Midazolam inhibits tumor necrosis factor-alpha-induced endothelial activation: involvement of the peripheral benzodiazepine receptor.
BACKGROUND
Midazolam is widely used as an intravenous sedative. However, the role of midazolam on vascular endothelial activation is still unknown. The present study explores the action of midazolam on endothelial activation and its role to peripheral benzodiazepine receptor (PBR) in cultured human umbilical vein endothelial cells.


METHODS
Intracellular localization of PBR in human umbilical vein endothelial cells was visualized with immunofluorescent staining. Monocyte adhesion and vascular cell adhesion molecule-1 expression were measured with monocyte adhesion assay and Western blot analysis. Involvement of PBR was assessed by using specific antagonists and small interfering RNA against PBR.


RESULTS
PBR was localized in the mitochondria of human umbilical vein endothelial cells. Midazolam significantly inhibited tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 and monocyte adhesion in a dose-dependent manner (1-30 microM). The midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression and monocyte adhesion were inhibited by the pretreatment of PK11195 and not inhibited by the flumazenil. Transfection of small interfering RNA for PBR decreased the expression of PBR (18 kDa) in human umbilical vein endothelial cells. Midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression was abrogated by the transfection of small interfering RNA for PBR.


CONCLUSIONS
These results suggest that midazolam has an inhibitory action on the endothelial activation and that its action is related to the activation of peripheral benzodiazepine receptor localized in mitochondria of the endothelial cells.
Joo
Hee Kyoung
HK
Department of Physiology, College of Medicine, Chungnam National University, Daejeon, Korea.
Oh
Sae Cheol
SC
Cho
Eun Jung
EJ
Park
Kyoung Sook
KS
Lee
Ji Young
JY
Lee
Eun Ji
EJ
Lee
Sang Ki
SK
Kim
Hyo Shin
HS
Park
Jin Bong
JB
Jeon
Byeong Hwa
BH
D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008874:Midazolam / Q000494:pharmacology*; D018079:Receptors, GABA / Q000032:analysis / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
D018079:Receptors, GABA; C499229:TSPO protein, human; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D008874:Midazolam