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    Iloprost relaxes phenylephrine-precontracted rat aortic rings
    (E-Century Publishing Corp, 2016) Peker, Recep Oktay; Donmez, Soner; Cankara, Fatma Nihan; Dogan, Emre; Gokalp, Osman
    Iloprost is a prostacyclin analogue mainly used in the treatment of pulmonary hypertension. It is also effective for renal dysfunction during renal transplant and coronary artery bypass grafting surgery, but there have been few comparative experimental studies with iloprost. We aimed to compare vasorelaxant properties of iloprost, with those of diltiazem, nitroglycerin and papaverine on rat thoracic aorta following phenylephrine-induced precontraction. Thirty-two young adult female Wistar albino rats were used in the study. After isolation of thoracic aorta distal to arcus, 3 mm aortic rings were placed in an organ bath and phenylephrine (10(-6) M) was added for precontraction. Subsequently, cumulative concentrations of iloprost, nitroglycerin, diltiazem and papaverine were added to aortic rings on separate chambers and dose-response curves were recorded. The mean (+/- SD) maximal relaxation (E-max) was 27.1 +/- 2.9% for iloprost, 111.7 +/- 2.1% for nitroglycerin, 77.4 +/- 2.9% for diltiazem and 147.2 +/- 2.8% for papaverine. The half maximal effective concentration (EC50) values were 2.4 x 10(-11) molar (M) for iloprost, 5.6 x 10(-8) M for nitroglycerin, 7.0 x 10(-7) M for papaverine and 2.1 x 10(-5) M for diltiazem. There was a statistically significant difference in Emax values and EC50 values between four groups (P<0.001 and P<0.01, respectively). Although a vasorelaxant response was observed with iloprost, it was less compared to papaverine, nitroglycerin and diltiazem on the isolated rat aortic rings. Iloprost has also the lowest EC50 value which could be valuable in clinical practice.
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    Öğe
    Vasorelaxant effects of dobutamine and levosimendan on rat aorta rings
    (Baycinar Medical Publ-Baycinar Tibbi Yayincilik, 2015) Dogan, Emre; Peker, Recep Oktay; Yener, Ali Umit; Donmez, Soner; Gokalp, Osman
    Background: In this experimental study, the vasorelaxant effects of levosimendan and dobutamine on isolated rat thoracic aorta preparations were compared. Methods: Sixteen Wistar albino type male rats were used. The thoracic aortas were removed carefully and were transferred to petri dishes containing Krebs solution. Aortic rings of approximately 5 mm in length were prepared and placed in the organ bath. Contraction and relaxation forces of the aortic rings were recorded. Contraction response was obtained by applying 10(-5)M phenylephrine to aortic rings. Subsequently, cumulative doses of levosimendan (10(-8)M-10(-4)M) was applied to eight aortic rings and cumulative doses of dobutamine (10(-8)M-10(-3)M) was applied to the other eight aortic rings and dose-response curves were recorded. The EC50 and pD2 values were calculated by the computer program named Graph Pad Prisim 4.0. The Mann-Whitney U-test was performed for statistical analysis. Results: The relaxation response of the aortic rings with levosimendan 10(-4)M administration was %92.33 while the relaxation response with dobutamine 10-4M administration was %82.48. It did not show a significant difference between both relaxation responses (p=0.059). The EC50 value was calculated as 6.605x10(-6)M for dobutamine and 5.093x10(-5)M for levosimendan. The pD2 value was found to be 5.2 +/- 0.4 for levosimendan and 4.3 +/- 0.2 for dobutamine. Conclusion: Levosimendan and dobutamine molecules in vitro rat aortic rings have similar vasorelaxant effects.