Developmental change in isoproterenol-mediated relaxation of pulmonary veins of fetal and newborn lambs.
Data(s) |
1998
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Resumo |
beta-Adrenergic agonists are important regulators of perinatal pulmonary circulation. They cause vasodilation primarily via the adenyl cyclase-adenosine 3',5'-cyclic monophosphate (cAMP) pathway. We examined the responses of isolated fourth-generation pulmonary veins of term fetal (145 +/- 2 days gestation) and newborn (10 +/- 1 days) lambs to isoproterenol, a beta-adrenergic agonist. In vessels preconstricted with U-46619 (a thromboxane A2 analog), isoproterenol induced greater relaxation in pulmonary veins of newborn lambs than in those of fetal lambs. The relaxation was eliminated by propranolol, a beta-adrenergic antagonist. Forskolin, an activator of adenyl cyclase, also caused greater relaxation of veins of newborn than those of fetal lambs. 8-Bromoadenosine 3',5'-cyclic monophosphate, a cell membrane-permeable analog of cAMP, induced a similar relaxation of all vessels. Biochemical studies show that isoproterenol and forskolin induced a greater increase in cAMP content and in adenyl cyclase activity of pulmonary veins in the newborn than in the fetal lamb. These results demonstrate that beta-adrenergic-agonist-mediated relaxation of pulmonary veins increases with maturation. An increase in the activity of adenyl cyclase may contribute to the change. |
Identificador |
http://serval.unil.ch/?id=serval:BIB_87D975BE92CC isbn:8750-7587 pmid:9572796 isiid:000073500800009 |
Idioma(s) |
en |
Fonte |
Journal of Applied Physiology, vol. 84, no. 5, pp. 1535-1539 |
Palavras-Chave | #15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology; 8-Bromo Cyclic Adenosine Monophosphate/pharmacology; Adenylate Cyclase/analysis; Animals; Animals, Newborn/physiology; Cyclic AMP/analysis; Fetus/physiology; Forskolin/pharmacology; Isoproterenol/pharmacology; Muscle Relaxation/drug effects; Muscle, Smooth, Vascular/drug effects; Propranolol/pharmacology; Pulmonary Veins/drug effects; Sheep/growth & development |
Tipo |
info:eu-repo/semantics/article article |