Descending Spinal Pathway Subserving the Adrenaline Secretion of the Adrenal

Abstract

Tournade, Hermann, Malmejac and Jourdan1) studied the descending spinal pathway of secretory fibers to the adrenal medulla. In their ex periments the method of suprareno jugular anastomosis was employed and the hemisection of the spinal cord was made at the level of Th2. The faradization of the spinal cord above the site of hemisection resulted in an increase in the adrenaline secretion from the ipsilateral as well as from the contralateral adrenal gland. From these results it was concluded by them that the adrenalino-secretory fibers partly passed down directly the spinal cord and partly decussated. Evidence given by them, however, is to be brought into question, since the possibility of the current spread to just below the site of section cannot be ruled out.Here, the adrenalino-secretory action of insulin hypoglycemia is recalled. The augmentation of adrenaline secretion induced by insulin hypoglycemia is well established. It was proved by Sato, Kanowoka and Ohmi2) that this augmentation was wholly abolished by the transection of the spinal cord at the lower cervical segments. And it was concluded that insulin hypoglycemia increased the adrenaline secretion in acting on the center situated above the level of the section.In the present investigation we have examined in the first place whether the findings of Sato et al. can be duplicated by our hands. Our success in the duplication led us to apply insulin hypoglycemia to the study of the descending spinal pathway. Experiments were performed in an attempt to know how the hemisection of the spinal cord at the lower cervical level acts on the secretion of adrenaline after insulin from each of both adrenal glands.