Castor Oil Induces Laxation and Uterus Contraction Via Ricinoleic Acid Activating Prostaglandin EP3 Receptors Sorin Tunarua, Till F
Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors Sorin Tunarua, Till F. Althoffa, Rolf M. Nüsingb, Martin Dienerc, and Stefan Offermannsa,d,1 aDepartment of Pharmacology, Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; dMedical Faculty, bInstitute for Clinical Pharmacology, J. W. Goethe University Frankfurt, 60590 Frankfurt, Germany; and cInstitute for Veterinary Physiology, Justus Liebig University, 35392 Giessen, Germany Edited by John H. Exton, Vanderbilt University School of Medicine, Nashville, TN, and approved April 25, 2012 (received for review January 30, 2012) Castor oil is one of the oldest drugs. When given orally, it has by the enteric nervous system or are direct effects on intestinal a laxative effect and induces labor in pregnant females. The smooth muscle remained unclear. effects of castor oil are mediated by ricinoleic acid, a hydroxylated The present study was undertaken to elucidate the molecular fatty acid released from castor oil by intestinal lipases. Despite the mechanism underlying the biological effect of castor oil-derived wide-spread use of castor oil in conventional and folk medicine, ricinoleic acid. Based on cellular signaling studies and an siRNA the molecular mechanism by which ricinoleic acid acts remains screening approach, we identified prostaglandin E2 receptors as unknown. Here we show that the EP3 prostanoid receptor is spe- targets of ricinoleic acid and show that the EP3 receptor medi- cifically activated by ricinoleic acid and that it mediates the phar- ates the effects of castor oil on the motility of the uterus and macological effects of castor oil. In mice lacking EP3 receptors, the the intestine.
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