Humanos , Isoproterenol/efectos adversos , Isoproterenol/farmacología , Nitratos/efectos adversos , Nitratos/farmacología , Pruebas de Mesa Inclinada/efectos adversos , Vasodilatadores/efectos adversos , Vasodilatadores/farmacologíaRESUMEN
Knockout of multifunction gene cysteine- and glycine-rich protein 3 (CSRP3) in cardiomyocytes (CMs) of mice leads to heart dilation, severely affecting its functions. In humans, CSRP3 mutations are associated with hypertrophic (HCM) and dilated cardiomyopathy (DCM). The absence of the CSRP3 expression produces unknown effects on in vitro neonatal CMs' metabolism. The metabolome changes in culture media conditioned by CSRP3 knockout (KO-CSRP3), and wild type (WT) neonatal cardiomyocytes were investigated under untreated or after metabolic challenging conditions produced by isoproterenol (ISO) stimulation, by in vitro high-resolution proton magnetic resonance spectroscopy (1H-MRS)-based metabolomics. Metabolic differences between neonatal KO-CSRP3 and WT rats' CMs were identified. After 72 h of culture, ISO administration was associated with increased CMs' energy requirements and increased levels of threonine, alanine, and 3-hydroxybutyrate in both neonatal KO-CSRP3 and WT CMs conditioned media. When compared with KO-CSRP3, culture media derived from WT cells presented higher lactate concentrations either under basal or ISO-stimulated conditions. The higher activity of ketogenic biochemical pathways met the elevated energy requirements of the contractile cells. Both cells are considered phenotypically indistinguishable in the neonatal period of animal lives, but the observed metabolic stress responses of KO-CSRP3 and WT CMs to ISO were different. KO-CSRP3 CMs produced less lactate than WT CMs in both basal and stimulated conditions. Mainly, ISO-stimulated conditions produced evidence for lactate overload within KO-CSRP3 CMs, while WT CMs succeeded to manage the metabolic stress. Thus, 1H-MRS-based metabolomics was suitable to identify early inefficient energetic metabolism in neonatal KO-CSRP3 CMs. These results may reflect an apparent lower lactate transport and consumption, in association with protein catabolism.
Asunto(s)
Medios de Cultivo/química , Proteínas con Dominio LIM/metabolismo , Proteínas Musculares/metabolismo , Miocitos Cardíacos/metabolismo , Espectroscopía de Protones por Resonancia Magnética , Animales , Animales Recién Nacidos , Forma de la Célula , Análisis Discriminante , Isoproterenol/farmacología , Proteínas con Dominio LIM/deficiencia , Análisis de los Mínimos Cuadrados , Proteínas Musculares/deficiencia , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Ratas , Estadística como AsuntoRESUMEN
Abstract Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.
Resumen El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).
Asunto(s)
Humanos , Niño , Síncope/diagnóstico , Pruebas de Mesa Inclinada/métodos , Síncope Vasovagal/diagnóstico , Vasodilatadores/efectos adversos , Vasodilatadores/farmacología , Pruebas de Mesa Inclinada/efectos adversos , Isoproterenol/efectos adversos , Isoproterenol/farmacología , Nitratos/efectos adversos , Nitratos/farmacologíaRESUMEN
The ß-blocker propranolol (PROP) has been proposed as a repurposed treatment for breast cancer. The similarity of action between ß-agonists and antagonists found on breast cells encouraged us to compare PROP and isoproterenol (ISO, agonist) signaling pathways on a human breast cell line. Cell proliferation was measured by cell counting and DNA-synthesis. Cell adhesion was measured counting the cells that remained adhered to the plastic after different treatments. Changes in actin cytoskeleton were observed by fluorescence staining and Western Blot. ISO and PROP caused a diminution of cell proliferation and an increase of cell adhesion, reverted by the pure ß-antagonist ICI-118551. ISO and PROP induced a reorganization of actin cytoskeleton increasing F-actin, p-COFILIN and p-LIMK. While ISO elicited a marked enhancement of cAMP concentrations and an increase of vasodilator-stimulated phosphoprotein (VASP) and cAMP response element-binding protein (CREB) phosphorylation, PROP did not. Clathrin-mediated endocytosis inhibition or ß-arrestin1 dominant-negative mutant abrogated PROP-induced cell adhesion and COFILIN phosphorylation. The fact that PROP has been proposed as an adjuvant drug for breast cancer makes it necessary to determine the specific action of PROP in breast models. These results provide an explanation for the discrepancies observed between experimental results and clinical evidence.
