RESUMEN
Using the pregnant uterus of mice, the effect of dinoprostone [PG E2] and misoprostol [PG E1] on uterine activity was compared. Both PG E1 and PG E2 were able to increase the uterine resting tone and amplitude of contractions. However, PG E1 caused magnification of the normal configuration of the wave of uterine contraction together with moderate increase of resting tone, while PG E2 caused initially a sharp increase in the tone with a sustained contraction showing only minimal oscillations. Both PG E1 and PG E2 were found to be effective in stimulating uterine activity. At the same time, PG E1 did induce a more physiological type of contraction that may be safer for labor induction than that produced by PG E2. Furthermore, the effect of both drugs was antagonized by the beta 2 sympathomimetric albuterol. The results indicated that beta 2 agonists could be used to stop uterine hypertonicity or to postpone uterine activity till the cervix is sufficiently ripened to minimize the effect of these contractions on both mother and fetus