Functional synapse formation in cultured neocortical neurons from prenatal X-irradiated rats.

产前X射线照射可导致子代脑部小头畸形。为了探讨宫内短暂性应激导致终生神经系统疾病的机制，研究了孕期X射线照射大鼠大脑皮质神经元的突触形成。胎儿期(E16)X射线照射大鼠的大脑皮质神经元总数在出生17时比对照组减少了16%，而GABA阳性神经元与MAP2阳性神经元的比率增加了2.2倍。培养的正常胚胎大鼠新皮质神经元在7-10DIV后表现出同步的突触驱动的节律性去极化电位(RDPs)。虽然在X射线照射的神经元和对照神经元中都观察到了RDPs，但它们的幅度和棘波的数量都减少了。这些结果表明，在X射线照射的大鼠脑中，抑制性输入比兴奋性输入占优势，尽管它们的神经元具有形成突触的能力。增加抑制性输入可能导致X射线照射大鼠随后的神经功能障碍。

Prenatal X-irradiation can induce microcephaly in the brain of offsprings. To investigate the mechanism how temporary stress in utero induces neurological disorders remaining throughout their life, synapse formation of neocortical neurons from prenatally X-irradiated rats was examined.Total number of neocortical neurons from prenatally (E16) X-irradiated rats decreased by 16 % relative to control when examined at E17, while the ratio of GABA-positive neurons to MAP2-positive ones increased 2.2 folds of control. Cultured neocortical neurons from normal embryonic rats exhibit synchronized synaptically-driven rhythmic depolarizing potentials (RDPs) after 7-10 DIV. Although RDPs were observed in X-irradiated neurons as well as in control neurons, their amplitude and the number of spikes decreased. These results suggest that inhibitory inputs hold predominance over excitatory inputs in X-irradiated rat's brain, although their neurons have the ability to form synapses. Increased inhibitory inputs might give rise to subsequent neurological disorders of X-irradiated rats.