Gall C, Murray K, Isackson P J
Department of Anatomy and Neurobiology, University of California, Irvine 92717.
Brain Res Mol Brain Res. 1991 Jan;9(1-2):113-23. doi: 10.1016/0169-328x(91)90136-l.
The influence of kainic acid (KA)-induced limbic seizure activity on the expression of mRNA for nerve growth factor (NGF) in adult rat brain was studied using in situ hybridization and S1 nuclease protection techniques with RNA probes complementary to murine and rat NGF mRNA. Within hippocampus, intracerebroventricular injection of 0.5 microgram KA caused a dramatic bilateral increase in hybridization of the 35S-labeled cRNA within stratum granulosum. This increase was first evident 1 h post-KA, appeared maximal at approximately 20-fold control levels at 2-3 h post-injection, and declined to control levels by 48 h post-injection. During the period of maximal hybridization, all but the deepest cells within stratum granulosum appeared to be autoradiographically labeled. Hybridization of the NGF cRNA probe was also increased within superficial layers of piriform and entorhinal cortex and, to much lesser extent, within scattered neurons of layers II and III of neocortex in KA-treated rats. In olfactory cortical areas, hybridization was maximally elevated 15.5-24.5 h after KA injection. In contrast to these effects, KA treatment did not consistently influence the density of hybridization, or number of neurons labeled, within the dentate gyrus hilus or the hippocampus proper (CA1-CA3). In agreement with the in situ hybridization results, S1 nuclease protection assay detected KA-induced increases in hybridization within pooled dentate gyrus/CA1 samples, but not hippocampal CA3 samples. These data support the conclusion that seizure activity stimulates a transient increase in NGF expression by select populations of forebrain neurons and indicates that experimental seizure paradigms might be further exploited for analyses of the mechanisms of NGF regulation and processing in the adult brain.
采用原位杂交和S1核酸酶保护技术，使用与小鼠和大鼠神经生长因子（NGF）mRNA互补的RNA探针，研究了海藻酸（KA）诱导的边缘系统癫痫活动对成年大鼠脑内NGF mRNA表达的影响。在海马内，脑室内注射0.5微克KA导致颗粒层内35S标记的cRNA杂交显著双侧增加。这种增加在KA注射后1小时首次明显，在注射后2 - 3小时达到约20倍对照水平的最大值，并在注射后48小时降至对照水平。在杂交最大值期间，颗粒层内除最深层细胞外的所有细胞似乎都被放射自显影标记。在KA处理的大鼠中，梨状皮质和内嗅皮质的浅层以及新皮质II层和III层的散在神经元内，NGF cRNA探针的杂交也增加，程度较小。在嗅觉皮质区域，杂交在KA注射后15.5 - 24.5小时最大程度升高。与这些效应相反，KA处理并未持续影响齿状回门或海马体本身（CA1 - CA3）内的杂交密度或标记神经元数量。与原位杂交结果一致，S1核酸酶保护试验检测到KA诱导了齿状回/CA1混合样本内杂交增加，但未检测到海马CA3样本内杂交增加。这些数据支持癫痫活动刺激前脑特定神经元群体中NGF表达短暂增加的结论，并表明实验性癫痫模型可能可进一步用于分析成年脑内NGF调节和加工机制。
