Abstract
The anaphylactic contraction (Schultz‐Dale response) of the isolated uterus from actively sensitized rats was partially suppressed by methysergide, 1.5 μg/ml. Although the inhibitory effect of indomethacin, 3.5 μg/ml, was only slight, the combination of indomethacin and methysergide abolished the response almost completely. These observations indicate that, although serotonin must be the primary mediator of the anaphylactic uterine response, prostaglandin is also involved. Metiamide, a histamine H2‐receptor antagonist, 10 μg/ml, did not affect the anaphylactic response, suggesting that histamine was not released in amounts sufficient to counteract the uterine contracting mediators.