Hamori J
Laboratory of Neurobiology, Semmelweis University, Budapest, Hungary.
J Exp Biol. 1990 Oct;153:251-60. doi: 10.1242/jeb.153.1.251.
Partial deafferentation of certain brain regions (septal nuclei, hippocampus, etc.) in adult animals results (1) in the disappearance of degenerating axon terminals and (2) in the short-term persistence of vacant postsynaptic sites. These postsynaptic sites have been shown to be re-supplied by sprouted axon terminals of intact axons. This paper will demonstrate that, in brain regions (e.g. cerebellar cortex, lateral geniculate nucleus) where axonal sprouting of local elements or of persisting afferent axons is negligible or absent, synaptic reorganization involves the active participation of postsynaptic dendritic and somatic elements of surviving local nerve cells. Synaptic regeneration can be demonstrated by morphological means both in developing and in adult central nervous system. The dendrites may show two types of response to deafferentation: (1) the formation of presynaptic specializations along their otherwise 'classical' postsynaptic membrane (the axonization of dendrites) resulting in the formation of new, dendrodendritic synapses, and (2) the 'adaptive' (structural) reduction in size ('atrophy') of the denervated nerve cell dendritic arborization, leading to a relative increase in density of the surviving (though non-sprouting) afferent axon terminals. In both cases a partial functional recovery can be demonstrated.
成年动物某些脑区（隔核、海马等）的部分传入神经切断会导致：（1）退化的轴突终末消失；（2）突触后空位点短期持续存在。已证实这些突触后位点会由完整轴突的发芽轴突终末重新供应。本文将证明，在局部元件或持续传入轴突的轴突发芽可忽略不计或不存在的脑区（如小脑皮质、外侧膝状体核），突触重组涉及存活的局部神经细胞的突触后树突和体细胞元件的积极参与。在发育中和成体中枢神经系统中，均可通过形态学方法证明突触再生。树突对传入神经切断可能表现出两种反应：（1）在其原本的“经典”突触后膜上形成突触前特化结构（树突的轴突化），从而形成新的树突 - 树突突触；（2）去神经支配的神经细胞树突分支大小的“适应性”（结构性）减小（“萎缩”），导致存活的（虽未发芽）传入轴突终末密度相对增加。在这两种情况下，均可证明有部分功能恢复。
