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Developmental changes in endothelium-dependent relaxation of the chicken ductus arteriosus

100%

Agren P., Van Der Sterren S., Cogolludo A. L., Frazziano G., De Mey J. G. R., Blanco C. E., Villamor E.

Journal of Physiology and Pharmacology

2008

tom 59

nr 1

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.

Effects of prenatal hypoxia on pulmonary vascular reactivity in chickens prone to pulmonary hypertension

84%

Zoer B., Kessels L., Vereijken A., De Mey J. G. R., Bruggeman V., Decuypere E., Blanco C. E., Villamor E.

Journal of Physiology and Pharmacology

2009

tom 60

nr 1

119-130

Among chickens, meat-producing broiler strains are highly prone to develop severe pulmonary hypertension (PH) that is accompanied by endothelial dysfunction in the conduit extrapulmonary arteries. We hypothesized that exposure to chronic prenatal mild hypoxia would accelerate PH and endothelial dysfunction in smaller intrapulpulmonary arteries from broiler chickens. Fertilized broiler and layer (White Leghorn, WL) eggs were incubated under normoxic or hypoxic conditions. Endothelium-dependent (tested with acetylcholine, ACh ) and -independent (tested with sodium nitroprusside, SNP) relaxations of the caudomedial intrapulmonary artery were studied on fetal day 19 and at 2 weeks post-hatch. The response to acute hypoxia in vitro was also studied in the 2 wk-old vessels. Relaxations induced by ACh and SNP were similar in broiler and layer chickens and were unaffected by chronic mild hypoxia during incubation. However, during in vitro acute hypoxia the broiler arteries showed a markedly enhanced contraction. Chronic prenatal hypoxia did not affect the response of intrapulmonary arteries to acute hypoxia. We conclude that early endothelial dysfunction is not present in the small pulmonary arteries of fast-growing broilers after incubation under normoxic or hypoxic conditions. The higher susceptibility of the broiler pulmonary arteries to acute hypoxia might, at least partially, explain the higher susceptibility to PH.

Ograniczanie wyników

2 Journal of Physiology and Pharmacology

2 Blanco C. E.

2 De Mey J. G. R.

2 Villamor E.

1 Agren P.

1 Bruggeman V.

1 Cogolludo A. L.

1 Decuypere E.

1 Frazziano G.

1 Kessels L.

1 Van Der Sterren S.

1 Vereijken A.

1 Zoer B.

1 2009

1 2008

Wyniki wyszukiwania

Developmental changes in endothelium-dependent relaxation of the chicken ductus arteriosus

Effects of prenatal hypoxia on pulmonary vascular reactivity in chickens prone to pulmonary hypertension