Pleural eosinophil infiltration induced by PAF-acether is not a desensitizable phenomenon.
This study investigated the effect of successive daily intrathoracic (it) injections of PAF-acether upon its demonstrated ability to generate eosinochemotaxin(s). Repeated administration of PAF-acether led to a selective state of desensitization, characterized by a gradual reduction of its ability to induce exudation. Concomitantly, however, there was a progressive pleural accumulation of eosinophils leading to a 7-fold increase in the eosinophil counts after the 4th restimulation. The generation of eosinochemotaxin(s) elicited by PAF-acether was not modified by desensitization, as detected by transferring the cell-free pleural fluid from donor to recipient animals. We conclude that, in contrast to exudation, eosinophil tissue infiltration induced by PAF-acether is not a desensitizable phenomenon.
Silva
P M
PM
Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brasil.
Martins
M A
MA
Castro-Faria-Neto
H C
HC
Bozza
P T
PT
Cruz
H N
HN
Dias
M T
MT
Cordeiro
R S
RS
Vargaftig
B B
BB
D000818:Animals; D002449:Cell Aggregation / Q000187:drug effects; D004802:Eosinophilia / Q000139:chemically induced*; D004804:Eosinophils / Q000502:physiology*; D005260:Female; D008297:Male; D010972:Platelet Activating Factor / Q000008:administration & dosage / Q000494:pharmacology*; D010996:Pleural Effusion / Q000139:chemically induced*; D051381:Rats; D011919:Rats, Inbred Strains
D010972:Platelet Activating Factor