Effect of the intraperitoneal administration of salmon-calcitonin on the "in vitro" actions of opioid agonists

Abstract

1. The interaction of intraperitoneal administration of salmon-calcitonin with opioids was studied. The study was carried out using guinea pig ileum (mu and kappa-opioid receptors), rabbit vas deferens (kappa-opioid receptors) and mouse vas deferens (delta-opioid receptors), and selective mu, delta and kappa agonists were used in the pertinent tissues. 2. The treatment with salmon-calcitonin increased, in a dose-dependent manner, the effect of U-50,488H in guinea pig ileum and rabbit vas deferens and the effects of [D-Pen2, D-Pen5] enkephalin in mouse vas deferens. 3. The treatment with analgesic doses of salmon-calcitonin enhances the in vitro effects of kappa- and delta-opioid agonists. The increase of the effectiveness of the opioid agonists may be one of the mechanisms involved on the analgesia induced by salmon-calcitonin.