Renehan W E, Massey J, Jin Z, Zhang X, Liu Y Z, Schweitzer L
Laboratory of Gastrointestinal, Henry Ford Health Sciences Center, Case Western Reserve University, Detroit, MI 48202, USA.
Brain Res Dev Brain Res. 1997 Sep 20;102(2):231-46. doi: 10.1016/s0165-3806(97)00104-1.
Recent studies have provided evidence that brainstem gustatory neurons undergo substantial dendritic growth during a period of postnatal development that coincides with the maturation of their response to salts, suggesting a relationship (perhaps causal) between the physiology and morphology of developing salt-sensitive neurons. In an initial effort to explore this issue, we used extracellular and intracellular recording and intracellular labeling techniques to examine the structure and function of individual gustatory neurons in the rostral nucleus of the solitary tract (rNST) of young (postnatal day [P] 22-28) and adult rats. We found that P22-28 cells that responded to all three of the salts in our taste array had a greater dendritic length, a greater cell volume, and more dendritic branches than the cells that responded to one salt. As a group, taste-sensitive neurons in P22-28 animals had a higher maximum dendritic branch order and a trend toward more dendritic branch points than gustatory neurons in adult animals. The dendritic arbors of P22-28 taste neurons that responded to all three salts were larger (greater surface area and volume), more extensive in the rostrocaudal axis and exhibited a higher maximum branch order, more branch points and higher swelling density than adult cells that responded to all three salts. These results demonstrate that the morphology of salt-sensitive gustatory neurons in developing animals is closely related to the number of salts that evoke a response. The data also support the postulate that gustatory neurons in the rat brainstem undergo substantial dendritic remodeling between the fourth week of life and adulthood. Dendritic remodeling may play an important role in the maturation of the rNST response to NaCl.
最近的研究表明，脑干味觉神经元在出生后发育阶段会经历显著的树突生长，这一时期与它们对盐的反应成熟相吻合，表明发育中的盐敏感神经元的生理和形态之间存在某种关系（可能是因果关系）。为了初步探索这个问题，我们使用细胞外和细胞内记录以及细胞内标记技术，来检查幼年（出生后第[P]22 - 28天）和成年大鼠孤束核吻侧部（rNST）中单个味觉神经元的结构和功能。我们发现，对我们味觉阵列中的所有三种盐都有反应的P22 - 28细胞，其树突长度更长、细胞体积更大，并且比只对一种盐有反应的细胞有更多的树突分支。总体而言，P22 - 28动物中的味觉敏感神经元比成年动物中的味觉神经元具有更高的最大树突分支阶数，并且有更多树突分支点的趋势。对所有三种盐都有反应的P22 - 28味觉神经元的树突分支比成年动物中对所有三种盐都有反应的细胞更大（表面积和体积更大），在前后轴上更广泛，并且表现出更高的最大分支阶数、更多分支点和更高的肿胀密度。这些结果表明，发育中动物的盐敏感味觉神经元的形态与引发反应的盐的数量密切相关。数据还支持这样一种假设，即大鼠脑干中的味觉神经元在出生后第四周和成年期之间会经历大量的树突重塑。树突重塑可能在rNST对NaCl反应的成熟过程中起重要作用。
