The purpose of this study was to investigate the ability of
yangambin to inhibit cardiovascular collapse and to reduce the mortality due to systemic
anaphylaxis induced by
antigen challenge in actively sensitized rats. The i.v. injection of the
antigen (
ovalbumin, 250 or 500 μg/kg), induced a systemic
anaphylactic reaction mainly characterized by sudden and marked arterial
hypotension and high mortality rates.
Yangambin, a PAF receptor antagonist isolated from the Brazilian plant Ocotea duckei Vattimo (Lauraceae), as well as the reference PAF receptor antagonist
SR 27417, significantly prevented and partially reversed the
circulatory collapse elicited by
antigen challenge. Moreover,
yangambin and
SR 27417, when administered 5 min before re-exposure of the animals to the
antigen, markedly improved the survival rate at 120 min. These results confirm that PAF plays an important role in the pathophysiology of
anaphylactic shock and show that
yangambin presents good therapeutic potential in the treatment of the cardiovascular alterations observed during
immediate hypersensitivity reactions.