Initiation of blanch-blush cycles in the mouse uterus by cholinergic drugs

¹ Department of Anatomy, Medical College of South Carolina, Charleston, South Carolina

Epinephrine, Mecholyl and acetylcholine were tested for their effects on the ‘blanch-blush’ phenomenon of the uterus in 29 mice in three groups (ovariectomized, ovariectomized and estrogen-treated, and intact animals in estrus and diestrus). Spontaneous blanch-blush cycles occurred in each group. They were longer and more intense in the ovariectomized animals. Local application of acetylcholine and Mecholyl were followed by blanch-blush cycles similar to spontaneous cycles. Duration and intensity of these cycles varied directly with the concentration of the drugs. Atropine locally applied effectively blocked or interrupted the cycles associated with acetylcholine and Mecholyl application. Local application of epinephrine was followed by constriction of the vessels in the uterus. The evidence for the probability that an acetylcholine-like substance plays some role in the regulation of the blanch-blush phenomenon is examined and discussed.