N-ACETYLSEROTONIN PREVENTS THE HYPOTENSION INDUCED BY BACTERIAL LIPOPOLYSACCHARIDES IN THE RAT

Nitric oxide is produced by the NO synthase, which catalyses the conve rsion of arginine to citrulline and NO using tetrahydrobiopterin as an essential cofactor. N-Acetylserotonin, an inhibitor of the tetrahydro biopterin biosynthesis, given 30 min before bacterial lipopolysacchari de to anesthetized rats, inhibited both the decrease in blood pressure and the increase in nitrite plasma levels induced by lipopolysacchari de. Thus, during endotoxemia the availability of tetrahydrobiopterin a pears to be essential for the activity of NO synthase.