Inflammation and pain

Inflammatory pain is characterized by an increased response to mechanical or heat stimuli, which are normally only mildly painful (mechanical or thermal hyperalgesia). Inflammatory mediators may elicit pain by activating peripheral nociceptors, by promoting further release of inflammatory mediators and, most significantly, by sensitizing primary afferent neurons to any kind of stimuli. On the other hand, leukocytes may counteract the aforementioned effects of inflammation by releasing opioid peptides in peripheral inflammed tissue.