Cardiovascular responses to electrical stimulation in the diencephalon

Abstract

Cardiovascular responses to stimulation of the diencephalon have been recorded in vagotomized cats under d-tubocurarine or alpha-chloralose anesthesia. These responses include vasoconstriction, augmentation of myocardial contraction and cardioacceleration. These types of response may occur as single phenomena, but more commonly the response consists of various combinations of the three phenomena. It has been demonstrated in many animals that the major component of a pressor response is often the result of increased force of myocardial contraction rather than vasoconstriction. The highly reactive area for eliciting these responses includes the lateral and posterior hypothalamus, and part of the subthalamus. The area is bounded rostrally by a plane through the posterior border of the optic chiasma, caudally by a plane through the anterior border of the red nucleus, dorsally by a plane through the ventral thalamic nuclei, and laterally by a plane 3–4 mm to each side of the mid-line.