Effect of 2,5-dimethylpyrazine on uterine contraction in late stage of pregnant female rats.

Effect of 2,5-dimethylpyrazine (2,5-DMP) on oxytocic agent-induced late pregnant uterine contraction in female rats was studied. Oxytocic agents induced-hypercontraction in the late phase of pregnant uterine movements were inhibited by administration of 2,5-DMP. The inhibition of uterine contraction was obtained more strengthening by presence of a low dose of ritodrine hydrochloride than 2,5-DMP alone. These results suggests that 2,5-DMP has an inhibitory action on uterine hypercontraction induced by oxytocic agent through the beta2-adrenoceptor in the pregnant uterus and supports the applicability of relaxing drugs for oxytocic agent-induced accidents.