Investigation of Miconazole as an Inhibitor of Endothelium-Derived Hyperpolarizing Factor

This study will investigate the effect of the drug miconazole on blood vessel dilation. Miconazole stops production of EDHF, a substance that causes arteries to dilate. EDHF is produced by the cells that line blood vessels.

Normal volunteers between the ages of 21 to 60 may participate in this study. Candidates will be screened for eligibility with a medical history, physical examination, electrocardiogram and routine laboratory tests. Those enrolled will be injected with miconazole to study its effects on blood vessels.

Study participants will take three aspirin tablets. After administration of a local anesthetic, small tubes will be inserted through a needle into the artery and vein of the forearm. These will be used to measure blood pressure and to draw blood samples during the study. Forearm blood flow will be measured using pressure cuffs placed on the wrist and upper arm, and a strain gauge (a rubber band device) placed around the forearm. When the cuffs are inflated, blood will flow into the arm, stretching the strain gauge, and the flow measurement will be recorded.

Small doses of four drugs-bradykinin, sodium nitroprusside, miconazole, and LNMMA-will be given through the arterial catheter. Bradykinin stimulates the release of EDHF and can lower blood pressure. Sodium nitroprusside causes blood vessels to dilate and is used to treat high blood pressure and heart failure. Miconazole is commonly prescribed to treat various infections, including vaginal yeast infections, jock itch and athlete's foot. In much higher doses, it is used to treat fungal infections that have spread to the lungs, brain, kidneys, or bladder. LNMMA inhibits production of nitric oxide, another substance produced by the lining cells of blood vessels.

Blood flow will be measured throughout the study, which will last approximately 3 hours.