INHIBITORY EFFECT OF A FULLERENE DERIVATIVE, MONOMALONIC ACID C-60, ON NITRIC OXIDE-DEPENDENT RELAXATION OF AORTIC SMOOTH-MUSCLE

1. Effects of a fullerene C-60 derivative, monomalonic acid C-60 (MMA C-60), On endothelium-containing or denuded aorta of rabbit, trachea a nd ileum of guinea pig, and stomach (fundus), vas deferens and uterus of rat were studied pharmacologically. 2. MMA C-60 (10(-5) M) signific antly reduced the maximum response of the relaxation induced by acetyl choline in endothelium-containing thoracic aorta of rabbit, and the ac etylcholine-induced relaxation was recovered in the presence of supero xide dismutase (SOD, 250 units/ml). 3. Nitric oxide-generating agent, S-nitroso-N-acetylpenicillamine, caused the relaxation of aorta withou t endothelium in a concentration-dependent manner, and the concentrati on-response curve was shifted to the right in the presence of MMA C-60 . This inhibitory effect of the derivative was also masked in the pres ence of superoxide dismutase (SOD). 4. Sodium nitroprusside-induced re laxation was not affected by either MMA C-60 Or SOD, In the other tiss ues, this C-60 derivative had no effect on the responses induced by an y agonist. 5. These observations indicate that MMA C-60 inhibits the e ndothelium-dependent relaxation induced by acetylcholine but does not affect the agonist-induced contractile response of smooth muscle. (C) 1997 Elsevier Science Inc.