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Öğe The in vitro effects of remifentanil and fentanyl on isolated human right atria and saphenous veins(W B SAUNDERS CO, 2003) Duman, A; Sahin, AS; Atalik, KE; Ogun, C; Ulusoy, HB; Durgut, K; Okesli, SObjective: To determine the myocardial and vascular effects of remifentanil and fentanyl in human atria and saphenous veins. Design: In vitro, prospective with repeated measures. Setting: University research laboratory. Interventions: The direct effects of remifentanil and fentanyl on the electrical stimulation-induced contraction of nonfailing human atrium and saphenous veins contracted with 5-hydroxytryptamine were studied. Measurements and Main Results: In human atrial trabeculae, cumulative (10(-9)-10(-5) mol/L) added remifentanil had in 0 effect on contractile force, compared with untreated muscles (p > 0.05). The force of contraction was significantly less than control values with concentrations of fentanyl ranging from 10(-8) to 10(-5) mol/L (p < 0.05). At the highest concentration (10(-5) mol/L), the inhibition by fentanyl of the electrical stimulation-induced contraction was 40.6% +/- 6.32%. In human saphenous vein strips preconstricted with 5-hydroxytryptamine, remifentanil (10(-8)-10(-5) mol/L) and fentanyl (10(-8)-10(-5) mol/L) produced "concentration-dependent" relaxation when compared with the control contraction value (p < 0.05). The IC50 was similar with remifentanil and fentanyl and the E-max of fentanyl was significantly higher than remifentanil (p < 0.05). The venodilatory effects of remifentanil and fentanyl were similar on veins with or without endothelium (p > 0.05). Conclusions: Remifentanil has no direct effect on the contraction of myocardium. Fentanyl inhibits the electrical stimulation-induced contraction in human right atrial muscles in vitro. Remifentanil and fentanyl produce "concentration-dependent" relaxation in human saphenous vein strips independent from the endothelium. (C) 2003 Elsevier Inc. All rights reserved.Öğe The role of K+ ions on the response to carbachol of calf coronary artery and cardiac vein during cooling(PROUS SCIENCE, SA, 2001) Atalik, KE; Sahin, AS; Ulusoy, HB; Dogan, NThe role of K+ ions on the vasoconstrictions induced by carbachol during cooling (28 degreesC) in the endothelium of a denuded calf coronary artery and cardiac vein (noncutaneous vessel) was studied. Carbachol (10(-9) - 3 X 10(-4)M) induced concentration-dependent contractions at both 37 degreesC and 28 degreesC. The sensitivity, but not the maximal response, of carbachol (10(-9) - 3 x 10(-4) M) was significantly lower at 28 degreesC than at 37 degreesC. Cooling to 28 degreesC after treatment with tetraethylammonium (TEA, 10(-3) M) or ouabain (10(-5) M), or after incubation in K+-free medium, increased the sensitivity to carbachol in both preparations. The results suggest a role for K+ ions in the cooling-induced changes of noncutaneous vessels. (C) 2001 Prous Science. All rights reserved.Öğe Warming and Response to Contractile Agents in Calf Cardiac Vein: Role of the Nitric Oxide(BLACKWELL PUBLISHING LTD, 2003) Atalik, Kısmet Esra; Sahin, AS; Ulusoy, HB; Dogan, NThe effects of warming on the response to various contractile agents of calf cardiac vein were studied using 2.5-mm long cylindrical segments. Concentration-response curves for carbachol (10(-9)-3 x 10(-4) M), 5-hydroxytryptamine (5-HT; 10(-8)-3 x 10(-3)), potassium chloride (KCl; 10(-4)-5 x 10(-2) m) and calcium chloride (CaCl2; 10(-4)-10(-2)) were isometrically recorded at 37 and 41degreesC (warming). During warming the sensitivity, but not the maximal response, of carbachol 5-HT, KCl, and CaCl2 was significantly higher than at 37degreesC. Warming to 41degreesC after treatment with N-G-nitro-L arginine methyl esther (10(-5) m) did not modify the effect of warming. These results suggest that nitric oxide seems to have no role in the warming-induced responses in calf cardiac vein.
