Study on the effects of stressor on a organism using the technology in neuroscience

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To study changes in synaptic morphology associated with steroid concentration, we visualized synaptic structures with high resolution imaging of confocal microscopy in hippocampal slices of adult rats. Synaptic structures are labeled by micro injection of a concentrated oil solution of Dil into the superfused slice as reported previously. Dye droplets are removed after 20 min. Estrogen and cortisol are exposed through ACSF solution or a dye ball. These sets of images were analyzed and compared in the dendritic spine density. No significant changes could be seen in the slices with exposure to high concentration of estrogen. Cortisol exposed slices showed significant reduction of spine density.We established organotypic culture using a filter. Confocal microscopy was applied to the slice to confirm the health of cells with propidium iodide. Optical recording to see the electrophysiological response on large area was applied and got good series of images which time resolution is 0.6 msec and spatial resolution is 128x128 pixels.We also studied the effect of TBT(tri-n-butyltin) that is one of the environmental endocrine disrupters to PC12 cell. It shows that TBT 10^<-12>-10^<-13> in concentration significantly reduced the ratio of apoptosis.The technique of electrophysiology (LTP:long-term potentiation) was applied to the hippocampal slices. Extracellular recording in the CA1 area showed that 5 μ M TBT decreased the slope of the EPSP (Excitatory Post-Synaptic Potential) significantly. It was studied at the early time (30 min after incubation of TBT). The induction of LTP needs NMDA receptor that is one kind of glutamate receptor. It means that NMDA receptor was damaged by the injection of TBT. It shows that if the concentration of TBT is higher it affects to the central nervous system.