Sugar Puncture

the mechanical stimulation with a needle or the tip of a scalpel of a limited area on the floor of the fourth ventricle of the medulla oblongata, which causes prolonged high levels of blood sugar (hyperglycemia) and the appearance of sugar in the urine (glycosuria). Sugar puncture was first performed on a rabbit in 1855 by the French scientist C. Bernard, who hypothesized that the medulla oblongata contains a special nerve center that regulates carbohydrate metabolism; this hypothesis was subsequently never proven to be correct. If both adrenals are removed from an animal, sugar puncture does not have any effect. The stimulation of a limited area of the brain by sugar puncture causes an increased secretion of adrenaline, which results in the intensified decomposition of hepatic glycogen and, consequently, hyperglycemia. This process is effected by the sympathetic nervous system.