ABSTRACT
In experiments on frogs, rats, rabbits, cats, dogs and simians the synchronization of cardiac and vagal rhythms was achieved during stimulation of vagus nerve. The relative bounds of the synchronization ranges were not dependent on the species of animal or level of sympathetic activity. In this connection, the whole variety of the cardiochronotropic reactions in vertebrates may be described with a general mathematical equation: B = A (0.769-0.098 log2N), where A is a current heart rate, B--the heart rate during the vagus nerve stimulation with bursts of N supramaximal pulses.
Subject(s)
Heart Rate , Vagus Nerve/physiology , Animals , Cats , Dogs , Macaca mulatta , Rabbits , Rana temporaria , Rats , Species SpecificityABSTRACT
Burst vagus stimulation led to synchronization of the cardiac and vagal rhythms at certain frequency ranges. The increase of the number of impulses in a burst from 1 to 16 extended the range of synchronization and shifted it towards lower frequencies forming a total range of exact regulation of the heart rate within 85--40% of the initial rate. It was suggested that vagal effect consists of tonic and synchronizing components.