Smooth muscle contractile action of the venom from the crown-of-thorns starfish, Acanthaster planci.

The fraction (venom B) of spine venom from the crown-of-thorns starfish (Acanthaster planci) caused contractions of the uterus of rats and enhanced vascular permeability in rabbits. The venom B-induced contraction of the smooth muscle was depressed by inhibitors of prostaglandin synthesis such as indomethacin or aspirin, but not by the anticholinergic agent, atropine. The fraction with the uterus contractile action was partially purified from venom B through column chromatography. This fraction contains phospholipase and proteinase activities and was different from the lethal factor in the venom. These results suggest that the uterine contractile action caused by venom B is mediated by prostaglandins and partly contributed by the activity of phospholipase in the venom.