NO and prostaglandin interactions during hemodynamic stress in the fetal ovine pulmonary circulation.
Am J Physiol Lung Cell Mol Physiol
; 281(5): L1157-63, 2001 Nov.
Article
em En
| MEDLINE
| ID: mdl-11597907
ABSTRACT
Nitric oxide (NO) and prostacyclin (PGI(2)) are potent fetal pulmonary vasodilators, but their relative roles and interactions in the regulation of the perinatal pulmonary circulation are poorly understood. We compared the separate and combined effects of nitric oxide synthase (NOS) and cyclooxygenase (COX) inhibition during acute hemodynamic stress caused by brief mechanical compression of the ductus arteriosus (DA) in chronically prepared fetal lambs. Nitro-L-arginine (L-NNA; NOS antagonist), meclofenamate (Mec; COX inhibitor), combined drugs (L-NNA-Mec), or saline (control) was infused into the left pulmonary artery (LPA) before DA compression. In controls, DA compression decreased pulmonary vascular resistance (PVR) by 43% (P < 0.01). L-NNA, but not Mec, treatment completely blocked vasodilation and caused a paradoxical increase in PVR (+31%; P < 0.05). The effects of L-NNA-Mec and L-NNA on PVR were similar. To determine if the vasodilator effect of PGI(2) is partly mediated by NO release, we studied PGI(2)-induced vasodilation before and after NOS inhibition. L-NNA treatment blocked the PGI(2)-induced rise in LPA blood flow by 73% (P < 0.001). We conclude that NO has a greater role than PGs in fetal pulmonary vasoregulation during acute hemodynamic stress and that PGI(2)-induced pulmonary vasodilation is largely mediated by NO release in the fetal lung.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Prostaglandinas
/
Circulação Pulmonar
/
GMP Cíclico
/
Hemodinâmica
/
Pulmão
/
Óxido Nítrico
Limite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Am J Physiol Lung Cell Mol Physiol
Assunto da revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos