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Mechanisms involved in the relaxing effect of midazolam on coronary arteries

  • A. P. Klockgether-Radke (a1), P. Pawlowski (a1), P. Neumann (a1) and G. Hellige (a1)



Background and objective: Hypotension, especially in elderly and hypovolaemic patients, is frequently associated with intravenous midazolam administration. The mechanisms are not completely understood. This study was designed to investigate the mechanisms involved in the relaxing effect of midazolam on coronary arteries.

Methods: The substance was studied in isolated porcine coronary artery rings precontracted by either potassium chloride or prostaglandin F.

Results: Midazolam caused vasodilatation in a concentration-dependent manner. Relaxation was more pronounced in prostaglandin F precontracted segments than in those treated with potassium chloride (P < 0.001). Vasodilatation was unaffected by Nω-nitro-l-arginine, indomethacin and glibenclamide. Tetraethylammonium chloride, an inhibitor of the BKCa K+ channel (a high conductance Ca2+-sensitive K+ channel), dose dependently attenuated the vasodilating effect of midazolam (P < 0.01).

Conclusions: Hyperpolarization of the smooth muscle cell in the vessel wall, elicited by the activation the BKCa K+ channel, may contribute to the vasorelaxing effect of midazolam.


Corresponding author

Correspondence to: Adelbert P. Klockgether-Radke, Department of Anaesthesiological Research, Centre of Anaesthesiology, Emergency and Intensive Care Medicine, Georg-August University of Göttingen, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany. E-mail:; Tel: +49 5561 73066; Fax: +49 5561 73917


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Mechanisms involved in the relaxing effect of midazolam on coronary arteries

  • A. P. Klockgether-Radke (a1), P. Pawlowski (a1), P. Neumann (a1) and G. Hellige (a1)


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