Effects of UTP and BzATP on the stimulation of the mitosis marker, phospho-histone 3, by FGF2. Quiescent cultures of rat cortical astrocytes were treated with FGF2 (25 ng/ml) alone or in combination with UTP (100 uM) or BzATP (100 uM) for 22 hr. Western blots were prepared and probed for phospho-histone 3 and for β-actin (loading control), as described in Materials and Methods. (A) Western blot representative of 6 experiments. (B) Ratios of phospho-histone 3/ β-actin were calculated, normalized to controls and group data were expressed as mean ± SEM (n= 6). Phospho-histone 3 levels in FGF2-treated cultures were increased compared to controls (*, p < 0.05). Compared to FGF2 alone, cultures treated with the combination of UTP and FGF2 had increased levels of phospho-histone 3 (*, p < 0.05) whereas those treated with FGF2 and BzATP had decreased levels of phospho-histone 3 (*, p < 0.05).