Morphological and functional changes of taste buds on the soft palate during development.

对出生后发育的大鼠软腭和舌头上的味蕾进行了定量观察，结果表明，出生时软腭上有200个味蕾，相当于3周龄时的数目，而在50个味蕾中观察到味孔。而新生大鼠舌前部菌状乳头中的味蕾不到100个，未见味孔，4周后味蕾数量逐渐增多，最多可达200个。大鼠和仓鼠GSP的电生理记录表明，在SOFR上用甜味物质刺激味觉，会在GSP神经上产生强烈的反应。大鼠GSP不仅对糖产生强烈的反应，而且对各种氨基酸也产生强烈的反应。在大鼠鼓索中，L氨基酸比D型更具刺激性，而GSP对D氨基酸的反应比对映体更好。此外，切断仓鼠的双侧GSP和/或CT神经可显著降低对蔗糖的条件性厌恶。切片效果依次为GSP+CT&GT；GSP()SY.gtoreq.()CT&GT；Sham。考虑到分布在软腭上的数量众多的味蕾，以及对含有多种氨基酸的甜味物质的强烈反应性，软腭的味觉功能应该在出生后早期发育阶段的乳汁摄取中发挥重要作用。

Quantitative examination of taste buds on the soft palate and the tongue in the rat during the postnatal development revealed that there exist 200 taste buds on the soft palate at birth as many as in 3-week-old although taste pore were observed in 50 taste buds. On the contrary, less than 100 taste buds, without observation of taste pore, existed in fungiform papillae on the anterior tongue in new born rats, and the number of taste buds postnatally increased during 4 weeks, reached to the maximum of 200. Electrophysiological recordings from the GSP in the rat and hamster showed that taste stimulation with sweet substances on the sofr palate produces robust responses on the GSP nerve. The rat GSP produced robust responses not only to sugars but also to various amino acids. In the rat chorda tympani, L-amino acids are more stimulatory than the D-forms, while the GSP responds better to Damino acids compared to the enantiomers. Also, bilateral transection of the GSP and/or CT nerves in the hamster resulted in a significant reduction of the conditioned taste aversion for sucrose. The order of the sectioning effects was GSP + CT > GSP (〕SY.gtoreq.〔) CT > sham. Considering numeral taste buds distributed on the soft palate, and the strong responsiveness for sweet substances including many amino acids, gustatory function of the soft palate should play an important role on the ingestion of milk during early development in postnatal stage.