Nitric Oxide and Cardiac Contraction: Clinical Studies

Author(s):  
Walter J. Paulus
1999 ◽  
Vol 77 (12) ◽  
pp. 950-957 ◽  
Author(s):  
Suresh C Tyagi ◽  
Lane M Smiley ◽  
Vibhas S Mujumdar

Homocyst(e)ine injured vascular endothelium and modulated endothelial-dependent vascular function. Endothelium plays an analogous role in both the vessel and the endocardium. Therefore, we hypothesized that homocyst(e)ine modulated endocardial endothelium (EE) dependent cardiac function. The ex vivo cardiac rings from normal male Wistar-Kyoto rats were prepared. The contractile responses of left and right ventricular rings were measured in an isometric myobath, using different concentrations of CaCl2. The response was higher in the left ventricle than right ventricle and was elevated in endocardium without endothelium. The half effective concentration (EC50) and maximum tension generated by homocyst(e)ine were 106 and 5-fold lower than endothelin (ET) and angiotensin II (AII), respectively. However, in endothelial-denuded endocardium, homocyst(e)ine response was significantly increased (p < 0.005, compared with intact endothelium) and equal to the response to ET and AII. To determine the physiological significance of ET, AII, homocyst(e)ine, and endothelial nitric oxide in EE function, cardiac rings were pretreated with AII (10-10 M) or ET (10-13 M) and then treated with homocyst(e)ine (10-8 M). Results suggested that at these concentrations AII, ET, or homocyst(e)ine alone had no effect on cardiac contraction. However, in the presence of 10-10 M AII or 10-13 M ET, the cardiac contraction to homocyst(e)ine (10-8 M) was significantly enhanced (p < 0.01, compared with without pretreatment) and further increased in the endocardium without endothelium. The pretreatment of cardiac ring with the inhibitor of nitric oxide, Nω-nitro-L-arginine methyl ester (L-NAME), increased contractile response to homocyst(e)ine. These results suggested that homocyst(e)ine impaired EE-dependent cardiac function and acted synergistically with AII and ET in enhancing the cardiac contraction.Key words: endocardial remodeling, homocyst(e)ine, contraction, endothelin, angiotensin, endothelial-derived relaxing factor (EDRF), Nω-nitro-L-arginine methyl ester (L-NAME), endothelial dysfunction, ex vivo cardiac function, heart failure.


2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Silvia Menendez Cepero

Ozone has been used as a therapeutical agent for the treatment of different diseases and beneficial effects have been observed. However, ozone biological effects remain controversial due to the scarce knowledge of its biochemical and pharmacodynamic mechanisms. Taking into account that ozone therapy is gathering more interest, day by day, and it has been used in apparently nonrelated diseases with beneficial effects, the National Center for Scientific Research (Havana, Cuba) in collaboration with different research centers and health institutions have studied the ozone toxicology and its pharmacological actions as well as its biochemical mechanisms. The most remarkable experiences, in preclinical and clinical studies, developed in Cuba during the last 30 years, in order to prove unequivocally ozone therapy validity, are presented in this lecture. On the basis of the oxidant properties of ozone, we postulate that controlled ozone administration (named as ozone oxidative pre-/postconditioning mechanism) is able to promote a slight and transient oxidative stress which in turn re-establishes the signalling pathways which have been lost in pathological conditions, preserving the cellular redox balance (increasing antioxidant endogenous system), mitochondrial function as well as the regulation of transcription factors and the modulation of the immunological system. It is evident that membrane-associated ozone peroxides, 4-hydroxialkenals, superoxide anion, nitric oxide, among others, are going to play an important role in cellular signals as well as in the pathology of different diseases. Regulation of these biomolecules by ozone preconditioning has been demonstrated in several preclinical and clinical studies as ischaemia-reperfusion phenomenom, parkinson, senile dementia, disk herniation, retinitis pigmentosa, ischemic cardiopathy, arterial insufficiencies, diabetes, osteoarthritis, asthma, vestibulocochlear syndrome, among others. Nitric oxide modulation, as well as the increase in A1 adenosine receptors achieved with this therapy has an important role in brain blood flux, in the formation of memory, in the release of neurotransmitters and in the inflammatory processes. Ozone therapy seems to induce a simultaneous resuscitation of functions that had gone wrong, reactivating and re-equilibrating physiological activities. This lecture contributes to clarify the ozone mechanism of action and its different pharmacology effects. It is concluded that ozone therapy can be useful in the treatment of several diseases, either as adjuvant of ortodox medicine or taking part positively in those where conventional therapy has had no success, all this with a common purpose: to favour the patients and contribute to a better quality of life.


2000 ◽  
Vol 278 (6) ◽  
pp. H1955-H1965 ◽  
Author(s):  
Jureta W. Horton ◽  
David Maass ◽  
Jean White ◽  
Billy Sanders

Whereas previous studies suggest that tumor necrosis factor-α (TNF-α) induces cardiac contraction-relaxation deficits, the mechanisms remain unclear. Our recent studies have implicated cardiac-derived nitric oxide (NO). This study examined the detrimental and protective effects of NO donors S-nitroso- N-acetyl-penicillamine (SNAP) or ( Z)-1- [ N-(3-ammonio-propyl)- N-( n-propyl)amino]diazen-1-ium- 1,2diolate (PAPA/NO) on TNF-α-related changes in cardiac contractile function (Langendorff), cellular injury, and intracellular myocyte Ca2+ concentration ([Ca2+]i). Myocytes were incubated in the presence/absence of TNF-α (200–500 pg/ml × 105 cells) for 3 h; subsets of myocytes were incubated with one of several concentrations of SNAP or PAPA/NO (0.1, 0.3, 0.5, and 1.5 mM) for 15 min before TNF-α challenge. Supernatant creatine kinase (CK), cell viability (Trypan blue dye exclusion), and myocyte [Ca2+]i (fura 2-acetoxymethyl ester) were measured. In parallel experiments, cardiac function (Langendorff) was examined after TNF-α challenge in the presence or absence of SNAP or PAPA/NO (0.1 and 1.5 mM). TNF-α in the absence of an NO donor impaired cardiac contraction and relaxation and produced cardiomyocyte injury. Pretreating perfused hearts or isolated cardiomyocytes with a low concentration of either SNAP or PAPA/NO decreased TNF-α-mediated cardiac injury and improved contractile dysfunction, whereas high concentrations of NO donor exacerbated TNF-α-mediated cardiac effects. These data provide one explanation for the conflicting reports of beneficial versus detrimental effects of NO in the face of inflammation and suggest that the effects of NO on organ function are concentration dependent; low concentrations of NO are cardioprotective, whereas high concentrations of NO are deleterious.


2019 ◽  
Vol 54 ◽  
pp. 68-76 ◽  
Author(s):  
Fernanda Blasina ◽  
Lucía Vaamonde ◽  
Fernando Silvera ◽  
Gonzalo Solla ◽  
Juan Andrés Abin-Carriquiry ◽  
...  

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