Effects of prostaglandin E1 and indomethacin on fetal and neonatal lamb mesenteric artery responses to norepinephrine.

The effects of prostaglandin E1 (PGE1) and indomethacin on isolated fetal and neonatal lamb mesenteric artery responses to norepinephrine were investigated. PGE1 (1.5 micrometer) significantly reduced vasoconstriction responses to 0.5 to 5 micrometer norepinephrine. Indomethacin (1 micrometer) markedly potentiated the constrictor effects of 0.5 to 10 micrometer norepinephrine. PGE1 prevented the potentiating effect of indomethacin. Neither PGE1 nor indomethacin altered basal muscle tension. These results suggest that endogenous PGs modify adrenergic responses in the isolated mesenteric arteries of preterm and newborn lambs.