Sweet and Bitter Tastes Evoked Different Neuronal Activation in the Rostral Portion of the Nucleus of the Solitary Tract of Developing Rats

摘要

The impact of the gustatory stimuli on the rostral portion of the nucleus of the solitary tract (rNST) was investigated in developing rats, by using c-fos immunohistochemical staining. Wistar male rats of 5, 15, and 25 days of age were isolated from the mother for 12 h, then stimulated via the intraoral route with quinine, sucrose, or NaCl, and sacrificed 90 min later. The water-stimulated group showed minimal c-fos-like immunoreactivity (FLI) compared with taste-stimulated groups that exhibited different FLI in the rNST at the different ages. At all ages the quinine-stimulated group induced FLI in the medial subfield, while sucrose induced FLI in the lateral subfield of the rNST. The intensity of FLI was highest at P15, and it declined at P25. These findings provide detailed insight into the anatomical basis of rNST activation that is involved in early food intake and the learning capacity of the newborn.