SYNTHESIS OF NITRIC-OXIDE BY THE HEMOCYTES OF THE AMERICAN HORSESHOE-CRAB (LIMULUS-POLYPHEMUS)

Nitric oxide (NO) synthase, the enzyme responsible for the production of NO from L-arginine, is present in haemocytes of the American horseshoe crab (Limulus polyphemus). The synthesis of NO results in down-regulation of the aggregatory function of these cells in a manner similar to that previously described for mammalian platelets. These data indicate that formation of NO from L-arginine is a pathway of early evolutionary origin.