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1.
Acta Physiol (Oxf) ; 223(1): e13035, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29338122

RESUMO

The gasotransmitters nitric oxide (NO), carbon monoxide (CO), and hydrogen sulphide (H2 S), long considered only toxicant, are produced in vivo during the catabolism of common biological molecules and are crucial for a large variety of physiological processes. Mounting evidence is emerging that in poikilotherm vertebrates, as in mammals, they modulate the basal performance of the heart and the response to stress challenges. In this review, we will focus on teleost fish and amphibians to highlight the evolutionary importance in vertebrates of the cardiac control elicited by NO, CO and H2 S, and the conservation of the intracellular cascades they activate. Although many gaps are still present due to discontinuous information, we will use examples obtained by studies from our and other laboratories to illustrate the complexity of the mechanisms that, by involving gasotransmitters, allow beat-to-beat, short-, medium- and long-term cardiac homoeostasis. By presenting the latest data, we will also provide a framework in which the peculiar morpho-functional arrangement of the teleost and amphibian heart can be considered as a reference tool to decipher cardiac regulatory networks which are difficult to explore using more conventional vertebrates, such as mammals.


Assuntos
Anfíbios/metabolismo , Monóxido de Carbono/metabolismo , Peixes/metabolismo , Gasotransmissores/metabolismo , Sulfeto de Hidrogênio/metabolismo , Miocárdio/metabolismo , Óxido Nítrico/metabolismo , Transdução de Sinais , Anfíbios/anatomia & histologia , Animais , Evolução Molecular , Peixes/anatomia & histologia , Homeostase , Humanos , Óxido Nítrico Sintase/metabolismo , Especificidade da Espécie
2.
Cell Mol Life Sci ; 75(4): 743-756, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28965207

RESUMO

Phoenixin-14 (PNX) is a newly identified peptide co-expressed in the hypothalamus with the anorexic and cardioactive Nesfatin-1. Like Nesfatin-1, PNX is able to cross the blood-brain barrier and this suggests a role in peripheral modulation. Preliminary mass spectrography data indicate that, in addition to the hypothalamus, PNX is present in the mammalian heart. This study aimed to quantify PNX expression in the rat heart, and to evaluate whether the peptide influences the myocardial function under basal condition and in the presence of ischemia/reperfusion (I/R). By ELISA the presence of PNX was detected in both hypothalamus and heart. In plasma of normal, but not of obese rats, the peptide concentrations increased after meal. Exposure of the isolated and Langendorff perfused rat heart to exogenous PNX induces a reduction of contractility and relaxation, without effects on coronary pressure and heart rate. As revealed by immunoblotting, these effects were accompanied by an increase of Erk1/2, Akt and eNOS phosphorylation. PNX (EC50 dose), administered after ischemia, induced post-conditioning-like cardioprotection. This was revealed by a smaller infarct size and a better systolic recovery with respect to those detected on hearts exposed to I/R alone. The peptide also activates the cardioprotective RISK and SAFE cascades and inhibits apoptosis. These effects were also observed in the heart of obese rats. Our data provide a first evidence on the peripheral activity of PNX and on its direct cardiomodulatory and cardioprotective role under both normal conditions and in the presence of metabolic disorders.


Assuntos
Citoproteção , Coração/efeitos dos fármacos , Coração/fisiologia , Hormônios Hipotalâmicos/farmacologia , Hormônios Hipotalâmicos/fisiologia , Miocárdio/metabolismo , Hormônios Peptídicos/farmacologia , Hormônios Peptídicos/fisiologia , Animais , Cardiotônicos/metabolismo , Cardiotônicos/farmacologia , Citoproteção/efeitos dos fármacos , Citoproteção/genética , Hormônios Hipotalâmicos/isolamento & purificação , Hormônios Hipotalâmicos/metabolismo , Masculino , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/patologia , Hormônios Peptídicos/isolamento & purificação , Hormônios Peptídicos/metabolismo , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos
3.
Gen Comp Endocrinol ; 240: 1-9, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27633326

