Testing the Bradycardiac Effect of Newly Synthesized Potential Ultrashort Beta--Blockers on the Laboratory Rat

Overview

With the use of normotensive laboratory Wistar strain rats, changes in heart rate induced by threenewly synthesized potential ultrashort beta-blockers were tested. The animals were administeredthe tested substances intravenously in general anesthesia. In all animals, heart rate was measuredat predetermined time intervals. All obtained values were converted into the per cents of the heartrate deviation and the results were statistically processed. Using F-test, variability of dispersionwas determined, and using Student t-test, statistical significance of the particular change wasdetermined. In all three substances tested, a statistically demonstrable short-time bradycardiaceffect was observed. The most marked decrease took place in the first minute after intravenousadministration. Substance 44Bu induced the significantly deepest decrease in heart rate (by13.00%), which lasted longest. No statistically significant difference was found between the actionsof substances 42Bu and 43Bu. In all three substances tested, marked changes in the ECG recordwere observed immediately after intravenous administration. PQ and QT intervals and QRScomplex were prolonged, and marked S wave, elevation of the T wave, and a decrease in R waveoccurred. The changes were accompanied by a change in the electric cardiac axis.

Key words:
ultrashort-acting beta-blockers – heart rate – changes in ECG – ion channels