Effects of a new C5a receptor antagonist on C5a-and endotoxin- Induced neutropenia n the rat

摘要

A new C5a receptor antagonist, the cyclic peptide Phe-[Orn-Pro-D-cyclohexylalanine-Trp-Arg], (F- [OpdChaWR]), was tested for its ability to antagonize the neutropenic effects of both c5a and endotomxin in rats. Human recombinant C5a (2 ug kg ~-1 i. v.) cause rapid neutropenia, characterized by an 83/100 decrease in circulating polymorphonuclear leukocytes (PMNs) at 5 min. Administration of F-[OpdChaWR] (0.3-3 mg kg~-1 i.v.), did not affect the levels of circulating PMNs but, when given 10 min prior to C5a, it inhibited the C5a-induced neutropenia by up to 70/100.)