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Agonistas Adrenérgicos beta/farmacología , Mama/citología , Propranolol/farmacología , Citoesqueleto de Actina/efectos de los fármacos , Citoesqueleto de Actina/metabolismo , Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Adhesión Celular/efectos de los fármacos , Línea Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , AMP Cíclico/biosíntesis , Femenino , Humanos , Isoproterenol/farmacología , Quinasas Lim/metabolismo , Estabilidad Proteica/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Factores de TiempoRESUMEN
Aliskiren (ALS) is well known for its antihypertensive properties. However, the potential underlying the molecular mechanism and the anti-hypertrophic effect of ALS have not yet been fully elucidated. The aim of the present study was to investigate the role of ALS in mammalian target of rapamycin (mTOR) and apoptosis signaling using in vivo and in vitro models of cardiac hypertrophy. A rat model of cardiac hypertrophy was induced by isoproterenol treatment (5 mg·kg-1·day-1) for 4 weeks, with or without ALS treatment at 20 mg·kg-1·day-1. The expression of hypertrophic, fibrotic, and apoptotic markers was determined by RT-qPCR. The protein expression of apoptotic markers mTOR and p-mTOR was assessed by western blot analysis. The proliferation of H9C2 cells was monitored using the MTS assay. Cell apoptosis was analyzed using flow cytometry. In vivo, isoproterenol-treated rats exhibited worse cardiac function, whereas ALS treatment reversed these dysfunctions, which were associated with changes in p-mTOR, Bcl-2, Bax, and cleaved caspase-3 expression, as well as the number of apoptotic cells. In vitro, H9C2 cardiomyocyte viability was significantly inhibited and cardiac hypertrophy was induced by Ang II administration, but ALS reversed Ang II-induced H9C2 cardiomyocyte hypertrophy and death. Furthermore, Ang II triggered the activation of the mTOR and apoptosis pathways in hypertrophic cardiomyocytes that were inhibited by ALS treatment. These results indicated that ALS alleviated cardiac hypertrophy through inhibition of the mTOR and apoptosis pathways in cardiomyocytes.
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Amidas/administración & dosificación , Apoptosis/efectos de los fármacos , Cardiomegalia/prevención & control , Fumaratos/administración & dosificación , Serina-Treonina Quinasas TOR/metabolismo , Angiotensina II/farmacología , Animales , Western Blotting , Cardiomegalia/inducido químicamente , Cardiomegalia/metabolismo , Modelos Animales de Enfermedad , Fibrosis/inducido químicamente , Fibrosis/prevención & control , Citometría de Flujo , Isoproterenol/farmacología , Masculino , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/efectos de los fármacosRESUMEN
Aliskiren (ALS) is well known for its antihypertensive properties. However, the potential underlying the molecular mechanism and the anti-hypertrophic effect of ALS have not yet been fully elucidated. The aim of the present study was to investigate the role of ALS in mammalian target of rapamycin (mTOR) and apoptosis signaling using in vivo and in vitro models of cardiac hypertrophy. A rat model of cardiac hypertrophy was induced by isoproterenol treatment (5 mg·kg-1·day-1) for 4 weeks, with or without ALS treatment at 20 mg·kg-1·day-1. The expression of hypertrophic, fibrotic, and apoptotic markers was determined by RT-qPCR. The protein expression of apoptotic markers mTOR and p-mTOR was assessed by western blot analysis. The proliferation of H9C2 cells was monitored using the MTS assay. Cell apoptosis was analyzed using flow cytometry. In vivo, isoproterenol-treated rats exhibited worse cardiac function, whereas ALS treatment reversed these dysfunctions, which were associated with changes in p-mTOR, Bcl-2, Bax, and cleaved caspase-3 expression, as well as the number of apoptotic cells. In vitro, H9C2 cardiomyocyte viability was significantly inhibited and cardiac hypertrophy was induced by Ang II administration, but ALS reversed Ang II-induced H9C2 cardiomyocyte hypertrophy and death. Furthermore, Ang II triggered the activation of the mTOR and apoptosis pathways in hypertrophic cardiomyocytes that were inhibited by ALS treatment. These results indicated that ALS alleviated cardiac hypertrophy through inhibition of the mTOR and apoptosis pathways in cardiomyocytes.
