Newborn intrapulmonary veins are more reactive than arteries in normal and hypertensive piglets.
The reactivity of pulmonary veins during adaptation from pre- to postnatal life is not well characterized. With an in vitro organ bath technique, the responses to the contractile and relaxant agonists U-46619 (10(-10) to 3 x 10(-6) M) and acetylcholine (10(-9) to 10(-4) M) were compared in adjacent conduit pulmonary vein and artery rings from 66 piglets aged 1 wk preterm to 14 days of postnatal life and from adult tissue. Five additional piglets were made hypertensive by exposure to chronic hypoxia for 3 days after birth. Both arteries and veins showed smaller contractile and relaxant responses before birth than after. By 5 min after birth, the contraction by arteries and relaxation by veins had increased (P < 0.05). By 3 days of age, arterial relaxation increased, but in all animals, venous relaxation exceeded that in arteries (P < 0.05). Veins contracted more than arteries in animals aged 3-14 days. Neonatal hypoxia diminished the responses to both agonists in the veins (P < 0.05), whereas the response in the arteries remained similar to that in the normal newborn. We speculate that veins may be more important in postnatal adaptation than previously suggested.
Arrigoni
F I
FI
Developmental Vascular Biology Unit, Institute of Child Health, London WC1N 1EH, United Kingdom.
Hislop
A A
AA
Haworth
S G
SG
Mitchell
J A
JA
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology; D010100:Oxygen / Q000009:adverse effects; D011651:Pulmonary Artery / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D011667:Pulmonary Veins / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine; D010100:Oxygen