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Type: Artigo de periódico
Title: Platelet adhesion and intracellular calcium levels in antigen-challenged rats
Author: Baldissera, L
Monteiro, PF
de Mello, GC
Morganti, RP
Antunes, E
Abstract: There is considerable evidence that platelet activation occurs in allergic airways diseases. In this study we aimed to investigate platelet adhesion to immobilized fibrinogen and intracellular calcium levels in a rat model of allergic inflammation. Male Wistar rats were challenged with ovalbumin (OVA). At 30 min to 24 h after OVA-challenge, assays of platelet adhesion to immobilized fibrinogen and intracellular calcium levels using fura 2-AM loaded platelets were performed. The serum levels of IgE were approximately 5-fold greater in OVA-sensitized rats. A marked eosinophil influx in bronchoalveolar lavage (BAL) fluid of OVA-challenged rats at 24 h after OVA-challenge was also seen. OVA-challenge resulted in a marked thrombocytopenia, as observed within 12 h after OVA-challenge. The agonists ADP (0.5-50 mu M) and thrombin (30-100 mU/ml) concentration-dependently increased platelet adhesion to immobilized fibrinogen. At an early time after OVA-challenge (30 min), platelets exhibited greater platelet adhesion compared with the non-sensitized group, whereas at a late time (24 h) they exhibited lower platelet adhesion to both agonists. Moreover, at 30 min after OVA-challenge, intracellular calcium levels to ADP (20 mu M) and thrombin (100 mU/ml)-activated platelets were greater compared with non-challenged rats. As opposed, at 24 h after OVA challenge, a lower intracellular calcium level to ADP- and thrombin-activated platelets was observed. In conclusion, OVA-challenge in rats promotes a biphasic response in platelet adhesion consisting of an increased adhesion and intracellular calcium levels at an early phase (30 min), which progress to a reduction in adhesion and intracellular calcium levels at a late time (24 h) after antigen challenge. (C) 2010 Elsevier Ltd. All rights reserved.
Subject: Platelet adhesion
Platelet integrin
Calcium transport
Country: Inglaterra
Editor: Academic Press Ltd- Elsevier Science Ltd
Citation: Pulmonary Pharmacology & Therapeutics. Academic Press Ltd- Elsevier Science Ltd, v. 23, n. 4, n. 327, n. 333, 2010.
Rights: fechado
Identifier DOI: 10.1016/j.pupt.2010.03.006
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

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