Browsing by Author "Petkovic, D. (7006263342)"

The experiments done on the isolated right ventricle of rat hear suspended in the bath for isolated organs with oxygenated Tyrode's solution showed that PgI2 (2,3 x 10-6 mmol) produced its positive inotropic effect indirectly by promoting both beta-adrenoreceptors and calcium entry through slow calcium channels because this effect could be blocked by propranolol (2,3 x 10-2 mmol - beta adrenoreceptor blocker) or verapamil (4,3 x l0-3 mmol - slow calcium channel blocker).

The experiments done on the isolated right ventricle of rat hear suspended in the bath for isolated organs with oxygenated Tyrode's solution showed that PgI2 (2,3 x 10-6 mmol) produced its positive inotropic effect indirectly by promoting both beta-adrenoreceptors and calcium entry through slow calcium channels because this effect could be blocked by propranolol (2,3 x 10-2 mmol - beta adrenoreceptor blocker) or verapamil (4,3 x l0-3 mmol - slow calcium channel blocker).

It is known that adrenaline ( L - epinephraie) produces positive inotropic effect on isolated right ventricle of rat heart. Purpose : The aim of our study was to investigate inotropic effect of adrenaline on the isolated right ventricle of Wistar rat heart in the presence and absence of endocardial endothelium. Methods : Endocardial endothelium was damaged by immersion for I s of right ventricle with Triton X-100 dissolved in a Crebs-Ringer solution at 20°C followed by rapid abundant wash in Tyrode's solution at 35°C. Each ventricle was put on a boot electrode and than placed in a bath with Tyrode's solution bubbled with 95% O 2 /5% CO 2 The volume of the bath was 25 ml, pH=7.4 and it's temperature was kept on 37°C. Contractions were induced with square wave impulses of twice the diastolic threshold and a duration of 5 ms at a frequency on I Hz. The contractions were recorded via an isometric transducer (sensitivity of 0.05 g/cm) into a microdynarnometer (7050 Ugo Basile). After stabilization period of 30 min adrenaline (Sigma, USA), in a dose 10 5 mol/l, which produced maximal positive inotropic effect, was added into the bath and contractions were recorded continuously for another 60 min. Results : The positive inotropic effect of adrenaline in both groups was expressed immediately after the application. In the group with intact endocardial endothelium the maximal inotropic effect was reached in 2 nd min. (92% higher than in the controls, p<0.05). In the group with damaged endocardial endothelium it was reached in 3 rd min. (183% higher than the controls, p<0.05). The inotropic effect of adrenaline was approximately 100% higher in the experimental group without endocardial endothelium.