Connor J R, Diamond M C
J Comp Neurol. 1982 Sep 1;210(1):99-106. doi: 10.1002/cne.902100111.
The present study determined the effect of the housing condition experienced by old adult male rats on the appearance and number of dendritic spines. Specifically, 20-month-old rats were killed following 6 months of living in either a social environment (three to a cage) or living alone. The total number of dendritic spines per unit length was examined along segments of oblique, basal, and apical dendritic branches of pyramidal cells from layers II, III, Va, and Vb of the visual cortex. In addition to determining the total spine number, the spines were differentiated into two topographical categories: those with a lollipop configuration (type L) and those with a nubbin configuration (type N). Our results show that neither the total spine density nor the type L spine density were generally influenced by the two housing conditions. However, the density of type N spines was almost always greater on neurons from rats which had been living alone irrespective of the cortical layer or the dendritic segment counted. Some differences in total spine density and type L spine density were noted when neurons from the same environment but different cortical layers were compared, and these findings are discussed. However, the major focus of this paper was to extend our previous report of a selective increase in type N spines with age. We now show that in addition to increasing with age, type N spine density is also selectively increased by the condition of social deprivation.
本研究确定了老年雄性大鼠所处的饲养条件对树突棘外观和数量的影响。具体而言，20月龄大鼠在群居环境（每笼3只）或独居环境中生活6个月后被处死。沿着视觉皮层第II、III、Va和Vb层锥体细胞的斜向、基底和顶端树突分支段，检查每单位长度的树突棘总数。除了确定树突棘总数外，还将树突棘分为两种形态学类型：棒棒糖形态（L型）和瘤状形态（N型）。我们的结果表明，两种饲养条件通常都不会影响树突棘的总密度或L型树突棘的密度。然而，无论计数的是皮层层还是树突段，独居大鼠神经元上的N型树突棘密度几乎总是更高。当比较来自相同环境但不同皮层层的神经元时，发现树突棘总密度和L型树突棘密度存在一些差异，并对这些发现进行了讨论。然而，本文的主要重点是扩展我们之前关于N型树突棘随年龄选择性增加的报告。我们现在表明，N型树突棘密度除了随年龄增加外，还会因社会剥夺状况而选择性增加。
