Abstract
Cortex and hippocampus are two different structures in the brain and involved in different functions of the brain. A typical neuron consists of three distinct cellular compartments: cell body, dendrite and axon. Local protein synthesis in the axon participates in axonogenesis and axon guidance which contributes to establishing appropriate connectivity between neurons and their targets. In this study, I use a chip device which allows me to harvest pure axons from cultured rat cortical or hippocampal neurons. I use semi-quantitative RT-PCR survey to analyze 55 gene expressions in the axons isolated from two types of neurons. I find there are some unique transcripts only existed in the cortical or in the hippocampal axons. For example, Hnrnpk and Nefm have high expression in cortical axons and, however, their expressions in hippocampal axons are low and do not reach the threshold set for transcripts whose presence in the axons is primarily due to free diffusion. In contrast, Rn18s and other 14 gene are transcripts that are only found in hippocampal axons, but not in cortical axons. I also notice other differences in the expression levels of other transcripts in these two types of axons. For instance, Pfn1 has high expression in hippocampal axons, but the expression of same transcript is low in cortical axons. It is still unclear whether the differences in the expression of various transcript between the axons of cortical and hippocampal neurons may be related to any functional differences between the axons emitting from these two types of neurons. In the future, it will be interesting to learn the difference in protein compositions between the axons of cortical and hippocampal neurons by using mass spectrometry.