Role of cyclic nucleotides in relaxation of fetal lamb ductus arteriosus.

摘要: Although prostaglandin E1 is used to dilate the constricted ductus arteriosus in infants with cyanotic heart disease, mechanism unknown. To test hypothesis that cyclic nucleotides adenosine 3',5'-monophosphate (cAMP) and guanosine (cGMP) play a role relaxation, isolated rings of fetal lambs were studied. Tension isometric contraction was measured by force displacement transducers. After oxygen, control group compared which stimulus for relaxation either nitrogen gas, (PGE1), nitroglycerin (NTG), or nitroprusside (NPS). During tissue frozen at 30 seconds 1, 2, 5 minutes analyzed cAMP cGMP. PGE1 (10(-6) mol/L) decreased tension 33% 70% 81% NTG (10(-5) mol/L), 92% NPS mol/L). The maximal induced associated an 11-fold increase cAMP; had no significant effect on cGMP levels. Nitrogen NTG, produced similar increases cAMP, eight-, 25-, nine-fold cGMP, respectively. These results suggest patency dependent activation both guanylate cyclase adenylate nitrovasodilators may be clinically useful maintaining arteriosus.