ISSN:
1432-1912
Keywords:
Complement peptides
;
Leukocytes
;
Chemotaxis
;
Vascular permeability
;
Desensitization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of the spasmogenically active cleavage peptide from the third component of complement, C3a, and its spasmogenically inactive derivative, C3ai, on local leukocyte accumulation and vascular permeability in guinea pigs have been studied. 1. After intrapleural injection of 50, 100 or 150 μg both peptides induced a dose-dependent accumulation of leukocytes in the pleural cavity. This effect was significantly (P〈0.05) inhibited by colchicine (0.4 and 2.0 mg/kg), whereas pheniramine (5 mg/kg) and paramethasone (1 mg/kg) showed a slight inhibitory effect only. Indometacin (10 mg/kg) did not affect leukocyte accumulation. 2. C3a and C3ai also increased vascular permeability as shown by extravasation of i.v. applied Evans blue into the pleural cavity. This was partly inhibited by paramethasone and indometacin; pheniramine and colchicine were not inhibitory. When C3ai was injected intrapleurally (once 150 μg) and in addition intravenously (doses of 20, 100 and 150 μg injected every 20 min throughout the experiment), the accumulation of leukocytes in the pleural cavity was markedly decreased, whereas the extravasation of Evans blue was even increased. The inhibition of chemotaxis appears to be due to desensitization of the circulating leukocytes by the intravenously given C3ai thus rendering them unresponsive to the local stimulus of intrapleural C3ai. I.v. given C3ai induced a pronounced increase of the concentration of peripheral leukocytes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00586595
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