Burton Christie L, Chatterjee Diptendu, Chatterjee-Chakraborty Munmun, Lovic Vedran, Grella Stephanie L, Steiner Meir, Fleming Alison S
Department of Psychology, University of Toronto at Mississauga, Mississauga, ON, Canada.
Brain Res. 2007 Jul 16;1158:28-38. doi: 10.1016/j.brainres.2007.05.003. Epub 2007 May 8.
This study investigated the effects of prenatal stress and complete maternal deprivation, using the artificial rearing (AR) paradigm, on the expression of neural plasticity markers and hypothalamic-pituitary-adrenal (HPA) axis responsivity to stress. Rats were exposed to stress during gestation (day 10-21) and postnatally were either artificially reared (AR) or mother reared (MR). AR involves complete separation of the pup from both the dam and the litter throughout the pre-weaning period. In adulthood, we measured levels of corticosterone (CORT) in response to restraint stress. Also, we examined the expression of synaptophysin (SYN) and brain-derived neurotrophic factor (BDNF) in the medial prefrontal cortex (MPFC) and the nucleus accumbens (Nacc), areas of the brain that mediate behavioral activation and attention, among other behaviors. Earlier work on the same rats indicated that these behavioral endpoints, such as locomotor activity and sensorimotor gating, are affected by our prenatal and postnatal manipulations. Prenatal stress decreased CORT at 20 and 90 min post-stressor in MR, but not in AR, animals. Also, in comparison to MR groups, AR decreased SYN and BDNF expression in the MPFC and Nacc. Additional somatosensory 'licking-like' stroking stimulation partially reversed the effects of AR. Prenatal stress did not have a robust main effect but affected the impact of the postnatal rearing condition on SYN expression and stress-induced CORT. These results suggest that both prenatal and postnatal adversities have an influence on HPA axis responsivity and alter the expression of plasticity related neuronal proteins.
本研究采用人工饲养（AR）范式，调查产前应激和完全母体剥夺对神经可塑性标志物表达以及下丘脑 - 垂体 - 肾上腺（HPA）轴对应激反应性的影响。大鼠在妊娠期（第10 - 21天）暴露于应激，产后要么进行人工饲养（AR），要么由母亲饲养（MR）。AR包括在断奶前整个时期将幼崽与母鼠和同窝幼崽完全分离。成年后，我们测量了应激状态下皮质酮（CORT）的水平。此外，我们检测了内侧前额叶皮质（MPFC）和伏隔核（Nacc）中突触素（SYN）和脑源性神经营养因子（BDNF）的表达，这两个脑区介导行为激活和注意力等行为。之前对同一批大鼠的研究表明，这些行为终点，如运动活动和感觉运动门控，会受到我们产前和产后操作的影响。产前应激使MR组动物在应激后20分钟和90分钟时CORT降低，但AR组动物未出现这种情况。此外，与MR组相比，AR降低了MPFC和Nacc中SYN和BDNF的表达。额外的体感“舔舐样”抚摸刺激部分逆转了AR的影响。产前应激没有显著的主效应，但影响了产后饲养条件对SYN表达和应激诱导的CORT的作用。这些结果表明，产前和产后的逆境都会影响HPA轴的反应性，并改变可塑性相关神经元蛋白的表达。
