[THE EFFECT OF SEROTONIN ON THE INOTROPIC FUNCTION OF MYOCARDIUM OF THE LEFT VENTRICLE OF IMMATURE SPONTANEOUSLY...

The mechanisms of the serotonin effect on the inotropic function of the myocardium of the left ventricle of immature spontaneously hypertensive rats (SHR) are unexplored. It was found that systolic arterial blood pressure of 5-6 weeks SHR rats is 147.5 mm Hg, which is statistically significantly higher (more than 25 mm Hg) than in the same age of normotensive control Wistar- Kyoto rats. The weight of the heart, of the left ventricle myocardium, of the ventricular septum, of the aorta and the force of contraction of the left ventricle of 5-6-week-old SHR rats are increased significantly compared with the control. 0.1 pM serotonin increases and 1.0 pM and 10.0 AM serotonin reduce the force of contraction of the left ventricular myocardium in hypertensive rats, but there is a dose-dependent increase of the force of contraction in the control. Serotonin reduces the time of contraction of the myocardium of the left ventricular of SHR rats, these reactions are less pronounced as compared to the control.