The role of endogenous modulators of chemoreactivity in the regulation of coronary blood flow

32 circulatory bands of coronary arteries of 5 pigs were studied. It has been revealed that the bands develop long-term tonic contraction activity in Krebs's solution (30 mM of KCl). In this case adrenalin in concentration of 10(-7) g/ml causes mild relaxation. In concentration of 10(-6) g/ml, it causes obvious relaxation. Trimetazidin and mildronat do not affect tonic contraction of the bands. They can quickly and reversibly increase relaxation effects of adrenaline. The preparations can increase ten-fold beta-adrenoreactivity of smooth muscles. This shows an important role of endogenic sensibilizers of beta-adrenoreceptors in regulation of coronary blood flow in humans.