SELECTIVE VAGAL RHIZOTOMIES - A NEW DORSAL SURGICAL APPROACH USED FOR INTESTINAL DEAFFERENTATIONS

We have developed a dorsal intracranial surgery that is minimally invasive and gives excellent access to either afferent or efferent vagal rootlets to produce selective deafferentations or deefferentations in the rat. We have combined this new unilateral afferent rhizotomy with a contralateral celiac branch cut (to completely deafferent the intestines) and a duodenal catheter placement 4 cm distal to the pylorus. Animals were maintained with 17 h/day access to a nutritionally complete liquid diet. Measures of first meal size, daily intake, and body weight before and after both surgeries indicated that animals with unilateral vagal deafferentations recovered as fast and completely as sham-operated controls. Intraduodenal oleate (1.2 kcal) infusions reduced the size of the first meal in surgical controls (by 64%; P < 0.01) but not in the deafferented rats. A dual wheat germ agglutinin-horseradish peroxidase/Fluorogold protocol provides verification of sensory and motor lesions. The selective vagal deafferentation provided by the new surgery offers a useful model for determining gastrointestinal sites of nutrient detection and separating pre- and postabsorptive consequences of a meal.