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Animales , Masculino , Ratas , Apoptosis/efectos de los fármacos , Cardiomegalia/prevención & control , Serina-Treonina Quinasas TOR/metabolismo , Fumaratos/administración & dosificación , Amidas/administración & dosificación , Fibrosis/inducido químicamente , Fibrosis/prevención & control , Angiotensina II/farmacología , Transducción de Señal/efectos de los fármacos , Western Blotting , Ratas Sprague-Dawley , Cardiomegalia/inducido químicamente , Cardiomegalia/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Modelos Animales de Enfermedad , Serina-Treonina Quinasas TOR/efectos de los fármacos , Citometría de Flujo , Isoproterenol/farmacologíaRESUMEN
Extinction is the learned inhibition of retrieval of a previously acquired memory and is a major component of exposure therapy, which has attracted much attention because of the use in the treatment of drug addiction, phobias and particularly fear disorders such as post-traumatic stress disorder (PTSD). Exposure to a novel environment before or after extinction training can enhance the extinction of contextual fear conditioning, however the cellular and molecular substrates are still unclear. Here, we investigated the participation of H2-histaminergic, ß-adrenergic and 5-HT1A-serotonergic receptors of the hippocampus on the enhancement of extinction memory caused by novelty. The infusion into the CA1 region of the serotonin 5-HT1A-receptor agonist, 8-OH-DPAT and the ß-adrenergic blocker, Timolol, after the exposure to the novelty hindered the enhancement of extinction by novelty, while Timolol also hindered the extinction consolidation when infused post-extinction. These impairments were abolished by the coinfusion of 8-OH-DPAT plus the 5-HT1A receptor antagonist, NAN-190 and Timolol plus ß-adrenergic agonist, Isoproterenol. However, Dimaprit and Ranitidine blocked the retrieval of CFC, but did not prevented the extinction learning. Here we elucidated some of the molecular mechanisms that are involved on the enhancement of extinction by novelty, demonstrating that the ß-adrenoreceptors and 5-HT1A serotonergic receptors participate on this process alongside with dopaminergic D1 receptors previously described, while histamine H2 receptors, so ubiquitous in learning-related functions in hippocampus are not involved.
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Agonistas Adrenérgicos beta/farmacología , Antagonistas Adrenérgicos beta/farmacología , Aprendizaje por Asociación/efectos de los fármacos , Extinción Psicológica/efectos de los fármacos , Miedo/efectos de los fármacos , Hipocampo/efectos de los fármacos , Agonistas de Receptores de Serotonina/farmacología , 8-Hidroxi-2-(di-n-propilamino)tetralin/farmacología , Animales , Condicionamiento Clásico/efectos de los fármacos , Isoproterenol/farmacología , Masculino , Ratas Wistar , Timolol/farmacologíaRESUMEN
PURPOSE: To evaluate the cardioprotective response of the pharmacological modulation of ß-adrenergic receptors (ß-AR) in animal model of cardiac ischemia and reperfusion (CIR), in spontaneously hypertensive (SHR) and normotensive (NWR) rats. METHODS: CIR was induced by the occlusion of left anterior descendent coronary artery (10 min) and reperfusion (75 min). The SHR was treated with ß-AR antagonist atenolol (AT, 10 mg/kg, IV) 5 min before CIR, and NWR were treated with ß-AR agonist isoproterenol (ISO, 0.5 mg/kg, IV) 5 min before CIR. RESULTS: The treatment with AT increased the incidence of VA, AVB and LET in SHR, suggesting that spontaneous cardioprotection in hypertensive animals was abolished by blockade of ß-AR. In contrast, the treatment with ISO significantly reduced the incidence of ventricular arrhythmia, atrioventricular blockade and lethality in NWR (30%, 20% and 20%, respectively), suggesting that the activation of ß-AR stimulate cardioprotection in normotensive animals. Serum CK-MB were higher in SHR/CIR and NWR/CIR compared to respective SHAM group (not altered by treatment with AT or ISO). CONCLUSION: The pharmacological modulation of ß-AR could be a new cardioprotective strategy for the therapy of myocardial dysfunctions induced by CIR related to cardiac surgery and cardiovascular diseases.
