The Vagi and Appetite

Abstract

We desire to record an observation in regard to the relation of the vagus nerves to appetite, an observation indicating that afferent sensations mediated by the vagi may be responsible for anorexia in abnormal gastro-intestinal states. Our reasons for recording an observation on one animal are as follows: (a) The animal preparation on which the observation was made is difficult to care for in that the feeding requires almost the full-time attendance of one individual and there is no likelihood of our being able to repeat the observation on other animals in the near future; and (b) the observation has a direct bearing on the interpretation of the results of those who are now investigating the subject of appetite, especially as related to Vitamin B deficiency, a problem in which we are not interested immediately.

In September, 1930, a dog was prepared 1 with a pouch of the entire stomach with vagi intact and a jejunal fistula for feeding. The pylorus was cut across, the duodenum closed and the pyloric opening brought to the outside, the jejunal fistula having been made previously. Nothing was allowed the dog by mouth for 3 months. At this time we tried to induce the dog to eat, but failed. The dog was on a diet supplemented with vitamines, including Vitamin B concentrate. On rare occasions we were able with much effort to induce the animal to eat an ounce or 2 of food. This continued throughout the period of one year, during which the body weight and nutrition were maintained solely by jejunal feeding. We thought that the appetite mechanism had been “reconditioned”, i. e., the dog, “satisfied” with the jejunal method of feeding, had lost the desire to eat by mouth, since the animal was doing well and a desire to take food by mouth could not be stimulated by administration of the various vitamins in large quantities.