RESUMO

Chromogranin A (CgA) is an acidic protein co-stored with catecholamines, hormones and neuropeptides in the secretory granules of endocrine, neuronal and other cell types (including cardiomyocytes). Proteolytic cleavage in the C terminus of CgA generates a 2.9kDa peptide named serpinin (Serp; Ala26Leu) that can be modified at its N terminus to form a pyroglutamate residue (pGlu-Serp). In the rat heart, both peptides increase contractility and relaxation through a ß-adrenergic-like action mechanism. Accordingly, Serp and pGlu-Serp were proposed as novel myocardial sympatho-adrenergic modulators in mammals. On a comparative basis, here we report the actions of Serp and pGlu-Serp on myocardial contractility in three poikilotherm vertebrate species: the eel (Anguilla anguilla), the goldfish (Carassius auratus) and the frog (Rana esculenta). Using isolated working heart preparations, we show that pGlu-Serp reduces stroke volume in all species tested, while Serp reduces contractility in the frog heart, but is uneffective in eel and goldfish hearts. In the goldfish and frog hearts, pGlu-Serp activates the Nitric Oxide/cGMP pathway involving Endothelin-1 B receptors (frog) and ß3 adrenergic receptors (goldfish). pGlu-Serp-treated hearts from goldfish and frog show increased cGMP content. Moreover, the exposure of the frog heart to pGlu-Serp is accompanied by an increased expression of activated eNOS and Akt. In conclusion, this first report showing that pGlu-Serp inhibits mechanical cardiac performance in teleost and amphibians supports an evolutionary role of the CgA system, and particularly its serpinin component, in the sympatho-adrenergic control of the vertebrate heart.


Assuntos
Anfíbios/metabolismo , Cromogranina A/genética , Coração/efeitos dos fármacos , Miocárdio/metabolismo , Simpatomiméticos/metabolismo , Animais , Fragmentos de Peptídeos/metabolismo , Transdução de Sinais
4.
Gen Comp Endocrinol ; 224: 160-7, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26248227

RESUMO

The hypothalamic neuropeptide Nesfatin-1 is present in both mammals and teleosts in which it elicits anorexigenic effects. In mammals, Nesfatin-1 acts on the heart by inducing negative inotropism and lusitropism, and cardioprotection against ischemic damages. We evaluated whether in teleosts, Nesfatin-1 also influences cardiac performance. In the goldfish (Carassius auratus), mature, fully processed Nesfatin-1 was detected in brain, gills, intestine and skeletal muscle, but not in the cardiac ventricle. However, on the isolated and perfused working goldfish heart, exogenous Nesfatin-1 induced a positive inotropic effect, revealed by a dose-dependent increase of stroke volume (SV) and stroke work (SW). Positive inotropism was abolished by inhibition of adenylate cyclase (AC; MDL123330A) and cAMP-dependent kinase (PKA; KT5720), suggesting a cAMP/PKA-mediated pathway. This was confirmed by the increased cAMP concentrations revealed by ELISA on Nesfatin-1-treated hearts. Perfusion with Diltiazem, Thapsigargin and PD98059 showed the involvement of L-type calcium channels, SERCA2a pumps and ERK1/2, respectively. The role of ERK1/2 and phospholamban in Nesfatin-1-induced cardiostimulation was supported by Western blotting analysis. In conclusion, this is the first report showing that in teleosts, Nesfatin-1 potentiates mechanical cardiac performance, strongly supporting the evolutionary importance of the peptide in the control of the cardiac function of vertebrates.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/farmacologia , AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Proteínas de Ligação a DNA/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Coração/fisiologia , Proteínas do Tecido Nervoso/farmacologia , Animais , Western Blotting , Ensaio de Imunoadsorção Enzimática , Carpa Dourada , Coração/efeitos dos fármacos , Nucleobindinas
5.
Acta Physiol (Oxf) ; 214(2): 158-75, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25809182

RESUMO

Recent cardiovascular research showed that, together with ß1- and ß2-adrenergic receptors (ARs), ß3-ARs contribute to the catecholamine (CA)-dependent control of the heart. ß3-ARs structure, function and ligands were investigated in mammals because of their applicative potential in human cardiovascular diseases. Only recently, the concept of a ß3-AR-dependent cardiac modulation was extended to non-mammalian vertebrates, although information is still scarce and fragmentary. ß3-ARs were structurally described in fish, showing a closer relationship to mammalian ß1-AR than ß2-AR. Functional ß3-ARs are present in the cardiac tissue of teleosts and amphibians. As in mammals, activation of these receptors elicits a negative modulation of the inotropic performance through the involvement of the endothelium endocardium (EE), Gi/0 proteins and the nitric oxide (NO) signalling. This review aims to comparatively analyse data from literature on ß3-ARs in mammals, with those on teleosts and amphibians. The purpose is to highlight aspects of uniformity and diversity of ß3-ARs structure, ligands activity, function and signalling cascades throughout vertebrates. This may provide new perspectives aimed to clarify the biological relevance of ß3-ARs in the context of the nervous and humoral control of the heart and its functional plasticity.


