BASIC BIOLOGICAL SCIENCES Long-term Effects of Surgical Desalivation upon Taste Acuity, Fluid Intake, and Taste Buds in the Rat RAVINDRA NANDA and FRANK A. CATALANOTTO Departments of Orthodontics and Pediatric Dentistry, School of Dental Medicine, University of Con- necticut Health Center, Farmington, Connecticut 06032 Taste bud structure and taste preferences in intact and desalivated animals were evaluated to ascer- tain whether there was a structure-function rela- tionship. Thirty-three totally desalinated rats and 30 sham-operated controls were tested between 95 and 110 d after surgery with a 48-hour two-bottle preference paradigm; they were then sacrificed, and the tongue epithelium and circumvallate papillae taste buds were examined histologically. Desalivated rats manifested significantly increased preferences for normally avoided solutions. Histo- logical study of the dorsal tongue epithelium revealed increased keratosis. There were qualitative changes in the taste buds of the circumvallate papillae with some taste buds appearing shrunken and disorganized. J Dent Res(60)1:69-76, January 1981 Introduction. Vancel demonstrated significant alterations in intake of NaCl and quinine sulfate (QS) solutions after interruption of flow from the major salivary glands. Catalanotto and Sweeney2'3 confirmed these initial observa- tions and expanded them to include signif- icant long-term alterations in intake of NaCl, sucrose (S), QS, and hydrochloric acid (HCl) solutions in long-term desalinated rats. In addition, Catalanotto and Leffing- well4 demonstrated changes in preference- aversion behavior for potassium chloride (KCl), HCl, and QS solutions in desalinated rats tested immediately after surgery. Sup- porting studies have also been reported by Lawson et al.,5'6'9 Wong and Kranitz,8-10 and Galili et al.1 1 Received for publication March 31, 1980 Accepted for publication April 28, 1980 This project was supported in part by a grant from the University of Connecticut Research Foundation. F. Catalanotto was the recipient of a Research Career Development Award, DE00012, from the National Institute of Dental Research. While changes in gustatory function following alterations in salivary flow are well documented, the etiology of these changes, especially as they affect consum- matory behavior, is not well understood. Halpern12 postulated a generalized decrease in gustatory sensitivity related to the ab- sence of some component of the salivary secretions; he suggested that taste buds developing in the absence of this factor might function improperly. Catalanotto and Sweeney2'3 proposed that some component of saliva might be responsible for.maintain- ing the integrity of the oral epithelium, taste buds, and/or the specific gustatory recep- tors. Indeed, Henkin et al.13 described altered taste sensitivity and ultrastructural changes in taste buds of patients with xerostomia. Based upon these findings, one could hypothesize that, after desalination, taste buds might show structural changes which may be related to the impaired gustatory function. There have been few studies which systematically investigated these potential changes in the taste buds of desalinated rats. In an attempt to document behavior-structure relationships, various parameters of gusta- tory-related behavior and taste bud structure were studied in intact and long-term de- salivated rats. Materials and methods. The experimental animals were 63 male Sprague-Dawley rats.* The rats had been used in a previous study investigating the immediate effects of desalivation upon fluid intake.4 They were then maintained on an oil-lubricated diet and tap water until the studies described below were initiated. *Charles River Laboratories, Wilmington, MA 69