Abstract: AIM: To study the effects of morphine on tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) production in human whole blood and the possible mechanism. METHODS: The seven human whole blood samples were collected, and each was aliquoted in six tubes. A total of 100 μl of whole blood was added with morphine sulfate (200 mg·L ^-1 and 2 mg·L ^-1).Then lipopolysaccharide (LPS) (100 μg·L ^-1) was added to the blood and incubated for 6 h at 37 ℃.Each whole blood was divided into six groups:drug-alone groups (groupA₁ , morphine 200 mg·L ^-1;group A2, morphine 2 mg·L ^-1), activation groups (group B₁ , morphine 200 mg·L ^-1 +LPS; group B₂, morphine 2 mg·L ^-1 +LPS), control group (group C₁), and LPS group (group C₂).The concentrations of TNF-αand IL-6 in plasma were measured by ELISA. RESULTS: The values of TNF-αproduction in group A₁, A₂ and C₁ were 240, 251, and 279 ng·L ^-1 (P >0.05), respectively;the values of IL-6 were 444, 490, and 561 ng·L ^-1 (P >0.05), respectively.The cytokine production in groupB₁, B₂ and C₂ were 490, 534 and 1226 ng·L ^-1 (TNF-α), respectively;1177, 1310 and 1563 ng·L ^-1 (IL-6), respectively.The levels in group B₁ and B₂ were less than that in group C₂ (P < 0.01, or P <0.05), and the level in B1 was less than that in B₂. CONCLUSION: Morphine alone has no effects on TNF-αand IL-6 production, but attenuates LPSinduced TNF-αand IL-6 production, and the high dose of morphine-induced effects on attenuation of TNF-αand IL- 6 production increased are more than the low dose.

Key words: pharmacodynamics, morphine, tumor necrosis factor-α, interleukin-6