Kir4.1 expression in U373 glioblastoma cell line and in cultured human astrocytes after exposure to IL-1β. (A-C) Quantitative real-time PCR. Expression levels of Kir4.1 mRNA 24 h after exposure to IL-1β (10 ng/mL) in U373 glioblastoma cell line (A) and in cultured human astrocytes (B). (C) Expression levels of Kir4.1mRNA 24 h after exposure to IL-1β in U373 cell line in the presence or absence of the IL-1 β receptor antagonist (IL-1Ra; 1 μg/mL) or levetiracetam (LEV; 10 μg/mL). Data are expressed relative to the levels observed in unstimulated cells (untreated controls, Con) and are mean ± SEM from two separate experiments performed in triplicate (*P <0.05; ***P <0.0001 compared to control). (D, E). Western blot analysis of Kir4.1. Representative immunoblot of total homogenates from U373 glioblastoma cell line (D) and from human fetal astrocytes (E) untreated and treated for 24 h with 10 ng/mL IL-1β, in the presence or absence of the IL-1 β receptor antagonist (IL-1Ra; 1 μg/mL). Densitometric analysis: values (optical density units, O.D.) are mean ± SEM, relative to the optical density of β-actin; *P <0.05, compared to controls.