Effects of AGEPC on the intracellular levels of ions in Tetrahymena pyriformis.

1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine(Platelet Activating Factor) is a very potent stimulator of Ca2+ influx into the cells of Tetrahymena pyriformis; increases the levels of bound and free intracellular Ca2+ and this effect is time- and dose-dependent. Also AGEPC enhances the Na+ influx into the cells, while has no effect on the intracellular levels of K+ and on the packed cell volume. The effects of AGEPC on intracellular Ca2+ and Na+ are completely inhibited by verapamil which also inhibits the Ca2+ influx observed in the control, but has not any effect on the Na+ uptake observed in the control. These results provide evidence that the effect of AGEPC on Na+ influx, depends on its effect on free intracellular Ca2+. The non acetylated derivative of AGEPC, lyso-GEPC has no effect on all the studied parameters.