EFFECTS OF ETHER LIPID O-OCTADECYL-2-METHOXY-RAC-GLYCERO-3-PHOSPHOCHOLINE AND ITS ANALOGS PAF AND CPAF ON THE RELEASE OF NITRIC-OXIDE IN PRIMARY CULTURES OF RAT ASTROCYTES

Ether lipid octadecyl-2-O-methoxy-rac-glicero-3-phosphocholine (ET-18- OCH3) is an immunomodulator with antineoplastic activity. Its analog c ompounds PAF and CPAF share some of its biological effects. In our exp eriments, even very small amounts of ET-18-OCH3 released a remarkable quantity of nitric oxide (NO) from rat astrocytes cultured in vitro. T he NO biosynthesis was inhibited by pretreatment with the antagonist B N 50730. The effect of ET-18-OCH3 was greater than that of the LPS ind ucer. PAF did not produce NO, even at high doses, while the nonmetabol izable CPAF only induced a significant release of NO from 12 mu g/ml o nwards. These results demonstrate that ET-18-OCH3 is functionally acti ve also in astrocyte cultures. Stimulation of NO biosynthesis is of a great value on account of its the known effect as a neurotransmitter, potentiator of immune defences and possible modulator of cerebral circ ulation.