Tejedor-Real P, Costela C, Gibert-Rahola J
Department of Neurosciences, School of Medicine, University of Cádiz, Spain.
Life Sci. 1998;62(1):37-50. doi: 10.1016/s0024-3205(97)01036-9.
Environmental circumstances during the neonatal period are critical for the establishment of adult responses to stressful environmental situations. As these responses are underpinned by adaptations in the functioning of brain neurotransmitter systems, the present study was designed to assess the mediation of noradrenergic and dopaminergic systems in the long-lasting effects of neonatal handling on both emotionality and learned helplessness behaviour. Animals received either prazosin, propranolol, haloperidol or saline before infantile handling. When the animals were 2 months old, they were subjected first to an open field test and then to the learned helplessness paradigm. Non-treated handled animals exhibited lower emotional reactivity and reduced susceptibility to helplessness compared to non-treated non-handled rats. The results suggest that noradrenergic, but not D2-dopamine receptor systems mediate the influence of neonatal handling on the acquisition of learned helplessness in the adult. Only beta-adrenoceptors appear to play a role in emotional responsiveness.
新生儿期的环境状况对于成年后应对压力环境的反应的确立至关重要。由于这些反应是由大脑神经递质系统功能的适应性变化所支撑，本研究旨在评估去甲肾上腺素能和多巴胺能系统在新生儿期处理对情绪和习得性无助行为的长期影响中的介导作用。在进行婴儿期处理前，动物分别接受哌唑嗪、普萘洛尔、氟哌啶醇或生理盐水处理。当动物2个月大时，先对其进行旷场试验，然后进行习得性无助范式试验。与未处理未接受处理的大鼠相比，未处理但接受处理的动物表现出较低的情绪反应性和对无助的易感性降低。结果表明，去甲肾上腺素能系统而非D2 - 多巴胺受体系统介导了新生儿期处理对成年后习得性无助获得的影响。只有β - 肾上腺素能受体似乎在情绪反应中起作用。