Assuntos
Coração/fisiologia , Óxido Nítrico/metabolismo , Receptores Adrenérgicos beta 3/metabolismo , Transdução de Sinais/fisiologia , Vertebrados/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Animais , Humanos
6.
Nitric Oxide ; 42: 24-31, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25178168

RESUMO

Goldfish tolerate prolonged and severe hypoxia, thus representing a well-suited model to study the maintenance of cardiac function when O(2) availability represents a limiting factor. Using a working heart preparation, we explored the role of the intracardiac nitric oxide synthase (NOS)-derived nitric oxide (NO) under normoxic and hypoxic conditions. Cardiac performance was examined both under basal (constant preload and afterload) and loading conditions, i.e. preload-induced increases in stroke volume (SV) and hence cardiac output at constant afterload (the Frank-Starling response). Hypoxic hearts showed an increased basal mechanical performance compared to the normoxic counterpart. Under basal conditions, in both normoxic and hypoxic hearts, NOS and soluble guanylyl cyclase (sGC) inhibition increased SV, while exogenous NO supply decreased it. The normoxic heart was very sensitive to filling pressure increases; the maximum SV = 1.08 ± 0.09 mL/kg body mass was obtained at 0.4 kPa. Acute hypoxia increased this sensitivity, SV reaching the maximum value (1.45 ± 0.12 mL/kg body mass) at 0.25 kPa. NOS inhibition by L-NMMA reduced the Frank-Starling response under normoxia, but was ineffective under acute hypoxia, where NO may come from nitrite reduction. In both conditions, sGC inhibition induced a reduction of the cardiac response to preload. Moreover, under acute hypoxia, NO scavenging significantly reduced the Frank-Starling response. The hypoxia-induced hemodynamic patterns were complemented by Western blotting analysis which revealed increased expressions of NOS and hypoxia inducible factor α(HIF-1α). In conclusion, we demonstrated that intracardiac NO/NOS enhances goldfish heart performance, remarkably expanding its hypoxic tolerance.


Assuntos
Hemodinâmica , Hipóxia/fisiopatologia , Óxido Nítrico/fisiologia , Animais , Carpa Dourada
7.
Artigo em Inglês | MEDLINE | ID: mdl-23123761

RESUMO

The Frank-Starling law is a fundamental property of the vertebrate myocardium which allows, when the end-diastolic volume increases, that the consequent stretch of the myocardial fibers generates a more forceful contraction. It has been shown that in the eel (Anguilla anguilla) heart, nitric oxide (NO) exerts a direct myocardial relaxant effect, increasing the sensitivity of the Frank-Starling response (Garofalo et al., 2009). With the use of isolated working heart preparations, this study investigated the relationship between NO modulation of Frank-Starling response and temperature challenges in the eel. The results showed that while, in long-term acclimated fish (spring animals perfused at 20 °C and winter animals perfused at 10 °C) the inhibition of NO production by L-N5 (1-iminoethyl)ornithine (L-NIO) significantly reduced the Frank-Starling response, under thermal shock conditions (spring animals perfused at 10 or 15 °C and winter animals perfused at 15 or 20 °C) L-NIO treatment resulted without effect. Western blotting analysis revealed a decrease of peNOS and pAkt expressions in samples subjected to thermal shock. Moreover, an increase in Hsp90 protein levels was observed under heat thermal stress. Together, these data suggest that the NO synthase/NO-dependent modulation of the Frank-Starling mechanism in fish is sensitive to thermal stress.


