Abstract
Previous reports have provided evidence to support the view that the de novo synthesis of bradykinin (BK) B1 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-Arg9-BK, a selective BK B1 receptor agonist, were performed after 5 h of incubation. Tumor necrosis factor-α potentiated BK B1receptor responses at 5 h without modifying the maximal response to des-Arg9-BK. Pyrrolidine dithiocarbamate, an inhibitor of nuclear factor-κB activation, produced a concentration-dependent decrease of the BK B1 receptor sensitization. When tissues were continuously exposed to actinomycin D, a transcription inhibitor, or cycloheximide, a protein synthesis inhibitor, concentration-response curves to des-Arg9-BK were markedly diminished. On the other hand, transitory exposure to cycloheximide allowed the full recovery of BK B1 receptor-sensitized responses at 5 h. Finally, continuous incubation with the N-linked glycosylation inhibitor, tunicamycin, almost completely abolished des-Arg9-BK-mediated responses. In summary, this sensitization process is potentiated by tumor necrosis factor-α and is selectively inhibited by pyrrolidine dithiocarbamate, suggesting that BK B1 receptor up-regulation in HUV involves nuclear factor-κB 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 B1 up-regulation. The reversion of the cycloheximide effect on BK B1 response indicates that the time necessary for synthesis, trafficking, and functional membrane expression of this receptor would be less than 1 h.
Footnotes
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Send reprint requests to: Prof. Rodolfo Pedro Rothlin, Departamento de Farmacologı́a, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 15, C.P. 1121, Buenos Aires, Argentina. E-mail: farmaco3{at}fmed.uba.ar
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↵1 This study was supported by Universidad de Buenos Aires (UBA) Grant ME-041, and by the Fundación A. J. Roemmers. S.P.S. and V.R.A. are research fellows of the UBA.
- Abbreviations:
- BK
- bradykinin
- HUV
- human umbilical vein
- IL
- interleukin
- NF
- nuclear factor
- PDTC
- pyrrolidine dithiocarbamate
- 5-HT
- serotonin
- TNF
- tumor necrosis factor
- Received January 4, 1999.
- Accepted May 12, 1999.
- The American Society for Pharmacology and Experimental Therapeutics
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