Hypothalamic Control of Coronary Circulation in the Dog

Abstract

The hypothalamus of narcotized, open-chest dogs was explored by employing the stereotaxic technique for mapping the effects exerted on coronary circulation. In the medial and posterior hypothalamus an extensive representation of the adrenergic coronary constrictor system was found. Excitation of this area often resulted in a manifold increase of coronary resistance. The neural elements affecting coronary constriction proved to be spatially intermingled with those inducing hypertension and cardioacceleration; accordingly secondary metabolic coronary dilatation caused by the latter, frequently followed initial constriction. Coronary constriction occupies a fixed position in the flow patterns of the lasting hypertensions elicited from the posterolateral hypothalamus, which fact implies the physiological importance of coronary constriction in excitatory cardiovascular effects integrated on the diencephalic level.

It was possible to elicit cholinergic coronary dilatation from the ventral grey matter of the anterior hypothalamus. By successive stimulation of the region lying behind the N. supraopticus, prolonged coronary constrictor responses, differing in character from those mentioned above, were obtained. This latter type of effect was presumably due to the release of vasopressin.