A FURTHER STUDY OF VASODILATORS IN SYMPATHECTOMIZED ANIMALS

Abstract

In completely sympathectomized cats with the vagi cut, curare raises blood pressure (BP) ; section of the cervical spinal cord evokes no change or a slight transient fall; ergotoxine causes a considerable rise; reflex falls may be attended by dilation of the spleen; reflex rises and falls may not be accompanied bv any distinctive volume changes of either the spleen or the leg; stimulation of the depressor points in the 4th ventricle causes a fall of BP, whereas stimulation of neighboring regions, including the pressor points is negative, unless muscular activity is evoked. In sympathectomized animals, the dilator fibers in the dorsal roots are probably the efferent paths of the response to stimulation of the depressor points, of the vasomotor reflexes, and of the dilator impulses responsible for the fall of BP attending struggle.