Antitussive effect of nociceptin/orphanin FQ in experimental cough models

Cough is an important defensive pulmonary reflex that removes irritants, fluids or foreign materials from the airways. However, often cough is non-productive and requires suppression. Opioid mu receptor agonists, such as codeine are commonly used as antitussive agents and are among the most widely administered drugs in the world. Codeine suppresses the responsiveness of one or more components of the central reflex pathway for cough and is an efficacious antitussive drug for cough due to diverse aetiologies. However, opioids produce side effects that include sedation, addiction potential and constipation. Therefore, novel cough suppressant therapies should maintain or improve upon the antitussive efficacy profile of opioids. Moreover, these novel therapies should have a safety profile significantly better than current antitussive therapies. Presently, we discuss preclinical findings showing that activation of the 'opioid-like' receptor (NOP(1)) inhibits cough in the guinea pig and cat.