VIBRIO-VULNIFICUS HEMOLYSIN DILATES RAT THORACIC AORTA BY ACTIVATING GUANYLATE-CYCLASE

Hemolysin produced by Vibrio vulnificus caused hypotension and tachyca rdia in rats and dilated rat thoracic aorta. Hemolysin-induced vasodil atation of the aorta was not affected by N omega-nitro-L-arginine meth yl ester and aminoguanidine, NO synthase inhibitors, whereas the vasod ilatation was inhibited by LY 83,583, a guanylate cyclase inhibitor. H emolysin elevated cGMP levels, and the elevation was abolished by LY 8 3,583. These results suggest that V. vulnificus hemolysin activates gu anylate cyclase independently of NO synthase, and the subsequent incre ase in cGMP levels results in vasodilatation.