[Role of neuropeptides and "pain substances" in the formation of humoral mechanisms of experimental and postoperative pain].

Humoral mechanisms of pain caused by different factors vary. The authors compare blood concentrations of "painful substances" in experimental dogs and in patients suffering from postoperative pain relieved by electroacupuncture for assessing the role of these substances: serotonin, histamine, prostaglandin F2 alpha (PGF), and neuropeptides beta-endorphine, methionine- and leucine-enkephalines. Serotonin, histamine, and PGF participated in the nociception process in an equal measure both in dogs and humans. Notable differences were observed for neuropeptides, which can be explained by species-specific differences and by probable contribution of other neuropeptides to mechanisms of experimental and postoperative pain.