Assuntos
Aclimatação/efeitos da radiação , Enguias/fisiologia , Coração , Óxido Nítrico , Aclimatação/fisiologia , Animais , Proteínas de Choque Térmico HSP90/metabolismo , Coração/efeitos dos fármacos , Coração/fisiologia , Contração Miocárdica/efeitos dos fármacos , Contração Miocárdica/fisiologia , Óxido Nítrico/metabolismo , Óxido Nítrico/fisiologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Técnicas de Cultura de Órgãos , Ornitina/análogos & derivados , Ornitina/farmacologia , Temperatura
8.
Artigo em Inglês | MEDLINE | ID: mdl-22705557

RESUMO

Using morphological and physiological approaches we provided, for the first time, a structural and functional characterization of Carassius auratus L. heart. Besides to the classical four chambers, i.e. sinus venosus, atrium, ventricle, bulbus, we described two distinct structures corresponding to the atrio-ventricular (AV) region and the conus arteriosus. The atrium is very large and highly trabeculated; the ventricle shows an outer compacta, vascularized by coronary vessels, and an inner spongiosa; the bulbus wall is characterized by a high elastin/collagen ratio, which makes it extremely compliant. Immunolocalization revealed a strong expression of activated "eNOS-like" isoforms both at coronary endothelium and, to a lesser extent, in the myocardiocytes and the endocardial endothelium (EE). The structural design of the heart appears to comply with its mechanical function. Using an in vitro working heart preparation, cardiac performance was evaluated at different filling and afterload pressures. The hearts were very sensitive to filling pressure increases. Maximum Stroke volume (SV=1.08 ± 0.09 mL/kg body mass) was obtained with an input pressure of 0.4 kPa. The heart was not able to sustain afterload increases, values higher than 1.5 kPa impairing its performance. These morpho-functional features are consistent with a volume pump mechanical performance.


Assuntos
Carpa Dourada/anatomia & histologia , Coração/anatomia & histologia , Animais , Vasos Coronários/anatomia & histologia , Proteínas de Peixes/metabolismo , Carpa Dourada/fisiologia , Frequência Cardíaca , Técnicas In Vitro , Miocárdio/enzimologia , Óxido Nítrico Sintase Tipo III/metabolismo , Volume Sistólico
9.
Acta Physiol (Oxf) ; 205(1): 9-25, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22463608

RESUMO

Phospholamban (PLN) is a small phosphoprotein closely associated with the cardiac sarcoplasmic reticulum (SR). Dephosphorylated PLN tonically inhibits the SR Ca-ATPase (SERCA2a), while phosphorylation at Ser16 by PKA and Thr17 by Ca(2+) /calmodulin-dependent protein kinase (CaMKII) relieves the inhibition, and this increases SR Ca(2+) uptake. For this reason, PLN is one of the major determinants of cardiac contractility and relaxation. In this review, we attempted to highlight the functional significance of PLN in vertebrate cardiac physiology. We will refer to the huge literature on mammals in order to describe the molecular characteristics of this protein, its interaction with SERCA2a and its role in the regulation of the mechanic and the electric performance of the heart under basal conditions, in the presence of chemical and physical stresses, such as ß-adrenergic stimulation, response to stretch, force-frequency relationship and intracellular acidosis. Our aim is to provide the basis to discuss the role of PLN also on the cardiac function of nonmammalian vertebrates, because so far this aspect has been almost neglected. Accordingly, when possible, the literature on PLN will be analysed taking into account the nonuniform cardiac structural and functional characteristics encountered in ectothermic vertebrates, such as the peculiar and variable organization of the SR, the large spectrum of response to stresses and the disaptive absence of crucial proteins (i.e. haemoglobinless and myoglobinless species).


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Coração/fisiologia , Contração Miocárdica/fisiologia , Miocárdio/metabolismo , Animais , Retículo Sarcoplasmático/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
10.
Nutr Metab Cardiovasc Dis ; 22(6): 486-94, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21186112

