Fig. 4

Effects of HR antagonists on HA-induced suppression of astrocytic TNF-α and IL-1β production. a Incubation with histamine at the doses of 0.001, 0.01, 0.1, and 1 μg/ml for 24 h produced a concentration-dependent suppression of TNF-α and IL-1β secretion from primary cultured astrocytes. The H1R antagonist cetirizine (10 μM), the H2R antagonist ranitidine (10 μM), and the H3R antagonist carcinine (10 μM) were added to astrocytes alone or 30 min before addition of histamine (0.1 μg/ml) for 24 h. b Time courses of suppression of TNF-α and IL-1β release by histamine. Histamine at 0.1 μg/ml was incubated with astrocytes at 37 °C for 2, 6, 12, 24, 48, and 72 h. c The levels of TNF-α and IL-1β mRNA expression were analyzed by quantitative RT-PCR. *p < 0.05, **p < 0.01 versus the control group. ^#p < 0.05, ^##p < 0.01 versus histamine (0.1 μg/ml) treatment groups. The data are presented as the mean ± s.e.m. of three independent experiments