title: Nitric oxide synthase inhibition decreases tolerance to hyperoxia in newborn rats.
abstract: We evaluated the effects of sustained perinatal inhibition of NO synthase (NOS) on hyperoxia induced lung injury in newborn rats. N(G)-nitro-Larginine-methyl-ester (L-NAME) or untreated water was administered to pregnant rats for the final 7 days of gestation and during lactation; followed by postnatal exposure to hyperoxia (>95% O(2)) or room air. The survival rate of L-NAME treated pups when placed in > 95% O(2) at birth was significantly lower than controls from day 4 (L-NAME, 87%; control pups, 100%, p < 0.05) to 14 (L-NAME, 0%; control pups, 53%, p < 0.05). Foetal pulmonary artery vasoconstriction was induced by L-NAME with a decrease in internal diameter from 0.88 +/- 0.03 mm to 0.64 +/- 0.01 mm in control vs. L-NAME groups (p < 0.05), respectively. We conclude that perinatal NOS inhibition results in pulmonary artery vasoconstriction and a decreased tolerance to hyperoxia induced lung injury in newborn rats.
authors.affiliation: Department of Pediatrics Tulane Medical Center New Orleans LA USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Pierce
authors.forename: C A
authors.initials: CA
authors.lastname: Voelker
authors.forename: I R
authors.initials: IR
authors.lastname: Sosenko
authors.forename: S
authors.initials: S
authors.lastname: Bustamante
authors.forename: S M
authors.initials: SM
authors.lastname: Olister
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhang
authors.forename: D A
authors.initials: DA
authors.lastname: Clark
authors.forename: M J
authors.initials: MJ
authors.lastname: Miller