P2X7 receptor antagonist improves gastrointestinal disorders in spontaneously hypertensive rats

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon.

Plant food resources exploited by Blue-and-Yellow Macaws (Ara ararauna, Linnaeus 1758) at an urban area in Central Brazil / Plantas alimentares exploradas pela Arara Canindé (Ara ararauna, Linnaeus 1758) em uma área urbana do Brasil Central

In this study, we described the food plants available to Blue-and-Yellow Macaws (Ara ararauna), its feeding habits and the relationship between these parameters with feeding niche breadth. We established four transects, each one 12 km long, to sample fruiting plants and the feeding habits of this macaw (monthly 40 h, of observations), at the urban areas of Três Lagoas (Mato Grosso do Sul, Brazil). During all studied months, macaws foraged for palm fruits, mainly Syagrus oleracea and Acrocomia aculeata fruit pulp, both available all year, as well as Caryocar brasiliense and Anacardium occidentale seeds, in the wet season. The year-round feeding activity of macaws suggests Três Lagoas city as an adequate feeding area. The permanent availability of plant food resources, potentially, resulted from the diverse fruiting patterns of exotic and, mainly, native plant species, which provided a variety of suitable fruit patches.

Neste estudo, nós descrevemos as plantas alimentares disponíveis para Arara-Canindé (Ara ararauna), sua atividade alimentar, bem como a relação desses parâmetros com a amplitude do seu nicho alimentar. Para tanto, estabelecemos quatro trajetos, cada um com 12 km, dispersos na área urbana de Três Lagoas (Mato Grosso do Sul, Brasil). A partir deles amostramos, mensalmente durante 40 h, as espécies vegetais que frutificavam e a atividade alimentar dessa ave. As araras exploraram frutos em todos os meses do ano e consumiram principalmente frutos comuns e nutritivos. Entre os itens mais explorados pelas araras estiveram as sementes de Anacardium occidentale e Caryocar brasiliense, cuja frutificação ocorreu durante a estação chuvosa, bem como a polpa dos frutos das palmeiras Syagrus oleracea e Acrocomia aculeata, que frutificaram o ano todo. A presença de araras forrageando todos os meses em Três Lagoas sugere a adequação dessa área urbana como local de alimentação. A disponibilidade de recursos alimentares ao longo do ano, potencialmente, decorreu da combinação da variedade dos padrões de frutificação em espécies vegetais exóticas e, sobretudo, nativas que proporcionaram oferta abundante e variada de recurso alimentar.

Morphocytochemical, immunohistochemical and ultrastructural characterization of the head kidney of fat snook Centropomus parallelus

This study characterized the structure and the morphocytochemical, immunohistochemical and ultrastructural aspects of the head kidney (HK) of the fat snook Centropomus parallelus. The HK is enclosed by a thin capsule of connective tissue, from which fine trabeculae originate and branch into the interior of organ. In the parenchyma, there are aggregates of lymphoid cells containing populations of lymphocytes T immunopositive for CDRO45, in a nodular arrangement, around blood vessels and melano-macrophage centres. Among the cells that constituted these aggregates and surrounded them, were macrophages and monocytes, and their precursors, with strong immunopositivity for CD68, along with cells of the granulocytic lineage in various phases of maturation positive for lysozyme and PAS. Macrophages and chromaffin and interrenal cells are also present. Ultrastructurally, the HK comprises a reticulum-endothelial stroma consisting of endothelial cells, reticulocytes of the fibroblast type and macrophage type and a parenchyma with increased cellularity, principally blood cells of the erythrocytic, granulocytic, lymphocytic, monocytic and thrombocytic series.

Morphological, cytochemical, and ultrastructural observations on the blood cells of the reptile Tupinambis merianae (Squamata)

Tupinambis merianae is a lizard of the Brazilian fauna and belongs to the Squamata order. Blood cell data are scarce. Blood samples from six specimens of adult T. merianae were used to evaluate some hematological parameters. For structural analysis, 2 ml of blood was collected in the presence of EDTA. Part of the blood was used for preparing blood smears which were submitted to the methods of Leishman, Laür, and toluidine blue, and the cytochemical reactions of periodic acid-Schiff, sirius red, sudan black B, and ortho-toluidine-H2 O2. The remainder was centrifuged and the leukocyte buffy coat was fixed in Karnovsky's fluid for electron microscopy examination. The following blood cells were identified: mature and immature erythrocytes, spherical and elliptical thrombocytes, heterophilic granulocytes, eosinophils and basophils types I and II, lymphocytes, monocytes, and azurophilic cells. The more significant results obtained were: the presence of glycogen in the cytoplasm of the thrombocytes, heterophils, and basophils; the presence of basic polyaminoacid-rich proteins in the granules of heterophils and eosinophils and myeloperoxidase in the granules of the heterophils, eosinophils, and azurophilic cells; and sudanophilic small granules in the heterophils, eosinophils, and azurophilic cells. More detailed morphological aspects of the cells were observed by means of ultrastructural analysis.

The osteoinductive potential of MTA (Mineral Trioxide Aggregate): a histologic study in rabbits

The objective of this study was to investigatebone response after implantation of MTA (MineralTrioxide Aggregate) in the rabbit mandible.Experiments were carried out on the rightmandibular body of 8 adult male rabbits. Theanimals were divided into two groups (controlgroup and test group). In this in vivo study, MTAwas used as an interpositional graft material incritical-size bone defects of rabbit mandibles.The animals were sacrificed on day 30 after surgery.The samples obtained from the mandibleswere subjected to histological procedures, whichpermitted the collection of sections with a thicknessof 60±10ìm. The sections were stained withHaematoxylin and Eosin and Goldner Trichromestain and examined under a light microscope.No important inflammatory reactions weredetected in any of the samples of the treatedgroup. The results confirm the excellent biocompatibilityof MTA. The implantation of MTA inbone defects led to bone regeneration 4 weeksafter surgery. However, the growth rate was notsignificant and the amount of newly formed bonewas limited with the use of MTA in this specificapplication. Sample examination did not suggestcomplete evidence of new bone growth from eitheran inductive or conductive perspective.The objective of this study was to investigatebone response after implantation of MTA (MineralTrioxide Aggregate) in the rabbit mandible.Experiments were carried out on the rightmandibular body of 8 adult male rabbits. Theanimals were divided into two groups (controlgroup and test group). In this in vivo study, MTAwas used as an interpositional graft material incritical-size bone defects of rabbit mandibles.The animals were sacrificed on day 30 after surgery.The samples obtained from the mandibleswere subjected to histological procedures, whichpermitted the collection of sections with a thicknessof 60+-10microm. The sections were stained withHaematoxylin and Eosin and Goldner Trichromestain and examined under a light microscope.No important inflammatory reactions weredetected in any of the samples of the treatedgroup. The results confirm the excellent biocompatibilityof MTA. The implantation of MTA inbone defects led to bone regeneration 4 weeksafter surgery. However, the growth rate was notsignificant and the amount of newly formed bonewas limited with the use of MTA in this specificapplication. Sample examination did not suggestcomplete evidence of new bone growth from eitheran inductive or conductive perspective

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