Сhronobiological characteristic of postoperative pain and mechanism of its emergence

108 patients after performance of operations of high injury are examined. It is established that in the first three days of postoperative period anesthesia by narcotic analgetics was necessary on request of patients in night and early morning hours. It is shown that one of mechanisms of decrease the activity of antinociceptive system in these hours is reduction of neuropeptids (beta-endorphin, met-and ley-encephalin) secretion.