The degree of RNA editing of the 5-HT2C receptor dramatically changes during the cultivation period of primary cortical neurons. In this report, the changes in the mRNA expression levels of some factors that are essential to neuronal functions were determined using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) methods. The results suggested that neurite re-extension occurred until 9 or 12 days after starting the culture. This re-extension was followed by the reconstitution phase of the synapse. Based on this observation, the mRNA expression changes of BNIP-3, which is reportedly involved in depression and/or the actions of antidepressants in addition to be involved in mitochondrial cell death, were examined to determine its physiological functions beyond the previously reported mitochondrial cell death process. The results suggested that BNIP-3 also has basic cellular functions because its mRNA expression was detected during the early stages of the culture, was not inducible, and maintained a constant expression level during the culture period. The neuronal primary cell culture system may mimic the reconstruction process of a neuron recovering from damage. This system may be useful in estimating the physiological roles of the intrinsic factors and determining the pharmacological effects of drugs.
Keywords: Primary cultured neurons, RNA expression, cultivation duration, antidepressant, neurite elongation