Nobrega J N, Saari M J, Armstrong J N, Reed T
Neuroimaging Research Section, Clarke Institute of Psychiatry, Toronto, Ontario, Canada.
Dev Psychobiol. 1992 Apr;25(3):183-98. doi: 10.1002/dev.420250304.
Behavioral and neuromorphological data have suggested at least a partial interaction between the effects of norepinephrine-depleting neonatal 6-OHDA lesions and the effects of rearing in enriched environments. The present study examined the impact of both of these early manipulations upon regional brain uptake of 14C-2-deoxyglucose (14C-2DG) in adulthood. Newborn rats received 6-OHDA (50 mg/kg s.c.) or vehicle and, after weaning at 25 days, were reared in isolated versus enriched conditions. Regional brain 14C-2DG uptake was then examined at 70-80 days of age--either in the home cage or while animals were being exposed to novel, presumably arousing, stimulation. Ninety-seven brain regions were examined in eight separate groups. Results indicated that (1) Under baseline conditions, neither neonatal 6-OHDA nor differential rearing conditions produced widespread alterations in regional brain 14C-2DG uptake profiles. An overall enrichment effect was seen on only five brain areas, with rats reared in enriched environments showing lower levels of 14C-2DG uptake (-20% to -30%) than isolated rats. Neonatal 6-OHDA produced no main effect on 14C-2DG uptake in any brain region. (2) In contrast, when 14C-2DG uptake was assessed during exposure to a novel environment, five brain areas showed differential 14C-2DG uptake in 6-OHDA-treated rats, and 20 brain areas showed differential uptake in rats reared in enriched conditions. (3) No significant interaction effect on brain regional 14C-2DG uptake was observed between neonatal 6-OHDA and environmental complexity factors. These results are consistent with the notion that enduring effects of rearing and early 6-OHDA treatment may, independently, relate to a general reactivity factor. They also indicate that some effects of early neurochemical injury and subsequent experiential factors may not be apparent under normal resting conditions, but only become evident in the presence of appropriate "activating" stimulation.
行为学和神经形态学数据表明，去甲肾上腺素耗竭性新生鼠6-羟基多巴胺（6-OHDA）损伤的效应与在丰富环境中饲养的效应之间至少存在部分相互作用。本研究考察了这两种早期处理方式对成年大鼠脑区14C-2-脱氧葡萄糖（14C-2DG）摄取的影响。新生大鼠接受6-OHDA（50mg/kg皮下注射）或溶剂对照处理，在25日龄断奶后，分别在隔离或丰富环境中饲养。然后在70-80日龄时检测脑区14C-2DG摄取情况——要么在饲养笼中，要么在动物暴露于新奇的、可能引起兴奋的刺激时进行检测。对八个不同组别的97个脑区进行了检测。结果表明：（1）在基线条件下，新生鼠6-OHDA处理和不同饲养条件均未引起脑区14C-2DG摄取模式的广泛改变。仅在五个脑区观察到总体的丰富环境效应，即在丰富环境中饲养的大鼠14C-2DG摄取水平低于隔离饲养的大鼠（-20%至-30%）。新生鼠6-OHDA处理对任何脑区的14C-2DG摄取均无主要影响。（2）相反，当在暴露于新环境期间评估14C-2DG摄取时，五个脑区在6-OHDA处理的大鼠中显示出14C-2DG摄取差异，20个脑区在丰富环境中饲养的大鼠中显示出摄取差异。（3）未观察到新生鼠6-OHDA与环境复杂性因素对脑区14C-2DG摄取有显著的交互作用。这些结果与以下观点一致，即饲养和早期6-OHDA处理的持久效应可能独立地与一个一般反应性因素相关。它们还表明，早期神经化学损伤和随后的经验因素的某些效应在正常静息条件下可能不明显，但仅在存在适当的“激活”刺激时才变得明显。
