/ 4b O SUCROSE O SACCHARIN V SHAM INJ. Salivary Glands DAYS POST INJECTION Since the turnover rate parent changes in taste of salivary gland cells is perception may result qu;te low, one would not from the cancer itself or expect much damage by from the associated Xray' irradiation. therapy. If the cancer is However, loss of salivary localized in the oral flow is a common problem experienced by cavity, many of the patients undergoing problems regarding taste cither irradiation or are evident. Cancers located elsewhere have chemotherapy been reported to cause treatment. Experimental taste changes. but the studies with rats show evidence is strong that loss of gland weight, these changes are changes in salivary hedonic and not the protein composition, result of taste receptor decrease in flow rate, problems (27, 30—32). and cellular Many of the reports of degeneration. The acinar taste changes in cancer cells are the most patients have focused on sensitive cells of the changes in taste salivary gland. The detection thresholds. i.e. parotid gland is more , what is the minimum radiosensitive than the concentration of a taste submandibular or compound that is sublingual gland. perceived by the patient. The salivary glands are Bartoshuk (27) said that susceptible to damage by these threshold changes head and neck "have limited relevance irradiation. If severe. this for real-world taste." She may lead to complete measured both detection lack of salivary flow. threshold and Saliva is a complex suprathreshold taste FIG. 6. Daily rat preference function in a patient with for saccharin neck cancer. The in the days detection threshold following a returned to normal in 2 saline injection months following (open treatment. but the triangles) is suprathreshold functions compared with did not return to normal. preference for saccharin following a vinblastine injection (closed
/ 4b O SUCROSE O SACCHARIN V SHAM INJ. DAYS POST INJECTION parent changes in taste perception may result from the cancer itself or from the associated therapy. If the cancer is localized in the oral cavity, many of the problems regarding taste are evident. Cancers located elsewhere have been reported to cause taste changes. but the evidence is strong that these changes are hedonic and not the result of taste receptor problems (27, 30—32). Many of the reports of taste changes in cancer patients have focused on changes in taste detection thresholds. i.e. , what is the minimum concentration of a taste compound that is perceived by the patient. Bartoshuk (27) said that these threshold changes "have limited relevance for real-world taste." She measured both detection threshold and suprathreshold taste function in a patient with neck cancer. The detection threshold returned to normal in 2 months following treatment. but the suprathreshold functions did not return to normal. Salivary Glands Since the turnover rate of salivary gland cells is qu;te low, one would not expect much damage by Xray' irradiation. However, loss of salivary flow is a common problem experienced by patients undergoing cither irradiation or chemotherapy treatment. Experimental studies with rats show loss of gland weight, changes in salivary protein composition, decrease in flow rate, and cellular degeneration. The acinar cells are the most sensitive cells of the salivary gland. The parotid gland is more radiosensitive than the submandibular or sublingual gland. The salivary glands are susceptible to damage by head and neck irradiation. If severe. this may lead to complete lack of salivary flow. Saliva is a complex FIG. 6. Daily rat preference for saccharin in the days following a saline injection (open triangles) is compared with preference for saccharin following a vinblastine injection (closed
Beidler%20Smith%201991_Effects%20of%20Radiation%20Therapy%20and%20Drugs%20on%20Cell%20Turnover%20and%20Taste.docx