Role of histamine in the spasmogenic effect of the complement peptides C3a and C5a-desArg (classical anaphylatoxin).
The role of endogenous histamine in the spasmogenic effect of the complement-derived peptides C3a and C5a-desArg (isolated from yeast-activated hog serum) was studied in strips of terminal guinea-pig ileum. The effect of C3a is apparently histamine-independent; it neither induces histamine release from the test organ nor is its spasmogenic action inhibited by the H1-antihistaminics pheniramine and triprolidine, used in concentrations effective against histamine. However, endogenous histamine may be involved in the spasmogenic effect of C5a-desArg; when applied repeatedly C5a-desArg induces histamine release during its first and second application. Furthermore, both H1-antihistaminics inhibited C5a-desArg-induced contractions considerably, though less efficiently than those of added histamine.
D000706:Anaphylatoxins / Q000494:pharmacology*; D000818:Animals; D003176:Complement C3 / Q000494:pharmacology*; D015926:Complement C3a; D003182:Complement C5 / Q000031:analogs & derivatives* / Q000494:pharmacology; D015937:Complement C5a, des-Arginine; D006168:Guinea Pigs; D006632:Histamine / Q000502:physiology*; D006636:Histamine Release / Q000187:drug effects; D066298:In Vitro Techniques; D010455:Peptides / Q000494:pharmacology*; D010632:Pheniramine / Q000494:pharmacology; D013035:Spasm / Q000378:metabolism / Q000503:physiopathology*; D014311:Triprolidine / Q000494:pharmacology
D000706:Anaphylatoxins; D003176:Complement C3; D003182:Complement C5; D015937:Complement C5a, des-Arginine; D010455:Peptides; D010632:Pheniramine; D014311:Triprolidine; D015926:Complement C3a; D006632:Histamine