Quantitative study on the uterus-inhibiting activity of sodium naproxen in rat isolated uterus

Action of Sodium Naproxen on spontaneous and field stimulated motility of isolated rat uterus was studied. Sodium Naproxen inhibited both spontaneous and field stimulated motility. The IC50 on spontaneous motility was lower than the IC50 on stimulated motility. The inhibition produced on the field stimulated uterus was more regular in relationship to concentration used of Sodium Naproxen. The IC50 of Sodium Naproxen in these experimental conditions was 8.22 X 10(-4) M (pD2 = 3.09 +/- 0.02) and the maximum inhibitory effect was 100%. These results show that prostaglandin synthesis plays a necessary role in uterine contraction, spontaneous or induced by field stimulus.