RESUMO

BACKGROUND AND AIMS: The anorexigenic glucagon-like peptide (GLP)-2 is produced by intestinal L cells and released in response to food intake. It affects intestinal function involving G-protein-coupled receptors. To verify whether GLP-2 acts as a cardiac modulator in mammals, we analysed, in the rat heart, the expression of GLP-2 receptors and the myocardial and coronary responses to GLP-2. METHODS AND RESULTS: GLP-2 receptors were detected on ventricular extracts by quantitative real-time polymerase chain reaction (Q-RT-PCR) and Western blotting. Cardiac GLP-2 effects were analysed on Langendorff perfused hearts. Intracellular GLP-2 signalling was investigated on Langendorff perfused hearts and by Western blotting and enzyme-linked immunosorbent assay (ELISA) on ventricular extracts. By immunoblotting and Q-RT-PCR, we revealed the expression of ventricular GLP-2 receptors. Perfusion analyses showed that GLP-2 induces positive inotropism at low concentration (10-12 mol l(-1)), and negative inotropism and lusitropism from 10 to 10 mol l(-1). It dose-dependently constricts coronaries. The negative effects of GLP-2 were independent from GLP-1 receptors, being unaffected by exendin-3 (9-39) amide. GLP-2-dependent negative action involves Gi/o proteins, associates with a reduction of intracellular cyclic adenosine monophosphate (cAMP), an increase in extracellular signal regulated kinases 1 and 2 (ERK1/2) and a decrease in phospholamban phosphorylation, but is independent from endothelial nitric oxide synthase (eNOS) and protein kinase G (PKG). Finally, GLP-2 competitively antagonised ß-adrenergic stimulation. CONCLUSIONS: For the first time, to our knowledge, we found that: (1) the rat heart expresses functional GLP-2 receptors; (2) GLP-2 acts on both myocardium and coronaries, negatively modulating both basal and ß-adrenergic stimulated cardiac performance; and (3) GLP-2 effects are mediated by G-proteins and involve ERK1/2.


Assuntos
Peptídeo 2 Semelhante ao Glucagon/farmacologia , Receptores de Glucagon/genética , Receptores de Glucagon/metabolismo , Animais , Western Blotting , Cardiotônicos/farmacologia , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/genética , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Ensaio de Imunoadsorção Enzimática , Regulação da Expressão Gênica , Receptor do Peptídeo Semelhante ao Glucagon 1 , Receptor do Peptídeo Semelhante ao Glucagon 2 , Coração/efeitos dos fármacos , Técnicas In Vitro , Sistema de Sinalização das MAP Quinases , Masculino , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Fragmentos de Peptídeos/farmacologia , Fosforilação , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais
11.
Proc Biol Sci ; 276(1675): 4043-52, 2009 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-19726482

RESUMO

The Frank-Starling mechanism is a fundamental property of the vertebrate heart, which allows the myocardium to respond to increased filling pressure with a more vigorous contraction of its lengthened fibres. In mammals, myocardial stretch increases cardiac nitric oxide (NO) release from both vascular endothelium and cardiomyocytes. This facilitates myocardial relaxation and ventricular diastolic distensibility, thus influencing the Frank-Starling mechanism. In the in vitro working heart of the eel Anguilla anguilla, we previously showed that an endogenous NO release affects the Frank-Starling response making the heart more sensitive to preload. Using the same bioassay, we now demonstrate that this effect is confirmed in the presence of the exogenous NO donor S-nitroso-N-acetyl penicillamine, is independent from endocardial endothelium and guanylate cyclase/cGMP/protein kinase G and cAMP/protein kinase A pathways, involves a PI(3)kinase-mediated activation of endothelial NO synthase and a modulation of the SR-CA(2+)ATPase (SERCA2a) pumps. Furthermore, we show that NO influences cardiac response to preload through S-nitrosylation of phospholamban and consequent activation of SERCA2a. This suggests that in the fish heart NO modulates the Frank-Starling response through a beat-to-beat regulation of calcium reuptake and thus of myocardial relaxation. We propose that this mechanism represents an important evolutionary step for the stretch-induced intrinsic regulation of the vertebrate heart, providing, at the same time, a stimulus for mammalian-oriented studies.


Assuntos
Proteínas de Ligação ao Cálcio/farmacologia , Enguias/fisiologia , Coração/fisiologia , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Débito Cardíaco/efeitos dos fármacos , Circulação Coronária/efeitos dos fármacos , AMP Cíclico/metabolismo , Endocárdio/fisiologia , Endotélio/metabolismo , Regulação da Expressão Gênica/fisiologia , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/antagonistas & inibidores , S-Nitroso-N-Acetilpenicilamina/farmacologia , Transdução de Sinais , Pressão Ventricular/fisiologia
12.
Acta Physiol (Oxf) ; 193(3): 229-39, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18208582

