Similarity of cardiovascular responses to exercise and to diencephalic stimulation

Abstract

Devices to measure left ventricular pressure, diameter and heart rate in animals with closed chests were placed on the hearts of dogs. After recovery from this operation the dogs were trained to exercise on a treadmill and the cardiovascular responses to this exercise were recorded. Stimulating electrodes were then stereotaxically placed in the diencephalon. In some dogs the electrodes were chronically implanted, and the stimulation was carried out after recovery from this second operation. In other animals stimulation was carried out immediately while they were under chloralose anesthesia. Stimulation of the H₁ and H₂ fields of Forel and the periventricular gray of the third ventricle resulted in cardiovascular responses similar to those which result from exercise.