Taste bud distribution and regional responsiveness on the anterior tongue of the rat

Abstract

It has been shown that over 50% of the taste buds in fungiform papillae of the rat are located on the tongue tip. The half on the tip were isolated from the half on the mid-region for chemical stimulation while the summated response of the whole chorda tympani nerve was recorded. The tip grave responses which were 70–90% of the response to stimulation of the entire tongue, while the mid-region elicited responses which were 40–50% of the entire tongue responses. This result was consistent whether the stimulus was NaCl, HCl, or sucrose which shows that responsiveness to these 3 stimulus compounds is found in the same relative proportion within either region of the tongue. The density of papillae per unit of surface area on the tip is over 2.5 times greater than on the mid-region, so the greater responsiveness of the tip may be due to more potent lateral interaction among single taste bud inputs than on the mid-region.