[Show abstract][Hide abstract] ABSTRACT: The formation of nervous system depends on intercellular adhesion. This review covered the role of neural cell adhesion molecule (NCAM) and its polysialic acid (PSA) moiety on the neuronal development and regeneration. Mediation of cell adhesion is the fundamental role of NCAM, while the existence of PSA on NCAM decreases cell adhesion by its specific structure. It is known that during the development of chick embryo, the expression of PSA at three critical phases determines whether motoneurons can accurately innervate muscle. Following the peripheral nerve lesions of adult rats, the expression of NCAM is regulated by the state of innervation of muscle. In the adult rat brain, the disconnection of entorhinal cortex and hippocampus results in the elevation of PSA in the outer molecular layer of the dentate gyrus, with this increased expression remains for at least 60 days after lesion. Existing data strongly suggest that the reexpression of PSA in the denervated area may promote axonal outgrowth of transplanted neurons and reconstruct synaptic connection with host.
No preview · Article · May 1996 · Sheng li ke xue jin zhan [Progress in physiology]
[Show abstract][Hide abstract] ABSTRACT: To predicate the value of human fetal substantia nigra transplantation in clinical treatment of Parkinson's disease (PD), dissociated cells of substantia nigra from 8-12 week old abortive human fetus were grafted into the neostriatum of 5 adult rhesus monkeys with hemiparkinsonism induced by unilateral injection of MPTP. At 2, 5 and 12 months after transplanting the monkeys were sacrificed for tyrosine hydroxylase (TH) immunocytochemistry to examine the survival and possible synaptic contact of transplanted dopamine (DA) neurons. Transplanted TH immunoreactive cells took a pattern of patches scattered in the neostriatum. Each of the cell patches consisted of 3-10 cells. The TH immunoreactive fiber network was seen in the neostriatum. Electron microscopic survey revealed that TH+ buttons arising from grafted DA neurons formed symmetric or asymmetric synapses with TH- dendritic shafts/spines, and TH+ dendrites were seen to form synapses with TH- axons of the host. Additionally, there were a few synapses formed by TH+ axonal terminals with negative buttons. The results suggest that DA neurons from 8-12 week old abortive human fetus are able to survive grafting into the neostriatum of monkey, a species phylogenetically very close to human, and to establish reciprocal synaptic connectivity with the host even at 2 months post-transplanting. It is, therefore, inferable that embryonic human DA neurons transplanted into human neostriatum may have the same fate as in monkeys.
No preview · Article · Mar 1995 · Sheng li xue bao: [Acta physiologica Sinica]