Maturation of O2 sensing and signaling in the chicken ductus arteriosus.
The increase in O(2) tension after birth is a major factor stimulating ductus arteriosus (DA) constriction and closure. Here we studied the role of the mitochondrial electron transport chain (ETC) as sensor, H(2)O(2) as mediator, and voltage-gated potassium (K(V)) channels and Rho kinase as effectors of O(2)-induced contraction in the chicken DA during fetal development. Switching from 0% to 21% O(2) contracted the pulmonary side of the mature DA (mature pDA) but had no effect in immature pDA and relaxed the aortic side of the mature DA (mature aDA). This contraction of the pDA was attenuated by inhibitors of the mitochondrial ETC and by the H(2)O(2) scavenger polyethylene glycol (PEG)-catalase. Moreover, O(2) increased reactive oxygen species (ROS) production, measured with the fluorescent probes dihydroethidium and 2',7'-dichlorofluorescein, only in mature pDA. The H(2)O(2) analog t-butyl-hydroperoxide mimicked the responses to O(2) in the three vessels. In contrast to immature pDA cells, mature pDA cells exhibited high-amplitude O(2)-sensitive potassium currents. The K(V) channel blocker 4-aminopyridine prevented the current inhibition elicited by O(2). The L-type Ca(2+) (Ca(L)) channel blocker nifedipine and the Rho kinase inhibitors Y-27632 and hydroxyfasudil induced a similar relaxation when mature pDA were stimulated with O(2) or H(2)O(2). Moreover, the sensitivity to these drugs increased with maturation. Our results indicate the presence of a common mechanism for O(2) sensing/signaling in mammalian and nonmammalian DA and favor the idea that, rather than a single mechanism, a parallel maturation of the sensor and effectors is critical for O(2) sensitivity appearance during development.
Cogolludo
Angel L
AL
Dept. of Pharmacology, School of Medicine, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain. acogolludo@med.ucm.es
Moral-Sanz
Javier
J
van der Sterren
Saskia
S
Frazziano
Giovanna
G
van Cleef
Anne N H
AN
Menéndez
Carmen
C
Zoer
Bea
B
Moreno
Enrique
E
Roman
Angela
A
Pérez-Vizcaino
Francisco
F
Villamor
Eduardo
E
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D015153:Blotting, Western; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002642:Chick Embryo; D004373:Ductus Arteriosus / Q000378:metabolism*; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004594:Electrophysiology; D006861:Hydrogen Peroxide / Q000633:toxicity; D016877:Oxidants / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D020746:Calcium Channels, L-Type; D016877:Oxidants; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D054460:rho-Associated Kinases; D014450:Electron Transport Complex III; D010100:Oxygen