Presence of specific platelet-activating factor binding-sites in neuroblastoma N1E-115 cells.

In this study we reported evidence for the existence of specific binding sites for platelet-activating factor (PAF) in neuroblastoma N1E-115 cells. The specific [3H]PAF binding reached a steady state level within 60 min at 25 degrees C. Scatchard analysis of the specific [3H]PAF binding revealed the presence of two apparent populations of binding sites. The high-affinity binding site possessed a Kd1 of 2.5 +/- 0.6 pM and Bmax1 = 57.3 +/- 20.0 fmol/mg protein. The low-affinity binding site possessed a Kd2 = 3.2 +/- 1.0 nM and Bmax2 = 4.4 +/- 2.1 pmol/mg protein. Furthermore, the total [3H]PAF binding was partially displaced by unlabelled PAF, PAF antagonists BN 52021 and BN 50730 in a dose-dependent manner. This study confirms the presence of specific PAF receptors in neuronal cells.