Abstract
Serotonin plays an important role in the cardiovascular system and is a humoral system of regulators and modulators of physiological processes. Under pathological conditions, it can result in developing some factors contributing to the development of diseases, such as atherosclerosis, arterial and pulmonary hypertension. The 5-HT4 and 5-HT2B receptors have been identified in cardiomyocytes, which are involved in the regulation of the inotropic function of the myocardium. The serotonergic system is an essential link in embryonic development. As a key signaling molecule in heart progenitor cells, serotonin is involved in the development and differentiation of myocardial cells as well as the separation of the heart chambers. Therefore, interfering with this system in the womb and changing its concentration can disrupt normal development of the heart. It has been established that any change in the concentration of serotonin created by the blockade of the synthesis of serotonin and the membrane serotonin transporter in the embryonic period of ontogenesis, leads to a decrease in the contraction strength of the right ventricular myocardium in 7-day-old infant rats. However, at the age of 14 days, intergroup differences are not manifested. At 7 days of age, the response of the contraction strength to the maximum concentration of serotonin is lower in infant rats with an excess of serotonin and higher in infant rats with its deficiency, as compared to those animals in the control group. At the age of 14 days, the response of the contraction strength in both experimental groups has been reduced in comparison with the animals in the control group.