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Acta Physiologica 2012; Volume 206, Supplement 693
Joint FEPS and Spanish Physiological Society Scientific Congress 2012
9/8/2012-9/11/2012
Santiago de Compostela, Spain
ROLE OF COX-2 FROM BRAIN PERIVASCULAR MACROPHAGES IN THE INITIATION OF GASTROINTESTINAL (GI) MOTOR DISTURBANCES AND FEVER INDUCED BY LPS IN SHEEP
Abstract number: P244
Gimeno1 A, Castro2 M, F Martinez1 L, Latorre1 E, Grasa1 L, Alcalde1 A I, E Mesonero1 J, D Murillo1 M, P Arruebo1 M, A Plaza1 M
1Pharmacology and Physiology, University of Zaragoza, Spain,
2UMR 1043, INSERM, Toulouse, France
Objectives:
The aim of this study was to investigate the involvement of cerebral COX in the GI motor alterations and fever induced by LPS.
Materials:
GI motility was recorded by electromyography in conscious ewes. Body temperature was monitored with an intraperitoneal thermistor. Immunohistochemistry studies were carried out on samples of hypothalamus and medulla oblongata collected 1 or 4 h after an intravenous (iv) injection of either saline or Escherichia coli LPS (0.1 mg/kg). ANOVA and Scheffé tests were used for statistical purposes.
Results:
LPS increased body temperature and MMC frequency whereas it inhibited antral, duodenal and jejunal myoelectric activity. These effects were strongly reduced by the intracerebroventricular injection of the selective COX-2 inhibitor nimesulide (0.2 mg/kg). In control animals, COX-1 and COX-2 were expressed in the vascular endothelial cells of the hypothalamus and medulla oblongata. In addition, COX-1 was observed in cells related with the blood vessels wall. COX-2 was also expressed in some neurons that were particularly abundant in the hypothalamic preoptic area and in the paraventricular and ventromedial nuclei. In the brainstem and the hypothalamus positive immunostaining to the perivascular macrophage marker CD163 (ED2) was observed in scattered cells related with the blood vessels wall. LPS increased the number of these perivascular macrophages and induced their appearance throughout the parenchyma. All these cells coexpressed COX-2. In the hypothalamus, macrophages were particularly abundant in the organum vasculosum of the lamina terminalis (OVLT) and in the medial preoptic nucleus. In the hypothalamus, LPS also induced COX-2 expression in reactive microglia and increased the number of neurons positive to COX-2 in the paraventricular and ventromedial nuclei.
Conclusions:
Our data suggest that LPS disturbs GI motility and induces fever in sheep through the increase in the expression of COX-2 in perivascular macrophages located in the medulla oblongata and hypothalamus.
Supported by DGI (AGL2006-04317/GAN), FEDER, Gobierno de Aragón (I-2011/017, B61/2010, B090/2009) and Universidad de Zaragoza (UZ2010-BIO-13).
To cite this abstract, please use the following information:
Acta Physiologica 2012; Volume 206, Supplement 693 :P244