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We tested the hypothesis that endothelium-dependent relaxation in the chicken ductus arteriosus (DA) is developmentally regulated. Isolated DA rings from 15-, 19- and 21-day-old (externally pipped) chicken embryos relaxed to acetylcholine (ACh). This relaxation was unaffected by indomethacin but impaired by endothelium removal, by the NO synthase inhibitor L-NAME, and by the soluble guanylate cyclase inhibitor ODQ, suggesting the involvement of NO. This NO production was confirmed with the fluorescent probe DAF-2DA. The combination of apamin and charybdotoxin with L-NAME produced a further inhibition of ACh-induced relaxation, suggesting the participation of a putative EDHF. In the 21-day DA, the relaxations induced by ACh and sodium nitroprusside (SNP) were markedly reduced and scanning electron microscopy demonstrated an irregular endothelial lining with protrusion and detachment of endothelial cells. The relaxations induced by BAY 41-2272 and 8-Br cGMP were not affected by age. When compared with 5%, lower (0%) and higher (21, 95%) O2 concentrations impaired ACh-induced relaxation. In summary, we found that ACh induces endothelium-dependent relaxation of the chicken DA and that NO and EDHF are involved in this response. During chicken DA closure, endothelial cells undergo morphologic and functional alterations that result in the lack of endothelium-dependent relaxation.
Evaluation of biopotentials in the region of the amygdala of rats in the combined influence of alcohol and drugs, causing an imbalance of nitric oxide is described in this paper. Chronic alcoholism leads to structural morphological changes in the liver. A study of the amplitude of electrical activity showed that the electrical potential in the amygdala after 8 weeks chronic alcoholism was lower compared with normal rats. The frequency spectrum analysis showed decreased in the 2 times or more absolute spectral powers of all components. The relative spectral powers of its components: δ: θ: α: β was as a 2: 2: 2: 4. The use of sodium nitroprusside (donator of NO) together with the chronic consumption of ethanol reduces the effect of ethanol on low and high-frequence portion the performance of the bioelectrical activities spectrum in the amygdala. The use of non-selective blocker of NO-synthase – nitroarginine aggravated by the braking action of alcohol. The important role of nitric oxide in the development of adaptive-compensatory reactions of the damaged body is described. Our results may be useful to assess the contribution of NO in operation amygdala, conditions of chronic pathologies, and treatment of neuropsychiatric conditions, including diseases caused by alcohol abuse.
Nitric oxide (NO) is a mediator of a diverse array of inter- and intracellular signal transduction processes. The aim of the present study was to analyze its possible role as a second messenger in the process of neuronal differentiation of PC12 pheochromocytoma cells. Upon NGF treatment wildtype PC12 cells stop dividing and develop neurites. In contrast, a PC12 subclone (designated M-M17-26) expressing a dominant-negative mutant Ras protein keeps proliferating and fails to grow neurites after NGF treatment. Sodium nitroprusside (SNP), an NO donor, was found to induce the p53 protein and to inhibit proliferation of both PC12 and M-M17-26 cells, but failed to induce neuronal differentiation in these cell lines. Key signaling pathways (the ERK and Akt pathways) were also not affected by SNP treatment, and the phosphorylation of CREB transcription factor was only slightly stimulated. It is thus concluded from the results presented in this paper that NO is unable to activate signaling proteins acting downstream or independent of Ras that are required for neuronal differentiation.
We previously demonstrated that both mitogenicity and anabolism in rat L6 myoblasts even in the presence of insulin could be markedly reduced by milimolar concentrations of H202, SIN-1 (3-mor- pholinosydnonimine) and SNP (sodium nitroprusside) - donors of peroxynitrite (ONOO ) and nitric oxide (NO), respectively (Orzechowski and Grzelkowska 2000). In this paper we described the results of the experiment, which was carried out in order to confirm the assumption that muscle cell death occurred after treatment with high (milimolar) doses of ROS/RNS. Hydrogen peroxide (H202) or SIN-1, or SNP, all induced cell death in rat L6 myoblasts when given at 1 mM. Symptoms of cell shrinking with nuclear chromatin condensation collapse of chromatin into patches along nuclear membrane and formation of apoptotic bodies occurred within 24 hours of the study. Apoptosis was evaluated in situ on the basis of apoptotic index. The process of oligonucleosomal fragmentation of nuclear DNA was demonstrated whenever apoptotic cell death was observed. The verification of cell viability was monitored and the above-mentioned index confirmed the lack of cell respiration in dead myoblasts, especially those treated with SNP. On average 92%, 80%, 77% and 65% of cells were found apoptotic after 1 mM H202, 1 mM SIN-1 or 0.5 mM SNP and 1 mM SNP, respectively. However, necrotic cell death significantly contributed to overall cell death in cultures treated with NO donor and amounted to 6% and 21% for 0.5 mM SNP and 1 mM SNP, respectively. Taken together, these results indicate massive apoptosis induced by H202 and SIN-1, but, with regard to apoptotic action of NO, cell respiration was additionally attenuated and associated with necrotic cell death.
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