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Scorpion venom‐induced neutrophilia is inhibited by a PAF receptor antagonist in the rat
Author(s) -
Borges Cynthia M.,
Silveira Micheline R.,
Aparecida M.,
Beker C. L.,
FreireMaia Lineu,
Teixeira Mauro M.
Publication year - 2000
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.67.4.515
Subject(s) - neutrophilia , leukocytosis , pharmacology , biology , receptor antagonist , granulocytosis , antagonist , bone marrow , receptor , medicine , endocrinology , immunology , granulocyte
A dramatic blood neutrophilia is an important feature of the severe envenoming caused by the Brazilian scorpion Tityus serrulatus and may contribute to the development of lung injury in children. We examined the effects of an intravenous injection of T. serrulatus scorpion venom (TsV) on the total number of leukocytes and neutrophils in the blood of anesthetized rats. Injection of TsV (250 μg/kg) induces a significant leukocytosis 2 and 3 h after its injection, explained by an increase in the number of neutrophils. The release of catecholamines and action on adrenoceptors is responsible for most of the systemic manifestations of TsV. However, pretreatment with the β‐adreno‐ceptor antagonists metoprolol and propranolol or the α 1 ‐adrenoceptor antagonist prazosin (0.25 mg/kg) did not prevent TsV‐induced neutrophilia. Blood neutrophilia induced by TsV occurred simultaneously with a significant reduction of mature neutrophils in bone marrow. Pretreatment with the platelet‐activating factor (PAF) receptor antagonists UK‐74505 or WEB‐2086 prevented TsV‐induced increase in blood neutrophils and reduction in the number of neutrophils in the bone marrow. It is concluded that scorpion venom induces blood neutrophilia in rats, explained by a PAF receptor‐dependent mobilization of neutrophils from the bone marrow. J. Leukoc. Biol. 67:515–519; 2000.