Exposure of CMEC to OGD for 60 or 120 min also increased p-p38 abundance (3.11- or 4.57-fold, respectively). activity. Cultured cerebral microvascular endothelial cell NKCC activity was evaluated Elf2 as bumetanide-sensitive 86Rb influx. Activities of p38 and JNK were assessed by Western blot and immunofluorescence methods using antibodies that detect total vs. phosphorylated (activated) p38 or JNK. We report that p38 and JNK are present in cultured cerebral microvascular endothelial cells and in BBB endothelial cells in situ and that hypoxia (7% O2 and 2% O2), aglycemia, AVP, and O2-glucose deprivation (5- to 120-min exposures) all rapidly activate p38 and JNK in the cells. We also provide evidence that SB-239063 and SP-600125 reduce or abolish ischemic factor stimulation of BBB NKCC activity. These findings support the hypothesis that ischemic factor stimulation of the BBB NKCC involves activation of p38 and JNK MAPKs. 0.05 was considered significant. RESULTS Ischemic factors activate p38 MAPK in CMEC. If p38 MAPK is involved in ischemic factor stimulation of BBB Na-K-Cl cotransporter activity and the rapid development of edema that occurs during the early hours of ischemic stroke, we predict that one or more ischemic factors will increase activity of the kinase in these cells with a time course similar to that observed for edema formation, i.e., within 30 min. To NVP-AAM077 Tetrasodium Hydrate (PEAQX) test this, we evaluated p38 activity in cultured bovine CMEC following exposure to hypoxia, aglycemia, AVP, or OGD over a time course of 5C120 min. Total p38 protein and p-p38 were assessed by Western blot analysis using antibodies that detect p38 (nonphosphorylated and phosphorylated) and antibodies that detect only p-p38. As shown inFig. 1= 0.08). Abundance of total p38 protein was not altered by 7% or 2% O2 at any of the exposure times. Open in a separate window Fig. 1. Hypoxia-induced activation of p38. Cerebral microvascular endothelial cell (CMEC) monolayers were exposed to 19% O2 (normoxic control) or 7% or 2% O2 in HEPES-DMEM for 5, 30, 60, or 120 min. Cell lysates were prepared and NVP-AAM077 Tetrasodium Hydrate (PEAQX) subjected to Western blot analysis using antibodies that recognize only phosphorylated (activated) p38 (p-p38) or p-p38 and nonphosphorylated p38 (i.e., total p38 protein). 0.05 by 1-tailed paired = 0.058 for the 60-min value). Exposure of CMEC to OGD for 60 or 120 min also increased p-p38 abundance (3.11- or 4.57-fold, respectively). No significant increases in p-p38 were observed for OGD following 5- or 30-min exposures. As with the hypoxia experiments of Fig. 1, we found that abundance of total p38 protein did not change in response to aglycemia or OGD at any of the exposure times evaluated (data not shown). We further found that AVP (100 nM) also activated p38 in the CMEC (Fig. 3), with exposures of 5, 30, and 120 min significantly increasing p-p38 (1.7-, 1.52-, and 4.14-fold, respectively). The increase in p-p38 abundance following 60 min of AVP exposure (1.56-fold) did not reach statistical significance. Abundance of total p38 protein did not change following exposure to AVP at any of the times evaluated, indicating that, as with hypoxia, aglycemia, and OGD, changes in total p38 protein were not involved in these ischemic factor-induced increases in p-p38. Open in a separate window Fig. 2. Aglycemia- and O2-glucose deprivation (OGD)-induced activation of p38. CMEC monolayers were exposed to control normoxic HEPES-DMEM, aglycemic normoxic medium (glucose- and pyruvate-free HEPES-DMEM at 19% O2), or hypoxic/aglycemic medium (glucose- and pyruvate-free HEPES-DMEM at 2% O2) for 5, 30, 60, or 120 min. Cell lysates were subjected to Western blot analysis using antibodies that recognize p38 (total kinase) or p-p38 (phosphorylated, active kinase). 0.05 by NVP-AAM077 Tetrasodium Hydrate (PEAQX) 1-tailed paired 0.05 by 1-tailed paired 0.05 by 1-tailed paired 0.05 by 1-tailed paired 0.05 by 1-tailed paired 0.05 by repeated-measures ANOVA with Tukey’s post hoc test. Vehicle values are significantly different from control at 30, 60, 90, and 120 min ( 0.05 by 1-tailed paired and 0.05 by repeated-measures ANOVA with Tukey’s post hoc test. Vehicle values for ischemic factors are significantly different from vehicle control at 30, 60, 90, and 120 min (and 0.05 by 1-tailed paired 0.05 by 1-tailed paired 0.05 by 1-tailed paired shows images obtained using antibodies for p38 or p-p38 and GFAP. p38 can be observed in the BBB NVP-AAM077 Tetrasodium Hydrate (PEAQX) endothelial cells. Merged p38 and GFAP images reveal that p38 is also present in perivascular astrocytes. p-p38 is also detected in the BBB endothelial cells and the perivascular astrocytes (Fig. 10shows images obtained with antibodies for p38 or p-p38 and SMI 71. Here again, p38 and p-p38 are.