Bernard's Sugar Injection

Bernard's sugar injection, a prick to the floor of the fourth ventricle; an operation first described under this name (piqure) by Claude Bernard, accompanied by increased sugar formation in the liver, increased sugar content in the blood (hyperglycemia), and its appearance in urine (glycosuria). The pathway of irritation from the medulla oblongata passes through the spinal cord, the sympathetic trunk ganglia, and the nn. splanchnici. The glycosuria caused by the prick is temporary and in rabbits disappears after 4-5 hours, while in dogs it lasts somewhat longer. With small glycogen reserves in the liver (in a starving animal), it was not possible to cause glycosuria. Previously, according to Pflüger's views, the fibers going to the liver as part of the nn. splanchnici were attributed the property of specific action on liver cells in the sense of increasing their enzymatic activity. According to more recent research, this effect occurs through indirect transmission of irritation to the liver. Irritation through the nn. splanchnici is transmitted to the adrenal glands and causes increased production and entry of adrenaline into the blood, which in turn increases sugar formation in the liver. Injections of adrenaline indeed cause glycosuria, so that the glycosuria in sugar injection is in the proper sense an adrenaline glycosuria. The experiments of Kapp (Cann), which gave negative results with the prick in animals with removed adrenal glands, the experiments of Jarisch, who obtained glycosuria from the prick in a liver deprived of nervous connection with intact adrenal glands, as well as the experiments of Pollak and others - undoubtedly prove the participation of the adrenal glands in the origin of glycosuria in Bernard's sugar injection; as for the method of their action on the liver, this question remains insufficiently clarified to this day.