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Postnatal reorganization of primary afferent terminal fields in the rat gustatory brainstem is determined by prenatal dietary history
Author(s) -
Mangold Jamie E.,
Hill David L.
Publication year - 2008
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21760
Subject(s) - biology , solitary tract , sensory system , brainstem , sodium , solitary nucleus , anatomy , endocrinology , medicine , afferent , neuroscience , central nervous system , chemistry , organic chemistry
Dietary manipulation has been used as an experimental strategy to gain insight into the normal development of the gustatory system. Institution of a diet low in sodium chloride (NaCl) from embryonic day 3 (E3) to E12 (E3–E12 sodium‐restricted rats) yields dramatically enlarged terminal fields of the chorda tympani (CT), greater superficial petrosal (GSP), and glossopharyngeal (IX) nerves in the rostral pole of the nucleus of the solitary tract (NTS) at adulthood. To examine how this early, limited dietary manipulation affects postnatal terminal field development, we used a triple anterograde nerve label procedure at postnatal day 15 (P15), P25, P35, and ≥P40 (adults) in two groups: rats fed a commercial diet replete in sodium (controls) and E3–E12 sodium‐restricted rats. Results showed an age‐related decrease in terminal field volumes of all three nerves during normal development. In contrast, E3–E12 sodium‐restricted rats displayed age‐related increases of the CT and IX terminal fields, with the terminal field volume of the GSP remaining unchanged throughout development. NTS volume did not grow after P15; therefore, alterations in terminal field volumes are not due to parallel alterations in the size of the NTS. Our data suggest that the age‐related decrease in terminal fields observed in controls may reflect activity‐dependent pruning of afferent terminals, whereas terminal field increases seen in E3–E12 sodium‐restricted rats may reflect cellular/molecular differences in the NTS induced predominantly by activity‐independent mechanisms. These findings predict a significant difference in the development of neural coding and sensory‐guided behaviors between E3–E12 sodium‐restricted rats and controls. J. Comp. Neurol. 509:594–607, 2008. © 2008 Wiley‐Liss, Inc.