ABSTRACT
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 eosinophilis 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
Subject(s)
Rats , Animals , Male , Female , Eosinophils/physiology , Eosinophilia/chemically induced , Platelet Activating Factor/pharmacology , Pleural Effusion/chemically induced , Platelet Activating Factor/administration & dosage , Rats, WistarABSTRACT
O PAF-acether administrado por via endovenosa em cobaios induz trombocitopenia que persiste até 180 minutos após a administraçäo do agente. O número de leucócitos cai, às custas dos neutrófilos até aos 5 minutos, e após 180 minutos o seu número retorna aos níveis iniciais