Peripheral and Spinal Actions of Opioids in the Blockade of the Autonomic Response Evoked by Compression of the Inflamed Knee Joint

Abstract

The activity of the respective agonists and the intraarticular > intramuscular ordering of systemic potency in this model indicate that opioids, by an action at mu and kappa, can exert a direct antihyperalgesic action at the terminals of primary afferents projecting to a region of inflammation. These observations offer strong support for a peripheral action of opioids in certain states in inflammation-induced hyperalgesia.