Fig. 5. NF-B inhibitor blocks histamine-upregulated VCAM1 gene expression. (A) Intracellular-Ca²⁺-store-depleted EC monolayers were exposed to 1 µM histamine stimulation in the presence of an NF-B-specific inhibitor, SN50 (1 µM), or its inactive control, SN50M (1 µM), in Ca²⁺-free/EGTA HBS for 60 minutes. Total RNA was then isolated for real-time RT-PCR analysis. The histamine-stimulated VCAM1 mRNA expression in intracellular-Ca²⁺-store-depleted ECs is almost completely blocked by SN50, but not by SN50M (^* and , P<0.05 vs intracellular-Ca²⁺-store-depleted control ECs and SN50-treated ECs, respectively, n=3 for each). Note that related data from Fig. 3A is included here for comparison. (B) Intracellular-Ca²⁺-store-depleted EC monolayers were exposed to the conditions generating 0.3 [Ca²⁺]_i oscillations/minute in the presence of 1 µM histamine and 1 µM SN50 or SN50M for 60 minutes. Total RNA was then isolated for real-time RT-PCR analysis. The histamine-upregulated VCAM1 mRNA expression under this condition is significantly inhibited by SN50, but not by SN50M (^* and , P<0.05 vs intracellular-Ca²⁺-store-depleted control ECs and SN50-treated ECs, respectively, n=3 for each). Note that related data from Fig. 2 is included here for comparison.