[General principles of heart rate control during burst stimulation of the vagus nerve in various animals]. / Obshchie printsipy upravleneniia serdechnym ritmom pri zalpovom razdrazhenii bluzhdaiushchego nerva u razlichnykh zhivotnykh.

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.

Blood pressure in monkeys chronically exposed to psycho-emotional stress.

The influence of experimental neurosis due to repeated conflict situations on blood pressure was studied in male monkeys. All animals developed hypertension demonstrable in the conscious state but which disappeared under pentobarbital anaesthesia. Both in conscious and anaesthetized animals, the pulse pressure was in-elevated. The hypertension was accompanied by increased plasma volume to interstitial volume ratio, due to a decrease of the interstitial fluid compartment. The plasma renin concentration was not raised. It is suggested that chronic increase in blood pressure might be responsible for the decrease in compliance of large arteries (as evidenced by increased pulse pressure). This form of hypertension does not depend on the activity of the renin-angiotensin system.