Influence of dantrolene and methoxiverapamil channels Ca2 + -channels on the rating myocardial myocardial function of rats with changed serotonin level

The effect of dantrolene and methoxyverapamil calcium channel blockers on the inotropic function of the left ventricular myocardium of the heart of 7- and 10-day-old rat pups was studied, in the embryonic period of development of which there was a deficit of serotonin (5-HT), created by the chronic administration of p-chloro-phenyl-alanine (PCPA) . It was found that the initial value of the contraction force of the left ventricle in rats with altered serotonin metabolism is 33% lower than in rats of the control group. Dantrolene dose-dependently reduces the contraction force of the left ventricle by 51-80% in the control and only by 13-25% in the experimental group. Subsequent administration of serotonin increases left ventricular myocardial contractility by 37,5-72% in the control and by 55-66% in the experiment. Methoxyverapamil reduces the power of left ventricular contraction in the control by 48% and in the experiment by 54%, however, the subsequent response to serotonin is significantly reduced in rat pups with altered serotonin metabolism and is respectively 113% and 29%. Opposit the background of serotonin, calcium channel blockers dantrolene and methoxyverapamil also reduce the force of contraction of the left ventricle. We found that the negative inotropic effect of dantrolene on the contraction force of the left ventricular myocardium in rats with serotonin deficiency in the embryonic period is reduced, compared with the control.