Effect of Myelencephalic Stimulation on the Secretion of Noradrenaline and Adrenaline of the Adrenal Gland in the Cat

Abstract

The dorsal parts of the medulla oblongata in cats were stimulated electrically and the adrenal medullary response was directly evaluated. Adrenal venous blood was collected from cats anesthetized with sodium pentobarbital and was analyzed for noradrenaline and adrenaline by the fluorimetric method. Following stimulation of the inferior fovea a definite increase in noradrenaline secretion without any definite increase in adrenaline secretion was observed. Stimulation of some other parts of the floor of the fourth ventricle produced a definite increase in adrenaline secretion with or without an increase in noradrenaline secretion. In some cases a decrease in noradrenaline secretion was found. A rise of blood pressure producible by myelencephalic stimulation was not always accompanied with an increase in adrenal medullary secretion.