Search results for "Òxid nítric"
showing 10 items of 10 documents
Extracellular histones disarrange vasoactive mediators reléase through COX-NOS interaction in human endothelial cells
2017
Abstract Extracellular histones are mediators of inflammation, tissue injury and organ dysfunction. Interactions between circulating histones and vascular endothelial cells are key events in histone‐mediated pathologies. Our aim was to investigate the implication of extracellular histones in the production of the major vasoactive compounds released by human endothelial cells (HUVECs), prostanoids and nitric oxide (NO). HUVEC exposed to increasing concentrations of histones (0.001 to 100 μg/ml) for 4 hrs induced prostacyclin (PGI2) production in a dose‐dependent manner and decreased thromboxane A2 (TXA2) release at 100 μg/ml. Extracellular histones raised cyclooxygenase‐2 (COX‐2) and prostac…
Experimental diabetes induces hyperreactivity of rabbit renal artery to 5-hydroxytryptamine
2002
The influence of diabetes on the response of isolated rabbit renal arteries to 5-hydroxytryptamine (5-HT) was examined. 5-HT induced a concentration-related contraction that was higher in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal did not significantly modify 5-HT contractions in arteries from control rabbits but enhanced the response to 5-HT in arteries from diabetic rabbits. Incubation with NG-nitro-L-arginine (L-NA) enhanced contractions to 5-HT in arteries from control and diabetic rabbits. In arteries with endothelium, this L-NA enhancement was lower in diabetic rabbits than in control rabbits. In arteries without endothelium, incubation w…
Diabetes-induced changes in endothelial mechanisms implicated in rabbit carotid arterial response to 5-hydroxytryptamine
2000
The influence of diabetes on endothelial mechanisms implicated in the response of isolated rabbit carotid arteries to 5-hydroxytryptamine (5-HT)was studied. 5-HT induced a concentrationdependent contraction that was potentiated in arteries from diabetic rabbits with respect to that in arteries from control rabbits. Endothelium removal potentiated 5-HT contractions in arteries from both control and diabetic rabbits but increased the maximum effect only in arteries from diabetic rabbits. Incubation of arterial segments with Nº-nitro-L-arginine(L-NA)enhanced the contractile response to 5-HT. This L-NA enhancement was greater in arteries from diabetic rabbits than in arteries from control rabbi…
Different role of endothelin ETA and ETB receptors and endothelial modulators in diabetes-induced hyperreactivity of the rabbit carotid artery to end…
2004
The influence of diabetes on regulatory mechanisms and specific receptors implicated in the contractile response of isolated rabbit carotid arteries to endothelin-1 was examined. Endothelin-1 induced a concentration-dependent contraction that was greater in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal or NG-nitro-L-arginine enhanced contractions in response to endothelin-1 only in control arteries, without modifying the endothelin-1 response in diabetic arteries. Indomethacin, furegrelate (thromboxane A2 inhibitor), or cyclo-(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123; endothelin ETA receptor antagonist) inhibited the contractions in response to endothel…
Diabetes potentiates acetylcholine-induced relaxation in rabbit renal arteries
2001
The response of rabbit renal arteries to acetylcholine and its endothelial modulation in diabetes were investigated. Acetylcholine induced concentration-related endothelium-dependent relaxation of renal arteries that was significantly more potent in diabetic rabbits than in control rabbits. Pretreatment with NG-nitro-L-arginine L-NOArg., indomethacin, or L-NOArg plus indomethacin induced partial inhibition of acetylcholine-induced relaxation. Inhibition induced by L-NOArg plus indomethacin was significantly higher in arteries from diabetic rabbits than in arteries from control rabbits. In renal arteries depolarised with KCl 30 mM and incubated with L-NOArg plus indomethacin, acetylcholine-i…
Contribution of endothelin receptors and cyclooxygenase-derivatives to the altered response of the rabbit renal artery to endothelin-1 in diabetes
2006
The influence of diabetes on regulatory mechanisms and specific receptors implicated in the response of isolated rabbit renal artery to endothelin-1 was examined. Endothelin-1 induced a concentration-dependent contraction that was less potent in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal or NG-nitro-L-arginine (L-NOARG) enhanced contractions to endothelin-1 either in control and diabetic arteries. Indomethacin inhibited endothelin-1-induced response in control arteries, but enhanced it in diabetic arteries. In contrast to that observed in rubbed and in L-NOARG treated arteries, in the presence of indomethacin the contractile action of endotheli…
Mechanisms underlying diabetes enhancement of endothelin-1-induced contraction in rabbit basilar artery
2004
The influence of alloxan-induced diabetes on the reactivity of rabbit basilar artery to endothelin-1 was examined. Endothelin-1 induced concentration-dependent contraction of basilar arteries that was higher in diabetic than in control rabbits. Endothelium removal produced a higher enhancement of the endothelin-1-induced contraction in control than in diabetic rabbits. N(G)-nitro-L-arginine (L-NOArg) enhanced the maximal contraction induced by endothelin-1 in control rabbits and potentiated this response in diabetic rabbits. Endothelin ETA receptor antagonist, cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123), inhibited endothelin-1-induced contraction in both rabbit groups. Endothelin ETB receptor…
Electronic Structure Modulation in an Exceptionally Stable Non-Heme Nitrosyl Iron(II) Spin-Crossover Complex
2016
The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF6)(2) (bztpen=N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethylenediamine) displays an S=1/2 S=3/2 spin crossover (SCO) behavior (T-1/2=370 K, Delta H= 12.48 kJmol(-1), Delta S=33 JK(-1) mol(-1)) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0 S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120-420 K affording a detailed picture of how the electronic distribution of the t(2g)-e(g) orbitals modulates the structure of the {FeNO}(7) bond, providing valuable magneto-structural and spectroscopic correlat…
Nitric oxide mediates abnormal responsiveness of thyroid arteries in methimazole-treated patients
2005
Objective: We studied the intervention of nitric oxide (NO), prostacyclin (PGI2) and endothelium-derived hyperpolarizing factor (EDHF) in mediating responses to acetylcholine in thyroid arteries from euthyroid (E) and methimazole-treated (MT) patients. Design and methods: Branches of the superior thyroid artery were obtained from 19 E patients and 17 MT patients (euthyroid at the time of surgery) undergoing total thyroidectomy or hemithyroidectomy. Artery rings were suspended in organ baths for isometric recording of tension. Results and conclusions: Acetylcholine caused endothelium-dependent relaxation of greater magnitude in arteries from MT patients (pD2 7.68±0.19 in E and 8.17±0.26 in M…
Efecto de las ciclooxigenasas en la biodisponibilidad del óxido nítrico en la respuesta vascular al tromboxano A2 en un modelo murino de envejecimien…
2018
El envejecimiento y la pérdida de los estrógenos durante la menopausia se asocian a una menor biodisponibilidad del NO, un aumento de los niveles de O2- vascular y un incremento de sustancias contráctiles, entre ellas el TXA2. Queda por determinar si los efectos deletéreos vasculares inducidos por el TXA2 durante el envejecimiento median una disminución en la biodisponibilidad de NO y un aumento en la producción de O2- y si están modulados por estrógenos. Para ello, se validó un modelo de envejecimiento vascular en ratonas con senescencia acelerada (SAM), con ratonas de la cepa SAMP8 con predisposición a la senescencia acelerada y ratonas SAMR1, con resistencia al desarrollo de senescencia …