ALPHA-ADRENERGIC BLOCKING PROPERTIES OF DROPERIDOL ON ISOLATED BLOOD VESSELS OF THE DOG

Concentrations of droperidol which caused a shift to the rightof the dose-response curve to nor-adrenaline in the pulmonaryartery and the saphenous vein of the dog did not affect myogenicactivation by K⁺; they did not inhibit spontaneous activityof portal-mesenteric veins. Droperidol inhibited the contractileresponse to nerve stimulation, but did not affect the evokedrelease of ³H-noradrenaline. These experiments indicate thatthe vasodilator properties of smaller doses of droperidol area result of its ability to block alpha-adrenergic receptors. ^*Present address: Department of Anesthesiology, Mayo Clinic,Rochester, Minnesota, U.S.A.