EFFECTS OF NAFTIDROFURYL ON ADRENERGIC-NERVES, ENDOTHELIUM AND SMOOTH-MUSCLE IN ISOLATED CANINE BLOOD-VESSELS

  • 1 December 1986
    • journal article
    • research article
    • Vol. 239  (3) , 760-767
Abstract
Experiments were designed to determine the effects of the vasoactive drug naftidrofuryl on vascular smooth muscle, endothelial cells and adrenergic nerves in isolated canine blood vessels. Naftidrofuryl inhibited contractions of basilar arteries (in a decreasing order ofto potency), evoked by 5-hydroxytryptamine > KCl = anoxia (in rings with endothelium) > prostaglandin F2.alpha. = uridine-5''-triphosphate. Naftidrofuryl antagonized competitively the contractions evoked by 5-hydroxytryptamine in the femoral artery and the saphenous vein. Naftidrofuryl caused the release of an endothelium-derived relaxing factor(s) from the endothelium of femoral arteries. The compound depressed contractions of saphenous veins evoked by electrical stimulation of the adrenergic nerve endings, but not those caused by the indirect sympathomimetic amine tryramine or exogenous norepinephrine. In saphenous veins incubated previously with [3H]norepinephrine, the drug inhibited the contractions and the release of transmitter evoked by electrical stimulation. Thus, naftidrofuryl acts at different levels in the blood vessel wall to cause: 1) release of endothelium-derived relaxing factor(s); 2) inhibition of S2-serotonergic receptors on vascular smooth muscle; 3) prejunctional inhibition of adrenergic neurotransmission; and 4) nonselective inhibition of the contractile process in vascular smooth muscle, which is particularly pronounced in cerebral arteries.