The influence of β-endorphin on the functional activity of the isolated heart of rat. The role of δ-opioid receptors

The purpose of research is to learn the influence of β-endorphin on the functional activity indicators of the isolated heart of rat and to evaluate the role of opioid receptors. Materials and methods. The research was performed on isolated hearts of males nonlinear white rats. Perfusion of the heart was performed on the Langendorff System at constant flow. Register indicators are volume rate of coronary perfusion, perfusion pressure, the pressure in the left ventricle, pulse pressure, heart rate, speed of changing the pressure developed by the left ventricle. Additionally was calculated integral indicator minute performance of the left ventricle corresponding to the area under the curve of change of pressure in the left ventricle per a minute, index of contractile function and the integral indicator of the average performance of the left ventricle per one contraction. Results and discussion. It was identified depressant effect of β-endorphin in slightly declining trend to decrease of myocardial contractility indicators in a concentration range from 6.3x10 -10 to 6.3x10 -18 M. In the presence of a blocker of δ-opioid receptor naltrindole inhibitory effect of β-endorphin identified in isolated use, practically was not manifested. Thus, the peripheral δ-opioid receptors of cardiomyocytes mediate the decrease of myocardial contractility caused by β-endorphin using. Conclusions. β-endorphin in physiological concentrations has a depressing effect on functional parameters of the isolated heart of rat. Stimulation of δ-opioid receptors is one of the mechanisms leading to formation of the negative inotropic effect of β-endorphin as a component of local cardiac activity regulation.