The comparative actions of uterine inhibiting drugs in the pregnant rat.
Studies were made to determine the effect of various contraction-inhibitors against spontaneous uterine contraction in rats during late pregnancy. 1) The duration and rate of inhibitory activity differed from inhibitor to inhibitor, showing dose-response relationship. As a result of this investigation of the changes in the intensity and frequency for 17 inhibitors, Ca-blocker, beta 2-stimulants and dibutyryl c-AMP had the strongest effects, PG-antagonist, and the anti-inflammatory drugs such as aminophylline were much weaker in their inhibitory activity. 2) When the progress of uterine inhibition was investigated on the basis of quantitative changes of PG and c-AMP in bath medium, it was found that both PGE1 and PGF2 alpha were significantly reduced after administration of terbutaline and indomethacin, c-AMP decreased significantly after administration of PGE1 analogue, oxytocin and PGF2 alpha. The c-AMP levels increased significantly after administration of terbutaline and verapamil. These were no significant changes in c-AMP levels when indomethacin and aminophylline were used. During the administration of the uterine inhibitors, c-AMP increased significantly both in vivo and in vitro. Therefore, c-AMP may be regarded as an important parameter indicating the degree of inhibition of contraction.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology*; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D011247:Pregnancy; D011270:Pregnancy, Animal; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology*; D051381:Rats; D014590:Uterine Contraction / Q000187:drug effects*
D000318:Adrenergic beta-Agonists; D000893:Anti-Inflammatory Agents; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D000242:Cyclic AMP