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°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 K d1 of 2.5 ± 0.6 pM and B max1 = 57.3 ± 20.0 fmol/mg protein. The low-affinity binding site possessed a K d2 = 3.2 ± 1.0 nM and B max2 = 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.