THE INFLUENCE OF INDOLE SS-68 DERIVATIVE ON THE EXCITATION CENTER DYNAMICS IN THE SINOATRIAL NODE UNDER THE VAGUS NERVE STIMULATION

In experiments on anaesthetized cats in the sinoatrial node (SAN), located in induced high-frequency electric field, focus glow (FG) is visualized, which upon stimulation of the vagus nerve (VN) by periodic electrical impulses undergoes significant changes, characterized by FG weakening and its migration, the emergence of pacemaker cells odd pools (PCP); bradycardia and sinus arrhythmia are also observed. Intravenous indole SS-68 derivative (50 mkg/kg) injection which is included in III antiarrhythmic class and is M2 holinoblocator, causes the increase in the FG intensity, its returning to the original location, PCP combination, bradycardia relief and sinus arrhythmia arrest. Under vagal-cardiac synchronization (VCS), caused by VN volleys of electrical impulses stimulation, FG in SAN is intensified and increases its square. PCP are combining thus causing bradycardia. SS-68 (50 mkg/kg) intravenous injection does not cause visible changes in the SAN functional state. It is suggested that the lack of SS-68 activity under the experimental conditions is masked by the processes that occur in the SAN under VCS, that requires additional specific investigations.