Piercey M F, Ruwart M J
Br J Pharmacol. 1979 Jul;66(3):373-5. doi: 10.1111/j.1476-5381.1979.tb10840.x.
1 Subcutaneous prostaglandin E2 (2.5 mg/kg) produces profuse diarrhoea in fed rats. 2 Pretreatment of rats with subcutaneous loperamide (1.0 mg/kg) completely prevents prostaglandin-induced diarrhoea. If naloxone is administered prior to loperamide injections the activity of the antidiarrhoeal compound is completely destroyed. 3 These data provide strong evidence that the antidiarrhoeal activity of loperamide is mediated via the opiate receptor.