Inactivation of endothelium-dependent relaxing factor by liposome-encapsulated or cell-free hemoglobin

K. Nakai, T. Ohta, S. Tokuyama, H. Akama, Y. Kawakami, N. Matsuda, E. Tuschida, Y. Nakazato, S. Sekiguchi

Research output: Contribution to journalArticlepeer-review


The inhibitory effects of cellular and acellular hemoglobin (Hb) solutions on endothelium-dependent vasorelaxation were investigated in rabbit aortic strips. The tissues were precontracted with phenylephrine, after which acetylcholine (ACh) was added to induce a steady-state relaxation. All Hb solutions cumulatively reversed ACh-induced relaxation; liposome-encapsulated Hb and washed human red cells as cellular Hb reached a maximal vasconstriction at 1 mg/ml, while 2,3-diphosphoglycerae depleted Hb and pyridoxylated Hb as acellular Hb reached a plateau at 10 μg/ml. On the other hand, increases in oxygen affinity by pyridoxylation had little effect on this. These findings suggest that the cellularity is a very important factor influencing EDRF inhibition, and that acellular Hbs are more potent vasoconstrictors than cellular Hbs by a factor of about one hundred.

Original languageEnglish
Pages (from-to)854-857
Number of pages4
JournalJapanese Journal of Artificial Organs
Issue number3
Publication statusPublished - 1994 Jan 1
Externally publishedYes


  • EDRF
  • blood substitutes
  • hemoglobin
  • liposome
  • vasoconstriction

ASJC Scopus subject areas

  • Biophysics


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