Figure 3.

NPY inhibits IL-1β-induced phagocytosis via Y₁ receptor activation. (A) Representative photomicrographs illustrate the inhibitory effect of NPY acting via Y₁ receptor on IL-1β-induced cell phagocytosis. (B) Microglial cells were stimulated with IL-1β (1.5 ng/ml) and treated with NPY (1 μM). As NPY inhibited IL-1β-induced phagocytosis, a Y₁ receptor agonist [Leu³¹, Pro³⁴]NPY (1 μM) and a Y₁ receptor antagonist BIBP3226 (1 μM) were used to determine the effect of Y₁R activation on IL-1β-induced phagocytosis. The involvement of other NPY receptors was ruled out with the use of antagonists for the Y₂ receptor (BIIE0246, 1 μM) and the Y₅ receptor (L152-804, 1 μM). Data are expressed as mean ± SEM (n = 3-5) and as a percentage of control (***p < 0.001, using Bonferroni's Multiple Comparison Test). Scale bar 10 μm.