These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: TNF potentiates PAF-induced pulmonary vasoconstriction in the rat: role of neutrophils and thromboxane A2.
    Author: Chang SW.
    Journal: J Appl Physiol (1985); 1994 Dec; 77(6):2817-26. PubMed ID: 7896627.
    Abstract:
    Both tumor necrosis factor (TNF) and platelet-activating factor (PAF) are released during sepsis and are important mediators of septic lung injury. I investigated the interactions of TNF and PAF on vasoactive responses in the pulmonary circulation. In isolated rat lungs perfused with a cell- and plasma-free physiological salt solution, PAF (0.01- and 0.1-micrograms boluses) caused transient dose-dependent pulmonary arterial and venous constrictions. In vivo pretreatment of the rats with TNF (0.02 or 0.2 mg/kg i.v.) 1 h before lung isolation increased lung myeloperoxidase activity and markedly enhanced PAF-induced pulmonary vasoconstriction without affecting the pressor responses to angiotensin II or hypoxia. In contrast, pretreatment with lipopolysaccharide (10 mg/kg), which increased lung myeloperoxidase to the same extent as TNF, caused only a modest enhancement of PAF-induced vasoconstriction associated with reduced pressor responses to angiotensin II and hypoxia. Ex vivo perfusion of isolated lungs with TNF for 1 h did not affect PAF vasoconstriction. The TNF-induced potentiation of PAF vasoconstriction was not altered by depletion of circulating neutrophils with vinblastine but was blocked by Dazmegrel, a thromboxane synthase inhibitor. Thus, TNF potentiates PAF-induced pulmonary vasoconstriction by an in vivo mechanism that is neutrophil independent but thromboxane dependent. This TNF-PAF interaction likely contributes to the development of pulmonary hypertension during sepsis.
    [Abstract] [Full Text] [Related] [New Search]