Further pharmacological characterization of bradykinin B1 receptor up-regulation in human umbilical vein.

Previous reports have provided evidence to support the view that the de novo synthesis of bradykinin (BK) B(1) receptor is involved in the induction of vascular responses in human umbilical vein (HUV). In the present study, we evaluated different pharmacological tools to further analyze this up-regulation process in HUV. Concentration-response curves to des-Arg(9)-BK, a selective BK B(1) receptor agonist, were performed after 5 h of incubation. Tumor necrosis factor-alpha potentiated BK B(1) receptor responses at 5 h without modifying the maximal response to des-Arg(9)-BK. Pyrrolidine dithiocarbamate, an inhibitor of nuclear factor-kappaB activation, produced a concentration-dependent decrease of the BK B(1) receptor sensitization. When tissues were continuously exposed to actinomycin D, a transcription inhibitor, or cycloheximide, a protein synthesis inhibitor, concentration-response curves to des-Arg(9)-BK were markedly diminished. On the other hand, transitory exposure to cycloheximide allowed the full recovery of BK B(1) receptor-sensitized responses at 5 h. Finally, continuous incubation with the N-linked glycosylation inhibitor, tunicamycin, almost completely abolished des-Arg(9)-BK-mediated responses. In summary, this sensitization process is potentiated by tumor necrosis factor-alpha and is selectively inhibited by pyrrolidine dithiocarbamate, suggesting that BK B(1) receptor up-regulation in HUV involves nuclear factor-kappaB activation. The effects of actinomycin D and tunicamycin provide evidence that the de novo synthesis of a transmembrane glycoprotein has an obligatory role in the BK B(1) up-regulation. The reversion of the cycloheximide effect on BK B(1) response indicates that the time necessary for synthesis, trafficking, and functional membrane expression of this receptor would be less than 1 h.