RESUMO

AIMS: Using a model of isolated and Langendorff-perfused rat heart we analysed whether activation of beta3-adrenergic receptors (beta3-ARs) influences ventricular lusitropic performance. We also focused on the NOS/NO/cGMP/PKG cascade as the signal transduction mechanism. METHODS: Hearts were treated with increasing concentrations (from 10(-12) to 10(-6) m) of BRL(37344), a selective beta3-AR agonist, and cardiac performance was evaluated by analysing both lusitropic parameters and coronary motility. Cardiac preparations were also perfused with BRL(37344) in the presence of either isoproterenol (ISO) or nadolol, or pertussis toxin (PTx), or selective inhibitors of the NOS/NO/cGMP/PKG pathway. RESULTS: BRL(37344) caused a significant concentration-dependent reduction in (LVdP/dt)(min), a decrease in half time relaxation significant starting from 10(-12) m, and an increase in (LVdP/dt)(max)/(LVdP/dt)(min) ratio (T/-t). BRL(37344) abolished the ISO-mediated positive lusitropism. beta3-AR-dependent effects on relaxation were insensitive to beta(1)/beta2-AR inhibition by nadolol (100 nm), and were abolished by G(i/o) protein inhibition by PTx (0.01 nm). NO scavenging by haemoglobin (10 microm), and nitric oxide synthase (NOS) inhibition by NG-monomethyl-l-arginine (10 microm) revealed the involvement of NO signalling in BRL(37344) response. Pre-treatment with inhibitors of either soluble guanylate cyclase (ODQ; 10 microm) or PKG (KT(5823); 100 nm) abolished beta3-AR-dependent negative lusitropism. In contrast, anantin (10 nm), an inhibitor of particulate guanylate cyclase, did not modify the effect of BRL(37344) on relaxation. CONCLUSION: Taken together, our findings provide functional evidence for beta3-AR modulation of ventricular relaxation in the rat heart which involves PTx-sensitive inhibitory Gi protein and occurs via an NO-cGMP-PKG cascade. Whether the effects of beta3-AR stimulation on lusitropism are beneficial or detrimental remains to be established.


Assuntos
Proteínas Quinases Dependentes de GMP Cíclico/fisiologia , Óxido Nítrico/fisiologia , Receptores Adrenérgicos beta 3/fisiologia , Função Ventricular Esquerda/fisiologia , Agonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Relação Dose-Resposta a Droga , Etanolaminas/farmacologia , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/fisiologia , Isoproterenol/antagonistas & inibidores , Isoproterenol/farmacologia , Masculino , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Transdução de Sinais/fisiologia , Função Ventricular Esquerda/efeitos dos fármacos
13.
J Exp Biol ; 209(Pt 24): 4966-73, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17142685

RESUMO

Neuroendocrine regulation of cardiac function involves a population of three types of beta-adrenoceptors (ARs). In various mammalian species, beta1- and beta2-AR stimulation produces an increase in contractility; whereas beta3-AR activation mediates negative inotropic effects. At the moment, nothing is known about the physiological role of beta3-AR in fish. Using an isolated working heart preparation, we show that a beta3-AR selective agonist BRL(37344) (0.1-100 nmol l(-1)) elicits a dose-dependent negative inotropism in the freshwater eel Anguilla anguilla. This effect was insensitive to the beta1/beta2-AR inhibitor nadolol (10 mumol l(-1)), but was blocked by the beta3-AR-specific antagonist SR(59230) (10 nmol l(-1)). The analysis of the percentage of stroke work (SW) variations, in terms of EC(50) values, induced by BRL(37344) alone (10 nmol l(-1)), and in presence of SR(59230) (10 nmol l(-1)), indicated a competitive antagonism of SR(59230). In addition to the classic positive inotropism, the non-specific beta agonist isoproterenol (100 nmol l(-1)) induced, in 30% of the preparations, a negative inotropic effect that was abrogated by pre-treatment with SR(59230), pointing to a beta3-mediated pathway. The BRL(37344)-induced negative inotropic effect was abolished by exposure to a G(i/o) proteins inhibitor pertussis toxin (PTx; 0.01 nmol l(-1)), suggesting a G(i/o)-dependent mechanism. Using L-N5(l-imino-ethyl)ornithine (L-NIO; 10 mumol l(-1)), as a nitric oxide (NO) synthase (NOS) blocker and haemoglobin (Hb; 1 mumol l(-1)), as a NO scavenger, we demonstrated that NO signalling is involved in the BRL(37344)-induced response. Pre-treatment with either an inhibitor of soluble guanylate cyclase (GC) 1H-(1,2,4) oxadiazolo-(4,3-a)quinoxalin-1-one (ODQ; 10 mumol l(-1)), or an inhibitor of the cGMP-activated protein kinase (PKG) KT(5823) (100 nmol l(-1)), abolished the beta3-dependent negative inotropism, indicating the cGMP-PKG component as a crucial target of NO signalling. Taken together, our findings provide functional evidence for the presence of beta3-like adrenoceptors in the eel Anguilla anguilla heart identifying, for the first time in a working fish heart, the beta3-AR-dependent negative inotropy discovered in mammals.


