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Increase in the rat blood leukocyte counts induced by PAF‐acether is suppressed by general anesthesia
Author(s) -
Bozza Patricia T.,
Silva Patricia M. R.,
CastroFariaNeto Hugo C.,
Martins Marco A.,
Cordeiro Renato S. B.
Publication year - 1992
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.51.2.146
Subject(s) - leukocytosis , hemoconcentration , neutrophilia , pentobarbital , bone marrow , ed50 , endocrinology , white blood cell , pharmacology , medicine , immunology , biology , anesthesia , receptor , hematocrit
Abstract Blood leukocyte count alterations induced by PAF‐acether in anesthetized and nonanesthetized rats were investigated. Intravenous injection of increasing amounts of PAF‐acether (1.5‐8 μg/kg) in nonanesthetized animals induced dose‐dependent hemoconcentration and leukocytosis. The former was apparent within 10 min, peaked from 30 min to 1 h, and diminished thereafter. The leukocytosis was noted within 30 min, was maximal at 1 h, and was over 4 h after injection of PAF‐acether (4 μg/kg). It was characterized by a marked increase in the blood neutrophil counts under conditions in which the number of lymphocytes, monocytes, and eosinophils remained unchanged. PAF‐acether–induced leukocytosis occurred in parallel with a marked decrease in the number of bone marrow nucleated cells, suggesting that the latter phenomenon may determine the former one. Leukocytosis by PAF‐acether was inhibited dose‐dependently by specific PAF‐acether antagonists including BN 52021 (median effective dose ED 50 = 4.99 mg/kg), WEB 2086 (ED 50 = 4.59 mg/kg), and 48740 RP (ED 50 = 9.02 mg/kg). General anesthesia by either pentobarbital, urethane, or ether inhalation, but not by ketamine, also impaired the PAF‐acether–induced blood leukocytosis under conditions in which the hemoconcentration was not modified. In addition, pentobarbital‐anesthetized rats did not have reduced bone marrow nucleated cell counts after PAF‐acether stimulation. These findings are consistent with the assessment that PAF‐acether–induced rat leukocytosis is accounted for by a bone marrow neutrophil mobilization process that is clearly suppressed in animals anesthetized by pentobarbital.