Fig. 3From: Intrathecal morphine administration reduces postoperative pain and peripheral endocannabinoid levels in total knee arthroplasty patients: a randomized clinical trialSerum levels of NAEs and endocannabinoids in patients receiving intrathecal morphine or placebo. The levels of PEA, OEA, AEA, and 2-AG were quantified in serum obtained preoperatively and 4 h after TKA surgery. *, p < 0.05; **, p < 0.01; ***, p < 0.001Back to article page