Zeng J, Mattsson B, Schulz M K, Johansson B B, Sørensen J C
Experimental Neurology, Lund University Hospital, Lund, Sweden.
Exp Neurol. 2000 Jul;164(1):176-83. doi: 10.1006/exnr.2000.7423.
Zinc-positive neurons and terminals, known to be associated with the glutamatergic projections in the brain, can be demonstrated by the histochemical Timm method and later modifications thereof. The adult rat neocortex contain a uniform lamination of zinc-positive cells with specific projections to, e.g., the striatum. We have previously reported that fetal neocortical grafts implanted in the adult rat neocortex combined with rearing in an enriched environment can improve behavioral functions and reduce the secondary atrophy of thalamus after cortex infarction in adult rats. In order to examine whether the expression of zinc positivity is ontogenetically inherent to neocortical neurons we grafted fetal neocortical tissue to aspiration or ischemic lesions of the frontoparietal neocortex of adult rats, followed by histochemical visualization of the vesicular zinc pool by selenite or sulfide. One further aim of the study was to elucidate to what extent the distribution of zinc-containing neurons and terminals in the grafts depended on rearing under different environmental conditions. The foremost finding of the present study was that the overall density of zinc-containing terminals in fetal cortical transplants placed in brain infarcts of adult spontaneously hypertensive rats is higher when the rats are reared in an enriched environment. Moreover, the presence and expression of zinc-positive neurons and terminals do not seem to be ontogenetically inherent to the cortical neurons as the fetal neocortical grafts placed in aspiration lesions contained no zinc-selenide-positive neurons and few or no zinc-selenide-positive terminals. The presence or expression of zinc-positive cells may thus be induced by ingrowth of fibers and terminals from the host brain as transplants placed in the ischemic lesions expressed both zinc-positive neurons and terminals.
已知与大脑中的谷氨酸能投射相关的锌阳性神经元和终末，可以通过组织化学Timm方法及其后来的改进方法来显示。成年大鼠新皮层含有一层均匀的锌阳性细胞，并向例如纹状体发出特定投射。我们之前报道过，植入成年大鼠新皮层的胎儿新皮层移植体，结合在丰富环境中饲养，可以改善行为功能，并减少成年大鼠皮层梗死后丘脑的继发性萎缩。为了研究锌阳性的表达是否是新皮层神经元发育过程中固有的，我们将胎儿新皮层组织移植到成年大鼠额顶叶新皮层的抽吸或缺血性损伤部位，随后通过亚硒酸盐或硫化物对囊泡锌池进行组织化学可视化。该研究的另一个目的是阐明移植体中含锌神经元和终末的分布在多大程度上取决于在不同环境条件下的饲养。本研究的首要发现是，当成年自发性高血压大鼠在丰富环境中饲养时，置于其脑梗死部位的胎儿皮质移植体中含锌终末的总体密度更高。此外，锌阳性神经元和终末的存在和表达似乎并非皮层神经元发育过程中固有的，因为置于抽吸损伤部位的胎儿新皮层移植体中没有亚硒酸锌阳性神经元，且几乎没有或没有亚硒酸锌阳性终末。因此，锌阳性细胞的存在或表达可能是由宿主脑的纤维和终末长入诱导的，因为置于缺血性损伤部位的移植体同时表达了锌阳性神经元和终末。
