Background/Aim. Stevioside is a glycoside that supposedly possesses a number of pharmacodynamic effects such as anti-infective, hypoglycemic, along with the beneficial influence on the cardiovascular system. The aim of this study was to determine the effect of rats pretreatment with aqueous solution of stevioside on pharmacological actions of adrenaline, metoprolol and verapamil. Methods. Rats were administered (intraperitoneally 200 mg/kg/day) stevioside as aqueous solution or physiological

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... ine in the course of 5 days, then anaesthetized with urethane and the first ECG recording was made. The prepared jugular vein was connected to an infusion pump with adrenaline (0.1 mg/mL), verapamil (2.5 mg/mL) or metoprolol (1 mg/mL). Control animals, pretreated with saline, in addition to the mentioned drugs, were also infused with the solution of stevioside (200 mg/mL) in the course of recording ECG. Results. The infusion of stevioside produced no significant changes in ECG, even at a dose exceeding 1,600 mg/kg. In the control group, a dose of adrenaline of 0.07 ± 0.02 mg/kg decreased the heart rate, whereas in the stevioside-pretreated rats this occurred at a significantly higher dose (0.13 ± 0.03 mg/kg). In stevioside-pretreated rats, the amount of verapamil needed to produce the decrease in heart rate was significantly lower compared to the control. The pretreatment with stevioside caused no significant changes in the parameters registered on ECG during infusion of metoprolol. Conclusion. The results suggest that pretreatment with stevioside may change the effect of adrenaline and verapamile on the heart rate. Apstrakt Uvod/Cilj. Steviozid je glikozid za koji se pretpostavlja da poseduje niz farmakodinamskih efekata kao što su antiinfektivni, hipoglikemijski, kao i uticaj na kardiovaskularni sistem. Cilj rada bio je da se utvrdi uticaj pretretmana pacova vodenim rastvorom steviozida na farmakološko dejstvo adrenalina, metoprolola i verapamila. Metode. Pacovi su tretirani (intraperitonealno 200 mg/kg/dan) vodenim rastvorom steviozida ili fiziološkim rastvorom pet dana, nakon ega su anestezirani uretanom i ura en im je prvi EKG. U preparisanu venu jugularis infuzionom pumpom potom je primenjivan adrenalin (0,1 mg/mL), verapamil (2,5 mg/mL) ili metoprolol (1 mg/mL). Kontrolne životinje, pretretirane fiziološkim rastvorom, osim navedenih lekova, primale su i rastvor steviozida (200 mg/mL) preko infuzione pumpe. Sve vreme dok su lekovi davani u jugularnu venu, sniman je EKG. Rezultati. Infuzija steviozida nije uzrokovala zna ajne promene EKG-a, ak ni pri dozi koja je prelazila 1 600 mg/kg. U kontrolnoj grupi doza adrenalina od 0,07 ± 0,02 mg/kg smanjila je sr anu aktivnost, dok je kod pacova prethodno tretiranih steviozidom taj efekat postignut pri znatno višoj dozi (0,13 ± 0,03 mg/kg). Kod pacova koji su prethodno tretirani steviozidom doze verapamila potrebne za izazivanje smanjenja sr ane aktivnosti bile su zna ajno niže u odnosu na kontrolu. Prethodni tretman steviozidom nije izazvao zna ajne promene parametara koji su pra eni na EKG-u tokom infuzije metoprolola. Zaklju ak. Rezultati pokazuju da kod pacova pretretiranih steviozidom dolazi do promena dejstva adrenalina i verapamila na frekvenciju srca. Klju ne re i: stevia; fitoterapija; elektrokardiografija; adrenalin; metoprolol; verapamil; pacovi. Strana 668 VOJNOSANITETSKI PREGLED Volumen 71, Broj 7 Vasovi V, et al. Vojnosanit Pregl 2014; 71 (7) : 667-672.