RELAXANT AND CONTRACTILE RESPONSES TO PROSTAGLANDINS IN PREMATURE, NEWBORN AND ADULT BABOON CEREBRAL-ARTERIES

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  • 1 January 1985
    • journal article
    • research article
    • Vol. 233  (3) , 628-635
Abstract
Dose-dependent actions of prostaglandins (PG) were investigated on cerebral arterial strips isolated from premature, newborn and adult baboons. PGE1 and PGE2 in low concentrations (10-9 to 10-7 M) elicited significant relaxation in both premature and newborn baboon cerebral arteries. Arteries from adult baboons showed slight or small relaxation in response to these PG. PGE1 and PGE2 in higher concentrations (10-8 to 10-6 M) caused to contraction in premature and newborn arteries, but significant contraction in adult arteries. PGF2.alpha. (10-9 to 10-7 M) elictied relaxations in arteries from baboons of every age group, being greater in prematures and newborns than in adults. PGF2.alpha. (3 .times. 10-7 to 10-5 M) produced a slight or small contraction in prematures and newborns, respectively, whereas larger contraction was induced in the adult artery. PGI2 (prostacyclin) (10-8 to 10-6 M) produced dose-dependent relaxation in arteries from baboons of all groups with no significant difference in the relaxant effect among the 3 age groups. Effective concentration (EC25) values for relaxant effect of PGE1 and PGE2 were much less than those of PGF2.alpha. and PGI2 in premature and newborn arteries. In adult cerebral arteries, only PGF2.alpha. and PGI2 were effective in causing a significant relaxation. In premature and newborn arteries, PGE1 and PGE2 were not effective in causing a significant contraction, whereas in adult arteries EC25 values for contractile effects of PGE1 and PGE2 were less than those for PGF2.alpha.. Vasolilator responses to PGE1, PGE2 and PGE2.alpha. in low concentrations apparently decrease with developmental transition from the immature to the mature, whereas vasoconstrictor responses to these PG in high concentrations increase markedly. There seems to be no age-related alteration in vasodilating action to PGI2.