Roy T S, Sabherwal U
Department of Anatomy, All India Institute of Medical Sciences, New Delhi.
Neurotoxicol Teratol. 1994 Jul-Aug;16(4):411-21. doi: 10.1016/0892-0362(94)90030-2.
Human reports as well as animal studies have recorded accelerated motor activity, learning, and memory deficits in offsprings of mothers exposed to nicotine during pregnancy. Morphological correlation of these neurobehavioural defects has not been done to date. Here, the cerebral cortex has been evaluated after prenatal nicotine exposure. Groups of pregnant rats were injected IP with nicotine at 2.5 mg/kg/day dosage from gestational day (GD) 6 to term. Morphology of the somatosensory cortex was analysed and compared with that of the control group up to postnatal day (PND) 40. A significant reduction in body weight and brain weight on PND 10 and 20, respectively was observed in nicotine exposed group as compared to age matched controls. Morphometric analysis of the somatosensory cortex showed a reduction in cortical thickness up to PND 20 and decreased cell size at PND 10, 20, and 40 in nicotine-exposed brains. Neuronal density of Layer 5 of somatosensory cortex was greater at PND 20 and 40 in the experimental group. Golgi staining of large pyramidal neurons of Layer 5 showed significantly decreased dendritic branching and increased dendritic spine density in the experimental group at all ages studied. Irregular arrangement of cisternae of rough endoplasmic reticulum, paucity of free ribosomes, and frequent cytoplasmic vacuoles were noted by electron microscopy in many neurons up to PND 40. A large number of electron dense cells were observed in nicotine exposed brains at all the time intervals studied. The morphological features of somatosensory cortex observed after prenatal nicotine administration suggest that the drug delays neuronal maturation and affects intracytoplasmic membrane systems.
人体报告以及动物研究均记录了孕期接触尼古丁的母亲所生后代存在运动活动加速、学习和记忆缺陷的情况。迄今为止，尚未对这些神经行为缺陷进行形态学相关性研究。在此，对产前尼古丁暴露后的大脑皮层进行了评估。将怀孕大鼠分组，从妊娠第6天至足月，每天腹腔注射2.5mg/kg剂量的尼古丁。分析体感皮层的形态，并与对照组相比，直至出生后第40天。与年龄匹配的对照组相比，尼古丁暴露组在出生后第10天和第20天的体重和脑重分别显著降低。体感皮层的形态计量分析显示，在出生后第20天之前，皮层厚度减小，在出生后第10天、第20天和第40天，尼古丁暴露组大脑中的细胞大小减小。实验组在出生后第20天和第40天，体感皮层第5层的神经元密度更高。对第5层大锥体神经元进行高尔基染色显示，在所有研究年龄的实验组中，树突分支显著减少，树突棘密度增加。通过电子显微镜观察到，在出生后第40天之前，许多神经元中粗面内质网池排列不规则、游离核糖体稀少且细胞质空泡频繁出现。在所有研究的时间间隔内，尼古丁暴露组大脑中均观察到大量电子致密细胞。产前给予尼古丁后观察到的体感皮层形态特征表明，该药物会延迟神经元成熟并影响胞内膜系统。