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Antagonistas de Receptores Adrenérgicos beta 1/farmacología , Agonistas Adrenérgicos beta/farmacología , Atenolol/farmacología , Cardiotónicos/farmacología , Isoproterenol/farmacología , Daño por Reperfusión Miocárdica/tratamiento farmacológico , Receptores Adrenérgicos beta/efectos de los fármacos , Animales , Biomarcadores/sangre , Presión Sanguínea/efectos de los fármacos , Forma MB de la Creatina-Quinasa/sangre , Pruebas de Función Cardíaca , Masculino , Daño por Reperfusión Miocárdica/sangre , Daño por Reperfusión Miocárdica/fisiopatología , Ratas Endogámicas SHR , Reproducibilidad de los Resultados , Factores de Tiempo , Resultado del TratamientoRESUMEN
Background: Hypothyroidism, the most common endocrine disease, induces cardiac electrical remodeling that creates a substrate for ventricular arrhythmias. Recent studies report that high thyrotropin (TSH) levels are related to cardiac electrical abnormalities and increased mortality rates. The aim of the present work was to investigate the direct effects of TSH on the heart and its possible causative role in the increased incidence of arrhythmia in hypothyroidism. Methods: A new rat model of central hypothyroidism (low TSH levels) was created and characterized together with the classical propylthiouracil-induced primary hypothyroidism model (high TSH levels). Electrocardiograms were recorded in vivo, and ionic currents were recorded from isolated ventricular myocytes in vitro by the patch-clamp technique. Protein and mRNA were measured by Western blot and quantitative reverse transcription polymerase chain reaction in rat and human cardiac myocytes. Adult human action potentials were simulated in silico to incorporate the experimentally observed changes. Results: Both primary and central hypothyroidism models increased the L-type Ca2+ current (ICa-L) and decreased the ultra-rapid delayed rectifier K+ current (IKur) densities. However, only primary but not central hypothyroidism showed electrocardiographic repolarization abnormalities and increased ventricular arrhythmia incidence during caffeine/dobutamine challenge. These changes were paralleled by a decrease in the density of the transient outward K+ current (Ito) in cardiomyocytes from animals with primary but not central hypothyroidism. In vitro treatment with TSH for 24 hours enhanced isoproterenol-induced spontaneous activity in control ventricular cells and diminished Ito density in cardiomyocytes from control and central but not primary hypothyroidism animals. In human myocytes, TSH decreased the expression of KCND3 and KCNQ1, Ito, and the delayed rectifier K+ current (IKs) encoding proteins in a protein kinase A-dependent way. Transposing the changes produced by hypothyroidism and TSH to a computer model of human ventricular action potential resulted in enhanced occurrence of early afterdepolarizations and arrhythmia mostly in primary hypothyroidism, especially under ß-adrenergic stimulation. Conclusions: The results suggest that suppression of repolarizing K+ currents by TSH underlies most of the electrical remodeling observed in hypothyroidism. This work demonstrates that the activation of the TSH-receptor/protein kinase A pathway in the heart is responsible for the cardiac electrical remodeling and arrhythmia generation seen in hypothyroidism.
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Arritmias Cardíacas/metabolismo , Remodelación Atrial/fisiología , Hipotiroidismo/metabolismo , Miocitos Cardíacos/metabolismo , Tirotropina/metabolismo , Potenciales de Acción , Animales , Antitiroideos/toxicidad , Arritmias Cardíacas/etiología , Arritmias Cardíacas/fisiopatología , Bexaroteno/toxicidad , Calcio/metabolismo , Simulación por Computador , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Electrocardiografía , Humanos , Hipotiroidismo/complicaciones , Hipotiroidismo/fisiopatología , Isoproterenol/farmacología , Canal de Potasio KCNQ1/efectos de los fármacos , Canal de Potasio KCNQ1/genética , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Miocitos Cardíacos/efectos de los fármacos , Técnicas de Placa-Clamp , Propiltiouracilo/toxicidad , ARN Mensajero/metabolismo , Ratas , Canales de Potasio Shal/efectos de los fármacos , Canales de Potasio Shal/genética , Tirotropina/farmacologíaRESUMEN
The activity of L-type calcium channels is associated with the duration of the plateau phase of the cardiac action potential (AP) and it is controlled by voltage- and calcium-dependent inactivation (VDI and CDI, respectively). During ß-adrenergic stimulation, an increase in the L-type current and parallel changes in VDI and CDI are observed during square pulses stimulation; however, how these modifications impact calcium currents during an AP remains controversial. Here, we examined the role of both inactivation processes on the L-type calcium current activity in newborn rat cardiomyocytes in control conditions and after stimulation with the ß-adrenergic agonist isoproterenol. Our approach combines a self-AP clamp (sAP-Clamp) with the independent inhibition of VDI or CDI (by overexpressing CaVß2a or calmodulin mutants, respectively) to directly record the L-type calcium current during the cardiac AP. We find that at room temperature (20-23°C) and in the absence of ß-adrenergic stimulation, the L-type current recapitulates the AP kinetics. Furthermore, under our experimental setting, the activity of the sodium-calcium exchanger (NCX) does not affect the shape of the AP. We find that hindering either VDI or CDI prolongs the L-type current and the AP in parallel, suggesting that both inactivation processes modulate the L-type current during the AP. In the presence of isoproterenol, wild-type and VDI-inhibited cardiomyocytes display mismatched L-type calcium current with respect to their AP. In contrast, CDI-impaired cells maintain L-type current with kinetics similar to its AP, demonstrating that calcium-dependent inactivation governs L-type current kinetics during ß-adrenergic stimulation.