Browsing by Subject "vascular smooth muscle"

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    Immunolocalization of VEGF, VEGFR-1 and VEGFR-2 in lung tissues after acute hemorrhage in rats
    (2008) Ekerbicer N.; Tarakci F.; Barut T.; Inan S.
    In treatment of hypovolemia it is important to reestablish normal tissue hemodynamics after fluid resuscitation. Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) have been identified as important in many physiological and pathological processes. In this study, we aimed to investigate the histo-physiological effects of VEGF, VEGFR-1 (flt-1) and VEGFR-2 (KDR/flk-1) in resuscitation with different plasma substitutes on lung tissues after acute hemorrhage in rats. Male Sprague-Dawley rats (n=25) were used in this study. The left femoral vein and artery were cannulated for the administration of volume expanders and for direct measurement of mean arterial blood pressure (MAP) (Power-Lab) and heart rate (HR). Fifteen rats were bled (5 ml/10 min) and infused (5 ml/5 min) with one of three randomly selected fluids: (a) dextran-70 (Macrodex); (b) gelatin (Gelofusine); or (c) physiological saline (PS, 0.9% isotonic saline) solutions. Five rats were bled and none were infused (hypovolemia group) and five rats were untreated as the control group. At the end of the experiment, rats were sacrificed and lung tissues were removed for routine processing and paraffin wax embedding. Sections of tissue were stained with hematoxylin and eosin (H&E) and selected blocks were then prepared for indirect immunohistochemical labeling for anti-VEGF, anti-VEGFR-1 and anti-VEGFR-2 primary antibodies. It was observed that both MAP and HR decreased parallel to blood withdrawn in this time interval. The MAP and HR were restored in the following periods. In the control rats, positive immunoreactivity of VEGF and its receptors (VEGFR-1 and VEGFR-2) were detected in respiratory epithelial cells, respiratory and vascular smooth muscle cells, alveolar cells and endothelial cells. While strong immunoreactivities of VEGF and VEGFR-1 were observed in the hypovolemia group, only moderate immunoreactivity of VEGFR-2 was seen in this group. Moderately strong immunolabeling of VEGF and VEGFR-1 were observed in the dextran-70, gelatin and PS resuscitated groups, whereas only weak immunolabeling of VEGFR-2 was observed in these groups. In summary, the vascular protecting effects of these factors were observed with fluid resuscitation, contributing to the pathophysiological changes seen in hypovolemia. © 2007 Elsevier GmbH. All rights reserved.
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    Vasodilator effects of cromakalim and HA 1077 in diabetic rat aorta
    (SMW supporting association, 2012) Gurpinar T.; Gok S.
    BACKGROUND: Impairment of the vasorelaxant responses have been reported in diabetes mellitus. In this study, the roles of the KATP channel and rho kinase pathway were evaluated by using the KATP channel opener cromakalim and Rho-kinase inhibitor HA 1077 in diabetic rat aorta. METHODS: Adult male Wistar rats weighing (250-300 g) were divided into diabetic and control groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ, 55 mg/kg/i.p). RESULTS: Vasodilator responses induced by cromakalim (10-7 to 10-3M) and HA 1077 (10-6 to 10-4M) were significantly less in diabetic rings compared with control rings (p <0.01). The decrease in the relaxant effect of cromakalim was more in endothelium-denuded rings compared to the endothelium-intact rings (p <0.05). There were no significant differences between endothelium intact and nonintact rings in the presence of HA 1077. When two drugs were administered together, relaxation was significantly less than with seperate administration of each drug in the diabetic group (p <0.01). Pre-treatment with N omeganitro- L-arginine methylester (L-NAME) (10-6 to 10-4 M), an NO synthase inhibitor, significantly decreased the relaxant response to cromakalime and HA 1077 in both the control and diabetic groups (p <0.05). CONCLUSIONS: These results suggest that the impaired relaxant effects were further decreased depending on KATPchannel activity but the effects of Rho-kinase enzyme inhibitors on relaxation responses were not significantly changed in diabetes mellitus.