Assuntos
Anguilla/fisiologia , GMP Cíclico/metabolismo , Contração Miocárdica/fisiologia , Óxido Nítrico/metabolismo , Receptores Adrenérgicos beta 3/fisiologia , Agonistas de Receptores Adrenérgicos beta 3 , Agonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Depressão Química , Etanolaminas/farmacologia , Proteínas de Ligação ao GTP/metabolismo , Coração/efeitos dos fármacos , Coração/fisiologia , Técnicas In Vitro , Isoproterenol/farmacologia , Contração Miocárdica/efeitos dos fármacos , Nadolol/farmacologia , Propanolaminas/farmacologia , Transdução de Sinais
14.
J Exp Biol ; 207(Pt 16): 2867-75, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15235015

RESUMO

The morphodynamic changes occurring during growth were evaluated in the eel (Anguilla anguilla L.) heart. Using an in vitro working heart preparation, cardiac performance of small (body mass 96.76 +/- 27.49 g; mean +/- s.d.) and large (body mass 656 +/- 12 g; mean +/- s.d.) eels was compared under basal conditions and under loading (i.e. preload and afterload) challenges. A parallel morphometric evaluation of the ventricle was made using light and transmission electron microscope images. The small eel hearts show a basal cardiac output lower than their large counterparts (heart rate fh, 38.93 +/- 2.82 and 52.7 +/- 1.8 beats min(-1), respectively; stroke volume Vs, 0.27 +/- 0.017 and 0.37 +/- 0.016 ml kg(-1), respectively; means +/- s.e.m.). The two groups show similar responses at increasing preload, but differ remarkably at increasing afterload. Small eel hearts decreased Vs at afterload greater than 3 kPa, in contrast to larger hearts, which maintained constant Vs up to 6 kPa. These changes in mechanical performance are related to structural differences. Compared with the small eels, the large eels show an increase in the compacta thickness and in the diameter of the trabeculae in the spongiosa, together with reduction of the lacunary spaces. The increased compacta thickness is attained by enlargements of both the muscular and vascular compartments and reduction of the interstitium; consequently, this layer appears more compacted. Both compacta and spongiosa show higher number of myocytes together with reduced cross-sectional area and myofibrillar compartment. The compacta also shows an increased mitochondrial compartment. Our results document a cardiac morphodynamic remodelling in the growing eel.


Assuntos
Anguilla/fisiologia , Débito Cardíaco/fisiologia , Ventrículos do Coração/ultraestrutura , Coração/fisiologia , Análise de Variância , Anguilla/crescimento & desenvolvimento , Animais , Pesos e Medidas Corporais , Água Doce , Coração/anatomia & histologia , Coração/crescimento & desenvolvimento , Frequência Cardíaca/fisiologia , Perfusão , Volume Sistólico/fisiologia , Pressão Ventricular/fisiologia
15.
J Exp Biol ; 204(Pt 10): 1719-27, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11316492

