King C T, Hill D L
Department of Psychology, University of Virginia, Charlottesville 22903.
J Comp Neurol. 1993 Jul 22;333(4):531-42. doi: 10.1002/cne.903330406.
Restricting the NaCl content in the rat maternal and preweaning diet results in a significant and specific reduction (60%) of chorda tympani nerve responsiveness to sodium stimuli in the offspring. Repletion of dietary sodium at any time during postnatal development results in a complete and persistent recovery of chorda tympani nerve function. To learn whether the maturation of postsynaptic cells are also affected by the early dietary manipulation, dendritic morphology, neuronal and glial densities and numbers were studied within the area of the nucleus of the solitary tract (NTS). Examination of dendritic morphologies in Golgi-Cox stained neurons revealed that cells with multipolar and fusiform somata in the rostral NTS exhibited longer dendrites following dietary NaCl deprivation during development (deprived rats) than in controls. These changes were generally maintained in rats initially deprived of NaCl and then fed a NaCl-replete diet postweaning ("recovered" rats). In contrast, ovoid neurons were not affected by NaCl deprivation but had increases in the lengths of their dendrites following "recovery." Along with dendritic alterations, the packing density of neurons in the rostral NTS was greater in NaCl-deprived rats than in controls, but was similar to controls following "recovery." Glial packing density also increased following deprivation and remained high in "recovered" rats. These results indicate that activity-dependent events as well as events not related to afferent activity (e.g., hormonal changes) may influence the morphological development of NTS neurons. In addition, significant interactions among primary afferent fibers, central neurons, and glia may direct development within the central gustatory system.
限制大鼠母体及断奶前饮食中的氯化钠含量，会使后代鼓索神经对钠刺激的反应性显著且特异性降低（60%）。在出生后发育的任何时间补充饮食中的钠，都会使鼓索神经功能完全且持续恢复。为了了解突触后细胞的成熟是否也受早期饮食调控的影响，我们研究了孤束核（NTS）区域内的树突形态、神经元及神经胶质细胞的密度和数量。对高尔基-考克斯染色神经元的树突形态检查显示，在发育过程中饮食中缺乏氯化钠的大鼠（缺钠大鼠），其延髓头端NTS中具有多极和梭形胞体的细胞，其树突比对照组更长。这些变化在最初缺钠、断奶后喂食富含氯化钠饮食的大鼠（“恢复”大鼠）中通常得以维持。相比之下，卵圆形神经元不受氯化钠缺乏的影响，但在“恢复”后其树突长度增加。除了树突改变外，缺钠大鼠延髓头端NTS中神经元的堆积密度高于对照组，但“恢复”后与对照组相似。神经胶质细胞的堆积密度在缺钠后也增加，并在“恢复”大鼠中保持较高水平。这些结果表明，依赖活动的事件以及与传入活动无关的事件（如激素变化）可能会影响NTS神经元的形态发育。此外，初级传入纤维、中枢神经元和神经胶质细胞之间的显著相互作用可能会指导中枢味觉系统内的发育。
