The Journal of international medical research
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To measure the plasma concentrations of three endogenous opioid peptides and the levels of preproenkephalin (PPE) and preprodynorphin (PPD) mRNA in peripheral blood lymphocytes of patients during scheduled surgery performed under intravenous general anaesthesia combined with an epidural block. ⋯ The level of mRNA from two pre-endogenous opioid peptide genes either decreased or remained unchanged during surgery under intravenous general anaesthesia with epidural block, suggesting that patients remained pain free during surgery.