RESUMO

Nothing is known about the effects of nitric oxide (NO) on cardiac performance in fish. Using an in vitro working heart preparation that generates physiological values of output pressure, cardiac output and ventricular work and power, we assessed the effects of NO on the cardiac performance of the eel Anguilla anguilla. We examined basal cardiac performance (at constant preload, afterload and heart rate), the effects of cholinergic stimulation and the Frank-Starling response (preload-induced increases in cardiac output at constant afterload and heart rate). The NO synthase (NOS) inhibitors NG-monomethyl-L-arginine (L-NMMA) and L-N5(1-iminoethyl)ornithine (L-NIO), the guanylate cyclase inhibitor 1H-(1,2,4)oxadiazolo-(4,3-a)quinoxalin-1-one (ODQ) and Triton X-100, a detergent that damages the endocardial endothelium, all increased stroke volume (VS) and stroke work (WS). In contrast, the endogenous NOS substrate L-arginine, tested before and after treatment with haemoglobin, the NO donor 3-morpholinosydnonimine, tested with and without the superoxide scavenger superoxide dismutase, and the stable cGMP analogue 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) decreased VS and WS. Acetylcholine chloride produced a biphasic effect. At nanomolar concentrations, in 34 % of the preparations, it induced a NO-cGMP-dependent positive inotropism that required the integrity of the endocardial endothelium. Pretreatment with Triton X-100 or with NO-cGMP pathway inhibitors (L-NMMA, L-NIO, NG-nitro-l-arginine methyl ester, Methylene Blue and ODQ) abolished the positive effect of acetylcholine. In contrast, at micromolar concentrations, acetylcholine produced a negative effect that involved neither the endocardial endothelium nor the NO-cGMP pathway. Pre-treatment with L-arginine (10(-6 )mol x l(-1)) was without effect, whereas L-NIO (10(-5 )mol x l(-1)) significantly reduced the Frank-Starling response. Taken together, these three experimental approaches provide evidence that NO modulates cardiac performance in the eel heart.


Assuntos
Anguilla/fisiologia , Coração/fisiologia , Contração Miocárdica , Óxido Nítrico/fisiologia , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Acetilcolina/farmacologia , Animais , Arginina/farmacologia , Atropina/farmacologia , Detergentes/farmacologia , Inibidores Enzimáticos/farmacologia , Feminino , Sequestradores de Radicais Livres/farmacologia , Coração/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hemodinâmica , Técnicas In Vitro , Masculino , Molsidomina/análogos & derivados , Molsidomina/farmacologia , Antagonistas Muscarínicos/farmacologia , Contração Miocárdica/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Doadores de Óxido Nítrico/farmacologia , Octoxinol/farmacologia , Ornitina/análogos & derivados , Ornitina/farmacologia , Oxidiazóis/farmacologia , Parassimpatolíticos/farmacologia , Pirenzepina/análogos & derivados , Pirenzepina/farmacologia , Quinoxalinas/farmacologia , Superóxido Dismutase/farmacologia , ômega-N-Metilarginina/farmacologia
16.
Int J Sociol Fam ; 19(1): 1-19, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-12281908

RESUMO

"The USSR family is changing in form from that of a social collectivity, a bedrock conception to socialism, to that of an autonomous family. Autonomy discloses a lack of homogeneity, an independence of choices over life-styles and a flexibility toward an interpretation given to the meaning of a socialistic state. Women are exceedingly active in making greater use of their legal rights to divorce and abortion and demanding equal status with men both in the workplace and in the home. Women are initiating major social changes, are readily adapting to changing relations and patterns in a complex society and are serving to spearhead changes in the family unit. These factors have generated major changes in the normative, behavioral and structural dimensions of marriage and family life in the Soviet Union."


Assuntos
Aborto Induzido , Comportamento , Divórcio , Características da Família , Estilo de Vida , Casamento , Mudança Social , Socialismo , Direitos da Mulher , Países Desenvolvidos , Economia , Serviços de Planejamento Familiar , Sistemas Políticos , Fatores Socioeconômicos , U.R.S.S.
17.
Health Mark Q ; 2(4): 145-57, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-10314137

RESUMO

Devising plans to maintain individuals with a chronic mental disability in the community following a long-term hospitalization is a highly complex problem. One of the significant aspects of this problem is the availability of adequate living arrangements that promote individual growth and development, provide professional support and care, and elicit the concern of members in the community who will provide these living arrangements. Alternate living arrangements require social experimentation in efforts to ascertain and appraise which one(s) are most appropriate for any given community. This paper devises a method of sequential development of alternatives in which each arrangement is appraised as it emerges in the community in relation to cost, knowledge acquired and utilized, technology advanced, and other resources required. It was assumed that each living arrangement produces different results in development. It further assumes that each living arrangement learns in development to the best interest of the chronic mentally disabled. The result of this innovative systems design is that professionals can make decisions on placement based on knowledge, information, technology, and cost as it emerges in juxtaposition to the results such programs are having on those in need.


Assuntos
Serviços Comunitários de Saúde Mental/organização & administração , Desinstitucionalização , Marketing de Serviços de Saúde , Assistência ao Convalescente/organização & administração , Modelos Teóricos , Técnicas de Planejamento , Estados Unidos
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