The effect of serotonin on left ventricular myocardial contractility in immature rat model for drug-induced rhinitis

Chronic administration of intranasal adrenergic agonists causes to drug-induced rhinitis. Objective. The aim of the study is to analyze the effect of serotonin on left ventricular myocardial contractility in immature rat model for drug-induced rhinitis. Materials and Methods. Immature Wistar male and female rats aged 49 to 70 days were the object of the study. The effect of serotonin on the left ventricular (LV) myocardium contractility was studied on our own immature rat model for drug-induced rhinitis. The strain gauge method was used to evaluate the effect of increasing serotonin concentrations (0.1; 1.0; 10.0 μmol) on myocardium contractility in 2-month-old rats after 7- and 28-day intranasal administration of the alpha-adrenergic agonist Nazivin at a daily dose of 9 μg/100 g. Results. We observed a decrease in the contractile force of LV myocardium in young rats in the druginduced rhinitis model after 28-day intranasal nasivin administration. Serotonin at concentrations of 0.1, 1.0 and 10.0 μmol increases the contractile force of LV myocardium in young rats with drug-induced rhinitis. However, the reactions are weaker in young rats with 7-day nasivin administration, and in the 28-day nasivin administration model, they are stronger compared with the control animals. The duration of LV myocardial contraction and relaxation in young rats with 7-days nasivin administration decreases, and in young rats with 28-day nasivin administration it increases under the influence of serotonin at concentrations of 0.1 μmol, 1.0 and 10.0 μmol compared to the control (p<0.05). Conclusions. The contractile force of LV myocardium in rats in the drug-induced rhinitis model is reduced compared to the control. Serotonin increases the contractile force and relaxation time of the LV myocardium in immature rats compared to the control.